WorldWideScience

Sample records for residential ventilation rates

  1. The influence of opening windows and doors on the natural ventilation rate of a residential building

    Science.gov (United States)

    An analysis of air exchange rates due to intentional window and door openings in a research test house located in a residential environment is presented. These data inform the development of ventilation rate control strategies as building envelopes are tightened to improve the e...

  2. ASHRAE and residential ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max H.

    2003-10-01

    In the last quarter of a century, the western world has become increasingly aware of environmental threats to health and safety. During this period, people psychologically retreated away from outdoors hazards such as pesticides, smog, lead, oil spills, and dioxin to the seeming security of their homes. However, the indoor environment may not be healthier than the outdoor environment, as has become more apparent over the past few years with issues such as mold, formaldehyde, and sick-building syndrome. While the built human environment has changed substantially over the past 10,000 years, human biology has not; poor indoor air quality creates health risks and can be uncomfortable. The human race has found, over time, that it is essential to manage the indoor environments of their homes. ASHRAE has long been in the business of ventilation, but most of the focus of that effort has been in the area of commercial and institutional buildings. Residential ventilation was traditionally not a major concern because it was felt that, between operable windows and envelope leakage, people were getting enough outside air in their homes. In the quarter of a century since the first oil shock, houses have gotten much more energy efficient. At the same time, the kinds of materials and functions in houses changed in character in response to people's needs. People became more environmentally conscious and aware not only about the resources they were consuming but about the environment in which they lived. All of these factors contributed to an increasing level of public concern about residential indoor air quality and ventilation. Where once there was an easy feeling about the residential indoor environment, there is now a desire to define levels of acceptability and performance. Many institutions--both public and private--have interests in Indoor Air Quality (IAQ), but ASHRAE, as the professional society that has had ventilation as part of its mission for over 100 years, is the

  3. The influence of opening windows and doors on the natural ventilation rate of a residential building

    Science.gov (United States)

    Increased building energy efficiency is important in reducing national energy use and greenhouse gas emissions. An analysis of air change rates due to door and window openings in a research test house located in a residential environment are presented. These data inform developme...

  4. Residential ventilation standards scoping study

    Energy Technology Data Exchange (ETDEWEB)

    McKone, Thomas E.; Sherman, Max H.

    2003-10-01

    The goals of this scoping study are to identify research needed to develop improved ventilation standards for California's Title 24 Building Energy Efficiency Standards. The 2008 Title 24 Standards are the primary target for the outcome of this research, but this scoping study is not limited to that timeframe. We prepared this scoping study to provide the California Energy Commission with broad and flexible options for developing a research plan to advance the standards. This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the ventilation needs of California residences, determining the bases for setting residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and corresponding levels of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  5. Computer program for sizing residential energy recovery ventilator

    International Nuclear Information System (INIS)

    Koontz, M.D.; Lee, S.M.; Spears, J.W.; Kesselring, J.P.

    1991-01-01

    Energy recovery ventilators offer the prospect of tighter control over residential ventilation rates than manual methods, such as opening windows, with a lesser energy penalty. However, the appropriate size of such a ventilator is not readily apparent in most situations. Sizing of energy recovery ventilation software was developed to calculate the size of ventilator necessary to satisfy ASHRAE Standard 62-1989, Ventilation for Acceptable Air Quality, or a user-specified air exchange rate. Inputs to the software include house location, structural characteristics, house operations and energy costs, ventilation characteristics, and HVAC system COP/efficiency. Based on these inputs, the program estimates the existing air exchange rate for the house, the ventilation rate required to meet the ASHRAE standard or user-specified air exchange rate, the size of the ventilator needed to meet the requirement, and the expected changes in indoor air quality and energy consumption. In this paper an illustrative application of the software is provided

  6. Development of a Residential Integrated Ventilation Controller

    Energy Technology Data Exchange (ETDEWEB)

    Staff Scientist; Walker, Iain; Sherman, Max; Dickerhoff, Darryl

    2011-12-01

    The goal of this study was to develop a Residential Integrated Ventilation Controller (RIVEC) to reduce the energy impact of required mechanical ventilation by 20percent, maintain or improve indoor air quality and provide demand response benefits. This represents potential energy savings of about 140 GWh of electricity and 83 million therms of natural gas as well as proportional peak savings in California. The RIVEC controller is intended to meet the 2008 Title 24 requirements for residential ventilation as well as taking into account the issues of outdoor conditions, other ventilation devices (including economizers), peak demand concerns and occupant preferences. The controller is designed to manage all the residential ventilation systems that are currently available. A key innovation in this controller is the ability to implement the concept of efficacy and intermittent ventilation which allows time shifting of ventilation. Using this approach ventilation can be shifted away from times of high cost or high outdoor pollution towards times when it is cheaper and more effective. Simulations, based on the ones used to develop the new residential ventilation requirements for the California Buildings Energy code, were used to further define the specific criteria and strategies needed for the controller. These simulations provide estimates of the energy, peak power and contaminant improvement possible for different California climates for the various ventilation systems. Results from a field test of the prototype controller corroborate the predicted performance.

  7. Ventilation rates and health

    DEFF Research Database (Denmark)

    Sundell, Jan; Levin, H; Nazaroff, W W

    2011-01-01

    and health effects to inform the relationship. Consistency was found across multiple investigations and different epidemiologic designs for different populations. Multiple health endpoints show similar relationships with ventilation rate. There is biological plausibility for an association of health outcomes...... studies of the relationship between ventilation rates and health, especially in diverse climates, in locations with polluted outdoor air and in buildings other than offices. PRACTICAL IMPLICATIONS: Ventilation with outdoor air plays an important role influencing human exposures to indoor pollutants...

  8. Advanced Controls for Residential Whole-House Ventilation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Turner, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, Max [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-01

    Whole-house ventilation systems are becoming commonplace in new construction, remodeling/renovation, and weatherization projects, driven by combinations of specific requirements for indoor air quality (IAQ), health and compliance with standards, such as ASHRAE 62.2. Ventilation systems incur an energy penalty on the home via fan power used to drive the airflow, and the additional space-conditioning load associated with heating or cooling the ventilation air. Finding a balance between IAQ and energy use is important if homes are to be adequately ventilated while not increasing the energy burden. This study used computer simulations to examine RIVEC the Residential Integrated Ventilation Controller - a prototype ventilation controller that aims to deliver whole-house ventilation rates that comply with ventilation standards, for the minimum use of energy. Four different whole-house ventilation systems were simulated, both with and without RIVEC, so that the energy and IAQ results could be compared. Simulations were conducted for 13 US climate zones, three house designs, and three envelope leakage values. The results showed that the RIVEC controller could typically return ventilation energy savings greater than 40percent without compromising long-term chronic or short-term acute exposures to relevant indoor contaminants. Critical and average peak power loads were also reduced as a consequence of using RIVEC.

  9. Experimental evaluation of air distribution in mechanically ventilated residential rooms

    DEFF Research Database (Denmark)

    Tomasi, R.; Krajčík, M.; Simone, A.

    2013-01-01

    The effect of low ventilation rates (1 or 0.5 air change per hour) on thermal comfort and ventilation effectiveness was experimentally studied in a simulated residential room equipped with radiant floor heating/cooling and mixing ventilation systems. The tests were performed for various positions...... of supply and extract air terminals and different winter and summer boundary conditions. Vertical air temperature, operative temperature and air velocity profiles were measured in different positions in the room, and equivalent temperatures were derived, in order to characterize thermal comfort. Contaminant...... with unconditioned outdoor air supply, i.e. at the supply air temperatures higher than the room air temperature. Moreover, low floor temperatures were needed to maintain the desired reference temperature in the stratified thermal environment. Mainly in cooling conditions the ventilation effectiveness depended...

  10. Energy and IAQ Implications of Residential Ventilation Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Turner, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-01

    This study evaluates the energy, humidity and indoor air quality (IAQ) implications of residential ventilation cooling in all U.S. IECC climate zones. A computer modeling approach was adopted, using an advanced residential building simulation tool with airflow, energy and humidity models. An economizer (large supply fan) was simulated to provide ventilation cooling while outdoor air temperatures were lower than indoor air temperatures (typically at night). The simulations were performed for a full year using one-minute time steps to allow for scheduling of ventilation systems and to account for interactions between ventilation and heating/cooling systems.

  11. Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems

    OpenAIRE

    Sherman, Max H.

    2011-01-01

    Existing ventilation standards, including American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) Standard 62.2, specify continuous operation of a defined mechanical ventilation system to provide minimum ventilation, with time-based intermittent operation as an option. This requirement ignores several factors and concerns including: other equipment such as household exhaust fans that might incidentally provide ventilation, negative impacts of ventilation when outd...

  12. Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Toke Rammer; Svendsen, Sv Aa Højgaard

    1999-01-01

    The note concerns ventilation in residential buildings. Describes components in ventilation systems, electric energy consumption and different ventilation systems with heat exchanger.......The note concerns ventilation in residential buildings. Describes components in ventilation systems, electric energy consumption and different ventilation systems with heat exchanger....

  13. Ventilation in Commercial and Residential Buildings

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    A number of areas have to be considered in connection with indoor air quality and ventilation. The selection of ventilation principle and components in the ventilation system will have influence on the indoor air quality and this subject will be discussed on the following pages. The main object o...

  14. Why this crisis in residential ventilation

    NARCIS (Netherlands)

    Hasselaar, E.

    2008-01-01

    Ventilation is the cornerstone of good indoor air quality. Ventilation requirements have major attention in building regulations, but ventilation in practice is often poor, resulting in increased concentration of pollutants and hence exposure to health risk. Inspection of 500 houses with interviews

  15. Using a Ventilation Controller to Optimize Residential Passive Ventilation For Energy and Indoor Air Quality

    Energy Technology Data Exchange (ETDEWEB)

    Turner, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-01

    One way to reduce the energy impact of providing residential ventilation is to use passive and hybrid systems. However, these passive and hybrid (sometimes called mixed-mode) systems must still meet chronic and acute health standards for ventilation. This study uses a computer simulation approach to examine the energy and indoor air quality (IAQ) implications of passive and hybrid ventilation systems, in 16 California climate zones. Both uncontrolled and flow controlled passive stacks are assessed. A new hybrid ventilation system is outlined that uses an intelligent ventilation controller to minimise energy use, while ensuring chronic and acute IAQ standards are met. ASHRAE Standard 62.2-2010 – the United States standard for residential ventilation - is used as the chronic standard, and exposure limits for PM2.5, formaldehyde and NO2 are used as the acute standards.The results show that controlled passive ventilation and hybrid ventilation can be used in homes to provide equivalent IAQ to continuous mechanical ventilation, for less use of energy.

  16. Impact of Residential Mechanical Ventilation on Energy Cost and Humidity Control

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Eric [Building Science Corporation, Westford, MA (United States)

    2014-01-01

    Optimizing whole house mechanical ventilation as part of the Building Ameerica program's systems engineered approach to constructing housing has been an important subject of the program's research. Ventilation in residential buildings is one component of an effective, comprehensive strategy for creation and maintenance of a comfortable and healthy indoor air environment. The study described in this report is based on building energy modeling with an important focus on the indoor humidity impacts of ventilation. The modeling tools used were EnergyPlus version 7.1 (E+) and EnergyGauge USA (EGUSA). Twelve U.S. cities and five climate zones were represented. A total of 864 simulations (2*2*3*3*12= 864) were run using two building archetypes, two building leakage rates, two building orientations, three ventilation systems, three ventilation rates, and twelve climates.

  17. Procedures and Standards for Residential Ventilation System Commissioning: An Annotated Bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Stratton, J. Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wray, Craig P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-04-01

    Beginning with the 2008 version of Title 24, new homes in California must comply with ANSI/ASHRAE Standard 62.2-2007 requirements for residential ventilation. Where installed, the limited data available indicate that mechanical ventilation systems do not always perform optimally or even as many codes and forecasts predict. Commissioning such systems when they are installed or during subsequent building retrofits is a step towards eliminating deficiencies and optimizing the tradeoff between energy use and acceptable IAQ. Work funded by the California Energy Commission about a decade ago at Berkeley Lab documented procedures for residential commissioning, but did not focus on ventilation systems. Since then, standards and approaches for commissioning ventilation systems have been an active area of work in Europe. This report describes our efforts to collect new literature on commissioning procedures and to identify information that can be used to support the future development of residential-ventilation-specific procedures and standards. We recommend that a standardized commissioning process and a commissioning guide for practitioners be developed, along with a combined energy and IAQ benefit assessment standard and tool, and a diagnostic guide for estimating continuous pollutant emission rates of concern in residences (including a database that lists emission test data for commercially-available labeled products).

  18. An Overview of Residential Ventilation Activities in the Building America Program (Phase I)

    Energy Technology Data Exchange (ETDEWEB)

    Barley, D.

    2001-05-21

    This report provides an overview of issues involved in residential ventilation; provides an overview of the various ventilation strategies being evaluated by the five teams, or consortia, currently involved in the Building America Program; and identifies unresolved technical issues.

  19. Air Distribution Effectiveness for Residential Mechanical Ventilation: Simulation and Comparison of Normalized Exposures

    Energy Technology Data Exchange (ETDEWEB)

    Petithuguenin, T.D.P.; Sherman, M.H.

    2009-05-01

    The purpose of ventilation is to dilute indoor contaminants that an occupant is exposed to. Even when providing the same nominal rate of outdoor air, different ventilation systems may distribute air in different ways, affecting occupants' exposure to household contaminants. Exposure ultimately depends on the home being considered, on source disposition and strength, on occupants' behavior, on the ventilation strategy, and on operation of forced air heating and cooling systems. In any multi-zone environment dilution rates and source strengths may be different in every zone and change in time, resulting in exposure being tied to occupancy patterns.This paper will report on simulations that compare ventilation systems by assessing their impact on exposure by examining common house geometries, contaminant generation profiles, and occupancy scenarios. These simulations take into account the unsteady, occupancy-tied aspect of ventilation such as bathroom and kitchen exhaust fans. As most US homes have central HVAC systems, the simulation results will be used to make appropriate recommendations and adjustments for distribution and mixing to residential ventilation standards such as ASHRAE Standard 62.2.This paper will report on work being done to model multizone airflow systems that are unsteady and elaborate the concept of distribution matrix. It will examine several metrics for evaluating the effect of air distribution on exposure to pollutants, based on previous work by Sherman et al. (2006).

  20. Indoor air quality in mechanically ventilated residential dwellings/low-rise buildings: A review of existing information

    DEFF Research Database (Denmark)

    Aganovic, Amar; Hamon, Mathieu; Kolarik, Jakub

    Mechanical ventilation has become a mandatory requirement in multiple European standards addressing indoor air quality (IAQ) and ventilation in residential dwellings (single family houses and low-rise apartment buildings). This article presents the state of the art study through a review...... of the existing literature, to establish a link between ventilation rate and key indoor air pollutants. Design characteristics of a mechanical ventilation system such as supply/exhaustairflow, system and design of supply and exhaust outlets were considered. The performance of various ventilation solutionswas......-house ventilation rate was reported below 0.5h-1 or 14 l/s·person in bedrooms, the concentrations of the pollutants elevated above minimum threshold limits (CO2>1350 ppm; TVOC >3000 μg/m3) defined by the standard. Insufficient or non-existent supply of air was related to significantly higher pollutant...

  1. Natural Ventilation Effectiveness of Round Wall-Mounted Vent Caps in Residential Kitchens

    Directory of Open Access Journals (Sweden)

    Yi-Pin Lin

    2018-05-01

    Full Text Available This study explores the effect of different numbers of wall-mounted vent caps and their installation locations on the indoor air environment in residential kitchens, for which limited information is available. Wind tunnel tests were performed to study the induced ventilation rates of a vent cap, and the impact of vent caps on the natural ventilation efficiency in residential kitchens was examined using computational fluid dynamics (CFD numerical simulations. The results were then applied to determine the appropriate quantity of vent caps and their proper installation location. The wind tunnel test results indicated that outdoor winds with speeds of 0–6 m/s that flow parallel to the wall with a vent cap induce indoor air to exit through the cap with ventilation rates of 0–20 m3/h; when the wind blows perpendicular to the wall, outdoor air with 0–31.9 m3/h flows indoors. CFD numerical simulations showed that the installation of kitchen vent caps can reduce the average carbon monoxide concentration in the cook’s breathing zone. A sufficient quantity of vent caps and the proper installation location are required to ensure the natural ventilation effectiveness of wall-mounted vent caps.

  2. Impact of Residential Mechanical Ventilation on Energy Cost and Humidity Control

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-01-01

    The DOE Building America program has been conducting research leading to cost effective high performance homes since the early 1990's. Optimizing whole house mechanical ventilation as part of the program's systems engineered approach to constructing housing has been an important subject of the program's research. Ventilation in residential buildings is one component of an effective, comprehensive strategy for creation and maintenance of a comfortable and healthy indoor air environment. The study described in this white paper is based on building energy modeling with an important focus on the indoor humidity impacts of ventilation. The modeling tools used were EnergyPlus version 7.1 (E+) and EnergyGauge USA (EGUSA). Twelve U.S. cities and five climate zones were represented. A total of 864 simulations (2*2*3*3*12= 864) were run using two building archetypes, two building leakage rates, two building orientations, three ventilation systems, three ventilation rates, and twelve climates.

  3. Indoor Air Quality and Ventilation in Residential Deep Energy Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-06-01

    Because airtightening is a significant part of Deep Energy Retrofits (DERs), concerns about ventilation and Indoor Air Quality (IAQ) have emerged. To investigate this, ventilation and IAQ were assessed in 17 non-smoking California Deep Energy Retrofit homes. Inspections and surveys were used to assess household activities and ventilation systems. Pollutant sampling performed in 12 homes included six-day passive samples of nitrogen dioxide (NO2), formaldehyde and air exchange rate (AER); time-resolved data loggers were used to measure particle counts. Half of the homes provided continuous mechanical ventilation. Despite these homes being twice as airtight (3.0 and 7.6 ACH50, respectively), their median AER was indistinguishable from naturally vented homes (0.36 versus 0.37 hr-1). Numerous problems were found with ventilation systems; however, pollutant levels did not reach levels of concern in most homes. Ambient NO2 standards were exceeded in some gas cooking homes that used legacy ranges with standing pilots, and in Passive House-style homes without range hoods exhausted to outside. Cooking exhaust systems were installed and used inconsistently. The majority of homes reported using low-emitting materials, and formaldehyde levels were approximately half those in conventional new CA homes (19.7 versus 36 μg/m3), with emissions rates nearly 40percent less (12.3 versus 20.6 μg/m2/hr.). Presence of air filtration systems led to lower indoor particle number concentrations (PN>0.5: 8.80E+06 PN/m3 versus 2.99E+06; PN>2.5: 5.46E+0.5 PN/m3 versus 2.59E+05). The results indicate that DERs can provide adequate ventilation and IAQ, and that DERs should prioritize source control, particle filtration and well-designed local exhaust systems, while still providing adequate continuous ventilation.

  4. Analysis of the systems of ventilation of residential houses of Ukraine and Estonia

    Science.gov (United States)

    Savchenko, Olena; Zhelykh, Vasyl; Voll, Hendrik

    2017-12-01

    The most common ventilation system in residential buildings in Ukraine is natural ventilation. In recent years, due to increased tightness of structures, an increase in the content of synthetic finishing materials in them, the quality of microclimate parameters deteriorated. One of the measures to improve the parameters of indoor air in residential buildings is the use of mechanical inflow and exhaust ventilation system. In this article the regulatory documents concerning the design of ventilation systems in Ukraine and Estonia and the requirements for air exchange in residential buildings are considered. It is established that the existing normative documents in Ukraine are analogous to European norms, which allow design the system of ventilation of residential buildings according to European standards. However, the basis for the design of ventilation systems in Ukraine is the national standards, in which mechanical ventilation, unfortunately, is provided only for the design of high-rise buildings. To maintain acceptable microclimate parameters in residential buildings, it is advisable for designers to apply the requirements for designing ventilation systems in accordance with European standards.

  5. Analysis of the systems of ventilation of residential houses of Ukraine and Estonia

    Directory of Open Access Journals (Sweden)

    Savchenko Olena

    2017-12-01

    Full Text Available The most common ventilation system in residential buildings in Ukraine is natural ventilation. In recent years, due to increased tightness of structures, an increase in the content of synthetic finishing materials in them, the quality of microclimate parameters deteriorated. One of the measures to improve the parameters of indoor air in residential buildings is the use of mechanical inflow and exhaust ventilation system. In this article the regulatory documents concerning the design of ventilation systems in Ukraine and Estonia and the requirements for air exchange in residential buildings are considered. It is established that the existing normative documents in Ukraine are analogous to European norms, which allow design the system of ventilation of residential buildings according to European standards. However, the basis for the design of ventilation systems in Ukraine is the national standards, in which mechanical ventilation, unfortunately, is provided only for the design of high-rise buildings. To maintain acceptable microclimate parameters in residential buildings, it is advisable for designers to apply the requirements for designing ventilation systems in accordance with European standards.

  6. Measure Guideline: Ventilation Guidance for Residential High-Performance New Construction - Multifamily

    Energy Technology Data Exchange (ETDEWEB)

    Lstiburek, Joseph [Building Science Corporation, Westford, MA (United States)

    2017-01-01

    The measure guideline provides ventilation guidance for residential high performance multifamily construction that incorporates the requirements of the ASHRAE 62.2 ventilation and indoor air quality standard. The measure guideline focus is on the decision criteria for weighing cost and performance of various ventilation systems. The measure guideline is intended for contractors, builders, developers, designers and building code officials. The guide may also be helpful to building owners wishing to learn more about ventilation strategies available for their buildings. The measure guideline includes specific design and installation instructions for the most cost effective and performance effective solutions for ventilation in multifamily units that satisfies the requirements of ASHRAE 62.2-2016.

  7. Effects of types of ventilation system on indoor particle concentrations in residential buildings.

    Science.gov (United States)

    Park, J S; Jee, N-Y; Jeong, J-W

    2014-12-01

    The objective of this study was to quantify the influence of ventilation systems on indoor particle concentrations in residential buildings. Fifteen occupied, single-family apartments were selected from three sites. The three sites have three different ventilation systems: unbalanced mechanical ventilation, balanced mechanical ventilation, and natural ventilation. Field measurements were conducted between April and June 2012, when outdoor air temperatures were comfortable. Number concentrations of particles, PM2.5 and CO2 , were continuously measured both outdoors and indoors. In the apartments with natural ventilation, I/O ratios of particle number concentrations ranged from 0.56 to 0.72 for submicron particles, and from 0.25 to 0.60 for particles larger than 1.0 μm. The daily average indoor particle concentration decreased to 50% below the outdoor level for submicron particles and 25% below the outdoor level for fine particles, when the apartments were mechanically ventilated. The two mechanical ventilation systems reduced the I/O ratios by 26% for submicron particles and 65% for fine particles compared with the natural ventilation. These results showed that mechanical ventilation can reduce exposure to outdoor particles in residential buildings. Results of this study confirm that mechanical ventilation with filtration can significantly reduce indoor particle levels compared with natural ventilation. The I/O ratios of particles substantially varied at the naturally ventilated apartments because of the influence of variable window opening conditions and unsteadiness of wind flow on the penetration of outdoor air particles. For better prediction of the exposure to outdoor particles in naturally ventilated residential buildings, it is important to understand the penetration of outdoor particles with variable window opening conditions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. The renewal of the ventilation test for residential buildings in the Netherlands; Woonbond vernieuwt toets ventilatie

    Energy Technology Data Exchange (ETDEWEB)

    Koevoet, H. (ed.)

    2003-05-01

    It appears that many residential buildings in the Netherlands do not meet ventilation regulations as formulated in the Building Decree of 1992. The renewed checklist Ventilation is a tool by means of which the quality of the ventilation in residential buildings can be tested. [Dutch] De ventilatie schiet in onrustbarend veel woningen tekort. Het is echter niet altijd eenvoudig orn vast te stellen of de ventilatie onvoldoende is. De vernieuwde Toetstijst Ventilatie van de Woonbond, VEH en het Astma Fonds geeft een goede indicatie.

  9. Assessment of Natural Ventilation Potential for Residential Buildings across Different Climate Zones in Australia

    Directory of Open Access Journals (Sweden)

    Zijing Tan

    2017-09-01

    Full Text Available In this study, the natural ventilation potential of residential buildings was numerically investigated based on a typical single-story house in the three most populous climate zones in Australia. Simulations using the commercial simulation software TRNSYS (Transient System Simulation Tool were performed for all seasons in three representative cities, i.e., Darwin for the hot humid summer and warm winter zone, Sydney for the mild temperate zone, and Melbourne for the cool temperate zone. A natural ventilation control strategy was generated by the rule-based decision-tree method based on the local climates. Natural ventilation hour (NVH and satisfied natural ventilation hour (SNVH were employed to evaluate the potential of natural ventilation in each city considering local climate and local indoor thermal comfort requirements, respectively. The numerical results revealed that natural ventilation potential was related to the local climate. The greatest natural ventilation potential for the case study building was observed in Darwin with an annual 4141 SNVH out of 4728 NVH, while the least natural ventilation potential was found in the Melbourne case. Moreover, summer and transition seasons (spring and autumn were found to be the optimal periods to sustain indoor thermal comfort by utilising natural ventilation in Sydney and Melbourne. By contrast, natural ventilation was found applicable over the whole year in Darwin. In addition, the indoor operative temperature results demonstrated that indoor thermal comfort can be maintained only by utilising natural ventilation for all cases during the whole year, except for the non-natural ventilation periods in summer in Darwin and winter in Melbourne. These findings could improve the understanding of natural ventilation potential in different climates, and are beneficial for the climate-conscious design of residential buildings in Australia.

  10. The study of height variation on outdoor ventilation for Singapore's high-rise residential housing estates

    OpenAIRE

    Rou Xuan Lee; Steve Kardinal Jusuf; Nyuk Hien Wong

    2015-01-01

    This article is concerned with external ventilation levels within a multi-story Housing and Development Board (HDB) residential estate, focusing toward a deeper understanding of wind flow with respect to different levels of height variation (HV). This study analyzed through parametric study, using numerical simulations with the realizable k – ε turbulence model, the various scenarios of HV within a typical residential HDB estate or precinct. It is found that external wind flow within the prec...

  11. Thermal Insulation for Naturally Ventilated Residential Houses in Malaysia

    DEFF Research Database (Denmark)

    Reimann, Gregers Peter; Jensen, Kasper Lynge; Nielsen, Tryggvi

    Temperature logging for three Malaysian residential houses is used to validate the Malaysian weather data year (hourly values) and to validate the simulation software Bsim for use in Malaysia. The fit between simulated and measured data is satisfactory, as only a maximum difference of 0.5°C...

  12. The simulation of naturally ventilated residential buildings in semi-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    Ghiabaklou, Z.; Ballinger, J.A.; Prasad, D.K. [New South Wales Univ., Kensington, NSW (Australia). Solar Architecture Research Unit

    1995-12-31

    The most important consideration in hot arid and semi-arid zones is to reduce the internal day temperature and to maintain the interior spaces of buildings in a comfortable condition. An important contributor to errors in the thermal analysis of naturally ventilated buildings is inaccurate airflow predictions. These predictions are important for designers in regions where most buildings are naturally ventilated. Passive cooling by day and night natural ventilation in a single story residential building in Wagga Wagga, a semi-arid location in New South Wales has been compared and analyzed theoretically. A modified version of the computer simulation program CHEETAH, has been used to consider a building with continuous natural ventilation to simulate indoor air temperature. The aim of the study was to investigate the thermal behaviour of the building with continuous ventilation (24 hour/day) and the same building with only night time ventilation. Using night time ventilation in high mass buildings in such a climate, leads to a considerable decrease in room air temperature. Simulation results showed that increasing the effective area of windows is effective only when the wind blows. Using a steady averaged air change per hour can also cause a reduction in room air temperatures which results in different temperatures than the actual air changes per hour. (author). 3 figs., 4 refs.

  13. Development of an Outdoor Temperature Based Control Algorithm for Residential Mechanical Ventilation Control

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tang, Yihuan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-01

    The Incremental Ventilation Energy (IVE) model developed in this study combines the output of simple air exchange models with a limited set of housing characteristics to estimate the associated change in energy demand of homes. The IVE model was designed specifically to enable modellers to use existing databases of housing characteristics to determine the impact of ventilation policy change on a population scale. The IVE model estimates of energy change when applied to US homes with limited parameterisation are shown to be comparable to the estimates of a well-validated, complex residential energy model.

  14. Energy and exergy performance of residential heating systems with separate mechanical ventilation

    International Nuclear Information System (INIS)

    Zmeureanu, Radu; Yu Wu, Xin

    2007-01-01

    The paper brings new evidence on the impact of separate mechanical ventilation system on the annual energy and exergy performance of several design alternatives of residential heating systems, when they are designed for a house in Montreal. Mathematical models of residential heating, ventilation and domestic hot water (HVAC-DHW) systems, which are needed for this purpose, are developed and furthermore implemented in the Engineering Equation Solver (EES) environment. The Coefficient of Performance and the exergy efficiency are estimated as well as the entropy generation and exergy destruction of the overall system. The equivalent greenhouse gas emissions due to the on-site and off-site use of primary energy sources are also estimated. The addition of a mechanical ventilation system with heat recovery to any HVAC-DHW system discussed in the paper increases the energy efficiency; however, it decreases the exergy efficiency, which indicates a potential long-term damaging impact on the natural environment. Therefore, the use of a separate mechanical ventilation system in a house should be considered with caution, and recommended only when other means for controlling the indoor air quality cannot be applied

  15. Development of an Outdoor Temperature-Based Control Algorithm for Residential Mechanical Ventilation Control

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tang, Yihuan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-06-01

    Smart ventilation systems use controls to ventilate more during those periods that provide either an energy or IAQ advantage (or both) and less during periods that provide a dis advantage. Using detailed building simulations, this study addresses one of the simplest and lowest cost types of smart controllers —outdoor temperature- based control. If the outdoor temperature falls below a certain cut- off, the fan is simply turned off. T he main principle of smart ventilation used in this study is to shift ventilation from time periods with large indoor -outdoor temperature differences, to periods where these differences are smaller, and their energy impacts are expected to be less. Energy and IAQ performance are assessed relative to a base case of a continuously operated ventilation fan sized to comply with ASHRAE 62.2-2013 whole house ventilation requirements. In order to satisfy 62.2-2013, annual pollutant exposure must be equivalent between the temperature controlled and continuous fan cases. This requires ventilation to be greater than 62.2 requirements when the ventilation system operates. This is achieved by increasing the mechanical ventilation system air flow rates.

  16. Position paper -- Tank ventilation system design air flow rates

    International Nuclear Information System (INIS)

    Goolsby, G.K.

    1995-01-01

    The purpose of this paper is to document a project position on required ventilation system design air flow rates for the waste storage tanks currently being designed by project W-236A, the Multi-Function Waste Tank Facility (MWTF). The Title 1 design primary tank heat removal system consists of two systems: a primary tank vapor space ventilation system; and an annulus ventilation system. At the conclusion of Title 1 design, air flow rates for the primary and annulus ventilation systems were 960 scfm and 4,400 scfm, respectively, per tank. These design flow rates were capable of removing 1,250,000 Btu/hr from each tank. However, recently completed and ongoing studies have resulted in a design change to reduce the extreme case heat load to 700,000 Btu/hr. This revision of the extreme case heat load, coupled with results of scale model evaporative testing performed by WHC Thermal Hydraulics, allow for a reduction of the design air flow rates for both primary and annulus ventilation systems. Based on the preceding discussion, ICF Kaiser Hanford Co. concludes that the design should incorporate the following design air flow rates: Primary ventilation system--500 scfm maximum and Annulus ventilation system--1,100 scfm maximum. In addition, the minimum air flow rates in the primary and annulus ventilation systems will be investigated during Title 2 design. The results of the Title 2 investigation will determine the range of available temperature control using variable air flows to both ventilation systems

  17. Association between substandard classroom ventilation rates and students' academic achievement.

    Science.gov (United States)

    Haverinen-Shaughnessy, U; Moschandreas, D J; Shaughnessy, R J

    2011-04-01

    This study focuses on the relationship between classroom ventilation rates and academic achievement. One hundred elementary schools of two school districts in the southwest United States were included in the study. Ventilation rates were estimated from fifth-grade classrooms (one per school) using CO(2) concentrations measured during occupied school days. In addition, standardized test scores and background data related to students in the classrooms studied were obtained from the districts. Of 100 classrooms, 87 had ventilation rates below recommended guidelines based on ASHRAE Standard 62 as of 2004. There is a linear association between classroom ventilation rates and students' academic achievement within the range of 0.9-7.1 l/s per person. For every unit (1 l/s per person) increase in the ventilation rate within that range, the proportion of students passing standardized test (i.e., scoring satisfactory or above) is expected to increase by 2.9% (95%CI 0.9-4.8%) for math and 2.7% (0.5-4.9%) for reading. The linear relationship observed may level off or change direction with higher ventilation rates, but given the limited number of observations, we were unable to test this hypothesis. A larger sample size is needed for estimating the effect of classroom ventilation rates higher than 7.1 l/s per person on academic achievement. The results of this study suggest that increasing the ventilation rates toward recommended guideline ventilation rates in classrooms should translate into improved academic achievement of students. More studies are needed to fully understand the relationships between ventilation rate, other indoor environmental quality parameters, and their effects on students' health and achievement. Achieving the recommended guidelines and pursuing better understanding of the underlying relationships would ultimately support both sustainable and productive school environments for students and personnel. © 2010 John Wiley & Sons A/S.

  18. Waste tank ventilation rates measured with a tracer gas method

    International Nuclear Information System (INIS)

    Huckaby, J.L.; Evans, J.C.; Sklarew, D.S.; Mitroshkov, A.V.

    1998-08-01

    Passive ventilation with the atmosphere is used to prevent accumulation of waste gases and vapors in the headspaces of 132 of the 177 high-level radioactive waste Tanks at the Hanford Site in Southeastern Washington State. Measurements of the passive ventilation rates are needed for the resolution of two key safety issues associated with the rates of flammable gas production and accumulation and the rates at which organic salt-nitrate salt mixtures dry out. Direct measurement of passive ventilation rates using mass flow meters is not feasible because ventilation occurs va multiple pathways to the atmosphere (i.e., via the filtered breather riser and unsealed tank risers and pits), as well as via underground connections to other tanks, junction boxes, and inactive ventilation systems. The tracer gas method discussed in this report provides a direct measurement of the rate at which gases are removed by ventilation and an indirect measurement of the ventilation rate. The tracer gas behaves as a surrogate of the waste-generated gases, but it is only diminished via ventilation, whereas the waste gases are continuously released by the waste and may be subject to depletion mechanisms other than ventilation. The fiscal year 1998 tracer studies provide new evidence that significant exchange of air occurs between tanks via the underground cascade pipes. Most of the single-shell waste tanks are connected via 7.6-cm diameter cascade pipes to one or two adjacent tanks. Tracer gas studies of the Tank U-102/U-103 system indicated that the ventilation occurring via the cascade line could be a significant fraction of the total ventilation. In this two-tank cascade, air evidently flowed from Tank U-103 to Tank U-102 for a time and then was observed to flow from Tank U-102 to Tank U-103

  19. Determining the ventilation and aerosol deposition rates from routine indoor-air measurements.

    Science.gov (United States)

    Halios, Christos H; Helmis, Costas G; Deligianni, Katerina; Vratolis, Sterios; Eleftheriadis, Konstantinos

    2014-01-01

    Measurement of air exchange rate provides critical information in energy and indoor-air quality studies. Continuous measurement of ventilation rates is a rather costly exercise and requires specific instrumentation. In this work, an alternative methodology is proposed and tested, where the air exchange rate is calculated by utilizing indoor and outdoor routine measurements of a common pollutant such as SO2, whereas the uncertainties induced in the calculations are analytically determined. The application of this methodology is demonstrated, for three residential microenvironments in Athens, Greece, and the results are also compared against ventilation rates calculated from differential pressure measurements. The calculated time resolved ventilation rates were applied to the mass balance equation to estimate the particle loss rate which was found to agree with literature values at an average of 0.50 h(-1). The proposed method was further evaluated by applying a mass balance numerical model for the calculation of the indoor aerosol number concentrations, using the previously calculated ventilation rate, the outdoor measured number concentrations and the particle loss rates as input values. The model results for the indoors' concentrations were found to be compared well with the experimentally measured values.

  20. Experimental analysis of an air-to-air heat recovery unit for balanced ventilation systems in residential buildings

    International Nuclear Information System (INIS)

    Fernandez-Seara, Jose; Diz, Ruben; Uhia, Francisco J.; Dopazo, Alberto; Ferro, Jose M.

    2011-01-01

    This paper deals with the experimental analysis of an air-to-air heat recovery unit equipped with a sensible polymer plate heat exchanger (PHE) for balanced ventilation systems in residential buildings. The PHE is arranged in parallel triangular ducts. An experimental facility was designed to reproduce the typical outdoor and exhaust air conditions with regard to temperature and humidity. The unit was tested under balanced operation conditions, as commonly used in practice. A set of tests was conducted under the reference operating conditions to evaluate the PHE performance. Afterwards, an experimental parametric analysis was conducted to investigate the influence of changing the operating conditions on the PHE performance. Experiments were carried out varying the inlet fresh air temperature, the exhaust air relative humidity and the air flow rate. The experimental results are shown and discussed in this paper.

  1. Thermal Comfort and Ventilation Criteria for low Energy Residential Buildings in Building Codes

    DEFF Research Database (Denmark)

    Cao, Guangyu; Kurnitski, Jarek; Awbi, Hazim

    2012-01-01

    of the indoor air quality in such buildings. Currently, there are no global guidelines for specifying the indoor thermal environment in such low-energy buildings. The objective of this paper is to analyse the classification of indoor thermal comfort levels and recommended ventilation rates for different low...

  2. What does the scientific literature tell us about the ventilation-health relationship in public and residential buildings?

    DEFF Research Database (Denmark)

    Carrer, Paolo; Wargocki, Pawel; Fanetti, Annaclara

    2015-01-01

    . Effects on health were seen for a wide range of outdoor ventilation rates from 6 to 7 L/s per person, which were the lowest ventilation rates at which no effects on any health outcomes were observed in field studies, up to 25–40 L/s per person, which were in some studies the lowest outdoor ventilation...... rates at which no effects on health outcomes were seen. These data show that, in general, higher ventilation rates in many cases will reduce health outcomes, and that there are the minimum rates, at which some health outcomes can be avoided. But these data have many limitations, such as crude estimation...... of outdoor ventilation rates, diversity and variability of ventilation rates at which effects were seen, a diversity of outcomes (in case of health otcomes being mainly acute not chronic). Among other limitations there are incomplete data on the strength of pollution sources and exposures as well as a wide...

  3. Novel approach for evaluation of air change rate in naturally ventilated occupied spaces based on metabolic CO2 time variation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Markov, Detelin G.

    2014-01-01

    IAQ in many residential buildings relies on non-organized natural ventilation. Accurate evaluation of air change rate (ACR) in this situation is difficult due to the nature of the phenomenon - intermittent infiltration-exfiltration periods of mass exchange between the room air and the outdoor air...... at low rate. This paper describes a new approach for ACR evaluation in naturally ventilated occupied spaces. Actual metabolic CO2 time variation record in an interval of time is compared with the computed variation of metabolic CO2 for the same time interval under reference conditions: sleeping occupants...

  4. Improved air ventilation rate estimation based on a statistical model

    International Nuclear Information System (INIS)

    Brabec, M.; Jilek, K.

    2004-01-01

    A new approach to air ventilation rate estimation from CO measurement data is presented. The approach is based on a state-space dynamic statistical model, allowing for quick and efficient estimation. Underlying computations are based on Kalman filtering, whose practical software implementation is rather easy. The key property is the flexibility of the model, allowing various artificial regimens of CO level manipulation to be treated. The model is semi-parametric in nature and can efficiently handle time-varying ventilation rate. This is a major advantage, compared to some of the methods which are currently in practical use. After a formal introduction of the statistical model, its performance is demonstrated on real data from routine measurements. It is shown how the approach can be utilized in a more complex situation of major practical relevance, when time-varying air ventilation rate and radon entry rate are to be estimated simultaneously from concurrent radon and CO measurements

  5. Flexible Residential Test Facility: Impact of Infiltration and Ventilation on Measured Cooling Season Energy and Moisture Levels

    Energy Technology Data Exchange (ETDEWEB)

    Parker, Danny S. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Cummings, Jamie E. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Vieira, Robin K. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Fairey, III, Phillip W. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Sherwin, John S. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Withers, Jr., Charles [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Hoak, David [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Beal, David [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States)

    2016-09-01

    Air infiltration and ventilation in residential buildings is a very large part of the heating loads, but empirical data regarding the impact on space cooling has been lacking. Moreover, there has been little data on how building tightness might relate to building interior moisture levels in homes in a hot and humid climate. To address this need, BA-PIRC has conducted research to assess the moisture and cooling load impacts of airtightness and mechanical ventilation in two identical laboratory homes in the hot-humid climate over the cooling season.

  6. Flexible Residential Test Facility: Impact of Infiltration and Ventilation on Measured Cooling Season Energy and Moisture Levels

    Energy Technology Data Exchange (ETDEWEB)

    Parker, D.; Kono, J.; Vieira, R.; Fairey, P.; Sherwin, J.; Withers, C.; Hoak, D.; Beal, D.

    2014-05-01

    Air infiltration and ventilation in residential buildings is a very large part of the heating loads, but empirical data regarding the impact on space cooling has been lacking. Moreover, there has been little data on how building tightness might relate to building interior moisture levels in homes in a hot and humid climate. To address this need, BA-PIRC has conducted research to assess the moisture and cooling load impacts of airtightness and mechanical ventilation in two identical laboratory homes in the hot-humid climate over the cooling season.

  7. Measurements of waste tank passive ventilation rates using tracer gases

    International Nuclear Information System (INIS)

    Huckaby, J.L.; Olsen, K.B.; Sklarew, D.S.; Evans, J.C.; Remund, K.M.

    1997-09-01

    This report presents the results of ventilation rate studies of eight passively ventilated high-level radioactive waste tanks using tracer gases. Head space ventilation rates were determined for Tanks A-101, AX-102, AX-103, BY-105, C-107, S-102, U-103, and U-105 using sulfur hexafluoride (SF 6 ) and/or helium (He) as tracer gases. Passive ventilation rates are needed for the resolution of several key safety issues. These safety issues are associated with the rates of flammable gas production and ventilation, the rates at which organic salt-nitrate salt mixtures dry out, and the estimation of organic solvent waste surface areas. This tracer gas study involves injecting a tracer gas into the tank headspace and measuring its concentration at different times to establish the rate at which the tracer is removed by ventilation. Tracer gas injection and sample collection were performed by SGN Eurisys Service Corporation and/or Lockheed Martin Hanford Corporation, Characterization Project Operations. Headspace samples were analyzed for He and SF 6 by Pacific Northwest National Laboratory (PNNL). The tracer gas method was first demonstrated on Tank S-102. Tests were conducted on Tank S-102 to verify that the tracer gas was uniformly distributed throughout the tank headspace before baseline samples were collected, and that mixing was sufficiently vigorous to maintain an approximately uniform distribution of tracer gas in the headspace during the course of the study. Headspace samples, collected from a location about 4 in away from the injection point and 15, 30, and 60 minutes after the injection of He and SF 6 , indicated that both tracer gases were rapidly mixed. The samples were found to have the same concentration of tracer gases after 1 hour as after 24 hours, suggesting that mixing of the tracer gas was essentially complete within 1 hour

  8. Practical guidebook on the modulation of ventilation flow rates; Guide pratique sur la modulation des debits de ventilation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The modulation of ventilation flow rates aims at adapting the flow rate of ventilation systems to the real occupancy of rooms, at maintaining a good indoor air quality and at mastering the energy expenses due to air renewing in rooms. This technical guidebook presents the design of modulated ventilation systems (definition of occupancy areas in buildings, choice of presence sensors (CO{sub 2}, hygrometry, temperature, CO, VOC and other specific probes)), their principle and implementation. (J.S.)

  9. PowerChoice Residential Customer Response to TOU Rates

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Jane S.; Moezzi, Mithra; Lutzenhiser, Susan; Woods, James; Dethman, Linda; Kunkle, Rick

    2009-10-01

    Research Into Action, Inc. and the Sacramento Municipal Utility District (SMUD) worked together to conduct research on the behaviors and energy use patterns of SMUD residential customers who voluntarily signed on to a Time-of-Use rate pilot launched under the PowerChoice label. The project was designed to consider the how and why of residential customers ability and willingness to engage in demand reduction behaviors, and to link social and behavioral factors to observed changes in demand. The research drew on a combination of load interval data and three successive surveys of participating households. Two experimental treatments were applied to test the effects of increased information on households ability to respond to the Time-of-Use rates. Survey results indicated that participants understood the purpose of the Time-of-Use rate and undertook substantial appropriate actions to shift load and conserve. Statistical tests revealed minor initial price effects and more marked, but still modest, adjustments to seasonal rate changes. Tests of the two information interventions indicated that neither made much difference to consumption patterns. Despite the lackluster statistical evidence for load shifting, the analysis points to key issues for critical analysis and development of residential Time-of-Use rates, especially pertinent as California sets the stage for demand response in more California residences.

  10. Effect of a ventilator-focused intervention on the rate of Acinetobacter baumannii infection among ventilated patients.

    Science.gov (United States)

    Cohen, Regev; Shimoni, Zvi; Ghara, Riad; Ram, Ron; Ben-Ami, Ronen

    2014-09-01

    Acinetobacter baumannii is a leading cause of ventilator-associated pneumonia, often as a result of ventilator equipment contamination. Evidence-based guidance on optimal care of ventilator equipment to prevent infection is lacking. Here, we report on a significant and persistent reduction in A baumannii infection rates achieved by introducing a strict policy on ventilator care. We implemented an institution-wide ventilator care policy that included routine exchange of breathing circuits and external bacterial filters (every 7-14 days) and replacement followed by routine sterilization of internal bacterial filters (every 4-8 weeks). We analyzed sputum cultures and patient outcomes among ventilated patients before and after the intervention. Between January 2012 and March 2013, 321 patients ventilated for more than 3 days comprised the study cohort. Health care-associated A baumannii acquisition was significantly reduced during the postintervention period (33% vs 16%; odds ratio, 0.39; 95% confidence interval, 0.23-0.67; P = .0008). Additionally, the median time to A baumannii acquisition was significantly longer postintervention (59 vs 21 days; P < .0001). A baumannii ventilator-associated pneumonia risk was also reduced postintervention (odds ratio, 0.39; P = .005). Implementing a stricter standard of ventilator care than that currently defined in published guidelines can significantly decrease health care-associated A baumannii acquisition and related adverse outcomes among ventilated patients. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  11. Residential response to voluntary time-of-use electricity rates

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa Baladi, S. [Laurits R. Christensen Associates, Inc. Ames, IA 50011-1070 (United States); Herriges, Joseph A. [Iowa State University, 280D Heady Hall, Department of Economics, Iowa State University, Ames, IA 50011-1070 (United States); Sweeney, Thomas J. [MidAmerican Energy, Des Moines, Iowa (United States)

    1998-09-01

    The response of residential households to voluntary Time-of-Use (TOU) electricity rates is estimated using data from a recent experiment at Midwest Power Systems of Iowa. The study`s design allows us to examine both the participation decision and the customer`s load pattern changes once the TOU rate structure was in effect. Substitution elasticities between on-peak and off-peak electricity usage are estimated and compared to those obtained in earlier mandatory programs, indicating whether program volunteers are more responsive to TOU pricing than the typical household. Attitudinal questionnaires allow us to examine the role of usage perceptions in program participation

  12. Energy Savings Potential and Research, Development, & Demonstration Opportunities for Residential Building Heating, Ventilation, and Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    Goetzler, William [Navigant Consulting, Inc., Burlington, MA (United States); Zogg, Robert [Navigant Consulting, Inc., Burlington, MA (United States); Young, Jim [Navigant Consulting, Inc., Burlington, MA (United States); Schmidt, Justin [Navigant Consulting, Inc., Burlington, MA (United States)

    2012-10-01

    This report is an assessment of 135 different heating, ventilation, and air-conditioning (HVAC) technologies for U.S. residential buildings to identify and provide analysis on 19 priority technology options in various stages of development. The analyses include an estimation of technical energy-savings potential, descriptions of technical maturity, descriptions of non-energy benefits, descriptions of current barriers for market adoption, and descriptions of the technology's applicability to different building or HVAC equipment types. From these technology descriptions, are suggestions for potential research, development and demonstration (RD&D) initiatives that would support further development of the priority technology options.

  13. On the influence of the ventilation rate to the radiation burden in dwellings

    International Nuclear Information System (INIS)

    Tschurlovits, M.

    1980-01-01

    Calculations on the influence of the ventilation rate to the concentration of radon in dwellings from radioactive material of natural origin in building material are completed with a few examples of measurements. In addition, the optimization of the ventilation rate and the consequences of poorly ventilated dwellings are reported briefly. (author)

  14. Test Protocol for Room-to-Room Distribution of Outside Air by Residential Ventilation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Barley, C. D.; Anderson, R.; Hendron, B.; Hancock, E.

    2007-12-01

    This test and analysis protocol has been developed as a practical approach for measuring outside air distribution in homes. It has been used successfully in field tests and has led to significant insights on ventilation design issues. Performance advantages of more sophisticated ventilation systems over simpler, less-costly designs have been verified, and specific problems, such as airflow short-circuiting, have been identified.

  15. Study on pollution control in residential kitchen based on the push-pull ventilation system

    DEFF Research Database (Denmark)

    Zhou, Bin; Chen, Feng; Dong, Zhibo

    2016-01-01

    Highlights •The push-pull ventilation system is proposed to improve IAQ inside kitchen, where air is supplied through slot air curtain and then exhausted through range hood. •CO2 reduction efficiency with application of air curtain in experiment and simulation in breathing zone was 23.7% and 23.......1%, respectively. •By orthogonal method, the influence of factors on pollution control of the push-pull ventilation system was presented....

  16. Marketing time-of-day rates to the residential market

    International Nuclear Information System (INIS)

    Spangler, W.E.

    1990-01-01

    The Metropolitan Edison Company in Pennsylvania began to promote load management and conservation in the early 1970s. In 1976, time-of-day rates were introduced as a strategy to aid in providing adequate supply at a price which could sustain demand. At first, it was offered on a trial basis to a limited number of customers. The on-peak period was 8 a.m. to 8 p.m. weekdays, and if the customer used 60% or more of his electric energy during the off-peak period, costs could be saved on the new rate. Marketing of the new rates was conducted at a modest level and the marketing program emphasized changes in lifestyle such as the deferring of energy consuming tasks to the off-peak period. After the Three Mile Island incident in 1979, the utility lost some of its supply; this and other factors prompted new marketing strategies including more extensive publicity and targeted mailings to users of electric water heaters. Customers were required to take service under the time-of-day rate if they selected specific end-use applications or consumed over 1,000 kWh for 2 consecutive months. Special programs were initiated to aid customers in modifying water heaters to shift consumption to off-peak hours. These and other measures have led to the present situation in which 16.2% of the total residential rate class takes service under the time-of-day rate

  17. Building America Top Innovations 2014 Profile: ASHRAE Standard 62.2. Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-11-01

    This 2014 Top Innovations profile describes Building America research and support in developing and gaining adoption of ASHRAE 62.2, a residential ventilation standard that is critical to transforming the U.S. housing industry to high-performance homes.

  18. Development of an Integrated Residential Heating, Ventilation, Cooling, and Dehumidification System for Residences

    Energy Technology Data Exchange (ETDEWEB)

    Hoeschele, M.A.; D.A. Springer

    2008-06-18

    The Need and the Opportunity Codes such as ASHRAE 90.2 and IECC, and programs such as Energy Star and Builders Challenge, are causing new homes to be built to higher performance standards. As a result sensible cooling loads in new homes are going down, but indoor air quality prerogatives are causing ventilation rates and moisture loads to increase in humid climates. Conventional air conditioners are unable to provide the low sensible heat ratios that are needed to efficiently cool and dehumidify homes since dehumidification potential is strongly correlated with cooling system operating hours. The project team saw an opportunity to develop a system that is at least as effective as a conventional air conditioner plus dehumidifier, removes moisture without increasing the sensible load, reduces equipment cost by integrating components, and simplifies installation. Project Overview Prime contractor Davis Energy Group led a team in developing an Integrated Heating, Ventilation, Cooling, and Dehumidification (I-HVCD) system under the DOE SBIR program. Phase I and II SBIR project activities ran from July 2003 through December 2007. Tasks included: (1) Mechanical Design and Prototyping; (2) Controls Development; (3) Laboratory and Field Testing; and (4) Commercialization Activities Technology Description. Key components of the prototype I-HVCD system include an evaporator coil assembly, return and outdoor air damper, and controls. These are used in conjunction with conventional components that include a variable speed air handler or furnace, and a two-stage condensing unit. I-HVCD controls enable the system to operate in three distinct cooling modes to respond to indoor temperature and relative humidity (RH) levels. When sensible cooling loads are high, the system operates similar to a conventional system but varies supply airflow in response to indoor RH. In the second mode airflow is further reduced, and the reheat coil adds heat to the supply air. In the third mode, the

  19. Effect of Room Ventilation Rates in Rodent Rooms with Direct-Exhaust IVC Systems.

    Science.gov (United States)

    Geertsema, Roger S; Lindsell, Claire E

    2015-09-01

    When IVC are directly exhausted from a rodent housing room, the air quality of the room can become independent of the intracage air quality and may reduce the need for high room ventilation rates. This study assessed the effect of decreasing the ventilation rate in rodent rooms using direct-exhaust IVC systems. The study was conducted over 16 wk and compared conditions in 8 rodent rooms that had ventilation rates of 5 to 6 air changes per hour (ACH) with those in rooms at 10 to 12 ACH. At the low ventilation rate, rooms had higher CO₂ concentrations, higher dew point temperature, and lower particulate levels and spent a greater percentage of time above the temperature set point than did rooms at the high rate. The levels of allergens and endotoxins in room air were the same regardless of the ventilation rate. Differences seen in parameters within cages at the 2 ventilation rates were operationally irrelevant. We detected no total volatile organic compounds in the room that were attributable to ammonia, regardless of the ventilation rate. Clearing the air of ethanol after a spill took longer at the low compared with high rate. However, ethanol clearance was faster at the low rate when the demand-control system was activated than at the high ventilation rate alone. Air quality in the room and in the cages were acceptable with room ventilation rates of 5 to 6 ACH in rodent rooms that use direct-exhaust IVC systems.

  20. A First Approach to Natural Thermoventilation of Residential Buildings through Ventilation Chimneys Supplied by Solar Ponds

    Directory of Open Access Journals (Sweden)

    Ferdinando Salata

    2015-07-01

    Full Text Available The exploitation of natural ventilation is a good solution to improve buildings from an energetic point of view and to fulfill the requirements demanded by the thermohygrometric comfort and the air quality in enclosed spaces. Some past researches demonstrated how some devices, useful to this purpose, follow the principles of solar chimneys and are able to move air masses while exploiting the Archimedes thrust. The natural ventilation must be supplied by a flow moving upward, generated by a heat source performing at temperatures slightly higher than the one present in the environment. To have a minimum energetic effect, the heat can be extracted from solar ponds; solar ponds are able to collect and store solar energy in the geographical regions characterized by sufficient values of solar radiation. Thus it is possible, in summer, to provoke a nocturnal natural ventilation useful for the air change in indoor spaces (in those climatic areas where, during the night, there is a temperature gradient.

  1. Augmenting natural ventilation using solar heat and free cool energy for residential buildings

    Directory of Open Access Journals (Sweden)

    N. B. Geetha

    2014-03-01

    Full Text Available In many urban buildings ventilation is not sufficient that will increase the temperature and also create unhealthy atmosphere inside the room. In such buildings artificially induced ventilation through freely available energy promote comfort conditions by reducing the temperature by 2 to 3°C and also creating good circulation of fresh air inside the room. In the present work the concept of improving the ventilation by excess hot energy available during summer days from the solar flat plate collector and by storing cool energy available during the early morning hour in the Phase Change Material (PCM based storage system is attempted. An experimental setup is made to study the effect of improvement in natural ventilation and the results are reported. A visible reduction in temperature is observed through circulation of air from the bottom side of the room to the roof of the house using the stored hot and cool energy. A CFD analysis is also carried out using ANSYS-CFX software to simulate and evaluate the mass flow of air at the inlet and at the selected RTD location by matching the transient temperature profile of the simulated result with the experimental results at the selected RTD location.

  2. Impact of residential PV adoption on Retail Electricity Rates

    International Nuclear Information System (INIS)

    Cai, Desmond W.H.; Adlakha, Sachin; Low, Steven H.; De Martini, Paul; Mani Chandy, K.

    2013-01-01

    The price of electricity supplied from home rooftop photo voltaic (PV) solar cells has fallen below the retail price of grid electricity in some areas. A number of residential households have an economic incentive to install rooftop PV systems and reduce their purchases of electricity from the grid. A significant portion of the costs incurred by utility companies are fixed costs which must be recovered even as consumption falls. Electricity rates must increase in order for utility companies to recover fixed costs from shrinking sales bases. Increasing rates will, in turn, result in even more economic incentives for customers to adopt rooftop PV. In this paper, we model this feedback between PV adoption and electricity rates and study its impact on future PV penetration and net-metering costs. We find that the most important parameter that determines whether this feedback has an effect is the fraction of customers who adopt PV in any year based solely on the money saved by doing so in that year, independent of the uncertainties of future years. These uncertainties include possible changes in rate structures such as the introduction of connection charges, the possibility of PV prices dropping significantly in the future, possible changes in tax incentives, and confidence in the reliability and maintainability of PV. -- Highlights: •Households who install PV reduce their electricity consumption from the grid. •Electricity rates must increase for utility companies to recover its fixed costs. •However, higher electricity rates give households more incentives to adopt PV. •We find that this feedback has significant impact on PV uptake only in later years. •Utility companies could lose a significant fraction of high consumption customers

  3. Hybrid ventilation in residential buildings – the proposal of research for the Polish climatic conditions

    Directory of Open Access Journals (Sweden)

    Kostka Maria

    2017-01-01

    Full Text Available Due to the geographic location and the influence of the polar maritime and polar continental air masses we observe a large variety and variability of external air parameters in Poland. Both during the whole year and also in shorter, even several-day periods. The parameters of outside air indicate that combination of mechanical and natural ventilation in detached buildings can be cost-effective and allows keeping the thermal comfort and good indoor air quality.

  4. Indoor air pollutants, ventilation rate determinants and potential control strategies in Chinese dwellings: A literature review.

    Science.gov (United States)

    Ye, Wei; Zhang, Xu; Gao, Jun; Cao, Guangyu; Zhou, Xiang; Su, Xing

    2017-05-15

    After nearly twenty years of rapid modernization and urbanization in China, huge achievements have transformed the daily lives of the Chinese people. However, unprecedented environmental consequences in both indoor and outdoor environments have accompanied this progress and have triggered public awareness and demands for improved living standards, especially in residential environments. Indoor pollution data measured for >7000 dwellings (approximately 1/3 were newly decorated and were tested for volatile organic compound (VOC) measurements, while the rest were tested for particles, phthalates and other semi-volatile organic compounds (SVOCs), moisture/mold, inorganic gases and radon) in China within the last ten years were reviewed, summarized and compared with indoor concentration recommendations based on sensory or health end-points. Ubiquitous pollutants that exceed the concentration recommendations, including particulate matter, formaldehyde, benzene and other VOCs, moisture/mold, inorganic gases and radon, were found, indicating a common indoor air quality (IAQ) issue in Chinese dwellings. With very little prevention, oral, inhalation and dermal exposure to those pollutants at unhealthy concentration levels is almost inevitable. CO 2 , VOCs, humidity and radon can serve as ventilation determinants, each with different ventilation demands and strategies, at typical occupant densities in China; and particle reduction should be a prerequisite for determining ventilation requirements. Two directional ventilation modes would have profound impacts on improving IAQ for Chinese residences are: 1) natural (or window) ventilation with an air cleaner and 2) mechanical ventilation with an air filtration unit, these two modes were reviewed and compared for their applicability and advantages and disadvantages for reducing human exposure to indoor air pollutants. In general, mode 2 can more reliably ensure good IAQ for occupants; while mode 1 is more applicable due to its

  5. Probabilistic estimation of residential air exchange rates for ...

    Science.gov (United States)

    Residential air exchange rates (AERs) are a key determinant in the infiltration of ambient air pollution indoors. Population-based human exposure models using probabilistic approaches to estimate personal exposure to air pollutants have relied on input distributions from AER measurements. An algorithm for probabilistically estimating AER was developed based on the Lawrence Berkley National Laboratory Infiltration model utilizing housing characteristics and meteorological data with adjustment for window opening behavior. The algorithm was evaluated by comparing modeled and measured AERs in four US cities (Los Angeles, CA; Detroit, MI; Elizabeth, NJ; and Houston, TX) inputting study-specific data. The impact on the modeled AER of using publically available housing data representative of the region for each city was also assessed. Finally, modeled AER based on region-specific inputs was compared with those estimated using literature-based distributions. While modeled AERs were similar in magnitude to the measured AER they were consistently lower for all cities except Houston. AERs estimated using region-specific inputs were lower than those using study-specific inputs due to differences in window opening probabilities. The algorithm produced more spatially and temporally variable AERs compared with literature-based distributions reflecting within- and between-city differences, helping reduce error in estimates of air pollutant exposure. Published in the Journal of

  6. Adaptive Support Ventilation May Deliver Unwanted Respiratory Rate-Tidal Volume Combinations in Patients with Acute Lung Injury Ventilated According to an Open Lung Concept

    NARCIS (Netherlands)

    Dongelmans, Dave A.; Paulus, Frederique; Veelo, Denise P.; Binnekade, Jan M.; Vroom, Margreeth B.; Schultz, Marcus J.

    2011-01-01

    Background: With adaptive support ventilation, respiratory rate and tidal volume (V(T)) are a function of the Otis least work of breathing formula. We hypothesized that adaptive support ventilation in an open lung ventilator strategy would deliver higher V(T)s to patients with acute lung injury.

  7. Association between ventilation rates in 390 Swedish homes and allergic symptoms in children

    DEFF Research Database (Denmark)

    Bornehag, Carl Gustaf; Sundell, Jan; Hagerhed-Engman, L.

    2005-01-01

    in 390 homes, were examined by physicians. Ventilation rates were measured by a passive tracer gas method, and inspections were carried out in the homes. About 60% of the multi-family houses and about 80% of the single-family houses did not fulfill the minimum requirement regarding ventilation rate...

  8. Effect of ventilation rate on concentrations of indoor radon and its progenies

    International Nuclear Information System (INIS)

    Wang Chunhong; Liu Yanyang; Liu Fudong; Liu Senlin; Chen Ling

    2012-01-01

    To study concentrations of indoor radon and its progenies, ventilation rates and their corresponding concentrations of indoor radon and its progenies were measured using tracer-gas dilution method. Results show that both ventilation rates and concentrations of indoor radon varied insignificantly and radon concentration were higher than the outdoor environment while doors and windows were all closed with air-conditioner on and off respectively; the concentrations declined and close to the outdoor level when doors and windows were all open with ventilators in operation. Accordingly, in modern life, especially in summer, people's preference for air-conditioners but natural ventilation would result in an increase of indoor radon concentration. (authors)

  9. Residential Property Composition of School Districts: Its Effect on Tax Rate and Per Pupil Revenue.

    Science.gov (United States)

    Lundeen, Virginia; And Others

    This study related tax rate and per pupil revenue to residential assessed valuation, percent residential of total assessed valuation, and selected socioeconomic independent variables for school districts in Cook, DeKalb, DuPage, Kane, and Lake counties in Illinois. Findings suggest that for homeowners and the students of these counties in 1976,…

  10. Sustained Reduction of Ventilator-Associated Pneumonia Rates Using Real-Time Course Correction With a Ventilator Bundle Compliance Dashboard.

    Science.gov (United States)

    Talbot, Thomas R; Carr, Devin; Parmley, C Lee; Martin, Barbara J; Gray, Barbara; Ambrose, Anna; Starmer, Jack

    2015-11-01

    The effectiveness of practice bundles on reducing ventilator-associated pneumonia (VAP) has been questioned. To implement a comprehensive program that included a real-time bundle compliance dashboard to improve compliance and reduce ventilator-associated complications. DESIGN Before-and-after quasi-experimental study with interrupted time-series analysis. SETTING Academic medical center. In 2007 a comprehensive institutional ventilator bundle program was developed. To assess bundle compliance and stimulate instant course correction of noncompliant parameters, a real-time computerized dashboard was developed. Program impact in 6 adult intensive care units (ICUs) was assessed. Bundle compliance was noted as an overall cumulative bundle adherence assessment, reflecting the percentage of time all elements were concurrently in compliance for all patients. The VAP rate in all ICUs combined decreased from 19.5 to 9.2 VAPs per 1,000 ventilator-days following program implementation (Pdashboard was associated with significant sustained decreases in VAP rates and an increase in bundle compliance among adult ICU patients.

  11. Cost-benefit analysis of decreased ventilation rates and radon exhalation from building materials

    International Nuclear Information System (INIS)

    Ericson, S.O.

    1984-01-01

    Decreased ventilation, achieved by weather stripping and other tightening measures, is the most cost effective way to energy conservation. A very low investment can result in a considerable decrease in ventilation rate. For a typical detached house in Sweden this can be equivalent to a decrease in oil consumption of 0.5 m 3 . At present price this corresponds to a saving of SEK 1200, 150 US dollars per annum. The contribution of the building materials to the concentration of radon in indoor air is approximately the inverse to air exchange rate. For a small change in ventilation rate and cost, in SEK/man Sv or US dollar/man Sv, is a function of ventilation rate, exhalation from building materials, the ratio between surface of walls, floor and ceiling to the volume of air. Thus, it is possible to find the specific ventilation rate where the marginal cost for a small increase in ventilation rate and the marginal reduction in radon concentration will give a specific amount of money for each man Sv. Examples are given. Conclusions are that for most building materials in a climate like the Swedish, there are other factors than exhalation of radon from building materials that sets the lower limit of recommendable ventilation rate. (Author)

  12. Effect of ventilation rate on air cleanliness and energy consumption in operation rooms at rest.

    Science.gov (United States)

    Lee, Shih-Tseng; Liang, Ching-Chieh; Chien, Tsung-Yi; Wu, Feng-Jen; Fan, Kuang-Chung; Wan, Gwo-Hwa

    2018-02-27

    The interrelationships between ventilation rate, indoor air quality, and energy consumption in operation rooms at rest are yet to be understood. We investigate the effect of ventilation rate on indoor air quality indices and energy consumption in ORs at rest. The study investigates the air temperature, relative humidity, concentrations of carbon dioxide, particulate matter (PM), and airborne bacteria at different ventilation rates in operation rooms at rest of a medical center. The energy consumption and cost analysis of the heating, ventilating, and air conditioning (HVAC) system in the operation rooms at rest were also evaluated for all ventilation rates. No air-conditioned operation rooms had very highest PM and airborne bacterial concentrations in the operation areas. The bacterial concentration in the operation areas with 6-30 air changes per hour (ACH) was below the suggested level set by the United Kingdom (UK) for an empty operation room. A 70% of reduction in annual energy cost by reducing the ventilation rate from 30 to 6 ACH was found in the operation rooms at rest. Maintenance of operation rooms at ventilation rate of 6 ACH could save considerable amounts of energy and achieve the goal of air cleanliness.

  13. Adaptive support ventilation may deliver unwanted respiratory rate-tidal volume combinations in patients with acute lung injury ventilated according to an open lung concept.

    Science.gov (United States)

    Dongelmans, Dave A; Paulus, Frederique; Veelo, Denise P; Binnekade, Jan M; Vroom, Margreeth B; Schultz, Marcus J

    2011-05-01

    With adaptive support ventilation, respiratory rate and tidal volume (V(T)) are a function of the Otis least work of breathing formula. We hypothesized that adaptive support ventilation in an open lung ventilator strategy would deliver higher V(T)s to patients with acute lung injury. Patients with acute lung injury were ventilated according to a local guideline advising the use of lower V(T) (6-8 ml/kg predicted body weight), high concentrations of positive end-expiratory pressure, and recruitment maneuvers. Ventilation parameters were recorded when the ventilator was switched to adaptive support ventilation, and after recruitment maneuvers. If V(T) increased more than 8 ml/kg predicted body weight, airway pressure was limited to correct for the rise of V(T). Ten patients with a mean (±SD) Pao(2)/Fio(2) of 171 ± 86 mmHg were included. After a switch from pressure-controlled ventilation to adaptive support ventilation, respiratory rate declined (from 31 ± 5 to 21 ± 6 breaths/min; difference = 10 breaths/min, 95% CI 3-17 breaths/min, P = 0.008) and V(T) increased (from 6.5 ± 0.8 to 9.0 ± 1.6 ml/kg predicted body weight; difference = 2.5 ml, 95% CI 0.4-4.6 ml/kg predicted body weight, P = 0.02). Pressure limitation corrected for the rise of V(T), but minute ventilation declined, forcing the user to switch back to pressure-controlled ventilation. Adaptive support ventilation, compared with pressure-controlled ventilation in an open lung strategy setting, delivers a lower respiratory rate-higher V(T) combination. Pressure limitation does correct for the rise of V(T), but leads to a decline in minute ventilation.

  14. EnviroAtlas - Residential vacancy rate by Census Tract for the Conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset portrays the vacancy rate for residential addresses for each Census Tract for each year from 2010-2014. Vacant buildings are included if...

  15. Impact of Rate Design Alternatives on Residential Solar Customer Bills. Increased Fixed Charges, Minimum Bills and Demand-based Rates

    Energy Technology Data Exchange (ETDEWEB)

    Bird, Lori [National Renewable Energy Lab. (NREL), Golden, CO (United States); Davidson, Carolyn [National Renewable Energy Lab. (NREL), Golden, CO (United States); McLaren, Joyce [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miller, John [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    With rapid growth in energy efficiency and distributed generation, electric utilities are anticipating stagnant or decreasing electricity sales, particularly in the residential sector. Utilities are increasingly considering alternative rates structures that are designed to recover fixed costs from residential solar photovoltaic (PV) customers with low net electricity consumption. Proposed structures have included fixed charge increases, minimum bills, and increasingly, demand rates - for net metered customers and all customers. This study examines the electricity bill implications of various residential rate alternatives for multiple locations within the United States. For the locations analyzed, the results suggest that residential PV customers offset, on average, between 60% and 99% of their annual load. However, roughly 65% of a typical customer's electricity demand is non-coincidental with PV generation, so the typical PV customer is generally highly reliant on the grid for pooling services.

  16. Ventilation rate in equilibrium factor measurements with solid state nuclear track detectors (SSNTD)

    International Nuclear Information System (INIS)

    Gil, L.R.; Leitao, R.M.S.; Marques, A.; Rivera, A.

    1994-08-01

    Ventilation rate values are calculated from track density measurements in solid state nuclear track detectors (SSNTD), both when ventilation is the main cause of radioactive disequilibrium in radon progeny and when it shares importance with other agents. The method consists in exposing a SSNTD of high intrinsic efficiency (CR-39) in filtered and unfiltered conditions and, in addition, covered with a thin Aluminium foil, to stop alpha particles from 218 Po and 222 Rn. No calibrations are required but, when necessary, independent measurements of the loss rates of radioactivity to aerosol and to walls have to perform. Ventilation rates depend upon geometry detection efficiencies for alpha particles, here obtained by Monte Carlo simulation, taking into account the space distribution of emission positions. This may lead to sizeable corrections in ventilation and equilibrium factor values. Since geometric detection efficiencies depend upon alpha-particle ranges in air, the influences of barometric variables are also discussed. (author). 7 refs

  17. Low home ventilation rate in combination with moldy odor from the building structure increase the risk for allergic symptoms in children

    DEFF Research Database (Denmark)

    Hägerhed-Engman, L.; Sigsgaard, T.; Samuelson, I.

    2009-01-01

    There are consistent findings on associations between asthma and allergy symptoms and residential mold and moisture. However, definitions of 'dampness' in studies are diverse because of differences in climate and building construction. Few studies have estimated mold problems inside the building...... ventilation rate in combination with moldy odor along the skirting board further increased the risk for three out of four studied outcomes, indicating that the ventilation rate is an effect modifier for indoor pollutants.This study showed that mold odor at the skirting board level is strongly associated...... with allergic symptoms among children. Such odor at that specific place can be seen as a proxy for some kind of hidden moisture or mold problem in the building structure, such as the foundation or wooden ground beam. In houses with odor along the skirting board, dismantling of the structure is required...

  18. The declined levels of inflammatory cytokines related with weaning rate during period of septic patients using ventilators.

    Science.gov (United States)

    Yang, Chao-Huei; Hsiao, Jung-Lung; Wu, Ming-Feng; Lu, Mei-Hua; Chang, Hui-Ming; Ko, Wang-Sheng; Chiou, Ya-Ling

    2018-02-01

    Approximately 50% of patients with sepsis-induced acute lung injury and acute respiratory distress syndrome require mechanical ventilation. Patients with extended mechanical ventilator use routinely develop reinfections, which increases hospital stay, mortality, and health care cost. Some studies have pointed out inflammatory factors concentrations can affect ventilator weaning, but do not indicate changed inflammatory factors related to ventilator weaning during using ventilators. This study aimed to investigate during period of septic patients using ventilators, the inflammatory cytokines concentrations related with weaning rate. Blood was collected from 35 septic patients before and during ventilator use on days 1, 7, 14, and 21 (or weaning). 58.3% (N = 20) of septic patients with mechanical ventilators were weaned successfully within 21 days (ventilator weaned group, VW), 16.7% (N = 6) did not wean within 21 days (ventilator dependent group, VD), and 25% died (death group) in hospital. Before ventilator use, higher C-reactive protein (CRP), IL-6, and IL-8 levels were measured in the death group than in all other groups (P ventilator use, CRP, IL-6, and IL-8 concentrations declined significantly in VW and VD patients (P ventilators weaning successfully such as disease control, nutritional status, and so on. The declined levels of serum inflammatory cytokines, especially IL-6, improved inflammation status might be one factor of successfully weaning during septic patients on ventilators. © 2016 John Wiley & Sons Ltd.

  19. Effects of Classroom Ventilation Rate and Temperature on Students' Test Scores.

    Directory of Open Access Journals (Sweden)

    Ulla Haverinen-Shaughnessy

    Full Text Available Using a multilevel approach, we estimated the effects of classroom ventilation rate and temperature on academic achievement. The analysis is based on measurement data from a 70 elementary school district (140 fifth grade classrooms from Southwestern United States, and student level data (N = 3109 on socioeconomic variables and standardized test scores. There was a statistically significant association between ventilation rates and mathematics scores, and it was stronger when the six classrooms with high ventilation rates that were indicated as outliers were filtered (> 7.1 l/s per person. The association remained significant when prior year test scores were included in the model, resulting in less unexplained variability. Students' mean mathematics scores (average 2286 points were increased by up to eleven points (0.5% per each liter per second per person increase in ventilation rate within the range of 0.9-7.1 l/s per person (estimated effect size 74 points. There was an additional increase of 12-13 points per each 1°C decrease in temperature within the observed range of 20-25°C (estimated effect size 67 points. Effects of similar magnitude but higher variability were observed for reading and science scores. In conclusion, maintaining adequate ventilation and thermal comfort in classrooms could significantly improve academic achievement of students.

  20. Effects of Classroom Ventilation Rate and Temperature on Students' Test Scores.

    Science.gov (United States)

    Haverinen-Shaughnessy, Ulla; Shaughnessy, Richard J

    2015-01-01

    Using a multilevel approach, we estimated the effects of classroom ventilation rate and temperature on academic achievement. The analysis is based on measurement data from a 70 elementary school district (140 fifth grade classrooms) from Southwestern United States, and student level data (N = 3109) on socioeconomic variables and standardized test scores. There was a statistically significant association between ventilation rates and mathematics scores, and it was stronger when the six classrooms with high ventilation rates that were indicated as outliers were filtered (> 7.1 l/s per person). The association remained significant when prior year test scores were included in the model, resulting in less unexplained variability. Students' mean mathematics scores (average 2286 points) were increased by up to eleven points (0.5%) per each liter per second per person increase in ventilation rate within the range of 0.9-7.1 l/s per person (estimated effect size 74 points). There was an additional increase of 12-13 points per each 1°C decrease in temperature within the observed range of 20-25°C (estimated effect size 67 points). Effects of similar magnitude but higher variability were observed for reading and science scores. In conclusion, maintaining adequate ventilation and thermal comfort in classrooms could significantly improve academic achievement of students.

  1. Effects of Classroom Ventilation Rate and Temperature on Students’ Test Scores

    Science.gov (United States)

    2015-01-01

    Using a multilevel approach, we estimated the effects of classroom ventilation rate and temperature on academic achievement. The analysis is based on measurement data from a 70 elementary school district (140 fifth grade classrooms) from Southwestern United States, and student level data (N = 3109) on socioeconomic variables and standardized test scores. There was a statistically significant association between ventilation rates and mathematics scores, and it was stronger when the six classrooms with high ventilation rates that were indicated as outliers were filtered (> 7.1 l/s per person). The association remained significant when prior year test scores were included in the model, resulting in less unexplained variability. Students’ mean mathematics scores (average 2286 points) were increased by up to eleven points (0.5%) per each liter per second per person increase in ventilation rate within the range of 0.9–7.1 l/s per person (estimated effect size 74 points). There was an additional increase of 12–13 points per each 1°C decrease in temperature within the observed range of 20–25°C (estimated effect size 67 points). Effects of similar magnitude but higher variability were observed for reading and science scores. In conclusion, maintaining adequate ventilation and thermal comfort in classrooms could significantly improve academic achievement of students. PMID:26317643

  2. Summary of human responses to ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Seppanen, Olli A.; Fisk, William J.

    2004-06-01

    The effects of ventilation on indoor air quality and health is a complex issue. It is known that ventilation is necessary to remove indoor generated pollutants from indoor air or dilute their concentration to acceptable levels. But, as the limit values of all pollutants are not known, the exact determination of required ventilation rates based on pollutant concentrations and associated risks is seldom possible. The selection of ventilation rates has to be based also on epidemiological research (e.g. Seppanen et al., 1999), laboratory and field experiments (e.g. CEN 1996, Wargocki et al., 2002a) and experience (e.g. ECA 2003). Ventilation may also have harmful effects on indoor air quality and climate if not properly designed, installed, maintained and operated as summarized by Seppdnen (2003). Ventilation may bring indoors harmful substances that deteriorate the indoor environment. Ventilation also affects air and moisture flow through the building envelope and may lead to moisture problems that deteriorate the structures of the building. Ventilation changes the pressure differences over the structures of building and may cause or prevent the infiltration of pollutants from structures or adjacent spaces. Ventilation is also in many cases used to control the thermal environment or humidity in buildings. Ventilation can be implemented with various methods which may also affect health (e.g. Seppdnen and Fisk, 2002, Wargocki et al., 2002a). In non residential buildings and hot climates, ventilation is often integrated with air-conditioning which makes the operation of ventilation system more complex. As ventilation is used for many purposes its health effects are also various and complex. This paper summarizes the current knowledge on positive and negative effects of ventilation on health and other human responses. The focus of the paper is on office-type working environment and residential buildings. In the industrial premises the problems of air quality are usually

  3. A preliminary study on the association between ventilation rates in classrooms and student performance.

    Science.gov (United States)

    Shaughnessy, R J; Haverinen-Shaughnessy, U; Nevalainen, A; Moschandreas, D

    2006-12-01

    Poor conditions leading to substandard indoor air quality (IAQ) in classrooms have been frequently cited in the literature over the past two decades. However, there is limited data linking poor IAQ in the classrooms to student performance. Whereas, it is assumed that poor IAQ results in reduced attendance and learning potential, and subsequent poor student performance, validating this hypothesis presents a challenge in today's school environment. This study explores the association between student performance on standardized aptitude tests that are administered to students on a yearly basis, to classroom carbon dioxide (CO2) concentrations, which provide a surrogate of ventilation being provided to each room. Data on classroom CO2 concentrations (over a 4-5 h time span within a typical school day) were recorded in fifth grade classrooms in 54 elementary schools within a school district in the USA. Results from this preliminary study yield a significant (P classroom-level ventilation rate and test results in math. They also indicate that non-linear effects may need to be considered for better representation of the association. A larger sample size is required in order to draw more definitive conclusions. Practical Implications Future studies could focus on (1) gathering more evidence on the possible association between classroom ventilation rates and students' academic performance; (2) the linear/non-linear nature of the association; and (3) whether it is possible to detect 'no observed adverse effect level' for adequate ventilation with respect to academic performance in schools. All of this information could be used to improve guidance and take regulatory actions to ensure adequate ventilation in schools. The high prevalence of low ventilation rates, combined with the growing evidence of the positive impact that sufficient ventilation has on human performance, suggests an opportunity for improving design and management of school facilities.

  4. Metronome improves compression and ventilation rates during CPR on a manikin in a randomized trial.

    Science.gov (United States)

    Kern, Karl B; Stickney, Ronald E; Gallison, Leanne; Smith, Robert E

    2010-02-01

    We hypothesized that a unique tock and voice metronome could prevent both suboptimal chest compression rates and hyperventilation. A prospective, randomized, parallel design study involving 34 pairs of paid firefighter/emergency medical technicians (EMTs) performing two-rescuer CPR using a Laerdal SkillReporter Resusci Anne manikin with and without metronome guidance was performed. Each CPR session consisted of 2 min of 30:2 CPR with an unsecured airway, then 4 min of CPR with a secured airway (continuous compressions at 100 min(-1) with 8-10 ventilations/min), repeated after the rescuers switched roles. The metronome provided "tock" prompts for compressions, transition prompts between compressions and ventilations, and a spoken "ventilate" prompt. During CPR with a bag/valve/mask the target compression rate of 90-110 min(-1) was achieved in 5/34 CPR sessions (15%) for the control group and 34/34 sessions (100%) for the metronome group (pmetronome or control group during CPR with a bag/valve/mask. During CPR with a bag/endotracheal tube, the target of both a compression rate of 90-110 min(-1) and a ventilation rate of 8-11 min(-1) was achieved in 3/34 CPR sessions (9%) for the control group and 33/34 sessions (97%) for the metronome group (pMetronome use with the secured airway scenario significantly decreased the incidence of over-ventilation (11/34 EMT pairs vs. 0/34 EMT pairs; pmetronome was effective at directing correct chest compression and ventilation rates both before and after intubation. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  5. Effects of respiratory rate and tidal volume on gas exchange in total liquid ventilation.

    Science.gov (United States)

    Bull, Joseph L; Tredici, Stefano; Fujioka, Hideki; Komori, Eisaku; Grotberg, James B; Hirschl, Ronald B

    2009-01-01

    Using a rabbit model of total liquid ventilation (TLV), and in a corresponding theoretical model, we compared nine tidal volume-respiratory rate combinations to identify a ventilator strategy to maximize gas exchange, while avoiding choked flow, during TLV. Nine different ventilation strategies were tested in each animal (n = 12): low [LR = 2.5 breath/min (bpm)], medium (MR = 5 bpm), or high (HR = 7.5 bpm) respiratory rates were combined with a low (LV = 10 ml/kg), medium (MV = 15 ml/kg), or high (HV = 20 ml/kg) tidal volumes. Blood gases and partial pressures, perfluorocarbon gas content, and airway pressures were measured for each combination. Choked flow occurred in all high respiratory rate-high volume animals, 71% of high respiratory rate-medium volume (HRMV) animals, and 50% of medium respiratory rate-high volume (MRHV) animals but in no other combinations. Medium respiratory rate-medium volume (MRMV) resulted in the highest gas exchange of the combinations that did not induce choke. The HRMV and MRHV animals that did not choke had similar or higher gas exchange than MRMV. The theory predicted this behavior, along with spatial and temporal variations in alveolar gas partial pressures. Of the combinations that did not induce choked flow, MRMV provided the highest gas exchange. Alveolar gas transport is diffusion dominated and rapid during gas ventilation but is convection dominated and slow during TLV. Consequently, the usual alveolar gas equation is not applicable for TLV.

  6. Measurement of the Air Chance Rate and Ventilation Characteristics During Short Term Transient Phenomena

    DEFF Research Database (Denmark)

    Heiselberg, Per Kvols; Perino, M.

    2004-01-01

    Different measurement procedures are available for the experimental assessment of air change rates inside ventilated enclosures. These mainly consist of tracer gas techniques and can usually be applied to steady-state or moderately transient conditions and when a continous mixing of the indoor air...... ventilation. The results are critically compared with the air flow rates assessed through anemometric measurements. The measurement features, limitations, shortcomings and uncertainties are also discussed....... is assured throughout the test. However, due to the relatively slow response of the gas analysers, none of these procedures can usually be applied to fast transient phenomena that last 15 minutes or less. Moreover in many cases of natural ventilation strategies, the continuous mixing of the indoor air would...

  7. Measurement and Modelling of Air Flow Rate in a Naturally Ventilated Double Skin Facade

    DEFF Research Database (Denmark)

    Heiselberg, Per; Kalyanova, Olena; Jensen, Rasmus Lund

    2008-01-01

    Air flow rate in a naturally ventilated double skin façade (DSF) is extremely difficult to measure due to the stochastic nature of wind, and as a consequence non-uniform and dynamic flow conditions. This paper describes the results of two different methods to measure the air flow in a full...... by the thermal simulation program, BSim, based on measured weather boundary conditions are compared to the measured air temperature, temperature gradient and mass flow rate in the DSF cavity. The results show that it is possible to predict the temperature distribution and airflow in the DSF although some......-scale outdoor test facility with a naturally ventilated double skin façade. Although both methods are difficult to use under such dynamic air flow conditions, they show reasonable agreement and can be used for experimental validation of numerical models of natural ventilation air flow in DSF. Simulations...

  8. Probabilistic estimation of residential air exchange rates for population-based human exposure modeling

    Science.gov (United States)

    Residential air exchange rates (AERs) are a key determinant in the infiltration of ambient air pollution indoors. Population-based human exposure models using probabilistic approaches to estimate personal exposure to air pollutants have relied on input distributions from AER meas...

  9. Modeling ventilation rates in bedrooms based on building characteristics and occupant behavior

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Toftum, Jørn; Clausen, Geo

    2011-01-01

    Air change rate (ACR) data obtained from the bedrooms of 500 Danish children and presented in an earlier paper were analyzed in more detail. Questionnaires distributed to the families, home inspections and interviews with the parents provided information about a broad range of residential charact...

  10. Effect of ventilation rate and board loading on formaldehyde concentration : a critical review of the literature

    Science.gov (United States)

    George E. Myers

    1984-01-01

    A critical literature review has been carried out on the influence of ventilation rate (N, hr.-1) and board loading (L, m2/m3) on steady state formaldehyde concentrations (Cs, ppm) resulting from particleboard and plywood emissions. Large differences exist among boards in the extent to which their formaldehyde concentrations change with N or L in laboratory chambers....

  11. Emission of formaldehyde by particleboard : effect of ventilation rate and loading on air-contamination levels

    Science.gov (United States)

    George E. Myers; Muneo Nagaoka

    1981-01-01

    Dynamic tests for determining the formaldehyde emission behavior of UF-bonded boards involve the measurement of formaldehyde concentration in the air within a vessel which contains a specified board loading L (m2 of board area per m3 of vessel free volume) and is being ventilated at a specified air exchange rate N (hr.-1). Such tests constitute a primary...

  12. A Technical Basis for Employing Facility Ventilation Air Exchange Rates in the Decision to Downpost

    CERN Document Server

    Mantooth, D S

    2001-01-01

    Utilizing the ventilation exchange rate as a basis for the decision to downpost a location within a facility from an airborne radiation area (ARA) based on initial air count(DAC). Not used in the case of a confirmed or suspected contamination release.

  13. Review of existing residential energy efficiency certification and rating programs

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, P.L.

    1986-11-01

    This report was prepared for the Office of Buildings and Community Systems, US Department of Energy (DOE). The principal objective of the report is to present information on existing Home Energy Rating Systems (HERS) and their features. Much of the information in this report updates a 1982 report (PNL-4359), also prepared by the Pacific Northwest Laboratory (PNL) for DOE. Secondary objectives of the report are to qualitatively examine the benefits and costs of HERS programs, review survey results on the attitudes of various user groups toward the programs, and discuss selected design and implementation issues.

  14. Ventilation rates indicate stress-coping styles in Nile tilapia

    Indian Academy of Sciences (India)

    increase and act in an active (e.g. high-level aggression or avoidance) manner in ... hand, VR can be linked to metabolic rates (Alvarenga and. Volpato 1995). ... dry pellets (22% protein, Purina® Ltd, Campinas, SP, Brazil). Leftover food was ... food offered, but this technique guaranteed fish were able to eat until satiation.

  15. Development of a new energy efficiency rating system for existing residential buildings

    International Nuclear Information System (INIS)

    Koo, Choongwan; Hong, Taehoon; Lee, Minhyun; Seon Park, Hyo

    2014-01-01

    Building energy efficiency rating systems have been established worldwide to systematically manage the energy consumption of existing buildings. This study aimed to develop a new energy efficiency rating system for existing residential buildings from two perspectives: (i) establishment of reasonable and fair criteria for the building energy efficiency rating system; and (ii) establishment of comparative incentive and penalty programs to encourage the voluntary participation of all residents in the energy saving campaign. Based on the analysis of the conventional energy efficiency rating system for existing residential buildings, this study was conducted in five steps: (i) data collection and analysis; (ii) correlation analysis between the household size and the CO 2 emission density (i.e., CO 2 emission per unit area); (iii) cluster formation based on results of the correlation analysis using a decision tree; (iv) establishment of a new energy efficiency rating system for existing buildings; and (v) establishment of incentive and penalty programs using advanced case-based reasoning. The proposed system can allow a policymaker to establish a reasonable and fair energy efficiency rating system for existing residential buildings and can encourage the voluntary participation of all residents in the energy saving campaign. - Highlights: • A new energy efficiency rating system for the residential building was developed. • The incentive and penalty programs were established using an advanced CBR model. • The new system was established using reasonable and fair standards. • It allows all residents to voluntarily participate in the energy saving campaign. • It can be applied to any country or sector in the global environment

  16. Indoor radon concentration and its possible dependence on ventilation rate and flooring type

    International Nuclear Information System (INIS)

    Ashok, G. V.; Nagaiah, N.; Shiva Prasad, N. G.

    2012-01-01

    The results of radon concentration measurements carried out in dwellings with natural ventilation for 1 y in Bangalore are reported. Measurements, covering three sessions of the day (morning, afternoon, night) were performed two times in a month for 1 y at a fixed place of each dwelling at a height of 1 m above the ground surface in selected dwellings. The low-level radon detection system (LLRDS), an active method, was used for the estimation of radon concentration. The measurements were aimed to understand the diurnal variation and the effect of ventilation rate and flooring type on indoor radon concentration. The geometric mean (±geometric standard deviation) of indoor radon concentration from about 500 measurements carried out in 20 dwellings is found to be 25.4 ±1.54 Bq m -3 . The morning, afternoon and night averages were found to be 42.6 ±2.05, 15.3 ±2.18 and 28.5 ±2.2 Bq m -3 , respectively. The approximate natural ventilation rates of the dwellings were calculated using the PHPAIDA-the on-line natural ventilation, mixed mode and air infiltration rate calculation algorithm and their effects on indoor radon concentrations were studied. The inhalation dose and the lung cancer risk due to indoor radon exposure were found to be 0.66 mSv y -1 and 11.9 per 10 6 persons, respectively. The gamma exposure rate was also measured in all the dwellings and its correlation with the inhalation dose rate was studied. (authors)

  17. Measurement of Air Flow Rate in a Naturally Ventilated Double Skin Facade

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Jensen, Rasmus Lund; Heiselberg, Per

    2007-01-01

    Air flow rate in a naturally ventilated space is extremely difficult to measure due to the stochastic nature of wind, and as a consequence non-uniform and dynamic flow conditions. This paper describes three different methods to measure the air flow in a full-scale outdoor test facility...... with a naturally ventilated double skin façade. In the first method, the air flow in the cavity is estimated on the basis of six measured velocity profiles. The second method is represented by constant injection of tracer gas and in the third method a measured relation in the laboratory is used to estimate...... the flow rate on the basis of continues measurement of the pressure difference between the surface pressure at the opening and inside pressure of the double skin façade. Although all three measurement methods are difficult to use under such dynamic air flow conditions, two of them show reasonable agreement...

  18. The Impact of an Extensive Usage of Controlled Natural Ventilation in the Residential Sector on Large-Scale Energy Systems

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan

    The energy situation in the world is becoming alarming. The demand of electricity continues to grow whereas the means of production remain limited. In addition, the electricity generation in the world is mostly based on fossil fuels such as coal, oil and natural gas. Only a small share of the total...... to the atmosphere. On the other hand, the efficiency of the end-use energy consumption is also fundamental to decrease the electricity production thus to lower the emission of greenhouse gases. Thereby, the building sector is a very important target because it consumes approximately one quarter of the total annual...... be reflected in the reduction of the electricity production. The objective of the thesis is to show realistic benefits of utilizing natural ventilation at an extensive manner onto large-scale scenarios such as a national scenario by using a model of natural ventilation developed here. To do so, a building...

  19. Experiments to Evaluate and Implement Passive Tracer Gas Methods to Measure Ventilation Rates in Homes

    Energy Technology Data Exchange (ETDEWEB)

    Lunden, Melissa [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Heredia, Elizabeth [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cohn, Sebastian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dickerhoff, Darryl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Noris, Federico [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Logue, Jennifer [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hotchi, Toshifumi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, Max H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-10-01

    This report documents experiments performed in three homes to assess the methodology used to determine air exchange rates using passive tracer techniques. The experiments used four different tracer gases emitted simultaneously but implemented with different spatial coverage in the home. Two different tracer gas sampling methods were used. The results characterize the factors of the execution and analysis of the passive tracer technique that affect the uncertainty in the calculated air exchange rates. These factors include uncertainties in tracer gas emission rates, differences in measured concentrations for different tracer gases, temporal and spatial variability of the concentrations, the comparison between different gas sampling methods, and the effect of different ventilation conditions.

  20. Radon concentration; source strength and ventilation rate: how well do we know the connections

    International Nuclear Information System (INIS)

    Ring, J.W.

    1984-01-01

    The simple steady state model which is frequently used to relate radon concentration (C), source strength (S) and ventilation rate (l/'tau') is expressed in the equation C=S'tau'. The assumptions of this model are given and their validity explored in this paper. In particular the assumption of steady state conditions fot the ventilation rate is studied experimentally in a simple one chamber building, the Solar Classroom at Hamilton College. Even in this simple case variations are found of a factor of three or more in 'tau' which can be attributed to wind and stack effects. Studies of other houses are cited which show that variations of 'tau' between houses can be as large as factor of sixty or more. The implications of these results for developing ventilation standards or for mitigating the indoor radon problem are suggested. Individual houses can be understood and mitigating strategies implemented in them on a case by case basis but a statistical treatment of houses in general does not seem to be a fruitful approach. (Author)

  1. Experimental verification of air flow rate measurement for representative isokinetic air sampling in ventilation stacks

    International Nuclear Information System (INIS)

    Okruhlica, P.; Mrtvy, M.; Kopecky, Z.

    2009-01-01

    Nuclear facilities are obliged to monitor their discharge's influence on environment. Main monitored factions in NPP's ventilation stacks are usually noble gasses, particulates and iodine. These factions are monitored in air sampled from ventilation stack by means of sampling rosette and bypass followed with on-line measuring monitors and balance sampling devices with laboratory evaluations. Correct air flow rate measurement and representative iso-kinetic air sampling system is essential for physical correct and metrological accurate evaluation of discharge influence on environment. Pairs of measuring sensors (Anemometer, pressure gauge, thermometer and humidity meter) are symmetrically placed in horizontal projection of stack on positions based on measured air flow velocity distribution characteristic, Analogically diameter of sampling rosette nozzles and their placement in the middle of 6 - 7 annuluses are calculated for assurance of representative iso-kinetic sampling. (authors)

  2. Experimental verification of air flow rate measurement for representative isokinetic air sampling in ventilation stacks

    International Nuclear Information System (INIS)

    Okruhlica, P.; Mrtvy, M.; Kopecky, Z.

    2008-01-01

    Nuclear facilities are obliged to monitor their discharge's influence on environment. Main monitored factions in NPP's ventilation stacks are usually noble gasses, particulates and iodine. These factions are monitored in air sampled from ventilation stack by means of sampling rosette and bypass followed with on-line measuring monitors and balance sampling devices with laboratory evaluations. Correct air flow rate measurement and representative iso-kinetic air sampling system is essential for physical correct and metrological accurate evaluation of discharge influence on environment. Pairs of measuring sensors (Anemometer, pressure gauge, thermometer and humidity meter) are symmetrically placed in horizontal projection of stack on positions based on measured air flow velocity distribution characteristic, Analogically diameter of sampling rosette nozzles and their placement in the middle of 6- 7 annuluses are calculated for assurance of representative iso-kinetic sampling. (authors)

  3. Comparison of a Constant Air Volume (CAV) and a Demand Controlled Ventilation (DCV) System in a Residential Building

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig; Nielsen, Toke Rammer; Topp, Claus

    2008-01-01

    hygroscopic properties on indoor climate and energy consumption was investigated for the two systems. Dynamic simulations of the studio apartment were carried out in the program WUFI+ with weather data from Copenhagen including outside temperature end relative humidity. For the non-hygroscopic case...... it was found that the energy consumption for heating and operating the ventilation system could be reduced by respectively 8.0% and 10.6 % in the case of DCV without negative impact on the indoor climate. Including the hygroscopic properties of the materials resulted in a reduction of the energy consumption...

  4. Respiratory induced heart rate variability during slow mechanical ventilation Marker to exclude brain death patients

    Czech Academy of Sciences Publication Activity Database

    Jurák, Pavel; Halámek, Josef; Vondra, Vlastimil; Kružliak, P.; Šrámek, V.; Cundrle, I.; Leinveber, P.; Adamek, M.; Zvoníček, V.

    2017-01-01

    Roč. 129, 7-8 (2017), s. 251-258 ISSN 0043-5325 R&D Projects: GA ČR GAP103/11/0933; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01; GA MZd NS10105 Institutional support: RVO:68081731 Keywords : critical illness * sedation * brain death * respiratory rate variability * heart rate variability * mechanical ventilation Subject RIV: FS - Medical Facilities ; Equipment OBOR OECD: Medical engineering Impact factor: 0.974, year: 2016

  5. Influence of input data on airflow network accuracy in residential buildings with natural wind- and stack-driven ventilation

    Institute of Scientific and Technical Information of China (English)

    Krzysztof Arendt; Marek Krzaczek; Jacek Tejchman

    2017-01-01

    The airflow network (AFN) modeling approach provides an attractive balance between the accuracy and computational demand for naturally ventilated buildings. Its accuracy depends on input parameters such as wind pressure and opening discharge coefficients. In most cases, these parameters are obtained from secondary sources which are solely representative for very simplified buildings, i.e. for buildings without facade details. Although studies comparing wind pressure coefficients or discharge coefficients from different sources exist, the knowledge regarding the effect of input data on AFN is still poor. In this paper, the influence of wind pressure data on the accuracy of a coupled AFN-BES model for a real building with natural wind- and stack-driven ventilation was analyzed. The results of 8 computation cases with different wind pressure data from secondary sources were compared with the measured data. Both the indoor temperatures and the airflow were taken into account. The outcomes indicated that the source of wind pressure data had a significant influence on the model performance.

  6. Methodology for determination of radon-222 production rate of residential building and experimental verification

    International Nuclear Information System (INIS)

    Tung, Thomas C.W.; Niu, J.L.; Burnett, J.; Lau, Judy O.W.

    2005-01-01

    Indoor radon concentration is mainly associated with the radon production rate of building material, ventilation rate, and the outdoor radon concentrations. Radon production rate of a room is defined as the sum of the products of the radon emanation rates and the exposed areas of the materials. Since the selection of the building materials and the exposed areas are different from room to room, it makes the radon production rate of homes fall in a wide range. Here, the radon production rate of a room is suggested to be quantified by a sealing method, in which the systematic radon growth curve is obtained. The radon production rate of the room can be determined from the initial slope of the growth curve. Three rooms at different homes in Hong Kong were selected in the study for verifying the methodology. The uncertainty characterized by data scatter arisen from the coupling effect of the leakage rate and outdoor radon was also included in the discussion. During the measurements, no occupant was allowed into the home. No mechanical ventilation was involved in the measurement. The indoor and outdoor radon concentrations of the sampled homes were monitored simultaneously and lasted for more than three days. The radon production rates and the uncertainties of three rooms at Homes 1, 2, and 3 were found to be 232.8, 46.0, 414.6, and 20.3, 9.4, 59.2Bqh -1 , respectively. The approach is valid when the air leakage rate of the room is controlled below 0.1h -1

  7. Antibiotic consumption and ventilator-associated pneumonia rates, some parallelism but some discrepancies.

    Science.gov (United States)

    Nora, David; Póvoa, Pedro

    2017-11-01

    Ventilator-associated pneumonia (VAP) is a common infection in intensive care units (ICUs) but its clinical definition is neither sensitive nor specific and lacks accuracy and objectivity. New defining criteria were proposed in 2013 by the National Healthcare Safety Network (NHSN) in order to more accurately conduct surveillance and track prevention progress. Although there is a consistent trend towards a decrease in VAP incidence during the last decade, significant differences in VAP rates have been reported and are persistently lower in NHSN and other American reports (0.0 to 4.4 VAP per 1,000 ventilator-days in 2012) compared to the European Centre for Disease Prevention and Control (ECDC) data (10 VAP per 1,000 ventilator-days in 2014). In the United States, VAP has been proposed as an indicator of quality of care in public reporting, and the threat of financial penalties for this diagnosis has put pressure on hospitals to minimize VAP rates that may lead to artificial lower values, independently of patient care. Although prevention bundles may contribute for encouraging reductions in VAP incidence, both pathophysiologic and epidemiologic factors preclude a zero-VAP rate. It would be expected from the trend of reduction of VAP incidence that the consumption of antibiotics would also decrease in particular in those hospitals with lowest VAP rates. However, ICU reports show a steadily use of antibiotics for nosocomial pneumonia in 15% of patients and both ECDC and NHSN data on antibiotic consumption showed no significant trend. Knowledge of bacterial epidemiology and resistance profiles for each ICU has great relevance in order to understand trends of antibiotic use. The new NHSN criteria provide a more objective and quantitative data based VAP definition, including an antibiotic administration criterion, allowing, in theory, a more comprehensive assessment and a reportable benchmark of the observed VAP and antibiotic consumption variability.

  8. Increasing rate of middle ear ventilation tube insertion in children in denmark

    DEFF Research Database (Denmark)

    Djurhuus, Bjarki Ditlev; Skytthe, Axel; Christensen, Kaare

    2014-01-01

    ventilation tube insertions distributed among 269,459 different children were identified. From 1997 to 2010 the age standardized incidence rate in 0-15-year-olds increased from 26 to 40 per 1000 person years with an estimated annual increase of 2.0% (95% confidence interval 1.9-2.1%). The largest increase...... in incidence rate was found in 1-year-olds with an annual increase of 4.5% (95% confidence interval 4.4-4.6%). Age-specific incidence rates remained at maximum around the age of 14 months throughout the period. The cumulative incidence proportion for the 2010 birth cohort by the time they reach the age of 5......OBJECTIVE: To study the incidence rates of middle ear ventilation tube insertion in children aged 0 to 15 years in Denmark from 1997 to 2010. METHODS: Using two national registers, the Danish National Health Service Register and the Danish National Patient Register, practically all cases of middle...

  9. Impact of the humidification device on intubation rate during noninvasive ventilation with ICU ventilators: results of a multicenter randomized controlled trial.

    Science.gov (United States)

    Lellouche, François; L'Her, E; Abroug, F; Deye, N; Rodriguez, P O; Rabbat, A; Jaber, S; Fartoukh, M; Conti, G; Cracco, C; Richard, J C; Ricard, J D; Mal, H; Mentec, H; Loisel, F; Lacherade, J C; Taillé, S; Brochard, L

    2014-02-01

    The use of heat and moisture exchangers (HME) during noninvasive ventilation (NIV) can increase the work of breathing, decrease alveolar ventilation, and deliver less humidity in comparison with heated humidifiers (HH). We tested the hypothesis that the use of HH during NIV with ICU ventilators for patients with acute respiratory failure would decrease the rate of intubation (primary endpoint) as compared with HME. We conducted a multicenter randomized controlled study in 15 centers. After stratification by center and type of respiratory failure (hypoxemic or hypercapnic), eligible patients were randomized to receive NIV with HH or HME. Of the 247 patients included, 128 patients were allocated to the HME group and 119 to the HH group. Patients were comparable at baseline. The intubation rate was not significantly different: 29.7% in the HME group and 36.9% in the HH group (p = 0.28). PaCO2 did not significantly differ between the two arms, even in the subgroup of hypercapnic patients. No significant difference was observed for NIV duration, ICU and hospital LOS, or ICU mortality (HME 14.1 vs. HH 21.5%, p = 0.18). In this study, the short-term physiological benefits of HH in comparison with HME during NIV with ICU ventilators were not observed, and no difference in intubation rate was found. The physiologic effects may have been obscured by leaks or other important factors in the clinical settings. This study does not support the recent recommendation favoring the use of HH during NIV with ICU ventilators.

  10. Ventilation Control of Volatile Organic Compounds in New U.S. Homes: Results of a Controlled Field Study in Nine Residential Units

    Energy Technology Data Exchange (ETDEWEB)

    Willem, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hult, Erin L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hotchi, Toshifumi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Russell, Marion L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Maddalena, Randy L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-01-01

    In order to optimize strategies to remove airborne contaminants in residences, it is necessary to determine how contaminant concentrations respond to changes in the air exchange rate. The impact of air exchange rate on the indoor concentrations of 39 target volatile organic compounds (VOCs) was assessed by measuring air exchange rates and VOC concentrations at three ventilation settings in nine residences. Active sampling methods were used for VOC concentration measurements, and passive perfluorocarbon tracer gas emitters with active sampling were used to determine the overall air exchange rate corresponding to the VOC measurements at each ventilation setting. The concentration levels and emission rates of the target VOCs varied by as much as two orders of magnitude across sites. Aldehyde and terpene compounds were typically the chemical classes with highest concentrations, followed by alkanes, aromatics, and siloxanes. For each home, VOC concentrations tended to decrease as the air exchange rate was increased, however, measurement uncertainty was significant. The indoor concentration was inversely proportional to air exchange rate for most compounds. For a subset of compounds including formaldehyde, however, the indoor concentration exhibited a non-linear dependence on the timescale for air exchange

  11. Ventilation Control of Volatile Organic Compounds in New U.S. Homes: Results of a Controlled Field Study in Nine Residential Units

    Energy Technology Data Exchange (ETDEWEB)

    Willem, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hult, Erin L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hotchi, Toshifumi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Russell, Marion L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Maddalena, Randy L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-01-23

    In order to optimize strategies to remove airborne contaminants in residences, it is necessary to determine how contaminant concentrations respond to changes in the air exchange rate. The impact of air exchange rate on the indoor concentrations of 39 target volatile organic compounds (VOCs) was assessed by measuring air exchange rates and VOC concentrations at three ventilation settings in nine residences. Active sampling methods were used for VOC concentration measurements, and passive perfluorocarbon tracer gas emitters with active sampling were used to determine the overall air exchange rate corresponding to the VOC measurements at each ventilation setting. The concentration levels and emission rates of the target VOCs varied by as much as two orders of magnitude across sites. Aldehyde and terpene compounds were typically the chemical classes with highest concentrations, followed by alkanes, aromatics, and siloxanes. For each home, VOC concentrations tended to decrease as the air exchange rate was increased, however, measurement uncertainty was significant. The indoor concentration was inversely proportional to air exchange rate for most compounds. For a subset of compounds including formaldehyde, however, the indoor concentration exhibited a non-linear dependence on the timescale for air exchange.

  12. A Prospective Study of Ventilation Rates and Illness Absence in California Office Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Eliseeva, Ekaterina A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Spears, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chan, Wanyu R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cohn, Sebastian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sullivan, Douglas P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fisk, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-10-07

    Background – This study investigated the associations of ventilation rates (VRs), estimated from indoor CO2 concentrations, in offices with the amount of respiratory infections, illness absences, and building-related health symptoms in occupants. Methods – Office buildings were recruited from three California climate zones. In one or more study spaces within each building, real-time logging sensors measured carbon dioxide, temperature, and relative humidity for one year. Ventilation rates were estimated using daily peak CO2 levels, and also using an alternative metric. Data on occupants and health outcomes were collected through web-based surveys every three months. Multivariate models were used to assess relationships between metrics of ventilation rate or CO2 and occupant outcomes. For all outcomes, negative associations were hypothesized with VR metrics, and positive associations with CO2 metrics. Results – Difficulty recruiting buildings and low survey response limited sample size and study power. In 16 studied spaces within 9 office buildings, VRs were uniformly high over the year, from twice to over nine times the California office VR standard (7 L/s or 15 cfm per person). VR and CO2 metrics had no statistically significant relationships with occupant outcomes, except for a small significantly positive association of the alternative VR metric with respiratory illness-related absence, contrary to hypotheses. Conclusions– The very high time-averaged VRs in the California office buildings studied presumably resulted from “economizer cycles” bringing in large volumes of outdoor air; however, in almost all buildings even the estimated minimum VRs supplied (without the economizer) substantially exceeded the minimum required VR. These high VRs may explain the absence of hypothesized relationships with occupant outcomes. Among uniformly high VRs, little variation in contaminant concentration and occupant effects would be expected. These findings may

  13. Numerical investigation on the gas entrainment rate on ventilated supercavity body

    Directory of Open Access Journals (Sweden)

    WuGang Yang

    2016-12-01

    Full Text Available The supercavitation technique provides a means of significantly increasing the velocity of an underwater vehicle. This technique involves essentially the creation of stable supercavity shape. The method of artificial ventilation is most effective for generating and dominating the supercavity. This paper focuses on the numerical simulation of flow field around three-dimensional body. The method is based on the multiphase computational fluid dynamics model combined with the turbulence model and the full cavity model. The fundamental similarity parameters of ventilated supercavity flows that include cavitation number, Froude number Fr, entrainment rate CQ, and drag coefficient Cx are all investigated numerically in the case of steady flow and gravity field. We discuss the following simulations results in three parts: (1 the variations of the cavitation number and the supercavity’s relative diameter with entrainment rate; (2 the drag coefficient versus the cavitation number; and (3 deformation of supercavity axis caused by gravitational effect for three different fixed three Froude numbers. In the full paper, we give the comparison results of the drag reduction ratio among numerical simulation and experiment conducted in hydrodynamic tunnel and towing tank, respectively. We summarize our discussion of gravitational effect on the axis deformation of supercavity as follows: in the case of smaller Froude number, the inclination of the cavity axis increases monotonously with increasing horizontal length and reaches its maximal value at the end of supercavity; this deformation can be almost completely negligible when the Froude number Fr is larger than 7.0. The comparisons with the experimental data in the hydrodynamic tunnel and the towing tank indicate that the present method is effective for predicting the flows around ventilated supercavity; that the numerical results is in good agreement with the experimental ones and that the maximal value of the

  14. Ventilation effectiveness

    CERN Document Server

    Mathisen, Hans Martin; Nielsen, Peter V; Moser, Alfred

    2004-01-01

    Improving the ventilation effectiveness allows the indoor air quality to be significantly enhanced without the need for higher air changes in the building, thereby avoiding the higher costs and energy consumption associated with increasing the ventilation rates. This Guidebook provides easy-to-understand descriptions of the indices used to mesure the performance of a ventilation system and which indices to use in different cases.

  15. Did residential electricity rates fall after retail competition? A dynamic panel analysis

    International Nuclear Information System (INIS)

    Swadley, Adam; Yücel, Mine

    2011-01-01

    A key selling point for the restructuring of electricity markets was the promise of lower prices. There is not much consensus in earlier studies on the effects of electricity deregulation in the U.S., particularly for residential customers. Part of the reason for not finding a consistent link with deregulation and lower prices was that the removal of transitional price caps led to higher prices. In addition, the timing of the removal of price caps coincided with rising fuel prices, which were passed on to consumers in a competitive market. Using a dynamic panel model, we analyze the effect of participation rates, fuel costs, market size, a rate cap and switch to competition for 16 states and the District of Columbia. We find that an increase in participation rates, price controls, a larger market, and high shares of hydro in electricity generation lower retail prices, while increases in natural gas and coal prices increase rates. We also find that retail competition makes the market more efficient by lowering the markup of retail prices over wholesale costs. The effects of a competitive retail electricity market are mixed across states, but generally appear to lower prices in states with high participation rates. - Highlights: ► We analyze the effects of retail competition in electricity markets on residential retail prices. ► Analysis carried out using a dynamic panel model; monthly data for 17 U.S. states. ► More customer participation and larger market lead to lower prices. ► Higher fuel costs increase retail prices, but with a lag. ► Retail competition leads to a more efficient electricity market.

  16. An analysis of representative heating load lines for residential HSPF ratings

    Energy Technology Data Exchange (ETDEWEB)

    Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-07-01

    This report describes an analysis to investigate representative heating loads for single-family detached homes using current EnergyPlus simulations (DOE 2014a). Hourly delivered load results are used to determine binned load lines using US Department of Energy (DOE) residential prototype building models (DOE 2014b) developed by Pacific Northwest National Laboratory (PNNL). The selected residential single-family prototype buildings are based on the 2006 International Energy Conservation Code (IECC 2006) in the DOE climate regions. The resulting load lines are compared with the American National Standards Institute (ANSI)/Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 210/240 (AHRI 2008) minimum and maximum design heating requirement (DHR) load lines of the heating seasonal performance factor (HSPF) ratings procedure for each region. The results indicate that a heating load line closer to the maximum DHR load line, and with a lower zero load ambient temperature, is more representative of heating loads predicted for EnergyPlus prototype residential buildings than the minimum DHR load line presently used to determine HSPF ratings. An alternative heating load line equation was developed and compared to binned load lines obtained from the EnergyPlus simulation results. The effect on HSPF of the alternative heating load line was evaluated for single-speed and two-capacity heat pumps, and an average HSPF reduction of 16% was found. The alternative heating load line relationship is tied to the rated cooling capacity of the heat pump based on EnergyPlus autosizing, which is more representative of the house load characteristics than the rated heating capacity. The alternative heating load line equation was found to be independent of climate for the six DOE climate regions investigated, provided an adjustable zero load ambient temperature is used. For Region IV, the default DOE climate region used for HSPF ratings, the higher load line results in an ~28

  17. Test Plan for Measuring Ventilation Rates and Combustible Gas Levels in TWRS Active Catch Tanks

    Energy Technology Data Exchange (ETDEWEB)

    NGUYEN, D.M.

    1999-10-25

    The purpose of this sampling activity is to obtain data to support an initial evaluation of potential hazards due to the presence of combustible gas in catch tanks that are currently operated by the River Protection Project (RPP). Results of the hazard analysis will be used to support closure of the flammable gas unreviewed safety question for these facilities. The data collection will be conducted in accordance with the Tank Safety Screening Data Quality Objective (Dukelow et al. 1995). Combustible gas, ammonia, and organic vapor levels in the headspace of the catch tanks will be field-measured using hand-held instruments. If a combustible gas level measurement in a tank exceeds an established threshold, gas samples will he collected in SUMMA' canisters for more extensive laboratory analysis. In addition, ventilation rates of some catch tanks will be measured to evaluate removal of flammable gas by air flowing through the tanks. This test plan identifies the sample collection, laboratory analysis, quality assurance, and reporting objectives for this data collection effort. The plan also provides the procedures for field measurement of combustible gas concentrations and ventilation rates.

  18. Effect of solar chimney inclination angle on space flow pattern and ventilation rate

    Energy Technology Data Exchange (ETDEWEB)

    Bassiouny, Ramadan; Korah, Nader S.A. [Department of Mechanical Power Engineering and Energy, Minia University, Minia 61111 (Egypt)

    2009-02-15

    The solar chimney is a simple and practical idea that is applied to enhance space natural ventilation. The chimney could be vertical or inclined. The chimney inclination angle is an important parameter that greatly affects space flow pattern and ventilation rate. In the present study, the effect of chimney inclination angle on air change per hour and indoor flow pattern was numerically and analytically investigated. A numerical simulation using Ansys, a FEM-based code, was used to predict flow pattern. Then the results were compared with published experimental measurements. A FORTRAN program was developed to iteratively solve the mathematical model that was obtained through an overall energy balance on the solar chimney. The analytical results showed that an optimum air flow rate value was achieved when the chimney inclination is between 45 and 70 for latitude of 28.4 . The numerically predicted flow pattern inside the space supports this finding. Moreover, in the present study a correlation to predict the air change per hour was developed. The correlation was tested within a solar intensity greater than or equal to 500 W/m{sup 2}, and chimney width from 0.1 m to 0.35 m for different inclination angles with acceptable values. (author)

  19. Evaluation of the indoor air quality minimum ventilation rate procedure for use in California retail buildings.

    Science.gov (United States)

    Dutton, S M; Mendell, M J; Chan, W R; Barrios, M; Sidheswaran, M A; Sullivan, D P; Eliseeva, E A; Fisk, W J

    2015-02-01

    This research assesses benefits of adding to California Title-24 ventilation rate (VR) standards a performance-based option, similar to the American Society of Heating, Refrigerating, and Air Conditioning Engineers 'Indoor Air Quality Procedure' (IAQP) for retail spaces. Ventilation rates and concentrations of contaminants of concern (CoC) were measured in 13 stores. Mass balance models were used to estimate 'IAQP-based' VRs that would maintain concentrations of all CoCs below health- or odor-based reference concentration limits. An intervention study in a 'big box' store assessed how the current VR, the Title 24-prescribed VR, and the IAQP-based VR (0.24, 0.69, and 1.51 air changes per hour) influenced measured IAQ and perceived of IAQ. Neither current VRs nor Title 24-prescribed VRs would maintain all CoCs below reference limits in 12 of 13 stores. In the big box store, the IAQP-based VR kept all CoCs below limits. More than 80% of subjects reported acceptable air quality at all three VRs. In 11 of 13 buildings, saving energy through lower VRs while maintaining acceptable IAQ would require source reduction or gas-phase air cleaning for CoCs. In only one of the 13 retail stores surveyed, application of the IAQP would have allowed reduced VRs without additional contaminant-reduction strategies. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  20. Evaluation of an Incremental Ventilation Energy Model for Estimating Impacts of Air Sealing and Mechanical Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Jennifer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Turner, Willliam JN [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-07-01

    Changing the rate of airflow through a home affects the annual thermal conditioning energy. Large-scale changes to airflow rates of the housing stock can significantly alter the energy consumption of the residential energy sector. However, the complexity of existing residential energy models hampers the ability to estimate the impact of policy changes on a state or nationwide level. The Incremental Ventilation Energy (IVE) model developed in this study was designed to combine the output of simple airflow models and a limited set of home characteristics to estimate the associated change in energy demand of homes. The IVE model was designed specifically to enable modelers to use existing databases of home characteristics to determine the impact of policy on ventilation at a population scale. In this report, we describe the IVE model and demonstrate that its estimates of energy change are comparable to the estimates of a wellvalidated, complex residential energy model when applied to homes with limited parameterization. Homes with extensive parameterization would be more accurately characterized by complex residential energy models. The demonstration included a range of home types, climates, and ventilation systems that cover a large fraction of the residential housing sector.

  1. Use of ventilator associated pneumonia bundle and statistical process control chart to decrease VAP rate in Syria.

    Science.gov (United States)

    Alsadat, Reem; Al-Bardan, Hussam; Mazloum, Mona N; Shamah, Asem A; Eltayeb, Mohamed F E; Marie, Ali; Dakkak, Abdulrahman; Naes, Ola; Esber, Faten; Betelmal, Ibrahim; Kherallah, Mazen

    2012-10-01

    Implementation of ventilator associated pneumonia (VAP) bundle as a performance improvement project in the critical care units for all mechanically ventilated patients aiming to decrease the VAP rates. VAP bundle was implemented in 4 teaching hospitals after educational sessions and compliance rates along with VAP rates were monitored using statistical process control charts. VAP bundle compliance rates were steadily increasing from 33 to 80% in hospital 1, from 33 to 86% in hospital 2 and from 83 to 100% in hospital 3 during the study period. The VAP bundle was not applied in hospital 4 therefore no data was available. A target level of 95% was reached only in hospital 3. This correlated with a decrease in VAP rates from 30 to 6.4 per 1000 ventilator days in hospital 1, from 12 to 4.9 per 1000 ventilator days in hospital 3, whereas VAP rate failed to decrease in hospital 2 (despite better compliance) and it remained high around 33 per 1000 ventilator days in hospital 4 where VAP bundle was not implemented. VAP bundle has performed differently in different hospitals in our study. Prevention of VAP requires a multidimensional strategy that includes strict infection control interventions, VAP bundle implementation, process and outcome surveillance and education.

  2. Emission Rates of Multiple Air Pollutants Generated from Chinese Residential Cooking.

    Science.gov (United States)

    Chen, Chen; Zhao, Yuejing; Zhao, Bin

    2018-02-06

    Household air pollution generated from cooking is severe, especially for Chinese-style cooking. We measured the emission rates of multiple air pollutants including fine particles (PM 2.5 ), ultrafine particles (UFPs), and volatile organic compounds (VOCs, including formaldehyde, benzene, and toluene) that were generated from typical Chinese cooking in a residential kitchen. The experiment was designed through five-factor and five-level orthogonal testing. The five key factors were cooking method, ingredient weight, type of meat, type of oil, and meat/vegetable ratio. The measured emission rates (mean value ± standard deviation) of PM 2.5 , UFPs, formaldehyde, total volatile organic compounds (TVOCs), benzene, and toluene were 2.056 ± 3.034 mg/min, 9.102 ± 6.909 × 10 12 #/min, 1.273 ± 0.736 mg/min, 1.349 ± 1.376 mg/min, 0.074 ± 0.039 mg/min, and 0.004 ± 0.004 mg/min. Cooking method was the most influencing factor for the emission rates of PM 2.5 , UFPs, formaldehyde, TVOCs, and benzene but not for toluene. Meanwhile, the emission rate of PM 2.5 was also significantly influenced by ingredient weight, type of meat, and meat/vegetable ratio. Exhausting the range hood decreased the emission rates by approximately 58%, with a corresponding air change rate of 21.38/h for the kitchen room.

  3. Ventilation Effectiveness

    DEFF Research Database (Denmark)

    Mundt, M.; Mathisen, H. M.; Moser, M.

    Improving the ventilation effectiveness allows the indoor air quality to be significantly enhanced without the need for higher air changes in the building, thereby avoiding the higher costs and energy consumption associated with increasing the ventilation rates. This Guidebook provides easy-to-un...

  4. Energy and IAQ Implications of Alternative Minimum Ventilation Rates in California Retail and School Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, Spencer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fisk, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-01-01

    For a stand-alone retail building, a primary school, and a secondary school in each of the 16 California climate zones, the EnergyPlus building energy simulation model was used to estimate how minimum mechanical ventilation rates (VRs) affect energy use and indoor air concentrations of an indoor-generated contaminant. The modeling indicates large changes in heating energy use, but only moderate changes in total building energy use, as minimum VRs in the retail building are changed. For example, predicted state-wide heating energy consumption in the retail building decreases by more than 50% and total building energy consumption decreases by approximately 10% as the minimum VR decreases from the Title 24 requirement to no mechanical ventilation. The primary and secondary schools have notably higher internal heat gains than in the retail building models, resulting in significantly reduced demand for heating. The school heating energy use was correspondingly less sensitive to changes in the minimum VR. The modeling indicates that minimum VRs influence HVAC energy and total energy use in schools by only a few percent. For both the retail building and the school buildings, minimum VRs substantially affected the predicted annual-average indoor concentrations of an indoor generated contaminant, with larger effects in schools. The shape of the curves relating contaminant concentrations with VRs illustrate the importance of avoiding particularly low VRs.

  5. Model-based setting of inspiratory pressure and respiratory rate in pressure-controlled ventilation

    International Nuclear Information System (INIS)

    Schranz, C; Möller, K; Becher, T; Schädler, D; Weiler, N

    2014-01-01

    Mechanical ventilation carries the risk of ventilator-induced-lung-injury (VILI). To minimize the risk of VILI, ventilator settings should be adapted to the individual patient properties. Mathematical models of respiratory mechanics are able to capture the individual physiological condition and can be used to derive personalized ventilator settings. This paper presents model-based calculations of inspiration pressure (p I ), inspiration and expiration time (t I , t E ) in pressure-controlled ventilation (PCV) and a retrospective evaluation of its results in a group of mechanically ventilated patients. Incorporating the identified first order model of respiratory mechanics in the basic equation of alveolar ventilation yielded a nonlinear relation between ventilation parameters during PCV. Given this patient-specific relation, optimized settings in terms of minimal p I and adequate t E can be obtained. We then retrospectively analyzed data from 16 ICU patients with mixed pathologies, whose ventilation had been previously optimized by ICU physicians with the goal of minimization of inspiration pressure, and compared the algorithm's ‘optimized’ settings to the settings that had been chosen by the physicians. The presented algorithm visualizes the patient-specific relations between inspiration pressure and inspiration time. The algorithm's calculated results highly correlate to the physician's ventilation settings with r = 0.975 for the inspiration pressure, and r = 0.902 for the inspiration time. The nonlinear patient-specific relations of ventilation parameters become transparent and support the determination of individualized ventilator settings according to therapeutic goals. Thus, the algorithm is feasible for a variety of ventilated ICU patients and has the potential of improving lung-protective ventilation by minimizing inspiratory pressures and by helping to avoid the build-up of clinically significant intrinsic positive end

  6. Model-based setting of inspiratory pressure and respiratory rate in pressure-controlled ventilation.

    Science.gov (United States)

    Schranz, C; Becher, T; Schädler, D; Weiler, N; Möller, K

    2014-03-01

    Mechanical ventilation carries the risk of ventilator-induced-lung-injury (VILI). To minimize the risk of VILI, ventilator settings should be adapted to the individual patient properties. Mathematical models of respiratory mechanics are able to capture the individual physiological condition and can be used to derive personalized ventilator settings. This paper presents model-based calculations of inspiration pressure (pI), inspiration and expiration time (tI, tE) in pressure-controlled ventilation (PCV) and a retrospective evaluation of its results in a group of mechanically ventilated patients. Incorporating the identified first order model of respiratory mechanics in the basic equation of alveolar ventilation yielded a nonlinear relation between ventilation parameters during PCV. Given this patient-specific relation, optimized settings in terms of minimal pI and adequate tE can be obtained. We then retrospectively analyzed data from 16 ICU patients with mixed pathologies, whose ventilation had been previously optimized by ICU physicians with the goal of minimization of inspiration pressure, and compared the algorithm's 'optimized' settings to the settings that had been chosen by the physicians. The presented algorithm visualizes the patient-specific relations between inspiration pressure and inspiration time. The algorithm's calculated results highly correlate to the physician's ventilation settings with r = 0.975 for the inspiration pressure, and r = 0.902 for the inspiration time. The nonlinear patient-specific relations of ventilation parameters become transparent and support the determination of individualized ventilator settings according to therapeutic goals. Thus, the algorithm is feasible for a variety of ventilated ICU patients and has the potential of improving lung-protective ventilation by minimizing inspiratory pressures and by helping to avoid the build-up of clinically significant intrinsic positive end-expiratory pressure.

  7. The effect of time-dependent ventilation and radon (thoron) gas emanation rates in underground uranium mines

    International Nuclear Information System (INIS)

    Bigu, J.

    1987-01-01

    A theoretical radiation mine model, suitable for underground uranium mines, has been investigated. In this model, the rate of ventilation and/or the radon (thoron) gas emanation from mine walls are time-dependent. Several cases of practical interest have been investigated including sinusoidal, linear, exponential, stepwise, or a combination of two or more of the above. Analytical solutions were obtained for the time-dependent radon (thoron) gas emanation rate. However, because of the extreme analytical complexity of the solutions corresponding to the time-dependent ventilation rate case, numerical solutions were found using a special Runge-Kutta procedure and the Hamming's modified predictor-corrector method for the solution of linear initial-value problems. The mine model makes provisions for losses of radioactivity, other than by ventilation and radioactive decay, by, say, plate-out on mine walls, and by other mechanisms. Radioactivity data, i.e., radon, thoron, and their progeny, obtained with the above mine model for a number of ventilation and emanation conditions, are presented. Experimental data obtained in an inactive stope of an underground uranium mine for a time-dependent air flow case are shown. Air flow conditions (ventilation rate) were determined by tracer gas techniques using SF 6

  8. Estimation of the variations of ventilation rate and indoor radon concentration using the observed wind velocity and indoor-outdoor temperature difference

    International Nuclear Information System (INIS)

    Nagano, Katsuhiro; Inose, Yuichi; Kojima, Hiroshi

    2006-01-01

    The indoor radon concentration in the building depends on the ventilation rate. Measurement results of indoor-outdoor pressure difference showed the ventilation rate correlated closely with the indoor-outdoor pressure difference. The observation results showed that one of factor of indoor-outdoor pressure difference was the wind velocity. When the wind velocity is small, the ventilation rate is affected by the indoor-outdoor temperature difference and the effect depends on the wind velocity. The temporal variation of indoor radon concentration was predicted by the time depending indoor radon balance model and the ventilation rate estimated from the wind velocity and the indoor-outdoor temperature difference. The temporal variations of predicted radon concentration gave good agreement with the experimental values. The measurement method, indoor radon concentration and ventilation rate, factors of temporal variation of ventilation rate, and prediction of indoor radon concentration are reported. (S.Y.)

  9. 46 CFR 108.437 - Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Pipe sizes and discharge rates for enclosed ventilation systems for rotating electrical equipment. 108.437 Section 108.437 Shipping COAST GUARD, DEPARTMENT OF... Systems Fixed Carbon Dioxide Fire Extinguishing Systems § 108.437 Pipe sizes and discharge rates for...

  10. Test plan for measuring ventilation rates and combustible gas levels in TWRS active catch tanks

    Energy Technology Data Exchange (ETDEWEB)

    NGUYEN, D.M.

    1999-05-20

    The purpose of this test is to provide an initial screening of combustible gas concentrations in catch tanks that currently are operated by Tank Waste Remediation System (TWRS). The data will be used to determine whether or not additional data will be needed for closure of the flammable gas unreviewed safety question for these facilities. This test will involve field measurements of ammonia, organic vapor, and total combustible gas levels in the headspace of the catch tanks. If combustible gas level in a tank exceeds an established threshold, gas samples will be collected in SUMMA canisters for more extensive laboratory analysis. In addition, ventilation rates of some catch tanks will be measured to evaluate removal of flammable gas by air flow through the tanks.

  11. Test plan for measuring ventilation rates and combustible gas levels in RPP active catch tanks

    Energy Technology Data Exchange (ETDEWEB)

    NGUYEN, D.M.

    1999-06-03

    The purpose of this test is to provide an initial screening of combustible gas concentrations in catch tanks that currently are operated by River Protection Project (RPP). The data will be used to determine whether or not additional data will be needed for closure of the flammable gas unreviewed safety question for these facilities. This test will involve field measurements of ammonia, organic vapor, and total combustible gas levels in the headspace of the catch tanks. If combustible gas level in a tank exceeds an established threshold, gas samples will be collected in SUMMA canisters for more extensive laboratory analysis. In addition, ventilation rates of some catch tanks will be measured to evaluate removal of flammable gas by air flow through the tanks.

  12. Numerical Studies on Heat Release Rate in Room Fire on Liquid Fuel under Different Ventilation Factors

    Directory of Open Access Journals (Sweden)

    N. Cai

    2012-01-01

    Full Text Available Heat release rate (HRR of the design fire is the most important parameter in assessing building fire hazards. However, HRR in room fire was only studied by computational fluid dynamics (CFD in most of the projects determining fire safety provisions by performance-based design. In contrast to ten years ago, officers in the Far East are now having better knowledge of CFD. Two common questions are raised on CFD-predicted results on describing free boundaries; and on computing grid size. In this work, predicting HRR by the CFD model was justified with experimental room pool fire data reported earlier. The software fire dynamics simulator (FDS version 5 was selected as the CFD simulation tool. Prescribed input heating rate based on the experimental results was used with the liquid fuel model in FDS. Five different free boundary conditions were investigated to predict HRR. Grid sensitivity study was carried out using one stretched mesh and multiple uniform meshes with different grid sizes. As it is difficult to have the entire set of CFD predicted results agreed with experiments, macroscopic flow parameters on the mass flow rate through door opening predicted by CFD were also justified by another four conditions with different ventilation factors.

  13. Effectiveness of air vapor barriers combined with ventilated crawlspaces in decreasing residential exposure to radon daughters to radon daughters: preliminary report

    International Nuclear Information System (INIS)

    Sterling, T.D.; Arundel, A.; McIntyre, D.; Sterling, E.; Sterling, T.D.

    1986-01-01

    Radon gas is present in many homes. Concentrations may be increased in airtight, energy-efficient structures. This is especially true in cold climates where energy conservation is an important factor leading to the widespread application of sealing and tightening techniques both in older renovated homes and new construction. To reduce radon concentrations, it may be effective to ventilate crawlspaces and prevent infiltration of radon gas into the house by means of an air/vapor barrier. The authors report first results of comparing radon levels in homes with and without ventilated crawlspaces and air/vapor barriers. Radon emissions were measured in a tightly sealed home with ventilated crawlspaces and an air/vapor barrier and in two homes without such vapor barriers and ventilated crawlspaces, but differing in ventilation. Preliminary results suggest that use of ventilated crawlspaces and bottomside vapor barriers may reduce indoor radon levels by approximately 60%. 15 references, 1 table

  14. Heart Rate Variability in Patients with Chronic Obstructive Pulmonary Disease Treated by Noninvasive Mechanic Ventilation

    Directory of Open Access Journals (Sweden)

    Zekeriya Küçükdurmaz

    2011-08-01

    Full Text Available Aims: This study aimed to investigate heart rate variability (HRV of patients with severe COPD who are treated by noninvasive mechanic ventilation (NIMV.Patients and Method: Twenty-seven patient (58±8 years, 9 F with severe COPD treated by nocturnal NIMV at home and 23 sex and age matched volunteers (56±8 years, 11 F who has not dyspnea as a control group recruited in the study. Subjects underwent spirometry, blood gas analysis, transthoracic echocardiography, 24 hours ambulatory ECG analysis. Time domain HRV analysis performed from ambulatory ECG records. Results: 52% of patients at NYHA functional class II, 36% at class III, and 12% at class IV when they have been treated by NIMV. Groups were similar for age and sex (p>0.05 for both. Heart rates of patients were higher significantly than controls’ (p0.05. But, systolic pulmonary pressures were higher of COPD group (p<0.01. 24 hours heart rate was higher, and standard deviation of normal R-R intervals (SDNN 24 hours, SDNN night, SDNN day, SDNN index (SDNNI and standard deviation of mean R-R intervals (SDANNI values were lower in COPD group significantly. SDNN was inversely correlated with duration of daily NIMV usage, intensive care unit administration and entubation rate and PaCO2. SDNNI was inversely correlated with functional class, duration of daily NIMV usage, intensive care unit administration rate and PaCO2. Else, SDNNI was correlated with predicted forced vital capacity % (FVC% and predicted forced expiratory volume at 1 second % (FEV1%.Conclusion: Time domain HRV decreases in patients with severe COPD. Decrease is correlated with severity of disease, and it presents in despite of the chronic nocturnal NIMV application. These patients have high risk for cardiovascular morbidity and mortality and should be monitored and manegement for cardiovascular events.

  15. The effect of ventilation on the indoor air concentration of PCB

    DEFF Research Database (Denmark)

    Lyng, Nadja; Gunnarsen, Lars Bo; Andersen, Helle Vibeke

    2015-01-01

    The impact of increased ventilation on polychlorinated biphenyl (PCB) air concentration by installation of mechanical balanced ventilation units was studied. The intervention was carried out in three PCB-contaminated rooms; one classroom in an elementary school and two small bedrooms...... in an apartment in a residential building. In the classroom, the air exchange rate (ACH) was raised from 0.2 (without mechanical ventilation) to 5.5 /h during the intervention. In the two bedrooms, the highest ACH was 6.6 /h and 0.5 /h without mechanical ventilation. The corresponding concentration decrease...

  16. Ventilator-Associated Pneumonia in Trauma Patients: Different Criteria, Different Rates.

    Science.gov (United States)

    Leonard, Kenji L; Borst, Gregory M; Davies, Stephen W; Coogan, Michael; Waibel, Brett H; Poulin, Nathaniel R; Bard, Michael R; Goettler, Claudia E; Rinehart, Shane M; Toschlog, Eric A

    2016-06-01

    No consensus exists regarding the definition of ventilator-associated pneumonia (VAP). Even within a single institution, inconsistent diagnostic criteria result in conflicting rates of VAP. As a Level 1 trauma center participating in the Trauma Quality Improvement Project (TQIP) and the National Healthcare Safety Network (NHSN), our institution showed inconsistencies in VAP rates depending on which criteria was applied. The purpose of this study was to compare VAP definitions, defined by culture-based criteria, National Trauma Data Bank (NTDB) and NHSN, using incidence in trauma patients. A retrospective chart review of consecutive trauma patients who were diagnosed with VAP and met pre-determined inclusion and exclusion criteria admitted to our rural, 861-bed, Level 1 trauma and tertiary care center between January 2008 and December 2011 was performed. These patients were identified from the National Trauma Registry of the American College of Surgeons (NTRACS) database and an in-house infection control database. Ventilator-associated pneumonia diagnosis criteria defined by the U.S. Center for Disease Control and Prevention (used by the NHSN), the NTDB, and our institutional, culture-based criteria gold standard were compared among patients. Two hundred seventy-nine patients were diagnosed with VAP (25.4% met NHSN criteria, 88.2% met NTDB, and 76.3% met culture-based criteria). Only 58 (20.1%) patients met all three criteria. When NHSN criteria were compared with culture-based criteria, NHSN showed a high specificity (92.5%) and low sensitivity (28.2%). The positive predictive value (PPV) was 84.5%, but the negative predictive value (NPV) was 47.1%. The agreement between the NHSN and the culture-based criteria was poor (κ = 0.18). Conversely, the NTDB showed a lower specificity (57.8%), but greater sensitivity (86.4%) compared with culture-based criteria. The PPV and NPV were both 74% and the two criteria showed fair agreement (κ = 0.41). The lack of

  17. Developing evidence-based prescriptive ventilation rate standards for commercial buildings in California: a proposed framework

    Energy Technology Data Exchange (ETDEWEB)

    Mendell, Mark J.; Fisk, William J.

    2014-02-01

    Background - The goal of this project, with a focus on commercial buildings in California, was to develop a new framework for evidence-based minimum ventilation rate (MVR) standards that protect occupants in buildings while also considering energy use and cost. This was motivated by research findings suggesting that current prescriptive MVRs in commercial buildings do not provide occupants with fully safe and satisfactory indoor environments. Methods - The project began with a broad review in several areas ? the diverse strategies now used for standards or guidelines for MVRs or for environmental contaminant exposures, current knowledge about adverse human effects associated with VRs, and current knowledge about contaminants in commercial buildings, including their their presence, their adverse human effects, and their relationships with VRs. Based on a synthesis of the reviewed information, new principles and approaches are proposed for setting evidence-based VRs standards for commercial buildings, considering a range of human effects including health, performance, and acceptability of air. Results ? A review and evaluation is first presented of current approaches to setting prescriptive building ventilation standards and setting acceptable limits for human contaminant exposures in outdoor air and occupational settings. Recent research on approaches to setting acceptable levels of environmental exposures in evidence-based MVR standards is also described. From a synthesis and critique of these materials, a set of principles for setting MVRs is presented, along with an example approach based on these principles. The approach combines two sequential strategies. In a first step, an acceptable threshold is set for each adverse outcome that has a demonstrated relationship to VRs, as an increase from a (low) outcome level at a high reference ventilation rate (RVR, the VR needed to attain the best achievable levels of the adverse outcome); MVRs required to meet each

  18. Predicting residential air exchange rates from questionnaires and meteorology: model evaluation in central North Carolina.

    Science.gov (United States)

    Breen, Michael S; Breen, Miyuki; Williams, Ronald W; Schultz, Bradley D

    2010-12-15

    A critical aspect of air pollution exposure models is the estimation of the air exchange rate (AER) of individual homes, where people spend most of their time. The AER, which is the airflow into and out of a building, is a primary mechanism for entry of outdoor air pollutants and removal of indoor source emissions. The mechanistic Lawrence Berkeley Laboratory (LBL) AER model was linked to a leakage area model to predict AER from questionnaires and meteorology. The LBL model was also extended to include natural ventilation (LBLX). Using literature-reported parameter values, AER predictions from LBL and LBLX models were compared to data from 642 daily AER measurements across 31 detached homes in central North Carolina, with corresponding questionnaires and meteorological observations. Data was collected on seven consecutive days during each of four consecutive seasons. For the individual model-predicted and measured AER, the median absolute difference was 43% (0.17 h(-1)) and 40% (0.17 h(-1)) for the LBL and LBLX models, respectively. Additionally, a literature-reported empirical scale factor (SF) AER model was evaluated, which showed a median absolute difference of 50% (0.25 h(-1)). The capability of the LBL, LBLX, and SF models could help reduce the AER uncertainty in air pollution exposure models used to develop exposure metrics for health studies.

  19. Ventilation and Heart Rate Monitoring in Drivers using a Contactless Electrical Bioimpedance System

    Science.gov (United States)

    Macías, R.; García, M. A.; Ramos, J.; Bragós, R.; Fernández, M.

    2013-04-01

    Nowadays, the road safety is one of the most important priorities in the automotive industry. Many times, this safety is jeopardized because of driving under inappropriate states, e.g. drowsiness, drugs and/or alcohol. Therefore several systems for monitoring the behavior of subjects during driving are researched. In this paper, a device based on a contactless electrical bioimpedance system is shown. Using the four-wire technique, this system is capable of obtaining the heart rate and the ventilation of the driver through multiple textile electrodes. These textile electrodes are placed on the car seat and the steering wheel. Moreover, it is also reported several measurements done in a controlled environment, i.e. a test room where there are no artifacts due to the car vibrations or the road state. In the mentioned measurements, the system response can be observed depending on several parameters such as the placement of the electrodes or the number of clothing layers worn by the driver.

  20. Ventilation and Heart Rate Monitoring in Drivers using a Contactless Electrical Bioimpedance System

    International Nuclear Information System (INIS)

    Macías, R; García, M A; Ramos, J; Bragós, R; Fernández, M

    2013-01-01

    Nowadays, the road safety is one of the most important priorities in the automotive industry. Many times, this safety is jeopardized because of driving under inappropriate states, e.g. drowsiness, drugs and/or alcohol. Therefore several systems for monitoring the behavior of subjects during driving are researched. In this paper, a device based on a contactless electrical bioimpedance system is shown. Using the four-wire technique, this system is capable of obtaining the heart rate and the ventilation of the driver through multiple textile electrodes. These textile electrodes are placed on the car seat and the steering wheel. Moreover, it is also reported several measurements done in a controlled environment, i.e. a test room where there are no artifacts due to the car vibrations or the road state. In the mentioned measurements, the system response can be observed depending on several parameters such as the placement of the electrodes or the number of clothing layers worn by the driver.

  1. Review and Extension of CO2-Based Methods to Determine Ventilation Rates with Application to School Classrooms

    Directory of Open Access Journals (Sweden)

    Stuart Batterman

    2017-02-01

    Full Text Available The ventilation rate (VR is a key parameter affecting indoor environmental quality (IEQ and the energy consumption of buildings. This paper reviews the use of CO2 as a “natural” tracer gas for estimating VRs, focusing on applications in school classrooms. It provides details and guidance for the steady-state, build-up, decay and transient mass balance methods. An extension to the build-up method and an analysis of the post-exercise recovery period that can increase CO2 generation rates are presented. Measurements in four mechanically-ventilated school buildings demonstrate the methods and highlight issues affecting their applicability. VRs during the school day fell below recommended minimum levels, and VRs during evening and early morning were on the order of 0.1 h−1, reflecting shutdown of the ventilation systems. The transient mass balance method was the most flexible and advantageous method given the low air change rates and dynamic occupancy patterns observed in the classrooms. While the extension to the build-up method improved stability and consistency, the accuracy of this and the steady-state method may be limited. Decay-based methods did not reflect the VR during the school day due to heating, ventilation and air conditioning (HVAC system shutdown. Since the number of occupants in classrooms changes over the day, the VR expressed on a per person basis (e.g., L·s−1·person−1 depends on the occupancy metric. If occupancy measurements can be obtained, then the transient mass balance method likely will provide the most consistent and accurate results among the CO2-based methods. Improved VR measurements can benefit many applications, including research examining the linkage between ventilation and health.

  2. Identifying Housing and Meteorological Conditions Influencing Residential Air Exchange Rates in the DEARS and RIOPA Studies: Development of Distributions for Human Exposure Modeling

    Science.gov (United States)

    Appropriate prediction of residential air exchange rate (AER) is important for estimating human exposures in the residential microenvironment, as AER drives the infiltration of outdoor-generated air pollutants indoors. AER differences among homes may result from a number of fact...

  3. Ventilator-driven xenon ventilation studies

    International Nuclear Information System (INIS)

    Chilcoat, R.T.; Thomas, F.D.; Gerson, J.I.

    1984-01-01

    A modification of a common commercial Xe-133 ventilation device is described for mechanically assisted ventilation imaging. The patient's standard ventilator serves as the power source controlling the ventilatory rate and volume during the xenon study, but the gases in the two systems are not intermixed. This avoids contamination of the ventilator with radioactive xenon. Supplemental oxygen and positive end-expiratory pressure (PEEP) are provided if needed. The system can be converted quickly for conventional studies with spontaneous respiration

  4. Heat Release Rate of an Open Kitchen Fire of Small Residential Units in Tall Buildings

    OpenAIRE

    Chow, W.K.

    2014-01-01

    Many small units of area less than 30 m2 in residential buildings over 200 m tall are equipped with open kitchens in Asia, including Hong Kong. Fire safety provisions of these kitchens are determined by performance-based design (PBD). In most PBD projects, only the spread of smoke from the kitchen on fire to the outside was commonly studied. However, a fire load survey in Hong Kong indicated large quantities of combustibles are stored in residential units. Cooking oil was found to be ignited ...

  5. Assessment of heart rate, acidosis, consciousness, oxygenation, and respiratory rate to predict noninvasive ventilation failure in hypoxemic patients.

    Science.gov (United States)

    Duan, Jun; Han, Xiaoli; Bai, Linfu; Zhou, Lintong; Huang, Shicong

    2017-02-01

    To develop and validate a scale using variables easily obtained at the bedside for prediction of failure of noninvasive ventilation (NIV) in hypoxemic patients. The test cohort comprised 449 patients with hypoxemia who were receiving NIV. This cohort was used to develop a scale that considers heart rate, acidosis, consciousness, oxygenation, and respiratory rate (referred to as the HACOR scale) to predict NIV failure, defined as need for intubation after NIV intervention. The highest possible score was 25 points. To validate the scale, a separate group of 358 hypoxemic patients were enrolled in the validation cohort. The failure rate of NIV was 47.8 and 39.4% in the test and validation cohorts, respectively. In the test cohort, patients with NIV failure had higher HACOR scores at initiation and after 1, 12, 24, and 48 h of NIV than those with successful NIV. At 1 h of NIV the area under the receiver operating characteristic curve was 0.88, showing good predictive power for NIV failure. Using 5 points as the cutoff value, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for NIV failure were 72.6, 90.2, 87.2, 78.1, and 81.8%, respectively. These results were confirmed in the validation cohort. Moreover, the diagnostic accuracy for NIV failure exceeded 80% in subgroups classified by diagnosis, age, or disease severity and also at 1, 12, 24, and 48 h of NIV. Among patients with NIV failure with a HACOR score of >5 at 1 h of NIV, hospital mortality was lower in those who received intubation at ≤12 h of NIV than in those intubated later [58/88 (66%) vs. 138/175 (79%); p = 0.03). The HACOR scale variables are easily obtained at the bedside. The scale appears to be an effective way of predicting NIV failure in hypoxemic patients. Early intubation in high-risk patients may reduce hospital mortality.

  6. : ventilators for noninvasive ventilation

    OpenAIRE

    Fauroux , Brigitte; Leroux , Karl; Desmarais , Gilbert; Isabey , Daniel; Clément , Annick; Lofaso , Frédéric; Louis , Bruno

    2008-01-01

    International audience; The aim of the present study was to evaluate the performance characteristics of all the ventilators proposed for home noninvasive positive-pressure ventilation in children in France. The ventilators (one volume-targeted, 12 pressure-targeted and four dual) were evaluated on a bench which simulated six different paediatric ventilatory patterns. For each ventilator, the quality of the inspiratory and expiratory trigger and the ability to reach and maintain the preset pre...

  7. Alterations in the rate of limb movement using a lower body positive pressure treadmill do not influence respiratory rate or phase III ventilation.

    Science.gov (United States)

    Buono, Michael J; Burnsed-Torres, Marissa; Hess, Bethany; Lopez, Kristine; Ortiz, Catherine; Girodo, Ariel; Lolli, Karen; Bloom, Brett; Bailey, David; Kolkhorst, Fred W

    2015-01-01

    The purpose of this study was to determine the effect of alterations in rate of limb movement on Phase III ventilation during exercise, independent of metabolic rate, gait style, and treadmill incline. Subjects completed five submaximal exercise bouts on a lower body positive pressure treadmill (AlterG P 200). The percent body weight for the five exercise bouts was 100, 87, 75, 63, and 50% and each was matched for carbon dioxide production (V CO2 ). Naturally, to match the V CO2 while reducing the body weight up to 50% of normal required a significant increase in the treadmill speed from 3.0 ± 0.1 to 4.1 ± 0.2 mph, which resulted in a significant (P body weight) to 133 ± 6 at 4.1 mph (i.e., 50% of body weight). The most important finding was that significant increases in step frequency did not significantly alter minute ventilation or respiratory rate. Such results do not support an important role for the rate of limb movement in Phase III ventilation during submaximal exercise, when metabolic rate, gait style, and treadmill incline are controlled.

  8. Alterations in the Rate of Limb Movement Using a Lower Body Positive Pressure Treadmill Do Not Influence Respiratory Rate or Phase III Ventilation

    Directory of Open Access Journals (Sweden)

    Michael J. Buono

    2015-01-01

    Full Text Available The purpose of this study was to determine the effect of alterations in rate of limb movement on Phase III ventilation during exercise, independent of metabolic rate, gait style, and treadmill incline. Subjects completed five submaximal exercise bouts on a lower body positive pressure treadmill (AlterG P 200. The percent body weight for the five exercise bouts was 100, 87, 75, 63, and 50% and each was matched for carbon dioxide production (VCO2. Naturally, to match the VCO2 while reducing the body weight up to 50% of normal required a significant increase in the treadmill speed from 3.0±0.1 to 4.1±0.2 mph, which resulted in a significant (P<0.05 increase in the mean step frequency (steps per minute from 118±10 at 3 mph (i.e., 100% of body weight to 133±6 at 4.1 mph (i.e., 50% of body weight. The most important finding was that significant increases in step frequency did not significantly alter minute ventilation or respiratory rate. Such results do not support an important role for the rate of limb movement in Phase III ventilation during submaximal exercise, when metabolic rate, gait style, and treadmill incline are controlled.

  9. Final Report Balancing energy conservation and occupant needs in ventilation rate standards for Big Box stores in California. Predicted indoor air quality and energy consumption using a matrix of ventilation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Apte, Michael G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mendell, Mark J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sohn, Michael D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dutton, Spencer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Berkeley, Pam M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Spears, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-02-01

    Through mass-balance modeling of various ventilation scenarios that might satisfy the ASHRAE 62.1 Indoor Air Quality (IAQ) Procedure, we estimate indoor concentrations of contaminants of concern (COCs) in California “big box” stores, compare estimates to available thresholds, and for selected scenarios estimate differences in energy consumption. Findings are intended to inform decisions on adding performance-based approaches to ventilation rate (VR) standards for commercial buildings. Using multi-zone mass-balance models and available contaminant source rates, we estimated concentrations of 34 COCs for multiple ventilation scenarios: VRmin (0.04 cfm/ft2 ), VRmax (0.24 cfm/ft2 ), and VRmid (0.14 cfm/ft2 ). We compared COC concentrations with available health, olfactory, and irritant thresholds. We estimated building energy consumption at different VRs using a previously developed EnergyPlus model. VRmax did control all contaminants adequately, but VRmin did not, and VRmid did so only marginally. Air cleaning and local ventilation near strong sources both showed promise. Higher VRs increased indoor concentrations of outdoor air pollutants. Lowering VRs in big box stores in California from VRmax to VRmid would reduce total energy use by an estimated 6.6% and energy costs by 2.5%. Reducing the required VRs in California’s big box stores could reduce energy use and costs, but poses challenges for health and comfort of occupants. Source removal, air cleaning, and local ventilation may be needed at reduced VRs, and even at current recommended VRs. Also, alternative ventilation strategies taking climate and season into account in ventilation schedules may provide greater energy cost savings than constant ventilation rates, while improving IAQ.

  10. Demand specifying variables and current ventilation rate requirements with respect to the future use of voc sensing for dcv control

    DEFF Research Database (Denmark)

    Kolarik, Jakub

    be also taken into account in the ventilation control. Recent development in gas sensing technology resulted in a new generation of relatively cheap and practically applicable sensors that can offer measurements of some of the pollutants mentioned above – mainly Volatile Organic Compounds (VOC......Demand Controlled Ventilation (DCV) is a well established principle to provide a certain indoor environmental quality, defined both in the terms of air quality and thermal comfort. This is accomplished by adjusting the supplied airflow rate according to a certain demand indicator, which......). This seems to bring a new dimension into the control of DCV systems. This paper is a contribution to the workshop on utilization of VOC sensing technology used for DCV control. The aim of the paper is to provide a short review of different types of demand variables used to control DCV systems and summarize...

  11. Energy efficiency in U.S. residential rental housing: Adoption rates and impact on rent

    International Nuclear Information System (INIS)

    Im, Jongho; Seo, Youngme; Cetin, Kristen S.; Singh, Jasmeet

    2017-01-01

    Highlights: •Rental units listings collected and analyzed for 10 U.S. cities. •Energy efficient features included in 5.3–21.6% of rental units in each city. •The most common efficient features are lighting and appliance upgrades. •Propensity score matching and conditional mean comparison methods used. •Generally, energy efficient features increases the units’ rent, overall from 6% to 14%. -- Abstract: For 118 million residential housing units in the U.S., there is currently a gap between the potential energy savings that can be achieved through the use of existing energy efficiency technologies, and the actual level of energy savings realized, particularly for the 37% of housing units that are considered residential rental properties. Additional quantifiable benefits are needed beyond energy savings to help further motivate residential property owners to invest in energy efficiency upgrades. This research focuses on assessing the adoption of energy efficient upgrades in U.S. residential housing and the impact on rental prices. Ten U.S. cities are chosen for analysis; these cities vary in size across multiple climate zones, and represent a diverse set of housing market conditions. Data was collected for over 159,000 rental property listings, their characteristics, and their energy efficiency measures listed in rental housing postings across each city. Following an extensive data quality control process, over thirty different types energy efficient features were identified. The level of adoption was determined for each city, ranging from 5.3% to 21.6%. Efficient lighting and appliances were among the most common, with many features doubling as energy efficient and other desirable aesthetic or comfort improvements. Then using propensity score matching and conditional mean comparison methods, the relative impact on rent charged in each city was calculated, which ranged from a 6% to 14.1% increase in rent for properties with energy efficient features

  12. Test plan for headspace gas concentration measurement and headspace ventilation rate measurement for DCRTs 241-A-244, 241-BX-244, 241-S-244, 241-TX-244

    International Nuclear Information System (INIS)

    Bauer, R.E.

    1998-01-01

    This test plan provides the directions to characterize the headspace gas concentrations and the headspace ventilation rate for double contained receiver tanks 241-A-244, 241-BX-244, 241-S-244, and 241-TX-244

  13. Ventilation systems

    International Nuclear Information System (INIS)

    Gossler

    1980-01-01

    The present paper deals with - controlled area ventilation systems - ventilation systems for switchgear-building and control-room - other ventilation systems for safety equipments - service systems for ventilation systems. (orig./RW)

  14. Mechanical Ventilation

    Science.gov (United States)

    ... ventilation is a life support treatment. A mechanical ventilator is a machine that helps people breathe when ... to breathe enough on their own. The mechanical ventilator is also called a ventilator , respirator, or breathing ...

  15. Residential Customer Enrollment in Time-based Rate and Enabling Technology Programs: Smart Grid Investment Grant Consumer Behavior Study Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Todd, Annika [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cappers, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goldman, Charles [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-05-01

    The U.S. Department of Energy’s (DOE’s) Smart Grid Investment Grant (SGIG) program is working with a subset of the 99 SGIG projects undertaking Consumer Behavior Studies (CBS), which examine the response of mass market consumers (i.e., residential and small commercial customers) to time-varying electricity prices (referred to herein as time-based rate programs) in conjunction with the deployment of advanced metering infrastructure (AMI) and associated technologies. The effort presents an opportunity to advance the electric industry’s understanding of consumer behavior.

  16. Alterations in the Rate of Limb Movement Using a Lower Body Positive Pressure Treadmill Do Not Influence Respiratory Rate or Phase III Ventilation

    OpenAIRE

    Michael J. Buono; Marissa Burnsed-Torres; Bethany Hess; Kristine Lopez; Catherine Ortiz; Ariel Girodo; Karen Lolli; Brett Bloom; David Bailey; Fred W. Kolkhorst

    2015-01-01

    The purpose of this study was to determine the effect of alterations in rate of limb movement on Phase III ventilation during exercise, independent of metabolic rate, gait style, and treadmill incline. Subjects completed five submaximal exercise bouts on a lower body positive pressure treadmill (AlterG P 200). The percent body weight for the five exercise bouts was 100, 87, 75, 63, and 50% and each was matched for carbon dioxide production (V CO2 ). Naturally, to match the V CO2 while reducin...

  17. The influence of broiler activity, growth rate, and litter on carbon dioxide balances for the determination of ventilation flow rates in broiler production.

    Science.gov (United States)

    Calvet, S; Estellés, F; Cambra-López, M; Torres, A G; Van den Weghe, H F A

    2011-11-01

    Carbon dioxide balances are useful in determining ventilation rates in livestock buildings. These balances need an accurate estimation of the CO(2) produced by animals and their litter to determine the ventilation flows. To estimate the daily variation in ventilation flow, it is necessary to precisely know the daily variation pattern of CO(2) production, which mainly depends on animal activity. The objective of this study was to explore the applicability of CO(2) balances for determining ventilation flows in broiler buildings. More specifically, this work aimed to quantify the amount of CO(2) produced by the litter, as well as the amount of CO(2) produced by the broilers, as a function of productive parameters, and to analyze the influence of broiler activity on CO(2) emissions. Gas concentrations and ventilation flows were simultaneously measured in 3 trials, with 1 under experimental conditions and the other 2 in a commercial broiler farm. In the experimental assay, broiler activity was also determined. At the end of the experimental trial, on the day after the removal of the broilers, the litter accounted for 20% of the total CO(2) produced, and the broilers produced 3.71 L/h of CO(2) per kg of metabolic weight. On the commercial farm, CO(2) production was the same for the 2 cycles (2.60 L/h per kg of metabolic weight, P > 0.05). However, substantial differences were found between CO(2) and broiler activity patterns after changes in light status. A regression model was used to explain these differences (R(2) = 0.52). Carbon dioxide increased with bird activity, being on average 3.02 L/h per kg of metabolic weight for inactive birds and 4.73 L/h per kg of metabolic weight when bird activity was highest. Overall, CO(2) balances are robust tools for determining the daily average ventilation flows in broiler farms. These balances could also be applied at more frequent intervals, but in this case, particular care is necessary after light status changes because of

  18. Impact of ventilation rates on SBS symptoms and productivity in offices

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Fanger, Povl Ole

    1999-01-01

    Perceived air quality, Sick Building Syndrome (SBS) symptoms and productivity were studied in a normally furnished office space ventilated with an outdoor air flow of 3, 10 and 30 L/s per person (corresponding to aiur changes of 0.6, 2.0 and 6 h-1, respectively), while all other environmental...... subjects occupied the office for 4.6 hours in the afternoon, six subjects at a time; they remained thermally neutral by adjusting their clothing. Subjects assessed perceived air quality and SBS symptoms, and performed simulated office work so that their productivity could be assessed. Increasing the supply...

  19. Effect of metronome rates on the quality of bag-mask ventilation during metronome-guided 30:2 cardiopulmonary resuscitation: A randomized simulation study.

    Science.gov (United States)

    Na, Ji Ung; Han, Sang Kuk; Choi, Pil Cho; Shin, Dong Hyuk

    2017-01-01

    Metronome guidance is a feasible and effective feedback technique to improve the quality of cardiopulmonary resuscitation (CPR). The rate of the metronome should be set between 100 to 120 ticks/minute and the speed of ventilation may have crucial effect on the quality of ventilation. We compared three different metronome rates (100, 110, 120 ticks/minute) to investigate its effect on the quality of ventilation during metronome-guided 30:2 CPR. This is a prospective, randomized, crossover observational study using a RespiTrainer○ r . To simulate 30 chest compressions, one investigator counted from 1 to 30 in cadence with the metronome rate (1 count for every 1 tick), and the participant performed 2 consecutive ventilations immediately following the counting of 30. Thirty physicians performed 5 sets of 2 consecutive (total 10) bag-mask ventilations for each metronome rate. Participants were instructed to squeeze the bag over 2 ticks (1.0 to 1.2 seconds depending on the rate of metronome) and deflate the bag over 2 ticks. The sequence of three different metronome rates was randomized. Mean tidal volume significantly decreased as the metronome rate was increased from 110 ticks/minute to 120 ticks/minute (343±84 mL vs. 294±90 mL, P =0.004). Peak airway pressure significantly increased as metronome rate increased from 100 ticks/minute to 110 ticks/minute (18.7 vs. 21.6 mmHg, P =0.006). In metronome-guided 30:2 CPR, a higher metronome rate may adversely affect the quality of bag-mask ventilations. In cases of cardiac arrest where adequate ventilation support is necessary, 100 ticks/minute may be better than 110 or 120 ticks/minute to deliver adequate tidal volume during audio tone guided 30:2 CPR.

  20. Development of energy-efficient comfort ventilation plants with air quality controlled volume flow rate and continuous detection of the status of the windows aperture. Part 3. Final report with documentation of the field test; Entwicklung energieeffizienter Komfortlueftungsanlagen mit luftqualitaetsgefuehrter Volumenstromregelung und kontinuierlicher Erfassung des Fensteroeffnungszustandes. Teilbericht 3. Endbericht mit Dokumentation des Feldtests

    Energy Technology Data Exchange (ETDEWEB)

    Grossklos, Marc; Hacke, Ulrike [Institut Wohnen und Umwelt GmbH, Darmstadt (Germany)

    2012-10-25

    Residential ventilation systems with a heat recovery contribute to the improvement of the air quality and to the reduction of heat losses caused by ventilation. An additional opening of the windows in residential buildings results in a clearly increasing consumption of thermal heat because the thermal heat of the out coming air cannot be utilized furthermore. Continuous information on the energetic effects of the opening of windows is helpful. Under this aspect, the authors of the contribution under consideration report on the development of energy efficient comfort ventilation systems with an air quality controlled volume flow rate and continuous detection of the status of the windows aperture. The contribution under consideration is the third part of a project concerning to this theme. This part encompasses a field test with four single-family houses in which the air quality control as well as the detection of the status of the windows aperture is tested and optimized for a long period. This contribution also contains the results of the second part of the project. The second project investigate the technical implementation of a air quality regulation at prototypes and test facilities.

  1. Healthy Zero Energy Buildings (HZEB) Program - Cross-Sectional Study of Contaminant Levels, Source, Strengths, and Ventilation Rates in Retail Stores

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Wanyu R.; Sidheswaran, Meera; Cohn, Sebastian; Sullivan, Douglas P.; Fisk, William

    2014-02-01

    This field study measured ventilation rates and indoor air quality parameters in 21 visits to retail stores in California. The data was collected to guide the development of new, science-based commercial building ventilation rate standards that balance the dual objectives of increasing energy efficiency and maintaining acceptable indoor air quality. Data collection occurred between September 2011 and March 2013. Three types of stores participated in this study: grocery stores, furniture/hardware stores, and apparel stores. Ventilation rates and indoor air contaminant concentrations were measured on a weekday, typically between 9 am and 6 pm. Ventilation rates measured using a tracer gas decay method exceeded the minimum requirement of California’s Title 24 Standard in all but one store. Even though there was adequate ventilation according to Title 24, concentrations of formaldehyde, acetaldehyde, and acrolein exceeded the most stringent chronic health guidelines. Other indoor air contaminants measured included carbon dioxide (CO{sub 2}), carbon monoxide (CO), ozone (O{sub 3}), and particulate matter (PM). Concentrations of CO{sub 2} were kept low by adequate ventilation, and were assumed low also because the sampling occurred on a weekday when retail stores were less busy. CO concentrations were also low. The indoor-outdoor ratios of O{sub 3} showed that the first-order loss rate may vary by store trade types and also by ventilation mode (mechanical versus natural). Analysis of fine and ultrafine PM measurements showed that a substantial portion of the particle mass in grocery stores with cooking-related emissions was in particles less than 0.3 μm. Stores without cooking as an indoor source had PM size distributions that were more similar indoors and outdoors. The whole-building emission rates of volatile organic compounds (VOCs) and PM were estimated from the measured ventilation rates and indoor and outdoor contaminant concentrations. Mass balance models were

  2. In China, students in crowded dormitories with a low ventilation rate have more common colds: evidence for airborne transmission.

    Directory of Open Access Journals (Sweden)

    Yuexia Sun

    Full Text Available OBJECTIVE: To test whether the incidence of common colds among college students in China is associated with ventilation rates and crowdedness in dormitories. METHODS: In Phase I of the study, a cross-sectional study, 3712 students living in 1569 dorm rooms in 13 buildings responded to a questionnaire about incidence and duration of common colds in the previous 12 months. In Phase II, air temperature, relative humidity and CO(2 concentration were measured for 24 hours in 238 dorm rooms in 13 buildings, during both summer and winter. Out-to indoor air flow rates at night were calculated based on measured CO(2 concentrations. RESULTS: In Phase I, 10% of college students reported an incidence of more than 6 common colds in the previous 12 months, and 15% reported that each infection usually lasted for more than 2 weeks. Students in 6-person dorm rooms were about 2 times as likely to have an incidence of common colds ≥6 times per year and a duration ≥2 weeks, compared to students in 3-person rooms. In Phase II, 90% of the measured dorm rooms had an out-to indoor air flow rate less than the Chinese standard of 8.3 L/s per person during the heating season. There was a dose-response relationship between out-to indoor air flow rate per person in dorm rooms and the proportion of occupants with annual common cold infections ≥6 times. A mean ventilation rate of 5 L/(s•person in dorm buildings was associated with 5% of self reported common cold ≥6 times, compared to 35% at 1 L/(s•person. CONCLUSION: Crowded dormitories with low out-to indoor airflow rates are associated with more respiratory infections among college students.

  3. The impact of rate design and net metering on the bill savings from distributed PV for residential customers in California

    International Nuclear Information System (INIS)

    Darghouth, Naim R.; Barbose, Galen; Wiser, Ryan

    2011-01-01

    Net metering has become a widespread mechanism in the U.S. for supporting customer adoption of distributed photovoltaics (PV), but has faced challenges as PV installations grow to a larger share of generation in a number of states. This paper examines the value of the bill savings that customers receive under net metering, and the associated role of retail rate design, based on a sample of approximately two hundred residential customers of California's two largest electric utilities. We find that the bill savings per kWh of PV electricity generated varies by more than a factor of four across the customers in the sample, which is largely attributable to the inclining block structure of the utilities' residential retail rates. We also compare the bill savings under net metering to that received under three potential alternative compensation mechanisms, based on California's Market Price Referent (MPR). We find that net metering provides significantly greater bill savings than a full MPR-based feed-in tariff, but only modestly greater savings than alternative mechanisms under which hourly or monthly net excess generation is compensated at the MPR rate. - Highlights: → We examine the value of bill savings under net metering to PV owners in California. → Bill savings per kWh of PV generation varies by a factor of four with net metering. The variation is attributable to rate design, the unique inclining block structure. → The median value of bill savings is reduced by 40-67% with MPR feed-in tariff. → The median value of bill savings is reduced by 6-12% with hourly netting.

  4. Heart rate and leukocytes after air and ground transportation in artificially ventilated neonates: a prospective observational study.

    Science.gov (United States)

    Grosek, Stefan; Mlakar, Gorazd; Vidmar, Ivan; Ihan, Alojz; Primozic, Janez

    2009-01-01

    To evaluate the effect of interhospital air and ground transportation of artificially ventilated neonates on heart rate and peripheral blood leukocyte counts. Prospective, observational study. Level III multidisciplinary Neonatal and Pediatric Intensive Care Unit. Fifty-eight near-term artificially ventilated transported neonates between May 2006 and April 2007. Day-helicopter, day- and night-ground transportation. Heart rate at retrieval, on admission to the ICU and 1 h later, and peripheral blood leukocyte counts on admission and 1 d later were compared. Fifteen neonates were transported by helicopter during the daytime (D-HEL), 20 by daytime ground and 23 by nighttime ground transportation (D-GROUND, N-GROUND). No differences in delivery mode, birth weight, gestational age, gender, primary diagnoses for transportation, response time and duration of transportation were found between the groups. Similarly, no differences in pH, pCO(2), blood pressure and skin temperature at retrieval and on admission to the ICU were found between the three groups. The mean heart rate at retrieval did not differ significantly, while on arrival in the ICU and 1 h later the D-GROUND group of patients showed a significantly higher mean heart rate compared to the D-HEL and N-GROUND groups. Moreover, leukocyte counts on arrival in the ICU showed significantly higher leukocyte counts in the D-GROUND group of patients compared to the D-HEL group of patients. These results demonstrate that there is an association between daytime ground transportation and higher heart rate and peripheral blood leukocytes.

  5. The impact of area residential property values on self-rated health: A cross-sectional comparative study of Seattle and Paris

    Directory of Open Access Journals (Sweden)

    Junfeng Jiao

    2016-12-01

    Full Text Available This study analyzed the impact of area residential property values, an objective measure of socioeconomic status (SES, on self-rated health (SRH in Seattle, Washington and Paris, France. This study brings forth a valuable comparison of SRH between cities that have contrasting urban forms, population compositions, residential segregation, food systems and transportation modes. The SOS (Seattle Obesity Study was based on a representative sample of 1394 adult residents of Seattle and King County in the United States. The RECORD Study (Residential Environment and Coronary Heart Disease was based on 7131 adult residents of Paris and its suburbs in France. Socio-demographics, SRH and body weights were obtained from telephone surveys (SOS and in-person interviews (RECORD. All home addresses were geocoded using ArcGIS 9.3.1 (ESRI, Redlands, CA. Residential property values were obtained from tax records (Seattle and from real estate sales (Paris. Binary logistic regression models were used to test the associations among demographic and SES variables and SRH. Higher area property values significantly associated with better SRH, adjusting for age, gender, individual education, incomes, and BMI. The associations were significant for both cities. A one-unit increase in body mass index (BMI was more detrimental to SRH in Seattle than in Paris. In both cities, higher area residential property values were related to a significantly lower obesity risk and better SRH. Ranked residential property values can be useful for health and weight studies, including those involving social inequalities and cross-country comparisons.

  6. Anaesthesia ventilators

    Directory of Open Access Journals (Sweden)

    Rajnish K Jain

    2013-01-01

    Full Text Available Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV. PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits.

  7. Anaesthesia ventilators.

    Science.gov (United States)

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-09-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits.

  8. Anaesthesia ventilators

    Science.gov (United States)

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-01-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits. PMID:24249886

  9. Optimal Chest Compression Rate and Compression to Ventilation Ratio in Delivery Room Resuscitation: Evidence from Newborn Piglets and Neonatal Manikins

    Science.gov (United States)

    Solevåg, Anne Lee; Schmölzer, Georg M.

    2017-01-01

    Cardiopulmonary resuscitation (CPR) duration until return of spontaneous circulation (ROSC) influences survival and neurologic outcomes after delivery room (DR) CPR. High quality chest compressions (CC) improve cerebral and myocardial perfusion. Improved myocardial perfusion increases the likelihood of a faster ROSC. Thus, optimizing CC quality may improve outcomes both by preserving cerebral blood flow during CPR and by reducing the recovery time. CC quality is determined by rate, CC to ventilation (C:V) ratio, and applied force, which are influenced by the CC provider. Thus, provider performance should be taken into account. Neonatal resuscitation guidelines recommend a 3:1 C:V ratio. CCs should be delivered at a rate of 90/min synchronized with ventilations at a rate of 30/min to achieve a total of 120 events/min. Despite a lack of scientific evidence supporting this, the investigation of alternative CC interventions in human neonates is ethically challenging. Also, the infrequent occurrence of extensive CPR measures in the DR make randomized controlled trials difficult to perform. Thus, many biomechanical aspects of CC have been investigated in animal and manikin models. Despite mathematical and physiological rationales that higher rates and uninterrupted CC improve CPR hemodynamics, studies indicate that provider fatigue is more pronounced when CC are performed continuously compared to when a pause is inserted after every third CC as currently recommended. A higher rate (e.g., 120/min) is also more fatiguing, which affects CC quality. In post-transitional piglets with asphyxia-induced cardiac arrest, there was no benefit of performing continuous CC at a rate of 90/min. Not only rate but duty cycle, i.e., the duration of CC/total cycle time, is a known determinant of CC effectiveness. However, duty cycle cannot be controlled with manual CC. Mechanical/automated CC in neonatal CPR has not been explored, and feedback systems are under-investigated in this

  10. Whole house particle removal and clean air delivery rates for in-duct and portable ventilation systems.

    Science.gov (United States)

    Macintosh, David L; Myatt, Theodore A; Ludwig, Jerry F; Baker, Brian J; Suh, Helen H; Spengler, John D

    2008-11-01

    A novel method for determining whole house particle removal and clean air delivery rates attributable to central and portable ventilation/air cleaning systems is described. The method is used to characterize total and air-cleaner-specific particle removal rates during operation of four in-duct air cleaners and two portable air-cleaning devices in a fully instrumented test home. Operation of in-duct and portable air cleaners typically increased particle removal rates over the baseline rates determined in the absence of operating a central fan or an indoor air cleaner. Removal rates of 0.3- to 0.5-microm particles ranged from 1.5 hr(-1) during operation of an in-duct, 5-in. pleated media filter to 7.2 hr(-1) for an in-duct electrostatic air cleaner in comparison to a baseline rate of 0 hr(-1) when the air handler was operating without a filter. Removal rates for total particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) mass concentrations were 0.5 hr(-1) under baseline conditions, 0.5 hr(-1) during operation of three portable ionic air cleaners, 1 hr(-1) for an in-duct 1-in. media filter, 2.4 hr(-1) for a single high-efficiency particle arrestance (HEPA) portable air cleaner, 4.6 hr(-1) for an in-duct 5-in. media filter, 4.7 hr(-1) during operation of five portable HEPA filters, 6.1 hr(-1) for a conventional in-duct electronic air cleaner, and 7.5 hr(-1) for a high efficiency in-duct electrostatic air cleaner. Corresponding whole house clean air delivery rates for PM2.5 attributable to the air cleaner independent of losses within the central ventilation system ranged from 2 m3/min for the conventional media filter to 32 m3/min for the high efficiency in-duct electrostatic device. Except for the portable ionic air cleaner, the devices considered here increased particle removal indoors over baseline deposition rates.

  11. Anaesthesia ventilators

    OpenAIRE

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-01-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bello...

  12. Residential Surrounding Greenness, Self-Rated Health and Interrelations with Aspects of Neighborhood Environment and Social Relations.

    Science.gov (United States)

    Orban, Ester; Sutcliffe, Robynne; Dragano, Nico; Jöckel, Karl-Heinz; Moebus, Susanne

    2017-04-01

    Previous research suggests that green environments positively influence health. Several underlying mechanisms have been discussed; one of them is facilitation of social interaction. Further, greener neighborhoods may appear more aesthetic, contributing to satisfaction and well-being. Aim of this study was to analyze the association of residential surrounding greenness with self-rated health, using data from 4480 women and men aged 45-75 years that participated in the German population-based Heinz Nixdorf Recall study. We further aimed to explore the relationships of greenness and self-rated health with the neighborhood environment and social relations. Surrounding greenness was measured using the Normalized Difference Vegetation Index (NDVI) within 100 m around participants' residence. As a result, we found that with higher greenness, poor self-rated health decreased (adjusted OR 0.90, 95% CI 0.82-0.98; per 0.1 increase in NDVI), while neighborhood satisfaction (1.41, 1.23-1.61) and neighborhood social capital (1.22, 1.12-1.32) increased. Further, we observed inverse associations of neighborhood satisfaction (0.70, 0.52-0.94), perceived safety (0.36, 0.22-0.60), social satisfaction (0.43, 0.31-0.58), and neighborhood social capital (0.53, 0.44-0.64) with poor self-rated health. These results underline the importance of incorporating green elements into neighborhoods for health-promoting urban development strategies.

  13. Paying the full cost of power : an indicative comparative analysis of residential electricity rates across Canadian provinces

    International Nuclear Information System (INIS)

    Goulding, A.J.; Sabatier, G.

    2005-01-01

    This study was commissioned to review electricity rates charged to residential consumers across Canada and to determine how the basics of ratemaking change from province to province. Rates in each province vary significantly due to differences in the industry structure and their resource base. It was noted that direct comparisons are difficult because some rates reflect the financing, fuel and opportunity costs of power. For that reason, a simple adjustment factor was developed for fair comparison between jurisdictions. This assessment compared the all-in cost to final consumers which includes power generation, transmission, distribution and all other charges, as calculated by Statistics Canada. It was revealed that Alberta is Canada's only province where prices to final consumers reflect the market value of the underlying commodity. Ratepayers have the advantage of not being responsible for bad investment choices in the power sector and there are no hidden subsidies due to provincial ownership of power resources. Another consumer advantage is that they receive appropriate price signals in terms of energy consumption and conservation. This report suggests that low electricity rates in other provinces can be expected to rise much more rapidly than those in Alberta in the coming decade as consumers may be charged the full value of the electricity they use. 18 refs., 9 figs

  14. Dataset for Probabilistic estimation of residential air exchange rates for population-based exposure modeling

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset provides the city-specific air exchange rate measurements, modeled, literature-based as well as housing characteristics. This dataset is associated with...

  15. Thermal Plumes in Ventilated Rooms

    DEFF Research Database (Denmark)

    Kofoed, P.; Nielsen, Peter Vilhelm

    The main objective of ventilation is to provide good air quality for the occupants. For this purpose the necessary ventilating air change rate must be determined. Within displacement ventilation the estimation is closely related to the air flow rate in the thermal plumes when an air quality based...

  16. The effect of low ventilation rate with elevated bioeffluent concentration on work performance, perceived indoor air quality, and health symptoms.

    Science.gov (United States)

    Maula, H; Hongisto, V; Naatula, V; Haapakangas, A; Koskela, H

    2017-11-01

    The aim of this laboratory experiment was to study the effects of ventilation rate, and related changes in air quality, predominantly bioeffluents, on work performance, perceived indoor air quality, and health symptoms in a typical conditions of modern open-plan office with low material and equipment emissions. In Condition A, outdoor air flow rate of 28.2 l/s person (CO 2 level 540 ppm) was applied and in Condition B, outdoor air flow rate was 2.3 l/s person (CO 2 level 2260 ppm). CO 2 concentration level was used as an indicator of bioeffluents. Performance was measured with seven different tasks which measure different cognitive processes. Thirty-six subjects participated in the experiment. The exposure time was 4 hours. Condition B had a weak negative effect on performance only in the information retrieval tasks. Condition B increased slightly subjective workload and perceived fatigue. No effects on health symptoms were found. The intensity of symptoms was low in both conditions. The experimental condition had an effect on perceived air quality and observed odor intensity only in the beginning of the session. Although the room temperature was controlled in both conditions, the heat was perceived to impair the performance more in Condition B. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Can we establish relationship between outdoor air ventilation and health based on the published epidemiological data?

    DEFF Research Database (Denmark)

    Carrer, Paolo; Wargocki, Pawel; Fanetti, Annaclara

    2015-01-01

    Appropriate exposure control is prerogative for reducing the burden of disease (BOD) due to inadequate air quality indoors (IAQ). Ventilation with outdoor air is one of the available exposure control methods and is widespread. It is often assumed that this method will bring tangible effects...... exposures at various levels of ventilation were no characterized. It was observed that available data have many limitations, such as insufficient statistical power, incomplete data on the strength of pollution sources, diversity and variability of ventilation rates, at which effects have been seen...... exposures affecting health. It is concluded, that currently available epidemiological data do not provide sound basis for outdoor air ventilation requirements that can be universally applicable in different public and residential buildings to protect against health risks. They show minimum rates at which...

  18. Displacement ventilation

    DEFF Research Database (Denmark)

    Kosonen, Risto; Melikov, Arsen Krikor; Mundt, Elisabeth

    The aim of this Guidebook is to give the state-of-the art knowledge of the displacement ventilation technology, and to simplify and improve the practical design procedure. The Guidebook discusses methods of total volume ventilation by mixing ventilation and displacement ventilation and it gives...... insights of the performance of the displacement ventilation. It also shows practical case studies in some typical applications and the latest research findings to create good local micro-climatic conditions....

  19. Decrease in delivery room intubation rates after use of nasal intermittent positive pressure ventilation in the delivery room for resuscitation of very low birth weight infants.

    Science.gov (United States)

    Biniwale, Manoj; Wertheimer, Fiona

    2017-07-01

    The literature supports minimizing duration of invasive ventilation to decrease lung injury in premature infants. Neonatal Resuscitation Program recommended use of non-invasive ventilation (NIV) in delivery room for infants requiring prolonged respiratory support. To evaluate the impact of implementation of non-invasive ventilation (NIV) using nasal intermittent positive pressure ventilation (NIPPV) for resuscitation in very low birth infants. Retrospective study was performed after NIPPV was introduced in the delivery room and compared with infants receiving face mask to provide positive pressure ventilation for resuscitation of very low birth weight infants prior to its use. Data collected from 119 infants resuscitated using NIPPV and 102 infants resuscitated with a face mask in a single institution. The primary outcome was the need for endotracheal intubation in the delivery room. Data was analyzed using IBM SPSS Statistics software version 24. A total of 31% of infants were intubated in the delivery room in the NIPPV group compared to 85% in the Face mask group (p=rates were 11% in the NIPPV group and 31% in the Face mask group (p<0.001). Epinephrine administration was also lower in NIPPV group (2% vs. 8%; P=0.03). Only 38% infants remained intubated at 24hours of age in the NIPPV group compared to 66% in the Face mask group (p<0.001). Median duration of invasive ventilation in the NIPPV group was shorter (2days) compared to the Face mask group (11days) (p=0.01). The incidence of air-leaks was not significant between the two groups. NIPPV was safely and effectively used in the delivery room settings to provide respiratory support for VLBW infants with less need for intubation, chest compressions, epinephrine administration and subsequent invasive ventilation. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Uncertainties in the Value of Bill Savings from Behind-the-Meter, Residential Photovoltaic Systems: The Roles of Electricity Market Conditions, Retail Rate Design, and Net Metering

    Science.gov (United States)

    Darghouth, Naim Richard

    Net metering has become a widespread policy mechanism in the U.S. for supporting customer adoption of distributed photovoltaics (PV), allowing customers with PV systems to reduce their electric bills by offsetting their consumption with PV generation, independent of the timing of the generation relative to consumption. Although net metering is one of the principal drivers for the residential PV market in the U.S., the academic literature on this policy has been sparse and this dissertation contributes to this emerging body of literature. This dissertation explores the linkages between the availability of net metering, wholesale electricity market conditions, retail rates, and the residential bill savings from behind-the-meter PV systems. First, I examine the value of the bill savings that customers receive under net metering and alternatives to net metering, and the associated role of retail rate design, based on current rates and a sample of approximately two hundred residential customers of California's two largest electric utilities. I find that the bill savings per kWh of PV electricity generated varies greatly, largely attributable to the increasing block structure of the California utilities' residential retail rates. I also find that net metering provides significantly greater bill savings than alternative compensation mechanisms based on avoided costs. However, retail electricity rates may shift as wholesale electricity market conditions change. I then investigate a potential change in market conditions -- increased solar PV penetrations -- on wholesale prices in the short-term based on the merit-order effect. This demonstrates the potential price effects of changes in market conditions, but also points to a number of methodological shortcomings of this method, motivating my usage of a long-term capacity investment and economic dispatch model to examine wholesale price effects of various wholesale market scenarios in the subsequent analysis. By developing

  1. Behavioral Treatments and Pharmacotherapy: Acceptability Ratings by Elderly Individuals in Residential Settings.

    Science.gov (United States)

    Burgio, Louis D.; Sinnott, Jan

    1990-01-01

    Presented residents of life care community and nursing homes with scenarios of older woman. Client varied by cognitive capacity and behavior problem (aggression, verbal abuse, noncompliance). Participants rated three treatments: differential reinforcement of incompatible behavior (DRI), time-out, and haloperidol. All treatments were acceptable;…

  2. Determination by a CFD code of the heat release rate in a confined and mechanically-ventilated compartment fire

    International Nuclear Information System (INIS)

    Nasr, Ayoub

    2011-01-01

    For several years, many experimental/numerical research programs have been carried out at IRSN in order to provide sufficient data on the burning process and understand the behavior of a pool fire in a confined and mechanically ventilated compartment. Several experimental tests have shown that in some cases, the oxygen concentration in the local decreases then stabilizes until fire extinction. The fuel mass loss rate is instantaneously adjusted according to the ventilation in the local, which may leads to a lower fuel consumption rate as compared to that in free atmosphere. The fire duration is then 2 to 3 times greater than that obtained in free atmosphere, which may damages some specific safety equipment used to reduce the spread of fire between compartments such as fire doors. The objective of this work is to propose a theoretical approach that allows the determination of the burning rate of fuels for pool fires in a closed compartment. Fuel response to vitiated air as well as burning enhancement due to hot gases and confinement should be taken into account. Thus, a theoretical formulation, based on an energy balance equation at the pool fire surface, was developed and compared with the empirical correlation of Peatross and Beyler before being implemented in a CFD code 'ISIS', developed at IRSN and validated against PRISME fire test results. The main advantage of this global approach is that no assumptions were made on the relative importance of each mode of heat transfer from the flame. In fact, the convective and the radiant components of the heat flux from the flame to the fuel surface were determined taking into account the air vitiation effect. In addition to this theoretical approach, an experimental work was conducted at the Institut PPRIME to study heptane pool fires in a reduced-scale fire compartment, in the aim to investigate the effects of vitiated air on fire parameters. These results were used to validate the theoretical formulation developed

  3. Demand Controlled Ventilation in a Combined Ventilation and Radiator System

    OpenAIRE

    Hesaraki, Arefeh; Holmberg, Sture

    2013-01-01

    With growing concerns for efficient and sustainable energy treatment in buildings there is a need for balanced and intelligent ventilation solutions. This paper presents a strategy for demand controlled ventilation with ventilation radiators, a combined heating and ventilation system. The ventilation rate was decreased from normal requirements (per floor area) of 0.375 l·s-1·m-2 to 0.100 l·s-1·m-2 when the residence building was un-occupied. The energy saving potential due to decreased ventil...

  4. Technology Solutions Case Study: Selecting Ventilation Systems for Existing Homes

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-12-01

    In multifamily buildings, particularly in the Northeast, exhaust ventilation strategies are the norm as a means of meeting both local exhaust and whole-unit mechanical ventilation rates. The issue of where the "fresh" air is coming from is gaining significance as air-tightness standards for enclosures become more stringent, and the normal leakage paths through the building envelope disappear. Researchers from the Consortium for Advanced Residential Buildings (CARB) found that the majority of high performance, new construction, multifamily housing in the Northeast use one of four general strategies for ventilation: continuous exhaust only with no designated supply or make-up air source, continuous exhaust with ducted make-up air to apartments, continuous exhaust with supply through a make-up air device integral to the unit HVAC, and continuous exhaust with supply through a passive inlet device, such as a trickle vent. Insufficient information is available to designers on how these various systems are best applied. In this project, the CARB team evaluated the four different strategies for providing make-up air to multifamily residential buildings and developed guidelines to help contractors and building owners choose the best ventilation systems.

  5. Ventilation measurements as an adjunct to radon measurements in buildings

    International Nuclear Information System (INIS)

    Knutson, E.O.; Franklin, H.

    1977-01-01

    The concentration of radon in a building is a function of the radon sources within the building and of the building's ventilation characteristics. To complement its radon measurement program, HASL is currently assessing apparatus and procedures for measuring building ventilation. Results are reported from ventilation measurements made in the laboratory and in a residential building

  6. RedVent. Turned off ventilation at night in schools - risks and opportunities; RedVent. Avstaengd ventilation paa natten i skolor - risker och moejligheter

    Energy Technology Data Exchange (ETDEWEB)

    Haegerhed Engman, Linda; Fyhr, Kristina; Langer, Sarka; Ruud, Svein; Ylmen, Peter

    2011-07-01

    Reduced ventilation rates or shutdown ventilation during nights is often being used in school buildings in order to save energy and can decrease the energy cost for heating and ventilation with at least 30 %. Swedish Building Regulations (BBR) allows reduced ventilation flow in non-residential buildings when no one is using the building but it must not give rise to adverse health effects or damage the building or its installations. Potential risks are mould- and moisture damages and indoor air quality problems. Another question is whether the shut down itself might lead to indoor air quality problems due to chemical reactions between outdoor air and indoor emissions built-up during the night. The study was divided into three steps; an interview with property managers and care-taker, calculations of energy saving potentials and a field study. Measurements were per-formed in one classroom for two weeks in April 2010. Different set-ups for ventilation flow during night time and air tightness of the building envelope were studied; ventilation shut down, intermittent ventilation (15 min every second hour) and continuous full speed ventilation during night. In the studied classroom, shutdown ventilation during nights did not significantly affect the indoor air quality in the classroom during the school day even though there were effects seen during the night. We found a somewhat higher moisture accumulation those nights when the ventilation was shut down and some fractions of particles during intermittent ventilation compared to continues full ventilation during night time. This specific school and classroom were well ventilated and there was no moisture supply from new building material or other types of moisture producing activities. Schools with lower day-time ventilation rates, moisture in building construction, IAQ- or dampness problems as well as buildings close to heavy traffic should analyse the conditions for the specific building before reducing ventilation to

  7. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students.

    Science.gov (United States)

    Scheer, Krista S; Siebrant, Sarah M; Brown, Gregory A; Shaw, Brandon S; Shaw, Ina

    Nintendo Wii, Sony Playstation Move , and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, oxygen consumption, and ventilation were measured at rest and during a graded exercise test in 10 males and 9 females (19.8 ± 0.33 y, 175.4 ± 2.0 cm, 80.2 ± 7.7 kg,). On another day, in a randomized order, the participants played Wii Boxing, K inect Boxing, and Move Gladiatorial Combat while heart rate, ventilation, and oxygen consumption were measured. There were no differences in heart rate (116.0 ± 18.3 vs. 119.3 ± 17.6 vs. 120.1 ± 17.6 beats/min), oxygen consumption (9.2 ± 3.0 vs. 10.6 ± 2.4 vs. 9.6 ± 2.4 ml/kg/min), or minute ventilation (18.9 ± 5.7 vs. 20.8 ± 8.0 vs. 19.7 ± 6.4 L/min) when playing Wii boxing, Kinect boxing, or Move Gladiatorial Combat (respectively). Playing Nintendo Wii Boxing, XBOX Kinect Boxing, and Sony PlayStation Move Gladiatorial Combat all increase heart rate, oxygen consumption, and ventilation above resting levels but there were no significant differences between gaming systems. Overall, playing a "physically active" home video game system does not meet the minimal threshold for moderate intensity physical activity, regardless of gaming system.

  8. Effective Recruitment Challenges Faced by the Hospitality Industry in Bangladesh: A Study on Selected Star Rated Residential Hotels

    Directory of Open Access Journals (Sweden)

    Kazi HUDA

    2014-12-01

    Full Text Available In Human Resource Management (HRM, Recruitment is the first and foremost issue to be considered with full of sincerity, because its role is to create a positive impression about the employer in the job market by ensuring effective stimuli for the job seekers. At the beginning, the study sets a picture that focuses on the importance of effective recruitment in the hospitality sector of Bangladesh and then the study details obligatory determinants of attracting efficient human resource for the development of this sector. The main objective of the paper is to study the status and the scopes of recruitment function in hospitality industry with focus towards star rated residential hotels. This study is based on primary data collection through a formal questionnaire. The questionnaire was of mixed mode with most questions in likert-type scale and few were dichotomous in nature. The key finding of the study is that recruitment is a highly challenging task in hospitality and it is quite evident that attractive compensation package is the key factor to attract potential employees. The need and scope to modernize the recruitment practices along with the line of company and employer branding ideas are also recommended in details. There is a long way to go on the way of conceptualizing and actualizing recruitment functions and practices. A paper like this can help to discuss and debate on the necessity of developing better recruitment cultural and conceptual change in these sectors.

  9. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students

    OpenAIRE

    SCHEER, KRISTA S.; SIEBRANT, SARAH M.; BROWN, GREGORY A.; SHAW, BRANDON S.; SHAW, INA

    2014-01-01

    Nintendo Wii, Sony Playstation Move, and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, o...

  10. A COMPARISON BETWEEN VENTILATION AND HEART RATE AS INDICATOR OF OXYGEN UPTAKE DURING DIFFERENT INTENSITIES OF EXERCISE

    Directory of Open Access Journals (Sweden)

    Jacques Prioux

    2010-03-01

    Full Text Available The aim of this study is to compare the relation between ventilation (VE and oxygen uptake (VO2 [VO2=ƒ(VE] and between heart rate (HR and VO2 [VO2=ƒ(HR]. Each one of the subjects performed three types of activities of different intensities (walking without load, walking with load and intermittent work. VO2, VE, and HR were measured continuously by using indirect calorimetry and an electrocardiogram. Linear regressions and coefficients of determination (r² were calculated to compare the relation VO2 =ƒ(VE and VO2 =ƒ(HR for two different regroupings: by session duration (r²session and by subject (r²subject. Results showed that r²session of the relation VO2 =ƒ(VE were significantly higher than those of the relation VO2 =ƒ(HR for steady state activities (walking with or without load during 3 or 6 min, p < 0.01 and for activities without oxygen consumption steady state (walking with or without load during 1 min, p < 0.01 and intermittent work, p < 0.05. VE is more strongly correlated with VO2 than with HR. This is a very promising approach to develop a new method to estimate energy expenditure

  11. Rate of driving a ventilation tunnel by means of the GPK heading machine using roof bolting and steel supports. [USSR

    Energy Technology Data Exchange (ETDEWEB)

    Cheremnov, V.I.; Kruglyak, A.S.; Miroshnikova, L.A.; Sharov, V.N.

    1983-05-01

    The paper discusses a method for strata control during mine drivage tested in the im. Voroshilov coal mine in 1982. A ventilation tunnel with a crosscut of 16.4 m/sup 2/ was driven in coal with compression strength coefficient from 0.8 to 1.0, argillites and aleurites in the floor and the roof with compression strength coefficient from 4 to 6. Mining depth was 150 m, water influx was low. The tunnel was driven by means of the GPK heading machine with a 1PNB-2 loader. The AMK support system which consisted of arched steel supports, steel beams for joining steel arches and of roof bolts was used. Arched supports were installed each 0.8 m. The roof between the arches was supported by a system of roof bolts and junction beams. Support design is shown in a scheme. Increasing support spacing to 0.8 m (instead of 0.5 m) and roof bolting permitted drivage rate to be increased and steel consumption to be significantly reduced (by 244 kg/m). (3 refs.)

  12. Ventilation rates in classrooms and performances of students. Preliminary study on their association; Ventilatiedebieten in klaslokalen en prestaties van scholieren

    Energy Technology Data Exchange (ETDEWEB)

    Shaughnessy, R.J. [The University of Tulsa, Tulsa, OK (United States); Haverinen-Shaughnessy, U.; Nevalainen, A. [Department of Environmental Health, National Public Health Institute, Kuopio (Finland); Moschandreas, D. [Department of Chemical and Environmental Engineering, Illinois Institute of Technology, Chicago, IL (United States)

    2007-10-15

    Poor conditions leading to sub-standard indoor air quality (IAQ) in classrooms have been frequently cited in the literature over the past two decades. However, there is limited data linking poor IAQ in the classrooms to student performance. Whereas, it is assumed that poor IAQ results in reduced attendance and learning potential, and subsequent poor student performance, validating this hypothesis presents a challenge in today's school environment. This study explores the association between student performance on standardized aptitude tests that are administered to students on a yearly basis, to classroom carbon dioxide (CO2) concentrations, which provide a surrogate of ventilation being provided to each room. Data on classroom CO2 concentrations (over a 4-5h time span within a typical school day) were recorded in fifth grade classrooms in 54 elementary schools within a school district in the USA. Results from this preliminary study yield a significant (P<0.10) association between classroom-level ventilation rate and test results in math. They also indicate that non-linear effects may need to be considered for better representation of the association. A larger sample size is required in order to draw more definitive conclusions. [Dutch] Slechte omstandigheden die leiden tot een benedenmaatse binnenluchtkwaliteit (Indoor Air Quality - IAQ) in klaslokalen, zijn in de afgelopen twee decennia regelmatig aangehaald in de literatuur. Toch zijn er weinig onderzoeksresultaten waarin een verband wordt gelegd tussen een slechte IAQ in klaslokalen en de prestatie van scholieren. Er wordt verondersteld dat een slechte IAQ resulteert in een verminderde aanwezigheid en in een verminderd vermogen om te studeren, en daarop volgend in een slechte schoolprestatie. Om die reden zal het valideren van deze hypothese een uitdaging vormen in de schoolomgeving van dit moment. Dit onderzoek bestudeert het verband tussen de prestaties van scholieren en de concentraties koolstofdioxide

  13. New opportunities for ventilation assistance in buildings under Saharan climatic conditions

    Directory of Open Access Journals (Sweden)

    Kaoulal Rabea

    2017-01-01

    Full Text Available The aim of this paper is devoted to the coupling of ventilation systems with buildings with low energy performances under a specific Saharan climate. In the second part, the objective is to diagnose and quantify energy consumptions due to the ventilation of a real residential building in Ghardaia site. As result, ventilation system can bring a positive support to the thermos-aeraulic comfort by controlling the mass flow rate of the air entering to the heated or/and cooled building zone. Heat losses due to the ventilation system represent 4.75% of the total losses; the provided heat exchange in this case requires an additional consumption of around 6.6058% of the total energy needs.

  14. VENTILATION MODEL

    International Nuclear Information System (INIS)

    V. Chipman

    2002-01-01

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their postclosure analyses

  15. [Anesthesia ventilators].

    Science.gov (United States)

    Otteni, J C; Beydon, L; Cazalaà, J B; Feiss, P; Nivoche, Y

    1997-01-01

    To review anaesthesia ventilators in current use in France by categories of ventilators. References were obtained from computerized bibliographic search. (Medline), recent review articles, the library of the service and personal files. Anaesthesia ventilators can be allocated into three groups, depending on whether they readminister expired gases or not or allow both modalities. Contemporary ventilators provide either constant volume ventilation, or constant pressure ventilation, with or without a pressure plateau. Ventilators readministering expired gases after CO2 absorption, or closed circuit ventilators, are either of a double- or a single-circuit design. Double-circuit ventilators, or pneumatical bag or bellows squeezers, or bag-in-bottle or bellows-in-bottle (or box) ventilators, consist of a primary, or driving circuit (bottle or box) and a secondary or patient circuit (including a bag or a bellows or membrane chambers). Bellows-in-bottle ventilators have either standing bellows ascending at expiration, or hanging bellows, descending at expiration. Ascending bellows require a positive pressure of about 2 cmH2O throughout exhalation to allow the bellows to refill. The expired gas volume is a valuable indicator for leak and disconnection. Descending bellows generate a slight negative pressure during exhalation. In case of leak or disconnection they aspirate ambient air and cannot act therefore as an indicator for integrity of the circuit and the patient connection. Closed circuit ventilators with a single-circuit (patient circuit) include a insufflating device consisting either in a bellows or a cylinder with a piston, operated by a electric or pneumatic motor. As the hanging bellows of the double circuit ventilators, they generate a slight negative pressure during exhalation and aspirate ambient air in case of leak or disconnection. Ventilators not designed for the readministration of expired gases, or open circuit ventilators, are generally stand

  16. Ventilation models

    Science.gov (United States)

    Skaaret, Eimund

    Calculation procedures, used in the design of ventilating systems, which are especially suited for displacement ventilation in addition to linking it to mixing ventilation, are addressed. The two zone flow model is considered and the steady state and transient solutions are addressed. Different methods of supplying air are discussed, and different types of air flow are considered: piston flow, plane flow and radial flow. An evaluation model for ventilation systems is presented.

  17. Industrial ventilation

    Science.gov (United States)

    Goodfellow, H. D.

    Industrial ventilation design methodology, using computers and using fluid dynamic models, is considered. It is noted that the design of a ventilation system must be incorporated into the plant design and layout at the earliest conceptual stage of the project. A checklist of activities concerning the methodology for the design of a ventilation system for a new facility is given. A flow diagram of the computer ventilation model shows a typical input, the initialization and iteration loop, and the output. The application of the fluid dynamic modeling techniques include external and internal flow fields, and individual sources of heat and contaminants. Major activities for a ventilation field test program are also addressed.

  18. Indoor particle dynamics in a school office: determination of particle concentrations, deposition rates and penetration factors under naturally ventilated conditions.

    Science.gov (United States)

    Cong, X C; Zhao, J J; Jing, Z; Wang, Q G; Ni, P F

    2018-05-09

    Recently, the problem of indoor particulate matter pollution has received much attention. An increasing number of epidemiological studies show that the concentration of atmospheric particulate matter has a significant effect on human health, even at very low concentrations. Most of these investigations have relied upon outdoor particle concentrations as surrogates of human exposures. However, considering that the concentration distribution of the indoor particulate matter is largely dependent on the extent to which these particles penetrate the building and on the degree of suspension in the indoor air, human exposures to particles of outdoor origin may not be equal to outdoor particle concentration levels. Therefore, it is critical to understand the relationship between the particle concentrations found outdoors and those found in indoor micro-environments. In this study, experiments were conducted using a naturally ventilated office located in Qingdao, China. The indoor and outdoor particle concentrations were measured at the same time using an optical counter with four size ranges. The particle size distribution ranged from 0.3 to 2.5 μm, and the experimental period was from April to September, 2016. Based on the experimental data, the dynamic and mass balance model based on time was used to estimate the penetration rate and deposition rate at air exchange rates of 0.03-0.25 h -1 . The values of the penetration rate and deposition velocity of indoor particles were determined to range from 0.45 to 0.82 h -1 and 1.71 to 2.82 m/h, respectively. In addition, the particulate pollution exposure in the indoor environment was analyzed to estimate the exposure hazard from indoor particulate matter pollution, which is important for human exposure to particles and associated health effects. The conclusions from this study can serve to provide a better understanding the dynamics and behaviors of airborne particle entering into buildings. And they will also highlight

  19. Uranium mine ventilation

    International Nuclear Information System (INIS)

    Katam, K.; Sudarsono

    1982-01-01

    Uranium mine ventilation system aimed basically to control and decreasing the air radioactivity in mine caused by the radon emanating from uranium ore. The control and decreasing the air ''age'' in mine, with adding the air consumption volume, increasing the air rate consumption, closing the mine-out area; using closed drainage system. Air consumption should be 60m 3 /minute for each 9m 2 uranium ore surfaces with ventilation rate of 15m/minute. (author)

  20. Validation of CARE-Q in residential aged-care: rating of importance of caring behaviours from an e-cohort sub-study.

    Science.gov (United States)

    Tuckett, Anthony G; Hughes, Karen; Schluter, Philip J; Turner, Cathy

    2009-05-01

    To validate the Caring Assessment Report Evaluation Q-sort questionnaire in the residential aged-care setting. Based on this determination, to conclude with what degree of confidence the questionnaire can be used to determine the ranking of the importance of caring behaviours amongst aged-care nurses and residents in residential aged-care. Perceptions of caring may be context specific. Caring in residential aged-care may stand in contrast to the sense of caring understood and practiced in other settings. Self-administered survey. Residents from three not-for-profit aged-care facilities, across both high-care (nursing-home) and low-care (hostel care) were surveyed relying on the Caring Assessment Report Evaluation Q-sort questionnaire. A sub-sample of registered and enrolled nurses working in residential aged-care and registered with the Nurses & Midwives e-cohort study completed the same survey. Although the Caring Assessment Report Evaluation Q-sort questionnaire showed good internal consistency for the sample of nurses, the results for the residents were more erratic. Both groups displayed large ranges for the inter-item correlations. The results of the Mann-Whitney U-test indicated that the nurses rated the Comforts, Anticipates and Trusting relationship as significantly more important than the residents. Both groups rated the Explains and facilitates subscale as least important. All subscales, however, received median scores greater than, or equal to, six (seven-point, Likert scale) indicating that all were considered important overall. Based on poor Cronbach's alpha coefficients, negative inter-item correlations and qualitative observations, without further development within the residential aged-care facility the free response format version of the Caring Assessment Report Evaluation Q-sort may not be an appropriate measure to use with residential aged-care residents. More research needs to be conducted into how residents and nurses are interpreting the items

  1. Bench performance of ventilators during simulated paediatric ventilation.

    Science.gov (United States)

    Park, M A J; Freebairn, R C; Gomersall, C D

    2013-05-01

    This study compares the accuracy and capabilities of various ventilators using a paediatric acute respiratory distress syndrome lung model. Various compliance settings and respiratory rate settings were used. The study was done in three parts: tidal volume and FiO2 accuracy; pressure control accuracy and positive end-expiratory pressure (PEEP) accuracy. The parameters set on the ventilator were compared with either or both of the measured parameters by the test lung and the ventilator. The results revealed that none of the ventilators could consistently deliver tidal volumes within 1 ml/kg of the set tidal volume, and the discrepancy between the delivered volume and the volume measured by the ventilator varied greatly. The target tidal volume was 8 ml/kg, but delivered tidal volumes ranged from 3.6-11.4 ml/kg and the volumes measured by the ventilator ranged from 4.1-20.6 ml/kg. All the ventilators maintained pressure within 20% of the set pressure, except one ventilator which delivered pressures of up to 27% higher than the set pressure. Two ventilators maintained PEEP within 10% of the prescribed PEEP. The majority of the readings were also within 10%. However, three ventilators delivered, at times, PEEPs over 20% higher. In conclusion, as lung compliance decreases, especially in paediatric patients, some ventilators perform better than others. This study highlights situations where ventilators may not be able to deliver, nor adequately measure, set tidal volumes, pressure, PEEP or FiO2.

  2. Mine ventilation engineering

    Energy Technology Data Exchange (ETDEWEB)

    Hall, C.J.

    1981-01-01

    This book on mine ventilation covers psychometrics, airflow through roadways and ducts, natural ventilation, fans, instruments, ventilation surveys, auxiliary ventilation, air quality, and planning and economics.

  3. Noninvasive ventilation.

    Science.gov (United States)

    Rabatin, J T; Gay, P C

    1999-08-01

    Noninvasive ventilation refers to the delivery of assisted ventilatory support without the use of an endotracheal tube. Noninvasive positive pressure ventilation (NPPV) can be delivered by using a volume-controlled ventilator, a pressure-controlled ventilator, a bilevel positive airway pressure ventilator, or a continuous positive airway pressure device. During the past decade, there has been a resurgence in the use of noninvasive ventilation, fueled by advances in technology and clinical trials evaluating its use. Several manufacturers produce portable devices that are simple to operate. This review describes the equipment, techniques, and complications associated with NPPV and also the indications for both short-term and long-term applications. NPPV clearly represents an important addition to the techniques available to manage patients with respiratory failure. Future clinical trials evaluating its many clinical applications will help to define populations of patients most apt to benefit from this type of treatment.

  4. Induced radioactivity in air-estimation of ventilation rates at the vault and experimental areas of the proposed K-500 superconducting cyclotron, Calcutta

    International Nuclear Information System (INIS)

    Ravishankar, R.

    1999-01-01

    Guidelines are given for the necessary ventilation rates in vault and experimental areas from radiological safety point of view, for the proposed K-500 super-conducting cyclotron at Calcutta. A method is presented for estimating the amount of short lived radioisotopes like 13 N and 15 O taking the (n,2n) mode of productions. Considering the operating conditions of K-500 machine for the production of maximum neutron flux (300 MeV, 50pnA Li beam on Ta target) the energy differential neutron flux and the energy differential production cross section of 13 N and 15 O have been generated using ALICE-91 computer code. The differential cross sections have been folded with radial neutron flux distribution and then integrated over the entire volume of the cyclotron vault, to obtain the total production of the two radioactive gases. The DAC values have been obtained by considering the immersion dose in a semi-infinite hemispherical cloud. Natural decay and removal due to ventilation have been considered to get the recommended ventilation rates. (author)

  5. Ventilation, indoor air quality, and health in homes undergoing weatherization.

    Science.gov (United States)

    Francisco, P W; Jacobs, D E; Targos, L; Dixon, S L; Breysse, J; Rose, W; Cali, S

    2017-03-01

    Ventilation standards, health, and indoor air quality have not been adequately examined for residential weatherization. This randomized trial showed how ASHRAE 62-1989 (n=39 houses) and ASHRAE 62.2-2010 (n=42 houses) influenced ventilation rates, moisture balance, indoor air quality, and self-reported physical and mental health outcomes. Average total airflow was nearly twice as high for ASHRAE 62.2-2010 (79 vs. 39 cfm). Volatile organic compounds, formaldehyde and carbon dioxide were all significantly reduced for the newer standard and first-floor radon was marginally lower, but for the older standard, only formaldehyde significantly decreased. Humidity in the ASHRAE 62.2-2010 group was only about half that of the ASHRAE 62-1989 group using the moisture balance metric. Radon was higher in the basement but lower on the first floor for ASHRAE 62.2-2010. Children in each group had fewer headaches, eczema, and skin allergies after weatherization and adults had improvements in psychological distress. Indoor air quality and health improve when weatherization is accompanied by an ASHRAE residential ventilation standard, and the 2010 ASHRAE standard has greater improvements in certain outcomes compared to the 1989 standard. Weatherization, home repair, and energy conservation projects should use the newer ASHRAE standard to improve indoor air quality and health. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. A comparison between tracer gas and aerosol particles distribution indoors: The impact of ventilation rate, interaction of airflows, and presence of objects

    DEFF Research Database (Denmark)

    Bivolarova, Mariya Petrova; Ondráček, Jakub; Melikov, Arsen Krikor

    2017-01-01

    for the exposure to all different-sized test particles. A change in the ventilation rate did not affect the difference in concentration distribution between tracer gas and larger particle sizes. Increasing the room surface area did not influence the similarity in the dispersion of the aerosol particles...... room with mixing ventilation. Three layouts were arranged: an empty room, an office room with an occupant sitting in front of a table, and a single-bed hospital room. The room occupant was simulated by a thermal manikin. Monodisperse particles of three sizes (0.07, 0.7, and 3.5 μm) and nitrous oxide...... tracer gas were generated simultaneously at the same location in the room. The particles and gas concentrations were measured in the bulk room air, in the breathing zone of the manikin, and in the exhaust air. Within the breathing zone of the sitting occupant, the tracer gas emerged as reliable predictor...

  7. Displacement Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    Displacement ventilation is an interesting new type of air distribution principle which should be considered in connection with design of comfort ventilation in both smal1 and large spaces. Research activities on displacement ventilation are large all over the world and new knowledge of design...... methods appears continuously. This book gives an easy introduction to the basis of displacement ventilation and the chapters are written in the order which is used in a design procedure. The main text is extended by five appendices which show some of the new research activities taking place at Aalborg...

  8. Demand Controlled Ventilation and Classroom Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mendell, Mark J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davies, Molly [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Eliseeva, Ekaterina [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hong, Tienzen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sullivan, Douglas P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-05-01

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling.

  9. Demand controlled ventilation and classroom ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mendell, Mark J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davies, Molly [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Eliseeva, Ekaterina [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hong, Tienzen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sullivan, Douglas P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-01-06

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling.

  10. IEA Project on Indoor Air Quality Design and Control in Low Energy Residential Buildings

    DEFF Research Database (Denmark)

    Rode, Carsten; Abadie, Marc; Qin, Menghao

    2016-01-01

    with heat recovery systems, one of the next focal points to limiting energy consumption for thermally conditioning the indoor environment will be to possibly reducing the ventilation rate, or to make it in a new way demand controlled. However, this must be done such that it has no have adverse effects...... on Indoor Air Quality (IAQ). Annex 68, Indoor Air Quality Design and Control in Low Energy Residential Buildings, is a project under IEA’s Energy Conservation in Buildings and Communities Program (EBC), which will endeavor to investigate how future residential buildings are able to have very high energy...... performance whilst providing comfortable and healthy indoor environments. New paradigms for demand control of ventilation will be investigated, which consider the pollution loads and occupancy in buildings. The thermal and moisture conditions of such will be considered because of interactions between...

  11. Equivalence in Ventilation and Indoor Air Quality

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max; Walker, Iain; Logue, Jennifer

    2011-08-01

    We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.

  12. Behovstyret ventilation

    DEFF Research Database (Denmark)

    Afshari, Alireza; Heiselberg, Per; Reinhold, Claus

    2010-01-01

    I en nylig afsluttet undersøgelse er der udført en række målinger på otte udvalgte børneinstitutioner. Fire af disse med mekanisk ventilation og fire med naturlig ventilation. Formålet er at udvide den erfaringsbaserede viden om funktionen af naturlige og mekaniske ventilationsløsninger i...

  13. Ventilation Model

    International Nuclear Information System (INIS)

    Yang, H.

    1999-01-01

    The purpose of this analysis and model report (AMR) for the Ventilation Model is to analyze the effects of pre-closure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts and provide heat removal data to support EBS design. It will also provide input data (initial conditions, and time varying boundary conditions) for the EBS post-closure performance assessment and the EBS Water Distribution and Removal Process Model. The objective of the analysis is to develop, describe, and apply calculation methods and models that can be used to predict thermal conditions within emplacement drifts under forced ventilation during the pre-closure period. The scope of this analysis includes: (1) Provide a general description of effects and heat transfer process of emplacement drift ventilation. (2) Develop a modeling approach to simulate the impacts of pre-closure ventilation on the thermal conditions in emplacement drifts. (3) Identify and document inputs to be used for modeling emplacement ventilation. (4) Perform calculations of temperatures and heat removal in the emplacement drift. (5) Address general considerations of the effect of water/moisture removal by ventilation on the repository thermal conditions. The numerical modeling in this document will be limited to heat-only modeling and calculations. Only a preliminary assessment of the heat/moisture ventilation effects and modeling method will be performed in this revision. Modeling of moisture effects on heat removal and emplacement drift temperature may be performed in the future

  14. Demand controlled ventilation in a bathroom

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig; Nielsen, Toke Rammer; Topp, Claus

    2008-01-01

    consumption during periods where the demand for ventilation is low and poor indoor climate during periods where the demand for ventilation is high. Controlling the ventilation rate by demand can improve the energy performance of the ventilation system and the indoor climate. This paper compares the indoor...... climate and energy consumption of a Constant Air Volume (CAV) system and a Demand Controlled Ventilation (DCV) system for two different bathroom designs. The air change rate of the CAV system corresponded to 0.5h-1. The ventilation rate of the DCV system was controlled by occupancy and by the relative...

  15. Liquid Ventilation

    Directory of Open Access Journals (Sweden)

    Qutaiba A. Tawfic

    2011-01-01

    Full Text Available Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. Keywords: Liquid ventilation; perfluorochemicals; perfluorocarbon; respiratory distress; surfactant.

  16. Ventilative Cooling

    DEFF Research Database (Denmark)

    Heiselberg, Per Kvols; Kolokotroni, Maria

    This report, by venticool, summarises the outcome of the work of the initial working phase of IEA ECB Annex 62 Ventilative Cooling and is based on the findings in the participating countries. It presents a summary of the first official Annex 62 report that describes the state-of-the-art of ventil......This report, by venticool, summarises the outcome of the work of the initial working phase of IEA ECB Annex 62 Ventilative Cooling and is based on the findings in the participating countries. It presents a summary of the first official Annex 62 report that describes the state......-of-the-art of ventilative cooling potentials and limitations, its consideration in current energy performance regulations, available building components and control strategies and analysis methods and tools. In addition, the report provides twenty six examples of operational buildings using ventilative cooling ranging from...

  17. A numerical study on the performance evaluation of ventilation systems for indoor radon reduction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Eun; Park, Hoon Chae; Choi, Hang Seok; Cho, Seung Yeon; Jeong, Tae Young; Roh, Sung Cheoul [Yonsei University, Wonju (Korea, Republic of)

    2016-03-15

    Numerical simulations were conducted using computational fluid dynamics to evaluate the effect of ventilation conditions on radon ({sup 222}Rn) reduction performance in a residential building. The results indicate that at the same ventilation rate, a mechanical ventilation system is more effective in reducing indoor radon than a natural ventilation system. For the same ventilation type, the indoor radon concentration decreases as the ventilation rate increases. When the air change per hour (ACH) was 1, the indoor radon concentration was maintained at less than 100 Bq/m{sup 3}. However, when the ACH was lowered to 0.01, the average indoor radon concentration in several rooms exceeded 148 Bq/ m{sup 3}. The angle of the inflow air was found to affect the indoor air stream and consequently the distribution of the radon concentration. Even when the ACH was 1, the radon concentrations of some areas were higher than 100 Bq/m{sup 3} for inflow air angles of 5 .deg. and 175 .deg.

  18. Residential Care

    Science.gov (United States)

    ... Kids For Teens For Parents & Teachers Resolving Family Conflicts The Holidays and Alzheimer's Glossary Virtual Library Online ... longer an option Costs Choosing a care setting Types of residential care A good long-term care ...

  19. Estimation of time-varying pollutant emission rates in a ventilated enclosure: inversion of a reduced model obtained by experimental application of the modal identification method

    International Nuclear Information System (INIS)

    Girault, M; Maillet, D; Bonthoux, F; Galland, B; Martin, P; Braconnier, R; Fontaine, J R

    2008-01-01

    A method is proposed for the estimation of time-varying emission rates of pollutant sources in a ventilated enclosure, through the resolution of an inverse forced convection problem. Unsteady transport–diffusion of the pollutant is considered, with the assumption of a stationary velocity field remaining unchanged during emission (passive contaminant). The pollutant transport equation is therefore linear with respect to concentration. The source's location is also supposed to be known. As the first step, a reduced model (RM) linking concentrations at a set of control points to emission rates of sources is identified from experimental data by using the modal identification method (MIM). This parameter estimation problem uses transient contaminant concentration measurements made at control points inside the ventilated enclosure, corresponding to increasing and decreasing steps of emission rates. Such experimental modelling allows us to avoid dealing with a CFD code involving turbulence modelling and to get rid of uncertainties about sensors position. In a second step, the identified RM is used to solve an inverse forced convection problem: from contaminant concentration measured at the same control points, rates of sources emitting simultaneously are estimated with a sequential in time algorithm using future time steps

  20. Effects of ground surface decontamination on the air radiation dose rate. Results of a decontamination trial at a playground lot in a Fukushima residential area

    International Nuclear Information System (INIS)

    Tagawa, Akihiro

    2012-01-01

    The Japan Atomic Energy Agency decontaminated schools, playgrounds, swimming pools, and houses in nonevacuated, less-contaminated areas in Fukushima for environmental restoration. A small, 150 m 2 playground lot in the residential area was chosen for decontamination demonstration, which used routinely available tools and commodities to carry out the work. The surfaces of playground lot equipment, such as swings, slides, and horizontal iron bars, were completely decontaminated by brushing with water and/or detergent. Side gutters around the playground lot were cleaned by removing the mud and then brushed and washed with a high-pressure water jet (7 MPa). The air dose rate at the playground lot was dominated by radiation from the ground surface and adjacent surroundings, such as apartments and rice fields. Two or three centimeters of the surface soil contaminated with cesium was removed manually with shovels, hoes, and other gardening tools. This significantly reduced the average air dose rate of the entire playground lot from 1.5 μSv/h before decontamination to 0.6 μSv/h. These results showed that ground surface decontamination can contribute measurably to the reduction in air dose rate in relatively small areas in residential areas. (author)

  1. Exercise capacity and selected physiological factors by ancestry and residential altitude

    DEFF Research Database (Denmark)

    Bianba; Berntsen, Sveinung; Andersen, Lars Bo

    2014-01-01

    AIM: Several physiological compensatory mechanisms have enabled Tibetans to live and work at high altitude, including increased ventilation and pulmonary diffusion capacity, both of which serve to increase oxygen transport in the blood. The aim of the present study was to compare exercise capacity...... Tibetans vs. Han Chinese may reflect a better adaptation to life at high altitude. Tibetans at the lower residential altitude of 3700 m demonstrated a better exercise capacity than residents at a higher altitude of 4300 m when measured at their respective residential altitudes. Such altitude- or ancestry...... (maximal power output) and selected physiological factors (arterial oxygen saturation and heart rate at rest and during maximal exercise, resting hemoglobin concentration, and forced vital capacity) in groups of native Tibetan children living at different residential altitudes (3700 vs. 4300 m above sea...

  2. Performance evaluation of ventilation radiators

    International Nuclear Information System (INIS)

    Myhren, Jonn Are; Holmberg, Sture

    2013-01-01

    A ventilation radiator is a combined ventilation and heat emission unit currently of interest due to its potential for increasing energy efficiency in exhaust-ventilated buildings with warm water heating. This paper presents results of performance tests of several ventilation radiator models conducted under controlled laboratory conditions. The purpose of the study was to validate results achieved by Computational Fluid Dynamics (CFD) in an earlier study and identify possible improvements in the performance of such systems. The main focus was on heat transfer from internal convection fins, but comfort and health aspects related to ventilation rates and air temperatures were also considered. The general results from the CFD simulations were confirmed; the heat output of ventilation radiators may be improved by at least 20% without sacrificing ventilation efficiency or thermal comfort. Improved thermal efficiency of ventilation radiators allows a lower supply water temperature and energy savings both for heating up and distribution of warm water in heat pumps or district heating systems. A secondary benefit is that a high ventilation rate can be maintained all year around without risk for cold draught. -- Highlights: ► Low temperature heat emitters are currently of interest due to their potential for increasing energy efficiency. ► A ventilation radiator is a combined ventilation and heat emission unit which can be adapted to low temperature heating systems. ► We examine how ventilation radiators can be made to be more efficient in terms of energy consumption and thermal comfort. ► Current work focuses on heat transfer mechanisms and convection fin configuration of ventilation radiators

  3. Pretest Predictions for Ventilation Tests

    International Nuclear Information System (INIS)

    Y. Sun; H. Yang; H.N. Kalia

    2007-01-01

    The objective of this calculation is to predict the temperatures of the ventilating air, waste package surface, concrete pipe walls, and insulation that will be developed during the ventilation tests involving various test conditions. The results will be used as input to the following three areas: (1) Decisions regarding testing set-up and performance. (2) Assessing how best to scale the test phenomena measured. (3) Validating numerical approach for modeling continuous ventilation. The scope of the calculation is to identify the physical mechanisms and parameters related to thermal response in the ventilation tests, and develop and describe numerical methods that can be used to calculate the effects of continuous ventilation. Sensitivity studies to assess the impact of variation of linear power densities (linear heat loads) and ventilation air flow rates are included. The calculation is limited to thermal effect only

  4. Ventilator-associated pneumonia: the influence of bacterial resistance, prescription errors, and de-escalation of antimicrobial therapy on mortality rates

    Directory of Open Access Journals (Sweden)

    Ana Carolina Souza-Oliveira

    2016-09-01

    Conclusion: Prescription errors influenced mortality of patients with Ventilator-associated pneumonia, underscoring the challenge of proper Ventilator-associated pneumonia treatment, which requires continuous reevaluation to ensure that clinical response to therapy meets expectations.

  5. Minimum ventilation rates as a function of the use and the frequency of use of rooms. Final report. Mindestluftwechsel in Abhaengigkeit von der Nutzungsart und -intensitaet. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Wegner, J; Schlueter, G; Angerer, C; Meyer, H D

    1986-12-01

    From a hygienic view-point optimum indoor air quality can be characterized as the complete absence of pollutants. The most important sources of such pollutants are reviewed, amongst them those entering a room from outside, those generated by man and his activities and those emanating from different materials such as building materials, furnishing, cleansing and polishing agents. In view of achieving acceptable indoor conditions all emissions have to be kept as low as possible. Carbon dioxide and body odors as well as pollutants, the concentrations of which cannot be reduced to non-relevant levels by product control, should be eliminated by ventilation measures. However, such measures should not exceed a given limit, since in order to minimize energy consumption, air exchange rates have to be kept at a minimum. As a result of the investigations, it is concluded that the minimum ventilation rate should be derived from the acceptable CO/sub 2/ concentration. The concentrations of all other pollutants (e.g., formaldehyde) should be limited by product control or source removal. With 75 refs., 10 tabs., 19 figs.

  6. Residential and Light Commercial HVAC. Teacher Edition.

    Science.gov (United States)

    Stephenson, David; Fulkerson, Dan, Ed.

    This curriculum guide contains 18 units of instruction for a competency-based course in residential and light commercial heating, ventilating, and air conditioning (HVAC). Introductory materials include a competency profile and an instructional/task analysis that correlates job training with related information for this course. Each instructional…

  7. A simplified model for estimating population-scale energy impacts of building envelope air-tightening and mechanical ventilation retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Jennifer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Turner, William J. N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Trinity College Dublin, Dublin (Ireland); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-01-19

    Changing the air exchange rate of a home (the sum of the infiltration and mechanical ventilation airflow rates) affects the annual thermal conditioning energy. Large-scale changes to air exchange rates of the housing stock can significantly alter the residential sector's energy consumption. However, the complexity of existing residential energy models is a barrier to the accurate quantification of the impact of policy changes on a state or national level. The Incremental Ventilation Energy (IVE) model developed in this study combines the output of simple air exchange models with a limited set of housing characteristics to estimate the associated change in energy demand of homes. The IVE model was designed specifically to enable modellers to use existing databases of housing characteristics to determine the impact of ventilation policy change on a population scale. The IVE model estimates of energy change when applied to US homes with limited parameterisation are shown to be comparable to the estimates of a well-validated, complex residential energy model.

  8. Residential Waste

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde; Matsufuji, Y.

    2011-01-01

    are discussed in this chapter. Characterizing residential waste is faced with the problem that many residences already divert some waste away from the official collection systems, for example performing home composting of vegetable waste and garden waste, having their bundled newspaper picked up by the scouts...... twice a year or bringing their used furniture to the flea markets organized by charity clubs. Thus, much of the data available on residential waste represents collected waste and not necessarily all generated waste. The latter can only be characterized by careful studies directly at the source......, but such studies are very expensive if fair representation of both spatial and temporal variations should be obtained. In addition, onsite studies may affect the waste generation in the residence because of the increased focus on the issue. Residential waste is defined in different ways in different countries...

  9. Ventilation system design for educational facilities

    Energy Technology Data Exchange (ETDEWEB)

    Elsafty, A.F.; Abo Elazm, M.M. [Arab Academy for Science, Alexandria (Egypt). Technology and Maritime Transport; Safwan, M. [Arab Academy for Science, Cairo (Egypt). Technology and Maritime Transport

    2010-07-01

    In order to maintain acceptable indoor air quality levels in classrooms, high ventilation rates are needed to dilute the concentration of indoor contaminants, resulting in higher energy consumption for the operation of mechanical ventilation systems. Three factors are usually considered when determining the adequate ventilation rate for classrooms in educational facilities. These include the maximum population served in the classroom; carbon dioxide (CO{sub 2}) production rate by occupants; and outdoor air conditions. CO{sub 2} concentrations usually indicate the rate of ventilation required. This paper presented a newly developed computer software program for determining the ventilation rates needed to enhance indoor air quality and to maintain CO{sub 2} concentration within the recommended levels by ANSI/ASHRAE standards for best student performance. This paper also presented design curves for determining the ventilation rates and air changes per hour required for the ventilated educational zone. 15 refs., 2 tabs., 5 figs.

  10. Occupants’ Utilization of Natural Ventilation: A Study of Selected Terrace House Designs in Hot-humid Climate

    Directory of Open Access Journals (Sweden)

    Ibiyeye AI

    2015-05-01

    Full Text Available With increased time spent indoors and demand for enhanced comfort levels, energy consumption in homes is rising mostly for cooling, particularly in hot-humid regions. Natural ventilation is seen as an alternative to mechanical cooling as it is totally independent on energy and has been reported to be of high potential. However, little information is available on the utilization of natural ventilation in individual living spaces in different house designs. Therefore, this paper aims to investigate occupants’ utilization of natural ventilation in living spaces under different terrace house designs in hot-humid climate and also the relationship between the openings and occupants’ satisfaction with natural ventilation. Five (5 different terrace house types in Putrajaya, Malaysia with different opening design characteristics were selected for the study. A total of 298 households from these house types were surveyed and results show that occupants mostly open their windows during the daytime to capture breeze from outside despite the fact that they owned air-conditioners. In terms of occupants’ level of satisfaction with indoor ventilation when utilizing natural ventilation, majority rated neither satisfied nor unsatisfied. Further regression analysis reveals that this level of satisfaction is significantly related to opening sizes that are in accordance with the law, duration of opening windows and AC ownership. Findings from this study will shed more light on behavioural pattern of occupants of residential buildings towards natural ventilation provisions and highlight the importance of conforming to the law governing them.

  11. Chemical Emissions of Residential Materials and Products: Review of Available Information

    Energy Technology Data Exchange (ETDEWEB)

    Willem, Henry; Singer, Brett

    2010-09-15

    This report is prepared in the context of a larger program whose mission is to advance understanding of ventilation and indoor air quality in U.S. homes. A specific objective of this program is to develop the scientific basis ? through controlled experiments, monitoring and analysis ? for health risk-based ventilation standards. Appropriate and adequate ventilation is a basic element of a healthy home. Ventilation provides outdoor air and in the process removes indoor odors and contaminants including potentially unhealthful chemicals emitted by indoor materials, products and activities. Ventilation traditionally was assured to occur via infiltration of outdoor air through cracks and other leakage pathways in the residential building envelope. As building air tightness is improved for energy efficiency, infiltration can be reduced to inadequate levels. This has lead to the development of standards requiring mechanical ventilation. Though nominally intended to ensure acceptable indoor air quality, the standards are not explicitly tied to health risk or pollutant exposure targets. LBNL is currently designing analyses to assess the impact of varying ventilation standards on pollutant concentrations, health risks and energy use. These analyses require information on sources of chemical pollutant emissions, ideally including emission rates and the impact of ventilation on emissions. Some information can be obtained from recent studies that report measurements of various air contaminants and their concentrations in U.S. residences. Another way to obtain this information is the bottom-up approach of collecting and evaluating emissions data from construction and interior materials and common household products. This review contributes to the latter approach by summarizing available information on chemical emissions from new residential products and materials. We review information from the scientific literature and public sources to identify and discuss the databases that

  12. Liquid ventilation.

    Science.gov (United States)

    Sarkar, Suman; Paswan, Anil; Prakas, S

    2014-01-01

    Human have lungs to breathe air and they have no gills to breath liquids like fish. When the surface tension at the air-liquid interface of the lung increases as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV) is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen as the inert carrier of oxygen and carbon dioxide offers a number of advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. It is well-known that respiratory diseases are one of the most common causes of morbidity and mortality in intensive care unit. During the past few years several new modalities of treatment have been introduced. One of them and probably the most fascinating, is of LV. Partial LV, on which much of the existing research has concentrated, requires partial filling of lungs with perfluorocarbons (PFC's) and ventilation with gas tidal volumes using conventional mechanical ventilators. Various physico-chemical properties of PFC's make them the ideal media. It results in a dramatic improvement in lung compliance and oxygenation and decline in mean airway pressure and oxygen requirements. No long-term side-effect reported.

  13. Ventilator-associated pneumonia rates at major trauma centers compared with a national benchmark: a multi-institutional study of the AAST.

    Science.gov (United States)

    Michetti, Christopher P; Fakhry, Samir M; Ferguson, Pamela L; Cook, Alan; Moore, Forrest O; Gross, Ronald

    2012-05-01

    Ventilator-associated pneumonia (VAP) rates reported by the National Healthcare Safety Network (NHSN) are used as a benchmark and quality measure, yet different rates are reported from many trauma centers. This multi-institutional study was undertaken to elucidate VAP rates at major trauma centers. VAP rate/1,000 ventilator days, diagnostic methods, institutional, and aggregate patient data were collected retrospectively from a convenience sample of trauma centers for 2008 and 2009 and analyzed with descriptive statistics. At 47 participating Level I and II centers, the pooled mean VAP rate was 17.2 versus 8.1 for NHSN (2006-2008). Hospitals' rates were highly variable (range, 1.8-57.6), with 72.3% being above NHSN's mean. Rates differed based on who determined the rate (trauma service, 27.5; infection control or quality or epidemiology, 11.9; or collaborative effort, 19.9) and the frequency with which VAP was excluded based on aspiration or diagnosis before hospital day 5. In 2008 and 2009, blunt trauma patients had higher VAP rates (17.3 and 17.6, respectively) than penetrating patients (11.0 and 10.9, respectively). More centers used a clinical diagnostic strategy (57%) than a bacteriologic strategy (43%). Patients with VAP had a mean Injury Severity Score of 28.7, mean Intensive Care Unit length of stay of 20.8 days, and a 12.2% mortality rate. 50.5% of VAP patients had a traumatic brain injury. VAP rates at major trauma centers are markedly higher than those reported by NHSN and vary significantly among centers. Available data are insufficient to set benchmarks, because it is questionable whether any one data set is truly representative of most trauma centers. Application of a single benchmark to all centers may be inappropriate, and reliable diagnostic and reporting standards are needed. Prospective analysis of a larger data set is warranted, with attention to injury severity, risk factors specific to trauma patients, diagnostic method used, VAP definitions

  14. Barrios, ghettos, and residential racial composition: Examining the racial makeup of neighborhood profiles and their relationship to self-rated health.

    Science.gov (United States)

    Booth, Jaime M; Teixeira, Samantha; Zuberi, Anita; Wallace, John M

    2018-01-01

    Racial/ethnic disparities in self-rated health persist and according to the social determinants of health framework, may be partially explained by residential context. The relationship between neighborhood factors and self-rated health has been examined in isolation but a more holistic approach is needed to understand how these factors may cluster together and how these neighborhood typologies relate to health. To address this gap, we conducted a latent profile analysis using data from the Chicago Community Adult Health Study (CCAHS; N = 2969 respondents in 342 neighborhood clusters) to identify neighborhood profiles, examined differences in neighborhood characteristics among the identified typologies and tested their relationship to self-rated health. Results indicated four distinct classes of neighborhoods that vary significantly on most neighborhood-level social determinants of health and can be defined by racial/ethnic composition and class. Residents in Hispanic, majority black disadvantaged, and majority black non-poor neighborhoods all had significantly poorer self-rated health when compared to majority white neighborhoods. The difference between black non-poor and white neighborhoods in self-rated health was not significant when controlling for individual race/ethnicity. The results indicate that neighborhood factors do cluster by race and class of the neighborhood and that this clustering is related to poorer self-rated health. Copyright © 2017. Published by Elsevier Inc.

  15. Personalized ventilation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor

    2004-01-01

    microenvironment. Furthermore, HVAC systems should be designed to protect occupants from airborne transmission of infectious agents that may be present in exhaled air. Personalized ventilation is a new development in the field of HVAC and has the potential to fulfill the above requirements. This paper reviews...... existing knowledge on performance of personalized ventilation (PV) and on human response to it. The airflow interaction in the vicinity of the human body is analyzed and its impact on thermal comfort and inhaled air quality is discussed together with control strategies and the application of PV in practice...

  16. The amazing Minivent ventilator

    African Journals Online (AJOL)

    Southern African Journal of Anaesthesia and Analgesia is co-published by Medpharm Publications, NISC (Pty) Ltd and Cogent, ... Respiratory rate was obtained by counting the clicking noise ... was appointed as a part-time lecturer to the University of the ... The Minivent became the first of three miniature ventilators that.

  17. Improved inhaled air quality at reduced ventilation rate by control of airflow interaction at the breathing zone with lobed jets

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Spilak, Michal

    2014-01-01

    Inhaled air quality at a reduced supply of clean air was studied by controlling the airflow interaction at the breathing zone of a person using lobed jets as part of personalized ventilation (PV). Experiments were performed in a full-scale test room at 23°C (73.4°F) with a breathing thermal manikin...... seated at a workstation, with realistic free-convection flow around the body and a normal breathing cycle. The air in the room was mixed with tracer gas R134a. Clean air was supplied isothermally from three nozzles with circular, four-leafed clover, and six-edged star openings of 0.025 m (0.08 ft...... over the interaction between the inserted jets and the free convection flow was efficient. Over 80% clean PV air was measured in inhalation. The worst performing nozzle was the four-leafed clover: its best performance yielded 23% clean air inhalation, at the shortest distance and the highest velocity...

  18. Influence of ventilation strategies on indoor radon concentrations based on a semiempirical model for Florida-style houses

    International Nuclear Information System (INIS)

    Hintenlang, D.E.; Al-Ahmady, K.K.

    1994-01-01

    Measurements in a full-scale experimental facility are used to benchmark a semiempirical model for predicting indoor radon concentrations for Florida-style houses built using slab-on-grade construction. The model is developed to provide time-averaged indoor radon concentrations from quantitative relationships between the time-dependent radon entry and elimination mechanisms that have been demonstrated to be important for this style of residential construction. The model successfully predicts indoor radon concentrations in the research structure for several pressure and ventilation conditions. Parametric studies using the model illustrate how different ventilation strategies affect indoor radon concentrations. It is demonstrated that increasing house ventilation rates by increasing the effective leakage area of the house shell does not reduce indoor radon concentrations as effectively as increasing house ventilation rates by controlled duct ventilation associated with the heating, ventilating, and air conditioning system. The latter strategy provides the potential to minimize indoor radon concentrations while providing positive control over the quality of infiltration air. 9 refs., 5 figs

  19. Displacement Ventilation

    DEFF Research Database (Denmark)

    Bjørn, Erik; Mattsson, Magnus; Sandberg, Mats

    Full-scale experiments were made in a displacement ventilated room with two breathing thermal manikins to study the effect of movements and breathing on the vertical contaminant distribution, and on the personal exposure of occupants. Concentrations were measured with tracer gas equipment...

  20. Mixing Ventilation

    DEFF Research Database (Denmark)

    Kandzia, Claudia; Kosonen, Risto; Melikov, Arsen Krikor

    In this guidebook most of the known and used in practice methods for achieving mixing air distribution are discussed. Mixing ventilation has been applied to many different spaces providing fresh air and thermal comfort to the occupants. Today, a design engineer can choose from large selection...

  1. Intelligent ventilation in the intensive care unit

    Directory of Open Access Journals (Sweden)

    Sigal Sviri

    2012-08-01

    Full Text Available Objectives. Automated, microprocessor-controlled, closed-loop mechanical ventilation has been used in our Medical Intensive Care Unit (MICU at the Hadassah Hebrew-University Medical Center for the past 15 years; for 10 years it has been the primary (preferred ventilator modality. Design and setting. We describe our clinical experience with adaptive support ventilation (ASV over a 6-year period, during which time ASV-enabled ventilators became more readily available and were used as the primary (preferred ventilators for all patients admitted to the MICU. Results. During the study period, 1 220 patients were ventilated in the MICU. Most patients (84% were ventilated with ASV on admission. The median duration of ventilation with ASV was 6 days. The weaning success rate was 81%, and tracheostomy was required in 13%. Sixty-eight patients (6% with severe hypoxia and high inspiratory pressures were placed on pressure-controlled ventilation, in most cases to satisfy a technical requirement for precise and conservative administration of inhaled nitric oxide. The overall pneumothorax rate was less than 3%, and less than 1% of patients who were ventilated only using ASV developed pneumothorax. Conclusions. ASV is a safe and acceptable mode of ventilation for complicated medical patients, with a lower than usual ventilation complication rate.

  2. Why we ventilate our houses - An historical look

    Energy Technology Data Exchange (ETDEWEB)

    Matson, Nance E.; Sherman, Max H.

    2004-05-14

    The knowledge of how to ventilate buildings, and how much ventilation is necessary for human health and comfort, has evolved over centuries of trial and error. Humans and animals have developed successful solutions to the problems of regulating temperature and removing air pollutants through the use of ventilation. These solutions include ingenious construction methods, such as engineered passive ventilation (termite mounds and passive stacks), mechanical means (wing-powered, fans), and an evolving effort to identify problems and develop solutions. Ventilation can do more than help prevent building occupants from getting sick; it can provide an improved indoor environment. Codes and standards provide minimum legal requirements for ventilation, but the need for ventilation goes beyond code minima. In this paper we will look at indoor air pollutant sources over time, the evolution of ventilation strategies, current residential ventilation codes and standards (e.g., recently approved ASHRAE Standard 62.2), and briefly discuss ways in which we can go beyond the standards to optimize residential ventilation, reduce indoor air quality problems, and provide corresponding social and economic benefit.

  3. Intrinsic positive end-expiratory pressure during one-lung ventilation of patients with pulmonary hyperinflation. Influence of low respiratory rate with unchanged minute volume.

    Science.gov (United States)

    Szegedi, L L; Barvais, L; Sokolow, Y; Yernault, J C; d'Hollander, A A

    2002-01-01

    We measured lung mechanics and gas exchange during one-lung ventilation (OLV) of patients with chronic obstructive pulmonary disease, using three respiratory rates (RR) and unchanged minute volume. We studied 15 patients about to undergo lung surgery, during anaesthesia, and placed in the lateral position. Ventilation was with constant minute volume, inspiratory flow and FIO2. For periods of 15 min, RR of 5, 10, and 15 bpm were applied in a random sequence and recordings were made of lung mechanics and an arterial blood gas sample was taken. Data were analysed with the repeated measures ANOVA and paired t-test with Bonferroni correction. PaO2 changes were not significant. At the lowest RR, PaCO2 decreased (from 42 (SD 4) mm Hg at RR 15-41 (4) mm Hg at RR 10 and 39 (4) mm Hg at RR 5, P<0.01), and end-tidal carbon dioxide increased (from 33 (5) mm Hg at RR 15 to 35 (5) mm Hg at RR 10 and 36 (6) mm Hg at RR 5, P<0.01). Intrinsic positive end-expiratory pressure (PEEPi) was reduced even with larger tidal volumes (from 6 (4) cm H2O at RR 15-5 (4) cm H2O at RR 10, and 3 (3) cm H2O at RR 5, P<0.01), most probably caused by increased expiratory time at the lowest RR. A reduction in RR reduces PEEPi and hypercapnia during OLV in anaesthetized patients with chronic obstructive lung disease.

  4. Modeling and Control of Livestock Ventilation Systems and Indoor Environments

    DEFF Research Database (Denmark)

    Wu, Zhuang; Heiselberg, Per; Stoustrup, Jakob

    2005-01-01

    The hybrid ventilation systems have been widely used for livestock barns to provide optimum indoor climate by controlling the ventilation rate and air flow distribution within the ventilated building structure. The purpose of this paper is to develop models for livestock ventilation systems and i...

  5. Thermal optimum for pikeperch (Sander lucioperca) and the use of ventilation frequency as a predictor of metabolic rate

    DEFF Research Database (Denmark)

    Frisk, Michael; Skov, Peter Vilhelm; Steffensen, John Fleng

    2012-01-01

    at six temperatures, ranging from 13 to 28 °C, in order to identify the temperature where pikeperch has the largest metabolic scope (MS). Between 13 and 25 °C, standard metabolic rates (SMR) increased as expected with a Q10=1.8 in response to increasing temperatures, while maximum metabolic rate (MMR...... consumption rate (M_ O2), during normoxia and progressive hypoxia. A strong correlation was found between fV and M_ O2 across all temperatures, and fV could predict M_ O2 with a high degree of accuracy in normoxia...

  6. Exposure to Exhaled Air from a Sick Occupant in a Two-Bed Hospital Room with Mixing Ventilation: Effect of Posture of Doctor and Air Change Rate

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor; Barova, Mariya

    2013-01-01

    Full-scale measurements were performed in a climate chamber set as a two-bed hospital room, ventilated at 3, 6 and 12 ACH with overhead mixing ventilation. Air temperature was kept constant at 22 °C. Two breathing thermal manikins were used to mimic a sick patient lying on one side in one of the ...

  7. Association between Self-Rated Health and the Ethnic Composition of the Residential Environment of Six Ethnic Groups in Amsterdam

    Science.gov (United States)

    Veldhuizen, Eleonore M.; Musterd, Sako; Dijkshoorn, Henriëtte; Kunst, Anton E.

    2015-01-01

    Background: Studies on the association between health and neighborhood ethnic composition yielded inconsistent results, possibly due to methodological limitations. We assessed these associations at different spatial scales and for different measures of ethnic composition. Methods: We obtained health survey data of 4673 respondents of Dutch, Surinamese, Moroccan, Turkish other non-Western and other Western origin. Neighborhood ethnic composition was measured for buffers varying from 50–1000 m. Associations with self-rated health were measured using logistic multilevel regression analysis, with control for socioeconomic position at the individual and area level. Results: Overall ethnic heterogeneity was not related to health for any ethnic group. The presence of other Surinamese was associated with poor self-rated health among Surinamese respondents. The presence of Moroccans or Turks was associated with poor health among some groups. The presence of Dutch was associated with better self-rated health among Surinamese and Turks. In most cases, these associations were stronger at lower spatial scales. We found no other associations. Conclusions: In Amsterdam, self-rated health was not associated with ethnic heterogeneity in general, but may be related to the presence of specific ethnic groups. Policies regarding social and ethnic mixing should pay special attention to the co-residence of groups with problematic interrelations. PMID:26569282

  8. Balancing energy conservation and occupant needs in ventilation rate standards for Big Box stores and other commercial buildings in California. Issues related to the ASHRAE 62.1 Indoor Air Quality Procedure

    Energy Technology Data Exchange (ETDEWEB)

    Mendell, Mark J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Apte, Mike G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2010-10-31

    This report considers the question of whether the California Energy Commission should incorporate the ASHRAE 62.1 ventilation standard into the Title 24 ventilation rate (VR) standards, thus allowing buildings to follow the Indoor Air Quality Procedure. This, in contrast to the current prescriptive standard, allows the option of using ventilation rate as one of several strategies, which might include source reduction and air cleaning, to meet specified targets of indoor air concentrations and occupant acceptability. The research findings reviewed in this report suggest that a revised approach to a ventilation standard for commercial buildings is necessary, because the current prescriptive ASHRAE 62.1 Ventilation Rate Procedure (VRP) apparently does not provide occupants with either sufficiently acceptable or sufficiently healthprotective air quality. One possible solution would be a dramatic increase in the minimum ventilation rates (VRs) prescribed by a VRP. This solution, however, is not feasible for at least three reasons: the current need to reduce energy use rather than increase it further, the problem of polluted outdoor air in many cities, and the apparent limited ability of increasing VRs to reduce all indoor airborne contaminants of concern (per Hodgson (2003)). Any feasible solution is thus likely to include methods of pollutant reduction other than increased outdoor air ventilation; e.g., source reduction or air cleaning. The alternative 62.1 Indoor Air Quality Procedure (IAQP) offers multiple possible benefits in this direction over the VRP, but seems too limited by insufficient specifications and inadequate available data to provide adequate protection for occupants. Ventilation system designers rarely choose to use it, finding it too arbitrary and requiring use of much non-engineering judgment and information that is not readily available. This report suggests strategies to revise the current ASHRAE IAQP to reduce its current limitations. These

  9. The effects of moderately raised classroom temperatures and classroom ventilation rate on the performance of schoolwork by children (RP-1257)

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Wyon, David Peter

    2007-01-01

    Two independent field intervention experiments were carried out in school classrooms in late summer (in 2004 and 2005). The air temperature was manipulated by either operating or idling split cooling units installed for the purpose. In one of these experiments, the outdoor air supply rate was also...... series. The above improvements were mainly in terms of the speed at which tasks were performed, with negligible effects on error rate. Most school classrooms worldwide experience raised air temperatures during increased thermal loads, e.g., in warm weather; these results show that providing some means...

  10. Residential greenhouse

    Energy Technology Data Exchange (ETDEWEB)

    1985-02-01

    The following report examines the technical and economic viability of residential greenhouse additions in Whitehorse, Yukon. The greenhouse was constructed using the south facing wall of an existing residence as a common wall. Total construction costs were $18,000, including labour. Annual fuel demand for the residence has been reduced by about 10 per cent for an annual saving of $425. In addition, produce to the value of $1,000 is grown annually in the greenhouse for domestic consumption and commercial resale. Typically the greenhouse operates for nine months each year. There is a net thermal loss during the months of November, December and January as a result of the large area of glazing. As well as supplementing the heating supply solar greenhouses can provide additional cash crops which can be used to offset the cost of construction. Humidity problems are minimal and can be dealt with by exhausting high humidity air. One system which has been considered for the greenhouse is to use a standard residential heat pump to remove excess moisture and to pump heat into the house. This would have a secondary benefit of excluding the need to circulate greenhouse air through the house. Thus any allergenic reactions to the greenhouse air would be prevented. 8 refs., 3 figs, 2 tabs.

  11. Optimal Chest Compression Rate and Compression to Ventilation Ratio in Delivery Room Resuscitation: Evidence from Newborn Piglets and Neonatal Manikins

    OpenAIRE

    Solev?g, Anne Lee; Schm?lzer, Georg M.

    2017-01-01

    Cardiopulmonary resuscitation (CPR) duration until return of spontaneous circulation (ROSC) influences survival and neurologic outcomes after delivery room (DR) CPR. High quality chest compressions (CC) improve cerebral and myocardial perfusion. Improved myocardial perfusion increases the likelihood of a faster ROSC. Thus, optimizing CC quality may improve outcomes both by preserving cerebral blood flow during CPR and by reducing the recovery time. CC quality is determined by rate, CC to vent...

  12. An International Project on Indoor Air Quality Design and Control in Low Energy Residential Buildings

    DEFF Research Database (Denmark)

    Rode, Carsten; Abadie, Marc; Qin, Menghao

    2016-01-01

    focal points to limiting energy consumption for thermally conditioning the indoor environment will be to possibly reducing the ventilation rate, or making it in a new way demand controlled. However, this must be done such that it does not have adverse effects on indoor air quality (IAQ). Annex 68......In order to achieve nearly net zero energy use, both new and energy refurbished existing buildings will in the future need to be still more efficient and optimized. Since such buildings can be expected to be already well insulated, airtight, and have heat recovery systems installed, one of the next......, Indoor Air Quality Design and Control in Low Energy Residential Buildings, is a project under IEA’s Energy Conservation in Buildings and Communities Program (EBC), which will endeavor to investigate how future residential buildings are able to have very high energy performance whilst providing...

  13. PERMEABILITY MAP OF RESIDENTIAL SETTLEMENTS IN THE TROPICS

    OpenAIRE

    I Gusti Ngurah Antaryama

    2002-01-01

    Source of information for ventilation design of residential settlement is generally derived from wind tunnel or, recently, CFD studies, which involves both modeling and simulation of wind flow pattern and speed. Yet this is not readily accessible to most architects. In order to gain similar objectives but without involving detailed studies, the present study introduces a graphical method of gathering information about permeability of residential. It describes how the way wind reaches and flow...

  14. Paradoxical Acinetobacter-associated ventilator-associated pneumonia incidence rates within prevention studies using respiratory tract applications of topical polymyxin: benchmarking the evidence base.

    Science.gov (United States)

    Hurley, J C

    2018-04-10

    Regimens containing topical polymyxin appear to be more effective in preventing ventilator-associated pneumonia (VAP) than other methods. To benchmark the incidence rates of Acinetobacter-associated VAP (AAVAP) within component (control and intervention) groups from concurrent controlled studies of polymyxin compared with studies of various VAP prevention methods other than polymyxin (non-polymyxin studies). An AAVAP benchmark was derived using data from 77 observational groups without any VAP prevention method under study. Data from 41 non-polymyxin studies provided additional points of reference. The benchmarking was undertaken by meta-regression using generalized estimating equation methods. Within 20 studies of topical polymyxin, the mean AAVAP was 4.6% [95% confidence interval (CI) 3.0-6.9] and 3.7% (95% CI 2.0-5.3) for control and intervention groups, respectively. In contrast, the AAVAP benchmark was 1.5% (95% CI 1.2-2.0). In the AAVAP meta-regression model, group origin from a trauma intensive care unit (+0.55; +0.16 to +0.94, P = 0.006) or membership of a polymyxin control group (+0.64; +0.21 to +1.31, P = 0.023), but not membership of a polymyxin intervention group (+0.24; -0.37 to +0.84, P = 0.45), were significant positive correlates. The mean incidence of AAVAP within the control groups of studies of topical polymyxin is more than double the benchmark, whereas the incidence rates within the groups of non-polymyxin studies and, paradoxically, polymyxin intervention groups are more similar to the benchmark. These incidence rates, which are paradoxical in the context of an apparent effect against VAP within controlled trials of topical polymyxin-based interventions, force a re-appraisal. Copyright © 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  15. The influence of the cigarette smoke pollution and ventilation rate on alpha-activities per unit volume due to radon and its progeny

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Flata, K.

    2003-01-01

    Alpha and beta activities per unit volume air due to radon, thoron and their decay products were evaluated in the air of various cafe rooms polluted by cigarette smoke. Both CR-39 and LR-115 type II solid state nuclear track detectors (SSNTD) were used. Equilibrium factors between radon and its progeny and thoron and its daughters have been evaluated in the air of the studied cafe rooms. The committed equivalent doses due to short-lived radon decay products were determined in different regions of the respiratory tract of non-smoker members of the public. The influence of cigarette smoke pollution, ventilation rate and exposure time on committed equivalent dose in the respiratory systems of non-smokers was investigated. Committed equivalent doses ranged from 1.15x10 -11 -2.7x10 -7 Sv.y -1 /h of exposure in the extrathoracic region and from 0.8x10 -12 -1.7x10 -8 Sv.y -1 /h of exposure in the thoracic region of the respiratory tract of non-smokers

  16. Effects of ventilation rate per person and per floor area on perceived air quality, sick building syndrome symptoms, and decision-making.

    Science.gov (United States)

    Maddalena, R; Mendell, M J; Eliseeva, K; Chan, W R; Sullivan, D P; Russell, M; Satish, U; Fisk, W J

    2015-08-01

    Ventilation rates (VRs) in buildings must adequately control indoor levels of pollutants; however, VRs are constrained by the energy costs. Experiments in a simulated office assessed the effects of VR per occupant on perceived air quality (PAQ), Sick Building Syndrome (SBS) symptoms, and decision-making performance. A parallel set of experiments assessed the effects of VR per unit floor area on the same outcomes. Sixteen blinded healthy young adult subjects participated in each study. Each exposure lasted four hours and each subject experienced two conditions in a within-subject study design. The order of presentation of test conditions, day of testing, and gender were balanced. Temperature, relative humidity, VRs, and concentrations of pollutants were monitored. Online surveys assessed PAQ and SBS symptoms and a validated computer-based tool measured decision-making performance. Neither changing the VR per person nor changing the VR per floor area, had consistent statistically significant effects on PAQ or SBS symptoms. However, reductions in either occupant-based VR or floor-area-based VR had a significant and independent negative impact on most decision-making measures. These results indicate that the changes in VR employed in the study influence performance of healthy young adults even when PAQ and SBS symptoms are unaffected. The study results indicate the importance of avoiding low VRs per person and low VRs per floor area to minimize decrements in cognitive performance. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Recommended Ventilation Strategies for Energy-Efficient Production Homes

    Energy Technology Data Exchange (ETDEWEB)

    Roberson, J.; Brown, R.; Koomey, J.; Warner, J.; Greenberg, S.

    1998-12-01

    This report evaluates residential ventilation systems for the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR{reg_sign} Homes program and recommends mechanical ventilation strategies for new, low-infiltration, energy-efficient, single-family, ENERGY STAR production (site-built tract) homes in four climates: cold, mixed (cold and hot), hot humid, and hot arid. Our group in the Energy Analysis Department at Lawrence Berkeley National Lab compared residential ventilation strategies in four climates according to three criteria: total annualized costs (the sum of annualized capital cost and annual operating cost), predominant indoor pressure induced by the ventilation system, and distribution of ventilation air within the home. The mechanical ventilation systems modeled deliver 0.35 air changes per hour continuously, regardless of actual infiltration or occupant window-opening behavior. Based on the assumptions and analysis described in this report, we recommend independently ducted multi-port supply ventilation in all climates except cold because this strategy provides the safety and health benefits of positive indoor pressure as well as the ability to dehumidify and filter ventilation air. In cold climates, we recommend that multi-port supply ventilation be balanced by a single-port exhaust ventilation fan, and that builders offer balanced heat-recovery ventilation to buyers as an optional upgrade. For builders who continue to install forced-air integrated supply ventilation, we recommend ensuring ducts are airtight or in conditioned space, installing a control that automatically operates the forced-air fan 15-20 minutes during each hour that the fan does not operate for heating or cooling, and offering ICM forced-air fans to home buyers as an upgrade.

  18. Ecological aspects of fan-assisted balanced ventilation systems in the residential area - a practical investigation with recommendations for design and installation; Oekologische Aspekte der Komfortlueftungen im Wohnbereich - Eine praxisnahe Untersuchung mit Hinweisen zu Planung und Bau von Wohnungslueftungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Haessig, W.; Primas, A. [Basler und Hofmann Ingenieure und Planer AG, Zuerich (Switzerland)

    2004-07-01

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) presents the results of a project that examined the environmental impact of fan-assisted balanced ventilation systems on the basis of a life-cycle analysis. The influence of various components and their operating parameters on the systems is compared. The results, which were calculated using the Eco-indicator 99 and the 'ecoinvent' data-base, are presented and commented on. Six variants for a six-apartment house with varying air-throughput and using various materials for the ducting are analysed. The results of the analysis are presented in tabular and graphical form and discussed in detail.

  19. Estimation of energy efficiency of residential buildings

    Directory of Open Access Journals (Sweden)

    Glushkov Sergey

    2017-01-01

    Full Text Available Increasing energy performance of the residential buildings by means of reducing heat consumption on the heating and ventilation is the last segment in the system of energy resources saving. The first segments in the energy saving process are heat producing and transportation over the main lines and outside distribution networks. In the period from 2006 to 2013. by means of the heat-supply schemes optimization and modernization of the heating systems. using expensive (200–300 $US per 1 m though hugely effective preliminary coated pipes. the economy reached 2.7 mln tons of fuel equivalent. Considering the multi-stage and multifactorial nature (electricity. heat and water supply of the residential sector energy saving. the reasonable estimate of the efficiency of the saving of residential buildings energy should be performed in tons of fuel equivalent per unit of time.

  20. Supporting Photovoltaics in Market-Rate Residential NewConstruction: A Summary of Programmatic Experience to Date and LessonsLearned

    Energy Technology Data Exchange (ETDEWEB)

    Barbose, Galen; Wiser, Ryan; Bolinger, Mark

    2006-02-10

    , particularly in ''hot'' housing markets where builders face little difficulty selling homes. Builders may also be concerned about the up-front cost of PV and its impact on new home prices and profits. The potential for project delays associated with PV module availability, installation scheduling, utility interconnection agreements, building inspections, permit processing, or other factors, may also be of great concern. Finally, many builders may believe that most homebuyers are not particularly interested in PV, given its cost, and that some may even be opposed based on concerns about aesthetics, maintenance, or reliability. In this paper, prepared on behalf of the Clean Energy States Alliance (CESA), we describe early efforts by state clean energy funds to support the deployment of PV in new, market-rate homes. (Other recent reports prepared for CESA describe experiences with programs targeting affordable housing.) We focus on the activities of clean energy funds in nine states that have funded specific projects and/or have offered targeted programs for PV in market-rate residential new construction. We also include in our review several other state or local organizations whose efforts are particularly noteworthy or have some direct bearing on the efforts of clean energy funds in the same state--however, we do not attempt to comprehensively review the activities of entities other than state clean energy funds.

  1. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Yu, Tao; Heiselberg, Per Kvols

    with conventional ventilation systems (mixing or displacement ventilation), diffuse ceiling ventilation can significantly reduce or even eliminate draught risk in the occupied zone. Moreover, this ventilation system presents a promising opportunity for energy saving, because of the low pressure loss, extended free...

  2. Diffuse ceiling ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen

    Diffuse ceiling ventilation is an innovative ventilation concept where the suspended ceiling serves as air diffuser to supply fresh air into the room. Compared with conventional ventilation systems, diffuse ceiling ventilation can significantly reduce or even eliminate draught risk due to the low...

  3. Variable mechanical ventilation.

    Science.gov (United States)

    Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini, Luiz Alberto; Friedman, Gilberto

    2017-01-01

    To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation.

  4. VENTILATION NEEDS DURING CONSTRUCTION

    International Nuclear Information System (INIS)

    C.R. Gorrell

    1998-01-01

    The purpose of this analysis is to determine ventilation needs during construction and development of the subsurface repository and develop systems to satisfy those needs. For this analysis, construction is defined as pre-emplacement excavation and development is excavation that takes place simultaneously with emplacement. The three options presented in the ''Overall Development and Emplacement Ventilation Systems'' analysis (Reference 5.5) for development ventilation will be applied to construction ventilation in this analysis as well as adding new and updated ventilation factors to each option for both construction and development. The objective of this analysis is to develop a preferred ventilation system to support License Application Design. The scope of this analysis includes: (1) Description of ventilation conditions; (2) Ventilation factors (fire hazards, dust control, construction logistics, and monitoring and control systems); (3) Local ventilation alternatives; (4) Global ventilation options; and (5) Evaluation of options

  5. Potential risk for bacterial contamination in conventional reused ventilator systems and disposable closed ventilator-suction systems.

    Science.gov (United States)

    Li, Ya-Chi; Lin, Hui-Ling; Liao, Fang-Chun; Wang, Sing-Siang; Chang, Hsiu-Chu; Hsu, Hung-Fu; Chen, Sue-Hsien; Wan, Gwo-Hwa

    2018-01-01

    Few studies have investigated the difference in bacterial contamination between conventional reused ventilator systems and disposable closed ventilator-suction systems. The aim of this study was to investigate the bacterial contamination rates of the reused and disposable ventilator systems, and the association between system disconnection and bacterial contamination of ventilator systems. The enrolled intubated and mechanically ventilated patients used a conventional reused ventilator system and a disposable closed ventilator-suction system, respectively, for a week; specimens were then collected from the ventilator circuit systems to evaluate human and environmental bacterial contamination. The sputum specimens from patients were also analyzed in this study. The detection rate of bacteria in the conventional reused ventilator system was substantially higher than that in the disposable ventilator system. The inspiratory and expiratory limbs of the disposable closed ventilator-suction system had higher bacterial concentrations than the conventional reused ventilator system. The bacterial concentration in the heated humidifier of the reused ventilator system was significantly higher than that in the disposable ventilator system. Positive associations existed among the bacterial concentrations at different locations in the reused and disposable ventilator systems, respectively. The predominant bacteria identified in the reused and disposable ventilator systems included Acinetobacter spp., Bacillus cereus, Elizabethkingia spp., Pseudomonas spp., and Stenotrophomonas (Xan) maltophilia. Both the reused and disposable ventilator systems had high bacterial contamination rates after one week of use. Disconnection of the ventilator systems should be avoided during system operation to decrease the risks of environmental pollution and human exposure, especially for the disposable ventilator system. ClinicalTrials.gov PRS / NCT03359148.

  6. Thermal Plumes in Ventilated Rooms

    DEFF Research Database (Denmark)

    Kofoed, Peter; Nielsen, Peter V.

    The design of a displacement ventilation system involves determination of the flow rate in the thermal plumes. The flow rate in the plumes and the vertical temperature gradient influence each other, and they are influenced by many factors. This paper shows some descriptions of these effects....

  7. Cellular phone interference with the operation of mechanical ventilators.

    Science.gov (United States)

    Shaw, Cheryl I; Kacmarek, Robert M; Hampton, Rickey L; Riggi, Vincent; El Masry, Ashraf; Cooper, Jeffrey B; Hurford, William E

    2004-04-01

    To determine whether a cellular phone would interfere with the operation of mechanical ventilators. Laboratory study. University medical center. Fourteen mechanical ventilators. We evaluated change in operation and malfunction of the mechanical ventilators. The cellular phone (Nokia 6120i) was computer controlled, operating at 828.750 MHz analog modulation. It was operated at 16, 40, 100, 250, and 600 mW, 30 cm from the floor and 30, 15, and ventilator. Six of the 14 ventilators tested malfunctioned when a cellular phone at maximum power output was placed ventilating when the cellular phone at maximum power output was placed ventilator. One ventilator doubled the ventilatory rate and another increased the displayed tidal volume from 350 to 1033 mL. In one of the infant ventilators, displayed tidal volume increased from 21 to 100 mL. In another ventilator, the high respiratory rate alarm sounded but the rate had not changed. In a controlled laboratory setting, cellular phones placed in close proximity to some commercially available intensive care ventilators can cause malfunctions, including irrecoverable cessation of ventilation. This is most likely to occur if the cellular phone is or =3 feet from all medical devices. The current electromagnetic compatibility standards for mechanical ventilators are inadequate to prevent malfunction. Manufacturers should ensure that their products are not affected by wireless technology even when placed immediately next to the device.

  8. Natural ventilation for reducing airborne infection in hospitals

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Hua [School of Energy and Environment, Southeast University, Nanjing (China); Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong (China); Li, Yuguo; Ching, W.H.; Sun, H.Q. [Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong (China); Seto, W.H.; Ching, Patricia [Department of Microbiology, Queen Mary Hospital, Hong Kong (China)

    2010-03-15

    High ventilation rate is shown to be effective for reducing cross-infection risk of airborne diseases in hospitals and isolation rooms. Natural ventilation can deliver much higher ventilation rate than mechanical ventilation in an energy-efficient manner. This paper reports a field measurement of naturally ventilated hospital wards in Hong Kong and presents a possibility of using natural ventilation for infection control in hospital wards. Our measurements showed that natural ventilation could achieve high ventilation rates especially when both the windows and the doors were open in a ward. The highest ventilation rate recorded in our study was 69.0 ACH. The airflow pattern and the airflow direction were found to be unstable in some measurements with large openings. Mechanical fans were installed in a ward window to create a negative pressure difference. Measurements showed that the negative pressure difference was negligible with large openings but the overall airflow was controlled in the expected direction. When all the openings were closed and the exhaust fans were turned on, a reasonable negative pressure was created although the air temperature was uncontrolled. The high ventilation rate provided by natural ventilation can reduce cross-infection of airborne diseases, and thus it is recommended for consideration of use in appropriate hospital wards for infection control. Our results also demonstrated a possibility of converting an existing ward using natural ventilation to a temporary isolation room through installing mechanical exhaust fans. (author)

  9. A pilot study using scripted ventilation conditions to identify key factors affecting indoor pollutant concentration and air exchange rate in a residence.

    Science.gov (United States)

    Johnson, Ted; Myers, Jeffrey; Kelly, Thomas; Wisbith, Anthony; Ollison, Will

    2004-01-01

    A pilot study was conducted using an occupied, single-family test house in Columbus, OH, to determine whether a script-based protocol could be used to obtain data useful in identifying the key factors affecting air-exchange rate (AER) and the relationship between indoor and outdoor concentrations of selected traffic-related air pollutants. The test script called for hourly changes to elements of the test house considered likely to influence air flow and AER, including the position (open or closed) of each window and door and the operation (on/off) of the furnace, air conditioner, and ceiling fans. The script was implemented over a 3-day period (January 30-February 1, 2002) during which technicians collected hourly-average data for AER, indoor, and outdoor air concentrations for six pollutants (benzene, formaldehyde (HCHO), polycyclic aromatic hydrocarbons (PAH), carbon monoxide (CO), nitric oxide (NO), and nitrogen oxides (NO(x))), and selected meteorological variables. Consistent with expectations, AER tended to increase with the number of open exterior windows and doors. The 39 AER values measured during the study when all exterior doors and windows were closed varied from 0.36 to 2.29 h(-1) with a geometric mean (GM) of 0.77 h(-1) and a geometric standard deviation (GSD) of 1.435. The 27 AER values measured when at least one exterior door or window was opened varied from 0.50 to 15.8 h(-1) with a GM of 1.98 h(-1) and a GSD of 1.902. AER was also affected by temperature and wind speed, most noticeably when exterior windows and doors were closed. Results of a series of stepwise linear regression analyses suggest that (1) outdoor pollutant concentration and (2) indoor pollutant concentration during the preceding hour were the "variables of choice" for predicting indoor pollutant concentration in the test house under the conditions of this study. Depending on the pollutant and ventilation conditions, one or more of the following variables produced a small, but

  10. Uncertainties in the Value of Bill Savings from Behind-the-Meter, Residential Photovoltaic Systems: The Roles of Electricity Market Conditions, Retail Rate Design, and Net Metering

    OpenAIRE

    Darghouth, Naim Richard

    2013-01-01

    Net metering has become a widespread policy mechanism in the U.S. for supporting customer adoption of distributed photovoltaics (PV), allowing customers with PV systems to reduce their electric bills by offsetting their consumption with PV generation, independent of the timing of the generation relative to consumption. Although net metering is one of the principal drivers for the residential PV market in the U.S., the academic literature on this policy has been sparse and this dissertation co...

  11. Patient-Ventilator Dyssynchrony

    Directory of Open Access Journals (Sweden)

    Elvira-Markela Antonogiannaki

    2017-11-01

    Full Text Available In mechanically ventilated patients, assisted mechanical ventilation (MV is employed early, following the acute phase of critical illness, in order to eliminate the detrimental effects of controlled MV, most notably the development of ventilator-induced diaphragmatic dysfunction. Nevertheless, the benefits of assisted MV are often counteracted by the development of patient-ventilator dyssynchrony. Patient-ventilator dyssynchrony occurs when either the initiation and/or termination of mechanical breath is not in time agreement with the initiation and termination of neural inspiration, respectively, or if the magnitude of mechanical assist does not respond to the patient’s respiratory demand. As patient-ventilator dyssynchrony has been associated with several adverse effects and can adversely influence patient outcome, every effort should be made to recognize and correct this occurrence at bedside. To detect patient-ventilator dyssynchronies, the physician should assess patient comfort and carefully inspect the pressure- and flow-time waveforms, available on the ventilator screen of all modern ventilators. Modern ventilators offer several modifiable settings to improve patient-ventilator interaction. New proportional modes of ventilation are also very helpful in improving patient-ventilator interaction.

  12. Short-term airing by natural ventilation

    DEFF Research Database (Denmark)

    Perino, Marco; Heiselberg, Per

    2009-01-01

    The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. This kind of system frequently integrates traditio......The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. This kind of system frequently integrates...... traditional mechanical ventilation components with natural ventilation devices, such as motorized windows and louvers. Among the various ventilation strategies that are currently available, buoyancy driven single-sided natural ventilation has proved to be very effective and can provide high air change rates...... that was aimed at developing and validating numerical models for the analysis of buoyancy driven single-sided natural ventilation systems. Once validated, these models can be used to optimize control strategies in order to achieve satisfactory indoor comfort conditions and IAQ....

  13. Bilevel vs ICU ventilators providing noninvasive ventilation: effect of system leaks: a COPD lung model comparison.

    Science.gov (United States)

    Ferreira, Juliana C; Chipman, Daniel W; Hill, Nicholas S; Kacmarek, Robert M

    2009-08-01

    Noninvasive positive-pressure ventilation (NPPV) modes are currently available on bilevel and ICU ventilators. However, little data comparing the performance of the NPPV modes on these ventilators are available. In an experimental bench study, the ability of nine ICU ventilators to function in the presence of leaks was compared with a bilevel ventilator using the IngMar ASL5000 lung simulator (IngMar Medical; Pittsburgh, PA) set at a compliance of 60 mL/cm H(2)O, an inspiratory resistance of 10 cm H(2)O/L/s, an expiratory resistance of 20 cm H(2)O/ L/s, and a respiratory rate of 15 breaths/min. All of the ventilators were set at 12 cm H(2)O pressure support and 5 cm H(2)O positive end-expiratory pressure. The data were collected at baseline and at three customized leaks. At baseline, all of the ventilators were able to deliver adequate tidal volumes, to maintain airway pressure, and to synchronize with the simulator, without missed efforts or auto-triggering. As the leak was increased, all of the ventilators (except the Vision [Respironics; Murrysville, PA] and Servo I [Maquet; Solna, Sweden]) needed adjustment of sensitivity or cycling criteria to maintain adequate ventilation, and some transitioned to backup ventilation. Significant differences in triggering and cycling were observed between the Servo I and the Vision ventilators. The Vision and Servo I were the only ventilators that required no adjustments as they adapted to increasing leaks. There were differences in performance between these two ventilators, although the clinical significance of these differences is unclear. Clinicians should be aware that in the presence of leaks, most ICU ventilators require adjustments to maintain an adequate tidal volume.

  14. Short Term Airing by Natural Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per; Perino, M.

    2010-01-01

    The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. Among the available ventilation strategies...... that are currently available, buoyancy driven, single-sided natural ventilation has proved to be very effective and can provide high air change rates for temperature and Indoor Air Quality (IAQ) control. However, to promote a wider distribution of these systems an improvement in the knowledge of their working...... airflow rate, ventilation efficiency, thermal comfort and dynamic temperature conditions. A suitable laboratory test rig was developed to perform extensive experimental analyses of the phenomenon under controlled and repeatable conditions. The results showed that short-term window airing is very effective...

  15. Mechanical ventilator - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007240.htm Mechanical ventilator - infants To use the sharing features on this page, please enable JavaScript. A mechanical ventilator is a machine that assists with breathing. ...

  16. Learning about ventilators

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000458.htm Learning about ventilators To use the sharing features on this page, ... fixed or changed. How Does Being on a Ventilator Feel? A person receives medicine to remain comfortable ...

  17. Residential Mechanical Precooling

    Energy Technology Data Exchange (ETDEWEB)

    German, Alea [Davis Energy Group, Davis, CA (United States). Alliance for Residential Building Innovation (ARBI); Hoeschele, Marc [Davis Energy Group, Davis, CA (United States). Alliance for Residential Building Innovation (ARBI)

    2014-12-01

    Residential air conditioning (AC) represents a challenging load for many electric utilities with poor load factors. Mechanical precooling improves the load factor by shifting cooling operation from on-peak to off-peak hours. This provides benefits to utilities and the electricity grid, as well as to occupants who can take advantage of time-of-use (TOU) electricity rates. Performance benefits stem from reduced compressor cycling, and shifting condensing unit operation to earlier periods of the day when outdoor temperatures are more favorable to operational efficiency. Finding solutions that save energy and reduce demand on the electricity grid is an important national objective and supports key Building America goals. The Alliance for Residential Building Innovation team evaluated mechanical AC precooling strategies in homes throughout the United States. EnergyPlus modeling was used to evaluate two homes with different performance characteristics in seven climates. Results are applicable to new construction homes and most existing homes built in the last 10 years, as well as fairly efficient retrofitted homes. A successful off-peak AC strategy offers the potential for increased efficiency and improved occupant comfort, and promotes a more reliable and robust electricity grid. Demand response capabilities and further integration with photovoltaic TOU generation patterns provide additional opportunities to flatten loads and optimize grid impacts.

  18. VENTILATION TECHNOLOGY SYSTEMS ANALYSIS

    Science.gov (United States)

    The report gives results of a project to develop a systems analysis of ventilation technology and provide a state-of-the-art assessment of ventilation and indoor air quality (IAQ) research needs. (NOTE: Ventilation technology is defined as the hardware necessary to bring outdoor ...

  19. Ventilation of nuclear facilities

    International Nuclear Information System (INIS)

    1982-01-01

    In this work an examination is made of ventilation problems in nuclear installations, of the fuel cycle or the handling of radioactive compounds. The study covers the detection of radioactive aerosols, purification, iodine trapping, ventilation equipment and its maintenance, engineering, safety of ventilation, fire efficiency, operation, regulations and normalization [fr

  20. Accuracy of an indirect calorimeter for mechanically ventilated infants and children: the influence of low rates of gas exchange and varying FIO2.

    Science.gov (United States)

    Joosten, K F; Jacobs, F I; van Klaarwater, E; Baartmans, M G; Hop, W C; Meriläinen, P T; Hazelzet, J A

    2000-08-01

    To test the accuracy and validity of the Deltatrac II MBM-200 metabolic monitor for use in mechanically ventilated infants and children in the pediatric intensive care unit. Laboratory validation of an indirect calorimeter with a ventilated lung model. The influence of low tidal volumes and low levels of oxygen consumption (V(O2)) and carbon dioxide production (V(CO2)) in combination with different levels of inspired oxygen concentrations (F(IO2)) was investigated. University research laboratory. Low tidal volumes were provided with two intermittent flow types of ventilators, a Servo 300 and a Servo 900C. A butane flame with a V(O2) approximating 20 mL/min and 40 mL/min was ventilated. To investigate the effect of different levels of F(IO2) on the accuracy of V(O2), V(CO2), and respiratory quotient (RQ), measurements were performed at F(IO2) target values of 0.25, 0.40, and 0.60. No significant differences were found between the ventilators regarding V(O2), V(CO2), and RQ measurements. The mean deviation of V(O2) increased significantly with increasing F(IO2) to -7.98% with a V(O2) of 21.0 mL/min and to -8.46% with a V(O2) of 38.9 mL/min (F(IO2), 0.558) with a variability (2 SD) of +/- 4.86% and +/- 6.82%, respectively. The mean deviation and variability of V(CO2) in all tests remained within 8%. The mean deviation of RQ increased significantly with increasing F(IO2) to 5.5% with a V(O2) of 21.0 mL/min and to 5.69% with a V(O2) of 38.9 mL/min (F(IO2), 0.558) with a variability (2 SD) of +/- 5.62% and +/- 5.76%, respectively. The minute to minute delivered F(IO2) fluctuated significantly when increasing the level of F(IO2). The Deltatrac II MBM-200 metabolic monitor appears accurate for low levels of V(O2) and V(CO2) during mechanical ventilation with F(IO2) levels up to 0.390. With increasing F(IO2) to 0.558, the increase in deviation of V(O2) for single measurements can be of clinical relevance for mechanically ventilated infants and children. The increased

  1. Ventilation effectiveness : health benefits of heat recovery ventilators

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2010-08-15

    Studies have shown that the installation of a heat recovery ventilator (HRV) in homes in northern Canada could improve indoor air quality and the respiratory health of inhabitants. Low ventilation rates are common in many homes in the North because the climate is severe, homes are smaller and lack basements, and occupancies are higher, leading to unhealthy indoor air quality. Northern communities also have a high rate of respiratory infections. HRVs recover much of the energy used to ventilate, which is desirable in cold regions with high heating costs. For the study, the test sample was divided into two types of houses, notably houses with active HRVs and those with control HRVs that were installed and operated but that did not function. The study results showed that HRVs provided increased ventilation. Complaints by residents about HRV noise, discomfort, or low humidity were common but equally spread between those with active and placebo HRVs. The study showed that the system design needs to be improved to better suit the needs of Inuit families. The nature of northern housing presents installation and maintenance challenges. It is hard to retrofit HRV ducting inside small, existing houses, and building supplies arrive infrequently, so detailed planning and careful take-offs of all supplies and materials must be done well in advance of construction. In addition, contractors are hard to locate and have variable expertise, and there is little technical follow-up. Robust technical support by local contractors and housing authorities is therefore important. 2 refs.

  2. Conservative fluid management prevents age-associated ventilator induced mortality.

    Science.gov (United States)

    Herbert, Joseph A; Valentine, Michael S; Saravanan, Nivi; Schneck, Matthew B; Pidaparti, Ramana; Fowler, Alpha A; Reynolds, Angela M; Heise, Rebecca L

    2016-08-01

    Approximately 800 thousand patients require mechanical ventilation in the United States annually with an in-hospital mortality rate of over 30%. The majority of patients requiring mechanical ventilation are over the age of 65 and advanced age is known to increase the severity of ventilator-induced lung injury (VILI) and in-hospital mortality rates. However, the mechanisms which predispose aging ventilator patients to increased mortality rates are not fully understood. Ventilation with conservative fluid management decreases mortality rates in acute respiratory distress patients, but to date there has been no investigation of the effect of conservative fluid management on VILI and ventilator associated mortality rates. We hypothesized that age-associated increases in susceptibility and incidence of pulmonary edema strongly promote age-related increases in ventilator associated mortality. 2month old and 20month old male C57BL6 mice were mechanically ventilated with either high tidal volume (HVT) or low tidal volume (LVT) for up to 4h with either liberal or conservative fluid support. During ventilation, lung compliance, total lung capacity, and hysteresis curves were quantified. Following ventilation, bronchoalveolar lavage fluid was analyzed for total protein content and inflammatory cell infiltration. Wet to dry ratios were used to directly measure edema in excised lungs. Lung histology was performed to quantify alveolar barrier damage/destruction. Age matched non-ventilated mice were used as controls. At 4h, both advanced age and HVT ventilation significantly increased markers of inflammation and injury, degraded pulmonary mechanics, and decreased survival rates. Conservative fluid support significantly diminished pulmonary edema and improved pulmonary mechanics by 1h in advanced age HVT subjects. In 4h ventilations, conservative fluid support significantly diminished pulmonary edema, improved lung mechanics, and resulted in significantly lower mortality rates in

  3. Ventilation and ventilation/perfusion ratios

    International Nuclear Information System (INIS)

    Valind, S.O.

    1989-01-01

    The thesis is based on five different papers. The labelling of specific tracer compounds with positron emitting radionuclides enables a range of structural, physiological and biochemical parameters in the lung to be measured non-invasively, using positron emission tomography. This concept affords a unique opportunity for in vivo studies of different expressions of pulmonary pathophysiology at the regional level. The present thesis describes the application of positron emission tomography to the measurements of ventilation and ventilation/perfusion ratios using inert gas tracers, neon-19 and nitrogen-13 respectively. The validity of the methods applied was investigated with respect to the transport of inert gas tracers in the human lung. Both ventilation and the ventilation/perfusion ratio may be obtained with errors less than 10 % in the normal lung. In disease, however, errors may increase in those instances where the regional ventilation is very low or the intra-regional gas flow distribution is markedly nonuniform. A 2-3 fold increase in ventilation was demonstrated in normal nonsmoking subjects going from ventral to dorsal regions in the supine posture. These large regional differences could be well explained by the intrinsic elastic properties of lung tissue, considering the gravitational gradient in transpulmonary pressure. In asymptomatic smokers substantial regional ventilatroy abnormalities were found whilst the regional gas volume was similar in smokers and nonsmokers. The uncoupling between ventilation and gas volume probably reflects inflammatory changes in the airways. The regional differences in dV/dt/dQ/dt were relatively small and blood flow was largely matched to ventilation in the supine posture. However, small regions of lung with very low ventilation, unmatched by blood flow commonly exists in the most dependent parts of the lung in both smokers and nonsmokers. (29 illustrations, 7 tables, 113 references)

  4. Limiting volume with modern ventilators.

    Science.gov (United States)

    Wing, Thomas J; Haan, Lutana; Ashworth, Lonny J; Anderson, Jeff

    2015-06-01

    The acute respiratory distress syndrome (ARDS) network low tidal-volume study comparing tidal volumes of 12 ml/kg versus 6 ml/kg was published in 2000. The study was stopped early as data revealed a 22% relative reduction in mortality rate when using 6 ml/kg tidal volume. The current generation of critical care ventilators allows the tidal volume to be set during volume-targeted, assist/control (volume A/C); however, some ventilators include options that may prevent the tidal volume from being controlled. The purpose of this bench study was to evaluate the delivered tidal volume, when these options are active, in a spontaneously breathing lung model using an electronic breathing simulator. Four ventilators were evaluated: CareFusion AVEA (AVEA), Dräger Evita® XL (Evita XL), Covidien Puritan Bennett® 840(TM) (PB 840), and Maquet SERVO-i (SERVO-i). Each ventilator was connected to the Hans Rudolph Electronic Breathing Simulator at an amplitude of 0 cm H2O and then 10 cm H2O. All four ventilators were set to deliver volume A/C, tidal volume 400 ml, respiratory rate 20 bpm, positive end-expiratory pressure 5 cm H2O, peak flowrate 60 L/min. The displayed tidal volume was recorded for each ventilator at the above settings with additional options OFF and then ON. The AVEA has two options in volume A/C: demand breaths and V-sync. When activated, these options allow the patient to exceed the set tidal volume. When using the Evita XL, the option AutoFlow can be turned ON or OFF, and when this option is ON, the tidal volume may vary. The PB 840 does not have any additional options that affect volume delivery, and it maintains the set tidal volume regardless of patient effort. The SERVO-i's demand valve allows additional flow if the patient's inspiratory flowrate exceeds the set flowrate, increasing the delivered tidal volume; this option can be turned OFF with the latest software upgrade. Modern ventilators have an increasing number of optional settings. These settings may

  5. MICRO-CHP System for Residential Applications

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Gerstmann

    2009-01-31

    This is the final report of progress under Phase I of a project to develop and commercialize a micro-CHP system for residential applications that provides electrical power, heating, and cooling for the home. This is the first phase of a three-phase effort in which the residential micro-CHP system will be designed (Phase I), developed and tested in the laboratory (Phase II); and further developed and field tested (Phase III). The project team consists of Advanced Mechanical Technology, Inc. (AMTI), responsible for system design and integration; Marathon Engine Systems, Inc. (MES), responsible for design of the engine-generator subsystem; AO Smith, responsible for design of the thermal storage and water heating subsystems; Trane, a business of American Standard Companies, responsible for design of the HVAC subsystem; and AirXchange, Inc., responsible for design of the mechanical ventilation and dehumidification subsystem.

  6. The role of the U.S. Department of Energy in indoor air quality and building ventilation policy development

    Energy Technology Data Exchange (ETDEWEB)

    Traynor, G.W. [Lawrence Berkeley Lab., Berkeley, CA (United States). Indoor Environment Program; Talbott, J.M. [U.S. Dept. of Energy, Washington, DC (United States). Office of Building Technologies; Moses, D.O. [U.S. Dept. of Energy, Washington, DC (United States). Office of Environmental Analysis

    1993-12-31

    Building ventilation consumes about 5.8 exajoules of energy each year in the U.S. The annual cost of this-energy, used for commercial building fans (1.6 exajoules/yr) and the heating and cooling of outside air (4.2 exajoules/yr), is about $US 33 billion per year. Energy conservation measures that reduce heating and cooling season ventilation rates 15 to 35 % in commercial and residential buildings can result in a national savings of about 0.6 to 15 exajoules (doll US 3-8 billion) per year assuming no reduction of commercial building fan energy use. The most significant adverse environmental impact of reduced ventilation and infiltration is the potential degradation of the building`s indoor air quality. Potential benefits to the U.S from the implementation of sound indoor air quality and building ventilation reduction policies include reduced building-sector energy consumption; reduced indoor, outdoor, and global pollution; reduced product costs; reduced worker absenteeism; reduced health care costs; reduced litigation; increased worker well-being and absenteeism; reduced health care costs; reduced litigation; increased productivity; and increased product quality and competitiveness. (author)

  7. Sensor-based demand controlled ventilation

    Energy Technology Data Exchange (ETDEWEB)

    De Almeida, A.T. [Universidade de Coimbra (Portugal). Dep. Eng. Electrotecnica; Fisk, W.J. [Lawrence Berkeley National Lab., CA (United States)

    1997-07-01

    In most buildings, occupancy and indoor pollutant emission rates vary with time. With sensor-based demand-controlled ventilation (SBDCV), the rate of ventilation (i.e., rate of outside air supply) also varies with time to compensate for the changes in pollutant generation. In other words, SBDCV involves the application of sensing, feedback and control to modulate ventilation. Compared to ventilation without feedback, SBDCV offers two potential advantages: (1) better control of indoor pollutant concentrations; and (2) lower energy use and peak energy demand. SBDCV has the potential to improve indoor air quality by increasing the rate of ventilation when indoor pollutant generation rates are high and occupants are present. SBDCV can also save energy by decreasing the rate of ventilation when indoor pollutant generation rates are low or occupants are absent. After providing background information on indoor air quality and ventilation, this report provides a relatively comprehensive discussion of SBDCV. Topics covered in the report include basic principles of SBDCV, sensor technologies, technologies for controlling air flow rates, case studies of SBDCV, application of SBDCV to laboratory buildings, and research needs. SBDCV appears to be an increasingly attractive technology option. Based on the review of literature and theoretical considerations, the application of SBDCV has the potential to be cost-effective in applications with the following characteristics: (a) a single or small number of dominant pollutants, so that ventilation sufficient to control the concentration of the dominant pollutants provides effective control of all other pollutants; (b) large buildings or rooms with unpredictable temporally variable occupancy or pollutant emission; and (c) climates with high heating or cooling loads or locations with expensive energy.

  8. Air Distribution and Ventilation Effectiveness in a room with Floor/Ceiling Heating and Mixing/Displacement Ventilation

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Fang, Lei; Olesen, Bjarne W.

    2014-01-01

    vertical air temperature differences and air velocities for different hybrid systems are less than 3 C and 0.2 m/s when supply air temperature is 19 C, air change rate is 4.2 h-1, and heated surface temperature of floor/ceiling heating system is 25 C. Ventilation effectiveness of mixing ventilation system...... combined with floor/ceiling heating systems is approximately equal to 1.0, and ventilation effectiveness of displacement ventilation system combined with floor/ceiling heating systems ranges from 1.0 to 1.2. The floor/ceiling heating systems combined with mixing ventilation system have more uniform indoor...... air distribution but smaller ventilation effectiveness compared with the floor/ceiling heating systems combined with displacement ventilation system. With regard to the building heat loss increased by non-uniform indoor air distribution and small ventilation effectiveness, there should be an optimal...

  9. Experimental study including subjective evaluations of mixing and displacement ventilation combined with radiant floor heating/cooling system

    DEFF Research Database (Denmark)

    Krajcik, Michal; Tomasi, Roberta; Simone, Angela

    2013-01-01

    Sixteen subjects evaluated the indoor environment in four experiments with different combinations of ventilation systems and radiant heating/cooling systems. In the first two tests, the simulated residential room was equipped either by a mixing ventilation system supplying warm air for space heat...

  10. Complications of mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Drašković Biljana

    2011-01-01

    Full Text Available Mechanical ventilation of the lungs, as an important therapeutic measure, cannot be avoided in critically ill patients. However, when machines take over some of vital functions there is always a risk of complications and accidents. Complications associated with mechanical ventilation can be divided into: 1 airway-associated complications; 2 complications in the response of patients to mechanical ventilation; and 3 complications related to the patient’s response to the device for mechanical ventilation. Complications of artificial airway may be related to intubation and extubation or the endotracheal tube. Complications of mechanical ventilation, which arise because of the patient’s response to mechanical ventilation, may primarily cause significant side effects to the lungs. During the last two decades it was concluded that mechanical ventilation can worsen or cause acute lung injury. Mechanical ventilation may increase the alveolar/capillary permeability by overdistension of the lungs (volutrauma, it can exacerbate lung damage due to the recruitment/derecruitment of collapsed alveoli (atelectrauma and may cause subtle damages due to the activation of inflammatory processes (biotrauma. Complications caused by mechanical ventilation, beside those involving the lungs, can also have significant effects on other organs and organic systems, and can be a significant factor contributing to the increase of morbidity and mortality in critically ill of mechanically ventilated patients. Complications are fortunately rare and do not occur in every patient, but due to their seriousness and severity they require extensive knowledge, experience and responsibility by health-care workers.

  11. Evaluation of ventilators for mouthpiece ventilation in neuromuscular disease.

    Science.gov (United States)

    Khirani, Sonia; Ramirez, Adriana; Delord, Vincent; Leroux, Karl; Lofaso, Frédéric; Hautot, Solène; Toussaint, Michel; Orlikowski, David; Louis, Bruno; Fauroux, Brigitte

    2014-09-01

    Daytime mouthpiece ventilation is a useful adjunct to nocturnal noninvasive ventilation (NIV) in patients with neuromuscular disease. The aims of the study were to analyze the practice of mouthpiece ventilation and to evaluate the performance of ventilators for mouthpiece ventilation. Practice of mouthpiece ventilation was assessed by a questionnaire, and the performance of 6 home ventilators with mouthpiece ventilation was assessed in a bench test using 24 different conditions per ventilator: 3 mouthpieces, a child and an adult patient profile, and 4 ventilatory modes. Questionnaires were obtained from 30 subjects (mean age 33 ± 11 y) using NIV for 12 ± 7 y. Fifteen subjects used NIV for > 20 h/day, and 11 were totally ventilator-dependent. The subject-reported benefits of mouthpiece ventilation were a reduction in dyspnea (73%) and fatigue (93%) and an improvement in speech (43%) and eating (27%). The bench study showed that none of the ventilators, even those with mouthpiece ventilation software, were able to deliver mouthpiece ventilation without alarms and/or autotriggering in each condition. Alarms and/or ineffective triggering or autotriggering were observed in 135 of the 198 conditions. The occurrence of alarms was more common with a large mouthpiece without a filter compared to a small mouthpiece with a filter (P ventilator. Subjects are satisfied with mouthpiece ventilation. Alarms are common with home ventilators, although less common in those with mouthpiece ventilation software. Improvements in home ventilators are needed to facilitate the expansion of mouthpiece ventilation. Copyright © 2014 by Daedalus Enterprises.

  12. Look-Ahead Energy Management of a Grid-Connected Residential PV System with Energy Storage under Time-Based Rate Programs

    Directory of Open Access Journals (Sweden)

    Kyeon Hur

    2012-04-01

    Full Text Available This paper presents look-ahead energy management system for a grid-connected residential photovoltaic (PV system with battery under critical peak pricing for electricity, enabling effective and proactive participation of consumers in the Smart Grid’s demand response. In the proposed system, the PV is the primary energy source with the battery for storing (or retrieving excessive (or stored energy to pursue the lowest possible electricity bill but it is grid-tied to secure electric power delivery. Premise energy management scheme with an accurate yet practical load forecasting capability based on a Kalman filter is designed to increase the predictability in controlling the power flows among these power system components and the controllable electric appliances in the premise. The case studies with various operating scenarios demonstrate the validity of the proposed system and significant cost savings through operating the energy management scheme.

  13. Protective garment ventilation system

    Science.gov (United States)

    Lang, R. (Inventor)

    1970-01-01

    A method and apparatus for ventilating a protective garment, space suit system, and/or pressure suits to maintain a comfortable and nontoxic atmosphere within is described. The direction of flow of a ventilating and purging gas in portions of the garment may be reversed in order to compensate for changes in environment and activity of the wearer. The entire flow of the ventilating gas can also be directed first to the helmet associated with the garment.

  14. Ventilation of uranium mines

    International Nuclear Information System (INIS)

    Francois, Y.; Pradel, J.; Zettwoog, P.; Dumas, M.

    1975-01-01

    In the first part of the paper the authors describe the ventilation of French mines in terms of the primary ventilation system, which brings the outside air close to the working places using the overall structure of the mine to form the airways, and the secondary ventilation system, which is for the distribution of the primary air or for the ventilation of the development drifts and blind tunnels. Brief mention is made of the French regulations on the ventilation of mines in general and uranium mines in particular. The authors describe the equipment used and discuss the installed capacities and air flow per man and per working place. The difficulties encountered in properly ventilating various types of working places are mentioned, such as sub-level development drifts, reinforced stopes, and storage chambers with an artificial crown. The second part of the paper is devoted to computer calculations of the primary ventilation system. It is explained why the Commissariat a l'energie atomique has found it necessary to make these calculations. Without restating the mathematical theories underlying the methods employed, the authors demonstrate how simple measuring instruments and a small-size computer can be used to solve the ventilation problems arising in French mines. Emphasis is given to the layout of the ventilation system and to air flow and negative pressure measurements at the base of the mine. The authors show how calculations can be applied to new heading operations, a change in resistance, the replacement or addition of a ventilator, and a new air inlet or outlet. The authors come to the conclusion that since ventilation is at present the most reliable way of avoiding the pollution of mines, a thorough knowledge of the capabilities in this respect can often help improve working conditions. Despite the progress made, however, constant surveillance of the ventilation systems in uranium mines by a separate team with no responsibility for production problems is

  15. Ventilation of uranium mines

    International Nuclear Information System (INIS)

    Francois, Y.; Pradel, J.; Zettwoog, P.; Dumas, M.

    1975-01-01

    In the first part of the paper the authors describe the ventilation of French mines in terms of the primary ventilation system, which brings the outside air close to the working places using the overall structure of the mine to form the airways, and the secondary ventilation system, which is for the distribution of the primary air or for the ventilation of the development drifts and blind tunnels. Brief mention is made of the French regulations on the ventilation of mines in general and uranium mines in particular. The authors describe the equipment used and discuss the installed capacities and air flow per man and per working place. The difficulties encountered in properly ventilating various types of working places are mentioned, such as sublevel development drifts, reinforced stopes, and storage chambers with an artificial crown. The second part of the paper is devoted to computer calculations of the primary ventilation system. It is explained why the Commissariat a l'energie atomique has found it necessary to make these calculations. Without restating the mathematical theories underlying the methods employed, the authors demonstrate how simple measuring instruments and a small-size computer can be used to solve the ventilation problems arising in French mines. Emphasis is given to the layout of the ventilation system and to air flow and negative pressure measurements at the base of the mine. The authors show how calculations can be applied to new heading operations, a change in resistance, the replacement or addition of a ventilator, and a new air inlet or outlet. The authors come to the conclusion that since ventilation is at present the most reliable way of avoiding the pollution of mines, a thorough knowledge of the capabilities in this respect can often help improve working conditions. Despite the progress made, however, constant surveillance of the ventilation systems in uranium mines by a separate team with no responsibility for production problems is

  16. Design Principles for Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per

    For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system -Hybrid Ventilation. ....... The hybrid ventilation concepts, design challenges and - principles are discussed and illustrated by four building examples....

  17. Natural Ventilation in Atria

    DEFF Research Database (Denmark)

    Svidt, Kjeld; Heiselberg, Per; Hendriksen, Ole Juhl

    This case study comprises a monitoring programme as well as a Computational Fluid Dynamics (CFD) analysis of a natural ventilated atrium. The purpose has been to analyse the performance of a typical natural ventilation system in Denmark under both summer and winter conditions.......This case study comprises a monitoring programme as well as a Computational Fluid Dynamics (CFD) analysis of a natural ventilated atrium. The purpose has been to analyse the performance of a typical natural ventilation system in Denmark under both summer and winter conditions....

  18. Experimental Investigation of Heat Transfer during Night-Time Ventilation

    DEFF Research Database (Denmark)

    Artmann, Nikolai; Jensen, Rasmus Lund; Manz, H.

    2010-01-01

    is the heat transfer at the internal room surfaces. Increased convection is expected due to high air flow rates and the possibility of a cold air jet flowing along the ceiling, but the magnitude of these effects is hard to predict. In order to improve the predictability, heat transfer during night......-time ventilation in case of mixing and displacement ventilation has been investigated in a full scale test room. The results show that for low air flow rates displacement ventilation is more efficient than mixing ventilation. For higher air flow rates the air jet flowing along the ceiling has a significant effect...

  19. 77 FR 28519 - Test Procedure Guidance for Room Air Conditioners, Residential Dishwashers, and Residential...

    Science.gov (United States)

    2012-05-15

    ... Guidance for Room Air Conditioners, Residential Dishwashers, and Residential Clothes Washers: Public... procedures for room air conditioners, residential dishwashers, and residential clothes washers. DATES: DOE...'s existing test procedures for residential room air conditioners, residential dishwashers, and...

  20. Tracheostomy and invasive mechanical ventilation in amyotrophic lateral sclerosis: decision-making factors and survival analysis.

    Science.gov (United States)

    Kimura, Fumiharu

    2016-04-28

    Invasive and/or non-invasive mechanical ventilation are most important options of respiratory management in amyotrophic lateral sclerosis. We evaluated the frequency, clinical characteristics, decision-making factors about ventilation and survival analysis of 190 people with amyotrophic lateral sclerosis patients from 1990 until 2013. Thirty-one percentage of patients underwent tracheostomy invasive ventilation with the rate increasing more than the past 20 years. The ratio of tracheostomy invasive ventilation in patients >65 years old was significantly increased after 2000 (25%) as compared to before (10%). After 2010, the standard use of non-invasive ventilation showed a tendency to reduce the frequency of tracheostomy invasive ventilation. Mechanical ventilation prolonged median survival (75 months in tracheostomy invasive ventilation, 43 months in non-invasive ventilation vs natural course, 32 months). The life-extending effects by tracheostomy invasive ventilation were longer in younger patients ≤65 years old at the time of ventilation support than in older patients. Presence of partners and care at home were associated with better survival. Following factors related to the decision to perform tracheostomy invasive ventilation: patients ≤65 years old: greater use of non-invasive ventilation: presence of a spouse: faster tracheostomy: higher progression rate; and preserved motor functions. No patients who underwent tracheostomy invasive ventilation died from a decision to withdraw mechanical ventilation. The present study provides factors related to decision-making process and survival after tracheostomy and help clinicians and family members to expand the knowledge about ventilation.

  1. Forecasting residential electricity demand in provincial China.

    Science.gov (United States)

    Liao, Hua; Liu, Yanan; Gao, Yixuan; Hao, Yu; Ma, Xiao-Wei; Wang, Kan

    2017-03-01

    In China, more than 80% electricity comes from coal which dominates the CO2 emissions. Residential electricity demand forecasting plays a significant role in electricity infrastructure planning and energy policy designing, but it is challenging to make an accurate forecast for developing countries. This paper forecasts the provincial residential electricity consumption of China in the 13th Five-Year-Plan (2016-2020) period using panel data. To overcome the limitations of widely used predication models with unreliably prior knowledge on function forms, a robust piecewise linear model in reduced form is utilized to capture the non-deterministic relationship between income and residential electricity consumption. The forecast results suggest that the growth rates of developed provinces will slow down, while the less developed will be still in fast growing. The national residential electricity demand will increase at 6.6% annually during 2016-2020, and populous provinces such as Guangdong will be the main contributors to the increments.

  2. Canadian energy standards : residential energy code requirements

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, K. [SAR Engineering Ltd., Burnaby, BC (Canada)

    2006-09-15

    A survey of residential energy code requirements was discussed. New housing is approximately 13 per cent more efficient than housing built 15 years ago, and more stringent energy efficiency requirements in building codes have contributed to decreased energy use and greenhouse gas (GHG) emissions. However, a survey of residential energy codes across Canada has determined that explicit demands for energy efficiency are currently only present in British Columbia (BC), Manitoba, Ontario and Quebec. The survey evaluated more than 4300 single-detached homes built between 2000 and 2005 using data from the EnerGuide for Houses (EGH) database. House area, volume, airtightness and construction characteristics were reviewed to create archetypes for 8 geographic areas. The survey indicated that in Quebec and the Maritimes, 90 per cent of houses comply with ventilation system requirements of the National Building Code, while compliance in the rest of Canada is much lower. Heat recovery ventilation use is predominant in the Atlantic provinces. Direct-vent or condensing furnaces constitute the majority of installed systems in provinces where natural gas is the primary space heating fuel. Details of Insulation levels for walls, double-glazed windows, and building code insulation standards were also reviewed. It was concluded that if R-2000 levels of energy efficiency were applied, total average energy consumption would be reduced by 36 per cent in Canada. 2 tabs.

  3. Thermodynamical double-flux ventilation system in individual house; Systeme de ventilation double flux thermodynamique en maison individuelle

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This guidebook written by the French scientific and technical committee of the space heating, ventilation and air-conditioning industry (Costic) with the collaboration of the French association of coldness production engineering (AFF) and Electricite de France (EdF), presents the technical rules and practical advices for the installation of thermodynamical double-flux ventilation systems in residential houses. Content: heat pumps (standardization and regulation, choice and dimensioning of the auxiliary electrical supply, installation, acoustic precautions), aeraulic networks (standardization and regulation, choice and dimensioning, installation), thermal insulation, thermoregulation, control and start-up, maintenance. (J.S.)

  4. Experimental analysis of energy performance of a ventilated window for heat recovery under controlled conditions

    DEFF Research Database (Denmark)

    Appelfeld, David; Svendsen, Svend

    2011-01-01

    balance of the ventilated window and clarified the methodology for thermal performance evaluation. Comparison between windows with and without ventilation using the window-room-ventilation heat balance revealed that a ventilated window can potentially contribute to energy savings. In addition...... transmittance introduced by the ventilation was higher than the effect of heat recovery. Accordingly, the use of the ventilated windows might be most suitable for window unit with low ventilation rates. The results correlated with theoretical calculations in standards and software. However, the concept...

  5. Prevalence of Residential Dampness and Mold Exposure in a University Student Population

    Directory of Open Access Journals (Sweden)

    Mathieu Lanthier-Veilleux

    2016-02-01

    Full Text Available The impact of residential dampness or mold on respiratory health is well established but few studies have focused on university students. This study aims to: (a describe the prevalence of exposure to residential dampness or mold in university students according to socio-geographic factors and (b identify associated housing characteristics. A web survey was conducted in 2014 among the 26,676 students registered at the Université de Sherbrooke (QC, Canada. Residential dampness and mold being closely intertwined, they were considered as a single exposure and assessed using a validated questionnaire. Exposure was compared according to socio-geographic and housing characteristics using chi-square tests and logistic regressions. Among the 2097 participants included in the study (response rate: 8.1%, over 80% were tenants. Residential exposure to dampness or mold was frequent (36.0%, 95% CI: 33.9–38.1. Marked differences for this exposure were noted according to home ownership (39.7% vs. 25.5% among tenants and owners respectively; OR = 1.92%, 95% CI: 1.54–2.38. Campus affiliation, household composition and the number of residents per building were associated with exposure to dampness or mold (p < 0.01, while sex and age were not. Exposure was also associated with older buildings, and buildings in need of renovations and lacking proper ventilation (p < 0.001. This study highlights the potential risk of university students suffering from mold-related health effects given their frequent exposure to this agent. Further research is needed to fully evaluate the mold-related health impact in this at risk group.

  6. Reducing the electricity consumption of small ventilation installations; Reduktion des Elektrizitaetsverbrauchs von Klein-Lueftungsanlagen - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Furter, R.; Casartelli, E.; Lang, M.

    2010-03-15

    This final report for the Swiss Federal Office of Energy (SFOE) takes a look at how the electricity consumption of small ventilation installations can be reduced. Residential ventilation systems - also known as comfort ventilation systems - have to fulfil demands placed on energy efficiency, comfort and hygiene. The results of exemplary measurements of the electrical power consumption that have been made in order to estimate the current situation of ventilation systems and of air handling units in apartments and single family houses are presented and discussed. Air networks were simulated at nominal air flow with different pressure losses for nine different ventilation units. The most important conclusion of this work is quoted as being that the internal pressure losses of the ventilation units have to be reduced and the design recommendation for the air network has to be reconsidered. Also the authors are of the opinion that hygiene requirements must be more rigorously respected.

  7. RESIDENTIAL MORTGAGE IN MODERN RUSSIA

    Directory of Open Access Journals (Sweden)

    Dementiev N. P.

    2015-03-01

    Full Text Available The article presents a comparative analysis of residential mortgages in Russia and the United States. The primary ways of mortgage refinancing are outlined. Predominance of the elements of two-level refinancing system of residential mortgage in Russia and the United States is shown. The activity of the Agency for Housing Mortgage Lending (AHML, the basic tool of the Russian government’s mortgage policy, is described in detail. In its objectives and functions the AHML is similar to the American mortgage agencies Ginnie Mae, Fannie Mae and Freddie Mac. Similarities were identified in the Russian and US residential mortgages in the pre-crisis period (high rates of mortgage growth, favourable economic conjuncture, low interest rates, large increase in house prices, speculative housing demand. During the mortgage crisis, the policies of the Russian and US governments and monetary authorities had also much in common (monetary policy easing, cheap central banks loans, extended facilities of mortgage refinancing on the part of state agencies, mortgage rescue scheme, social mortgage programs. But the scope of mortgage in Russia is enormously narrow as compared to the US mortgage. The most important reason for that - low incomes of the Russian population.

  8. Styret naturlig ventilation

    DEFF Research Database (Denmark)

    Morsing, S.; Strøm, J.S.

    Publikationen præsenterer et generelt dimensioneringsgrundlag for naturlig ventilation i husdyrstalde. Det er kontrolleret ved forsøg i slagtesvinestalde, hvor det ligeledes er undersøgt hvilken temperaturstabilitet, der kan opnås ved naturlig ventilation, samt produktions- og adfærdsmæssige...

  9. Multifamily Ventilation Retrofit Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation (BSC), Somerville, MA (United States); Lstiburek, J. [Building Science Corporation (BSC), Somerville, MA (United States); Bergey, D. [Building Science Corporation (BSC), Somerville, MA (United States)

    2012-12-01

    In multifamily buildings, central ventilation systems often have poor performance, overventilating some portions of the building (causing excess energy use), while simultaneously underventilating other portions (causing diminished indoor air quality). BSC and Innova Services Corporation performed a series of field tests at a mid-rise test building undergoing a major energy audit and retrofit, which included ventilation system upgrades.

  10. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Heiselberg, Per; Nielsen, Peter V.

    2014-01-01

    As a novel air distribution system, diffuse ceiling ventilation combines the suspended acoustic ceiling with ventilation supply. Due to the low-impulse supply from the large ceiling area, the system does not generate draught when supplying cold air. However, heat sources play an important role...

  11. Gentrification and Residential Mobility in Philadelphia.

    Science.gov (United States)

    Ding, Lei; Hwang, Jackelyn; Divringi, Eileen

    2016-11-01

    Gentrification has provoked considerable controversy surrounding its effects on residential displacement. Using a unique individual-level, longitudinal data set, this study examines mobility rates and residential destinations of residents in gentrifying neighborhoods during the recent housing boom and bust in Philadelphia for various strata of residents and different types of gentrification. We find that vulnerable residents, those with low credit scores and without mortgages, are generally no more likely to move from gentrifying neighborhoods compared with their counterparts in nongentrifying neighborhoods. When they do move, however, they are more likely to move to lower-income neighborhoods. Residents in gentrifying neighborhoods at the aggregate level have slightly higher mobility rates, but these rates are largely driven by more advantaged residents. These findings shed new light on the heterogeneity in mobility patterns across residents in gentrifying neighborhoods and suggest that researchers should focus more attention on the quality of residential moves and nonmoves for less advantaged residents, rather than mobility rates alone.

  12. Residential Pre-Cooling: Mechanical Cooling and Air-Side Economizers:

    OpenAIRE

    Turner, William J.N; Walker, Iain S.; Roux, Jordan

    2012-01-01

    This study used an advanced airflow, energy and humidity modeling tool to evaluate residential air-side economizers and mechanical pre-cooling strategies using the air conditioner, in all US DOE Climate Zones for a typical new home with ASHRAE Standard 62.2 compliant ventilation. A residential air-side economizer is a large supply fan used for night ventilation. Mechanical pre-cooling used the building air conditioner operating at lower than usual set before the peak demand period. The simula...

  13. Particle deposition in ventilation ducts

    Energy Technology Data Exchange (ETDEWEB)

    Sippola, Mark Raymond [Univ. of California, Berkeley, CA (United States)

    2002-09-01

    Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 μm were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on the

  14. Pulmonary perfusion ''without ventilation''

    International Nuclear Information System (INIS)

    Chapman, C.N.; Sziklas, J.J.; Spencer, R.P.; Rosenberg, R.J.

    1983-01-01

    An 88-yr-old man, with prior left upper lobectomy and phrenic nerve injury, had a ventilation/perfusion lung image. Both wash-in and equilibrium ventilation images showed no radioactive gas in the left lung. Nevertheless, the left lung was perfused. A similar result was obtained on a repeat study 8 days later. Delayed images, during washout, showed some radioactive gas in the left lung. Nearly absent ventilation (but continued perfusion) of that lung might have been related to altered gas dynamics brought about by the prior lobectomy, a submucosal bronchial lesion, phrenic nerve damage, and limited motion of the left part of the diaphragm. This case raises the issue of the degree of ventilation (and the phase relationship between the lungs) required for the entry of radioactive gas into a diseased lung, and the production of a ''reversed ventilation/perfusion mismatch.''

  15. Realtime mine ventilation simulation

    International Nuclear Information System (INIS)

    McDaniel, K.H.

    1997-01-01

    This paper describes the development of a Windows based, interactive mine ventilation simulation software program at the Waste Isolation Pilot Plant (WIPP). To enhance the operation of the underground ventilation system, Westinghouse Electric Corporation developed the program called WIPPVENT. While WIPPVENT includes most of the functions of the commercially available simulation program VNETPC and uses the same subroutine to calculate airflow distributions, the user interface has been completely rewritten as a Windows application with screen graphics. WIPPVENT is designed to interact with WIPP ventilation monitoring systems through the sitewise Central monitoring System. Data can be continuously collected from the Underground Ventilation Remote Monitoring and Control System (e.g., air quantity and differential pressure) and the Mine Weather Stations (psychrometric data). Furthermore, WIPPVENT incorporates regulator characteristic curves specific to the site. The program utilizes this data to create and continuously update a REAL-TIME ventilation model. This paper discusses the design, key features, and interactive capabilities of WIPPVENT

  16. Demand controlled ventilation for multi-family dwellings

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig

    for centrally balanced DCV systems with heat recovery. A design expected to fulfill this requirement was investigated in detail with regard to its electricity consumption by evaluating a control strategy that resets the static pressure set point at part load. The results showed that this control strategy can......The present thesis “Demand controlled ventilation for multi-family dwellings” constitutes the summary of a three year project period during which demand specification and system design of demand controlled ventilation for residential buildings were studied. Most standards and buildings codes...... can be reduced compared to a system with constant air flow. A literature study on indoor pollutants in homes, their sources and their impact on humans formed the basis for the demand specification. Emission of pollutants in residential buildings roughly fall into constantly emitted background sources...

  17. Comparison of airway pressure release ventilation to conventional mechanical ventilation in the early management of smoke inhalation injury in swine.

    Science.gov (United States)

    Batchinsky, Andriy I; Burkett, Samuel E; Zanders, Thomas B; Chung, Kevin K; Regn, Dara D; Jordan, Bryan S; Necsoiu, Corina; Nguyen, Ruth; Hanson, Margaret A; Morris, Michael J; Cancio, Leopoldo C

    2011-10-01

    The role of airway pressure release ventilation in the management of early smoke inhalation injury has not been studied. We compared the effects of airway pressure release ventilation and conventional mechanical ventilation on oxygenation in a porcine model of acute respiratory distress syndrome induced by wood smoke inhalation. Prospective animal study. Government laboratory animal intensive care unit. Thirty-three Yorkshire pigs. Smoke inhalation injury. Anesthetized female Yorkshire pigs (n = 33) inhaled room-temperature pine-bark smoke. Before injury, the pigs were randomized to receive conventional mechanical ventilation (n = 15) or airway pressure release ventilation (n = 12) for 48 hrs after smoke inhalation. As acute respiratory distress syndrome developed (PaO2/Fio2 ratio conventional mechanical ventilation for 48 hrs and served as time controls. Changes in PaO2/Fio2 ratio, tidal volume, respiratory rate, mean airway pressure, plateau pressure, and hemodynamic variables were recorded. Survival was assessed using Kaplan-Meier analysis. PaO2/Fio2 ratio was lower in airway pressure release ventilation vs. conventional mechanical ventilation pigs at 12, 18, and 24 hrs (p conventional mechanical ventilation animals between 30 and 48 hrs post injury (p animals between 6 and 48 hrs (p conventional mechanical ventilation and airway pressure release ventilation pigs. In this model of acute respiratory distress syndrome caused by severe smoke inhalation in swine, airway pressure release ventilation-treated animals developed acute respiratory distress syndrome faster than conventional mechanical ventilation-treated animals, showing a lower PaO2/Fio2 ratio at 12, 18, and 24 hrs after injury. At other time points, PaO2/Fio2 ratio was not different between conventional mechanical ventilation and airway pressure release ventilation.

  18. The influence of an estimated energy saving due to natural ventilation on the Mexican energy system

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan; Østergaard, Poul Alberg

    2014-01-01

    This article shows the impacts of the extensive use of NV (natural ventilation) in the Mexican residential sector on the Mexican energy system. By integrating a thermal-airflow simulation programme with an energy systems analysis model, the impact on the Mexican energy system of replacing air...... conditioning, in particular, with natural ventilation to cool residential buildings is determined. It is shown that when, as in Mexico, there is a relatively simple connection between supply and electricity demand, NV creates savings which could be used to reduce either the fossil-fuel-based generation...

  19. The impacts of balanced and exhaust mechanical ventilation on indoor radon

    International Nuclear Information System (INIS)

    Fisk, W.J.; Mowris, R.J.

    1987-02-01

    Models for estimating radon entry rates, indoor radon concentrations, and ventilation rates in houses with a basement or a vented crawl-space and ventilated by natural infiltration, mechanical exhaust ventilation, or balanced mechanical ventilation are described. Simulations are performed for a range of soil and housing characteristics using hourly weather data for the heating season in Spokane, WA. For a house with a basement, we show that any ventilation technique should be acceptable when the soil permeability is less than approximately 10 -12 m 2 . However, exhaust ventilation leads to substantially higher indoor radon concentrations than infiltration or balanced ventilation with the same average air exchange rate when the soil permeability is 10 -10 m 2 or greater. For houses with a crawl-space, indoor radon concentrations are lowest with balanced ventilation, intermediate with exhaust ventilation, and highest with infiltration

  20. Rational use of supply air in residential buildings

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig; Nielsen, Toke Rammer; Svendsen, Svend

    2009-01-01

    The ventilation rate influences the air quality by determining the intensity of pollution sources. This paper compared the intensity of the sensory pollution during occupied hours in an apartment ventilated by a constant air volume system and demand controlled ventilation systems controlled by oc...... by occupancy. The systems supplied the same total volume of air daily. It was found that the supply air could be used more rationally by redistributing it according to occupancy compared to maintaining a constant ventilation rate during all hours....

  1. Characteristics of rain penetration through a gravity ventilator used for natural ventilation.

    Science.gov (United States)

    Kim, Taehyeung; Lee, Dong Ho; Ahn, Kwangseog; Ha, Hyunchul; Park, Heechang; Piao, Cheng Xu; Li, Xiaoyu; Seo, Jeoungyoon

    2008-01-01

    Gravity ventilators rely simply on air buoyancy to extract air and are widely used to exhaust air contaminants and heat from workplaces using minimal energy. They are designed to maximize the exhaust flow rate, but the rain penetration sometimes causes malfunctioning. In this study, the characteristics of rain penetration through a ventilator were examined as a preliminary study to develop a ventilator with the maximum exhaust capacity while minimizing rain penetration. A model ventilator was built and exposed to artificial rain and wind. The paths, intensities and amounts of penetration through the ventilator were observed and measured in qualitative and quantitative fashions. In the first phase, the pathways and intensities of rain penetration were visually observed. In the second phase, the amounts of rain penetration were quantitatively measured under the different configurations of ventilator components that were installed based on the information obtained in the first-phase experiment. The effects of wind speed, grill direction, rain drainage width, outer wall height, neck height and leaning angle of the outer wall from the vertical position were analyzed. Wind speed significantly affected rain penetration. Under the low crosswind conditions, the rain penetration intensities were under the limit of detection. Under the high crosswind conditions, grill direction and neck height were the most significant factors in reducing rain penetration. The installation of rain drainage was also important in reducing rain penetration. The experimental results suggest that, with proper configurations of its components, a gravity ventilator can be used for natural ventilation without significant rain penetration problems.

  2. Analysis on ventilation pressure of fire area in longitudinal ventilation of underground tunnel

    Science.gov (United States)

    Li, Jiaxin; Li, Yanfeng; Feng, Xiao; Li, Junmei

    2018-03-01

    In order to solve the problem of ventilation pressure loss in the fire area under the fire condition, the wind pressure loss model of the fire area is established based on the thermodynamic equilibrium relation. The semi-empirical calculation formula is obtained by using the model experiment and CFD simulation. The validity of the formula is verified. The results show that the ventilation pressure loss in the fire zone is proportional to the convective heat release rate at the critical velocity, which is inversely proportional to the upstream ventilation velocity and the tunnel cross-sectional area. The proposed formula is consistent with the law of the tunnel fire test fitting formula that results are close, in contrast, the advantage lies in a clear theoretical basis and ventilation velocity values. The resistance of road tunnel ventilation system is calculated accurately and reliably, and then an effective emergency ventilation operation program is developed. It is necessary to consider the fire zone ventilation pressure loss. The proposed ventilation pressure loss formula can be used for design calculation after thorough verification.

  3. Factors Predicting Ventilator Dependence in Patients with Ventilator-Associated Pneumonia

    Directory of Open Access Journals (Sweden)

    Chia-Cheng Tseng

    2012-01-01

    Full Text Available Objectives. To determine risk factors associated with ventilator dependence in patients with ventilator-associated pneumonia (VAP. Study Design. A retrospective study was conducted at Chang Gung Memorial Hospital, Kaohsiung, from January 1, 2007 to January 31, 2008. Methods. This study evaluated 163 adult patients (aged ≥18 years. Eligibility was evaluated according to the criterion for VAP, Sequential Organ Failure Assessment (SOFA score, Acute Physiological Assessment and Chronic Health Evaluation II (APACHE II score. Oxygenation index, underlying comorbidities, septic shock status, previous tracheostomy status, and factors related to pneumonia were collected for analysis. Results. Of the 163 VAP patients in the study, 90 patients survived, yielding a mortality rate of 44.8%. Among the 90 surviving patients, only 36 (40% had been weaned off ventilators at the time of discharge. Multivariate logistic regression analysis was used to identify underlying factors such as congestive cardiac failure (P=0.009, initial high oxygenation index value (P=0.04, increased SOFA scores (P=0.01, and increased APACHE II scores (P=0.02 as independent predictors of ventilator dependence. Results from the Kaplan-Meier method indicate that initial therapy with antibiotics could increase the ventilator weaning rate (log Rank test, P<0.001. Conclusions. Preexisting cardiopulmonary function, high APACHE II and SOFA scores, and high oxygenation index were the strongest predictors of ventilator dependence. Initial empiric antibiotic treatment can improve ventilator weaning rates at the time of discharge.

  4. Thermal comfort and ventilation effectiveness in an office room with radiant floor cooling and displacement ventilation

    DEFF Research Database (Denmark)

    Krajcik, Michal; Tomasi, Roberta; Simone, Angela

    2016-01-01

    conditions, varying the nominal air change rate from 4.5h-1 down to 1.5h-1. Contaminant removal and mean-age-of-air measurements were performed to characterize the ventilation effectiveness and air velocity; air and operative temperature profiles were measured, together with thermal manikin equivalent...... temperatures, to evaluate the thermal environment. The combined system was able to achieve good ventilation effectiveness close to a heat source, so that in the occupant's breathing zone the ventilation effectiveness was significantly better than for ideal mixing, even at a nominal air change rate as low as 1......% at the highest nominal air change rate of 4.5h-1, even for an occupant sitting 1 meter in front of the supply diffuser, the local thermal discomfort occasioned by the excessive vertical temperature differences gives chilled ceilings the advantage over chilled floors for use with displacement ventilation....

  5. Weaning newborn infants from mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Paolo Biban

    2013-06-01

    Full Text Available Invasive mechanical ventilation is a life-saving procedure which is largely used in neonatal intensive care units, particularly in very premature newborn infants. However, this essential treatment may increase mortality and cause substantial morbidity, including lung or airway injuries, unplanned extubations, adverse hemodynamic effects, analgosedative dependency and severe infectious complications, such as ventilator-associated pneumonia. Therefore, limiting the duration of airway intubation and mechanical ventilator support is crucial for the neonatologist, who should aim to a shorter process of discontinuing mechanical ventilation as well as an earlier appreciation of readiness for spontaneous breathing trials. Unfortunately, there is scarce information about the best ways to perform an effective weaning process in infants undergoing mechanical ventilation, thus in most cases the weaning course is still based upon the individual judgment of the attending clinician. Nonetheless, some evidence indicate that volume targeted ventilation modes are more effective in reducing the duration of mechanical ventilation than traditional pressure limited ventilation modes, particularly in very preterm babies. Weaning and extubation directly from high frequency ventilation could be another option, even though its effectiveness, when compared to switching and subsequent weaning and extubating from conventional ventilation, is yet to be adequately investigated. Some data suggest the use of weaning protocols could reduce the weaning time and duration of mechanical ventilation, but better designed prospective studies are still needed to confirm these preliminary observations. Finally, the implementation of short spontaneous breathing tests in preterm infants has been shown to be beneficial in some centres, favoring an earlier extubation at higher ventilatory settings compared with historical controls, without worsening the extubation failure rate. Further

  6. The Effects of Ventilation in Homes on Health

    DEFF Research Database (Denmark)

    Wargocki, Pawel

    2013-01-01

    and many of them suffer from deficient experimental design, as well as a lack of proper characterization of actual exposures occurring indoors. Based on the available data, in the reviewed studies, it seems likely that health risks may occur when ventilation rates are below 0.4 air changes per hour...... with existing ventilation systems this positive effect was less evident, probably due to poor performance of the system (too low ventilation rates and/or poor maintenance). Studies are recommended in which exposures are much better characterized (by for example measuring the pollutants indicated by the WHO...... Guidelines for Indoor Air Quality and improving ventilation measurements). Exposures should also be controlled using different ventilation methods for comparison. Future studies should also advance the understanding of how ventilation systems should be operated to achieve optimal performance. These data...

  7. Academic Emergency Medicine Physicians’ Knowledge of Mechanical Ventilation

    Directory of Open Access Journals (Sweden)

    Susan R. Wilcox

    2016-05-01

    Full Text Available Introduction: Although emergency physicians frequently intubate patients, management of mechanical ventilation has not been emphasized in emergency medicine (EM education or clinical practice. The objective of this study was to quantify EM attendings’ education, experience, and knowledge regarding mechanical ventilation in the emergency department. Methods: We developed a survey of academic EM attendings’ educational experiences with ventilators and a knowledge assessment tool with nine clinical questions. EM attendings at key teaching hospitals for seven EM residency training programs in the northeastern United States were invited to participate in this survey study. We performed correlation and regression analyses to evaluate the relationship between attendings’ scores on the assessment instrument and their training, education, and comfort with ventilation. Results: Of 394 EM attendings surveyed, 211 responded (53.6%. Of respondents, 74.5% reported receiving three or fewer hours of ventilation-related education from EM sources over the past year and 98 (46% reported receiving between 0-1 hour of education. The overall correct response rate for the assessment tool was 73.4%, with a standard deviation of 19.9. The factors associated with a higher score were completion of an EM residency, prior emphasis on mechanical ventilation during one’s own residency, working in a setting where an emergency physician bears primary responsibility for ventilator management, and level of comfort with managing ventilated patients. Physicians’ comfort was associated with the frequency of ventilator changes and EM management of ventilation, as well as hours of education. Conclusion: EM attendings report caring for mechanically ventilated patients frequently, but most receive fewer than three educational hours a year on mechanical ventilation, and nearly half receive 0-1 hour. Physicians’ performance on an assessment tool for mechanical ventilation is

  8. Evaporation Controlled Emission in Ventilated Rooms

    DEFF Research Database (Denmark)

    Topp, Claus; Nielsen, Peter V.; Heiselberg, Per

    -scale ventilated room when the emission is fully or partly evaporation controlled. The objective of the present research work has been to investigate the change of emission rates from small-scale experiments to full-scale ventilated rooms and to investigate the influence of the local air velocity field near......Emission of volatile organic compounds (VOCs) from materials is traditionally determined from tests carried out in small-scale test chambers. However, a difference in scale may lead to a difference in the measured emission rate in a small-scale test chamber and the actual emission rate in a full...

  9. PERMEABILITY MAP OF RESIDENTIAL SETTLEMENTS IN THE TROPICS

    Directory of Open Access Journals (Sweden)

    I Gusti Ngurah Antaryama

    2002-01-01

    Full Text Available Source of information for ventilation design of residential settlement is generally derived from wind tunnel or, recently, CFD studies, which involves both modeling and simulation of wind flow pattern and speed. Yet this is not readily accessible to most architects. In order to gain similar objectives but without involving detailed studies, the present study introduces a graphical method of gathering information about permeability of residential. It describes how the way wind reaches and flows through built spaces and forms (streets, park/garden, buildings, and makes use of access graphs and numerical measures to indicate permeability of a given residential settlement. Since the method is still in the initial development, further study will be required for refinement and validation. Nevertheless, the method can be employed to provide information for ventilation design of low-rise residential settlements, particularly at the schematic level. Abstract in Bahasa Indonesia : Informasi untuk perancangan ventilasi alam pada permukiman selama ini sangat bergantung dari hasil-hasil yang diperoleh dari studi terowongan angin ataupun studi simulasi komputer dengan menggunakan CFD. Namun demikian ketersediaan informasi tersebut sangatlah terbatas bagi arsitek. Studi yang dilakukan penulis berusaha untuk mengisi kesenjangan yang ada dengan menyediakan tampilan grafis untuk menunjukkan permiabilitas sebuah permukiman. Perilaku angin di dalam dan permiablitas permukiman dijabarkan dengan menggunakan grafik akses dan pengukuran-pengukuran numerik. Oleh karena pengembangan metoda ini berada pada tahap awal, beberapa studi lanjutan sangatlah diperlukan. Kata kunci: morfologi permukiman, sains arsitektur, ventilasi alam, iklim tropis.

  10. The impact of a ventilator bundle on preventing ventilator-associated pneumonia: a multicenter study.

    Science.gov (United States)

    Eom, Joong Sik; Lee, Mi-Suk; Chun, Hee-Kyung; Choi, Hee Jung; Jung, Sun-Young; Kim, Yeon-Sook; Yoon, Seon Jin; Kwak, Yee Gyung; Oh, Gang-Bok; Jeon, Min-Hyok; Park, Sun-Young; Koo, Hyun-Sook; Ju, Young-Su; Lee, Jin Seo

    2014-01-01

    For prevention of ventilator-associated pneumonia (VAP), a bundle approach was applied to patients receiving mechanical ventilation in intensive care units. The incidence of VAP and the preventive efficacy of the VAP bundle were investigated. A quasi-experimental study was conducted in adult intensive care units of 6 university hospitals with similar VAP rates. We implemented the VAP bundle between March 2011 and June 2011, then compared the rate of VAP after implementation of the VAP bundle with the rate in the previous 8 months. Our ventilator bundle included head of bed elevation, peptic ulcer disease prophylaxis, deep venous thrombosis prophylaxis, and oral decontamination with chlorhexidine 0.12%. Continuous aspiration of subglottic secretions was an option. Implementation of the VAP bundle reduced the VAP rate from a mean of 4.08 cases per 1,000 ventilator-days to 1.16 cases per 1,000 ventilator-days. The incidence density ratio (rate) was 0.28 (95% confidence interval, 0.275-0.292). Implementing the appropriate VAP bundle significantly decreased the incidence of VAP in patients with mechanical ventilation. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  11. Ventilating Air-Conditioner

    Science.gov (United States)

    Dinh, Khanh

    1994-01-01

    Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

  12. Small Changes Yield Large Results at NIST's Net-Zero Energy Residential Test Facility.

    Science.gov (United States)

    Fanney, A Hunter; Healy, William; Payne, Vance; Kneifel, Joshua; Ng, Lisa; Dougherty, Brian; Ullah, Tania; Omar, Farhad

    2017-12-01

    The Net-Zero Energy Residential Test Facility (NZERTF) was designed to be approximately 60 % more energy efficient than homes meeting the 2012 International Energy Conservation Code (IECC) requirements. The thermal envelope minimizes heat loss/gain through the use of advanced framing and enhanced insulation. A continuous air/moisture barrier resulted in an air exchange rate of 0.6 air changes per hour at 50 Pa. The home incorporates a vast array of extensively monitored renewable and energy efficient technologies including an air-to-air heat pump system with a dedicated dehumidification cycle; a ducted heat-recovery ventilation system; a whole house dehumidifier; a photovoltaic system; and a solar domestic hot water system. During its first year of operation the NZERTF produced an energy surplus of 1023 kWh. Based on observations during the first year, changes were made to determine if further improvements in energy performance could be obtained. The changes consisted of installing a thermostat that incorporated control logic to minimize the use of auxiliary heat, using a whole house dehumidifier in lieu of the heat pump's dedicated dehumidification cycle, and reducing the ventilation rate to a value that met but did not exceed code requirements. During the second year of operation the NZERTF produced an energy surplus of 2241 kWh. This paper describes the facility, compares the performance data for the two years, and quantifies the energy impact of the weather conditions and operational changes.

  13. Minute Ventilation Limitations of Two Field Transport Ventilators.

    Science.gov (United States)

    Szpisjak, Dale F; Horn, Gregory; Shalov, Samuel; Abes, Alvin Angelo; Van Decar, Lauren

    2017-01-01

    Knowledge of transport ventilator performance impacts patient safety. This study compared minute ventilation (V E ) of the MOVES and Uni-Vent 731 when ventilating the VentAid Training Test Lung with compliance (C) ranging from 0.02 to 0.10 L/cm H 2 O and three different airway resistances (R) (none, Rp5, or Rp20). Tidal volume (V T ) was 800 ± 25 mL. Respiratory rate was increased to ventilator's maximum or until auto-PEEP > 5 cm H 2 O. Respiratory parameters were recorded with the RSS 100HR Research Pneumotach. Data were reported as median (interquartile range). Peak inspiratory pressure (PIP) of the Uni-Vent and MOVES ranged from 22.3 (22.2-22.5) to 82.6 (82.2-83.2) and 20.8 (20.6-20.9) to 50.6 (50.2-50.9) cm H 2 O, respectively. V E of the Uni-Vent and MOVES ranged from 17.7 (17.7-17.7) to 31.5 (31.5-31.5) and 11.3 (10.5-11.3) to 20.2 (19.7-20.5) L/min, respectively. Linear regression demonstrated strong, negative correlation of V E with PIP for the MOVES (V E [L/min] = 26 - 0.31 × PIP [cm H 2 O], r = -0.97) but weak, positive correlation for the Uni-Vent (r = 0.05). Uni-Vent V E exceeded MOVES V E under each test condition (p = 0.0002). If patient V E requirements exceed those predicted by the MOVES regression equation, then using the Uni-Vent should be considered. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

  14. Energy Saving Potential by Utilizing Natural Ventilation under Warm Conditions

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan; Østergaard, Poul Alberg

    2014-01-01

    The objective of this article is to show the potential of natural ventilation as a passive cooling method within the residential sector of countries which are located in warm conditions using Mexico as a case study. The method is proposed as performing, with a simplified ventilation model, thermal......–airflow simulations of 27 common cases of dwellings (considered as one thermal zone) based on the combination of specific features of the building design, occupancy and climate conditions. The energy saving potential is assessed then by the use of a new assessment method suitable for large-scale scenarios using...... the actual number of air-conditioned dwellings distributed among the 27 cases. Thereby, the energy saving is presented as the difference in the cooling demand of the dwelling during one year without and with natural ventilation, respectively. Results indicate that for hot-dry conditions, buildings with high...

  15. Hygrothermal performance of ventilated wooden cladding

    Energy Technology Data Exchange (ETDEWEB)

    Nore, Kristine

    2009-10-15

    This project contributes to more accurate design guidelines for high-performance building envelopes by analysis of hygrothermal performance of ventilated wooden cladding. Hygrothermal performance is defined by cladding temperature and moisture conditions, and subsequently by risk of degradation. Wood cladding is the most common facade material used in rural and residential areas in Norway. Historically, wooden cladding design varied in different regions in Norway. This was due to both climatic variations and the logistical distance to materials and craftspeople. The rebuilding of Norwegian houses in the 1950s followed central guidelines where local climate adaptation was often not evaluated. Nowadays we find some technical solutions that do not withstand all climate exposures. The demand for thermal comfort and also energy savings has changed hygrothermal condition of the building envelopes. In well-insulated wall assemblies, the cladding temperature is lower compared to traditional walls. Thus the drying out potential is smaller, and the risk of decay may be higher. The climate change scenario indicates a warmer and wetter future in Norway. Future buildings should be designed to endure harsher climate exposure than at present. Is there a need for refined climate differentiated design guidelines for building enclosures? As part of the Norwegian research programme 'Climate 2000', varieties of wooden claddings have been investigated on a test house in Trondheim. The aim of this investigation was to increase our understanding of the relation between microclimatic conditions and the responding hygrothermal performance of wooden cladding, according to orientation, design of ventilation gap, wood material quality and surface treatment. The two test facades, facing east and west have different climate exposure. Hourly measurements of in total 250 sensors provide meteorological data; temperature, radiation, wind properties, relative humidity, and test house data

  16. Why We Ventilate

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Jennifer M.; Sherman, Max H.; Price, Phil N.; Singer, Brett C.

    2011-09-01

    It is widely accepted that ventilation is critical for providing good indoor air quality (IAQ) in homes. However, the definition of"good" IAQ, and the most effective, energy efficient methods for delivering it are still matters of research and debate. This paper presents the results of work done at the Lawrence Berkeley National Lab to identify the air pollutants that drive the need for ventilation as part of a larger effort to develop a health-based ventilation standard. First, we present results of a hazard analysis that identified the pollutants that most commonly reach concentrations in homes that exceed health-based standards or guidelines for chronic or acute exposures. Second, we present results of an impact assessment that identified the air pollutants that cause the most harm to the U.S. population from chronic inhalation in residences. Lastly, we describe the implications of our findings for developing effective ventilation standards.

  17. What Is a Ventilator?

    Science.gov (United States)

    ... who are on ventilators for shorter periods. The advantage of this tube is that it can be ... other disease or condition. VAP is treated with antibiotics. You may need special antibiotics if the VAP ...

  18. Survival after Pneumocystis jirovecii pneumonia requiring ventilation ...

    African Journals Online (AJOL)

    Pneumocystis pneumonia (PCP) in patients with the human immunodeficiency virus (HIV) is associated with a high mortality rate, which increases substantially with the need for mechanical ventilation. Local experience of patients with PCP admitted to the intensive care unit has revealed mortality rates close to 100%.

  19. Procedures for Calculating Residential Dehumidification Loads

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Jon [National Renewable Energy Lab. (NREL), Golden, CO (United States); Booten, Chuck [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-06-01

    Residential building codes and voluntary labeling programs are continually increasing the energy efficiency requirements of residential buildings. Improving a building's thermal enclosure and installing energy-efficient appliances and lighting can result in significant reductions in sensible cooling loads leading to smaller air conditioners and shorter cooling seasons. However due to fresh air ventilation requirements and internal gains, latent cooling loads are not reduced by the same proportion. Thus, it's becoming more challenging for conventional cooling equipment to control indoor humidity at part-load cooling conditions and using conventional cooling equipment in a non-conventional building poses the potential risk of high indoor humidity. The objective of this project was to investigate the impact the chosen design condition has on the calculated part-load cooling moisture load, and compare calculated moisture loads and the required dehumidification capacity to whole-building simulations. Procedures for sizing whole-house supplemental dehumidification equipment have yet to be formalized; however minor modifications to current Air-Conditioner Contractors of America (ACCA) Manual J load calculation procedures are appropriate for calculating residential part-load cooling moisture loads. Though ASHRAE 1% DP design conditions are commonly used to determine the dehumidification requirements for commercial buildings, an appropriate DP design condition for residential buildings has not been investigated. Two methods for sizing supplemental dehumidification equipment were developed and tested. The first method closely followed Manual J cooling load calculations; whereas the second method made more conservative assumptions impacting both sensible and latent loads.

  20. Fire, safety and ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Hindle, D.

    1999-02-01

    Correct ventilation in tunnel environments is vital for the comfort and safety of the people passing through. This article gives details of products from several manufacturers of safety rescue and fire fighting equipment, fire and fume detection equipment, special fire resistant materials, fire resistant hydraulic oils and fire dampers, and ventilation systems. Company addresses and fax numbers are supplied. 4 refs., 5 tabs., 10 photos.

  1. Exploring the Relationship between Conduct Disorder and Residential Treatment Outcomes

    Science.gov (United States)

    Shabat, Julia Cathcart; Lyons, John S.; Martinovich, Zoran

    2008-01-01

    We examined the differential outcomes in residential treatment for youths with conduct disorder (CD)--with special attention paid to interactions with age and gender--in a sample of children and adolescents in 50 residential treatment centers and group homes across Illinois. Multi-disciplinary teams rated youths ages 6-20 (N = 457) on measures of…

  2. Design and optimization of zero-energy-consumption based solar energy residential building systems

    Science.gov (United States)

    Zheng, D. L.; Yu, L. J.; Tan, H. W.

    2017-11-01

    Energy consumption of residential buildings has grown fast in recent years, thus raising a challenge on zero energy residential building (ZERB) systems, which aim at substantially reducing energy consumption of residential buildings. Thus, how to facilitate ZERB has become a hot but difficult topic. In the paper, we put forward the overall design principle of ZERB based on analysis of the systems’ energy demand. In particular, the architecture for both schematic design and passive technology is optimized and both energy simulation analysis and energy balancing analysis are implemented, followed by committing the selection of high-efficiency appliance and renewable energy sources for ZERB residential building. In addition, Chinese classical residential building has been investigated in the proposed case, in which several critical aspects such as building optimization, passive design, PV panel and HVAC system integrated with solar water heater, Phase change materials, natural ventilation, etc., have been taken into consideration.

  3. Nunavut housing ventilation research 2003-2005

    Energy Technology Data Exchange (ETDEWEB)

    Fugler, D.

    2005-11-15

    Inuit children in Alaska and Nunavut have high rates of severe lower respiratory tract infections, with hospitalization rates of 300 per year for each 1000 infants. The aim of this research report was to summarize the findings of a pilot project measuring the indoor air quality (IAQ) in 20 Cape Dorset houses as well as a study measuring the ventilation rates of 100 house from 4 communities in Nunavut. The 20 house pilot study included a respiratory questionnaire; a detailed home inspection and data collection; a blower door airtightness test; 7 day measurements of nitrogen dioxide (NO{sub 2}), nicotine, carbon dioxide (CO{sub 2}), relative humidity and temperature; a natural air change rate testing using Brookhaven tracer gas technology; and settled floor dust and bed dust collection followed by biological analysis. The 100 house study recorded 3 to 5 days of house temperatures, relative humidity and CO{sub 2}. The Brookhaven tracer gas technique was used to establish house air change rate. A questionnaire was used to assess ventilation devices. A medical questionnaire was administered and an evaluation of hospitalization data was carried out. Results indicated that a large number of Nunavut houses were not adequately ventilated. In the 20 house study, a third of the houses showed air change rates that would be considered low by any ventilation standards, and that were very low when considering the high occupancy of the houses. In the hundred house study, almost all houses indicated a mean CO{sub 2} level over 1000 ppm, and peaks exceeded 2000 ppm in approximately half the houses. The concentrations were far higher than those seen in southern Canadian homes. It was concluded that the development and promotion of energy-efficient ventilation devices could help to resolve ventilation deficiencies in Nunavut. 2 figs.

  4. Outcome-based ventilation: A framework for assessing performance, health, and energy impacts to inform office building ventilation decisions.

    Science.gov (United States)

    Rackes, A; Ben-David, T; Waring, M S

    2018-04-23

    This article presents an outcome-based ventilation (OBV) framework, which combines competing ventilation impacts into a monetized loss function ($/occ/h) used to inform ventilation rate decisions. The OBV framework, developed for U.S. offices, considers six outcomes of increasing ventilation: profitable outcomes realized from improvements in occupant work performance and sick leave absenteeism; health outcomes from occupant exposure to outdoor fine particles and ozone; and energy outcomes from electricity and natural gas usage. We used the literature to set low, medium, and high reference values for OBV loss function parameters, and evaluated the framework and outcome-based ventilation rates using a simulated U.S. office stock dataset and a case study in New York City. With parameters for all outcomes set at medium values derived from literature-based central estimates, higher ventilation rates' profitable benefits dominated negative health and energy impacts, and the OBV framework suggested ventilation should be ≥45 L/s/occ, much higher than the baseline ~8.5 L/s/occ rate prescribed by ASHRAE 62.1. Only when combining very low parameter estimates for profitable impacts with very high ones for health and energy impacts were all outcomes on the same order. Even then, however, outcome-based ventilation rates were often twice the baseline rate or more. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Mobile communication devices causing interference in invasive and noninvasive ventilators.

    Science.gov (United States)

    Dang, Bao P; Nel, Pierre R; Gjevre, John A

    2007-06-01

    The aim of this study was to assess if common mobile communication systems would cause significant interference on mechanical ventilation devices and at what distances would such interference occur. We tested all the invasive and noninvasive ventilatory devices used within our region. This consisted of 2 adult mechanical ventilators, 1 portable ventilator, 2 pediatric ventilators, and 2 noninvasive positive pressure ventilatory devices. We operated the mobile devices from the 2 cellular communication systems (digital) and 1 2-way radio system used in our province at varying distances from the ventilators and looked at any interference they created. We tested the 2-way radio system, which had a fixed operation power output of 3.0 watts, the Global Systems for Mobile Communication cellular system, which had a maximum power output of 2.0 watts and the Time Division Multiple Access cellular system, which had a maximum power output of 0.2 watts on our ventilators. The ventilators were ventilating a plastic lung at fixed settings. The mobile communication devices were tested at varying distances starting at zero meter from the ventilator and in all operation modes. The 2-way radio caused the most interference on some of the ventilators, but the maximum distance of interference was 1.0 m. The Global Systems for Mobile Communication system caused significant interference only at 0 m and minor interference at 0.5 m on only 1 ventilator. The Time Division Multiple Access system caused no interference at all. Significant interference consisted of a dramatic rise and fluctuation of the respiratory rate, pressure, and positive end-expiratory pressure of the ventilators with no normalization when the mobile device was removed. From our experiment on our ventilators with the communication systems used in our province, we conclude that mobile communication devices such as cellular phones and 2-way radios are safe and cause no interference unless operated at very close distances of

  6. EVALUATION TOOL OF CLIMATE POTENTIAL FOR VENTILATIVE COOLING

    DEFF Research Database (Denmark)

    Belleri, Annamaria; Psomas, Theofanis Ch.; Heiselberg, Per Kvols

    2015-01-01

    . Within IEA Annex 62 project, national experts are working on the development of a climate evaluation tool, which aims at assessing the potential of ventilative cooling by taking into account also building envelope thermal properties, internal gains and ventilation needs. The analysis is based on a single......-zone thermal model applied to user-input climatic data on hourly basis. The tool identifies the percentage of hours when natural ventilation can be exploited to assure minimum air change rates required by state of the art research, standards and regulations and the percentage of hours when direct ventilative...

  7. Ventilation and perfusion display in a single image

    International Nuclear Information System (INIS)

    Lima, J.J.P. de; Botelho, M.F.R.; Pereira, A.M.S.; Rafael, J.A.S.; Pinto, A.J.; Marques, M.A.T.; Pereira, M.C.; Baganha, M.F.; Godinho, F.

    1991-01-01

    A new method of ventilation and perfusion display onto a single image is presented. From the data on regions of interest of the lungs, three-dimensional histograms are created, containing as parameters X and Y for the position of the pixels, Z for the perfusion and colour for local ventilation. The perfusion value is supplied by sets of curves having Z proportional to the local perfusion count rate. Ventilation modulates colour. Four perspective views of the histogram are simultaneously displayed to allow visualization of the entire organ. Information about the normal ranges for both ventilation and perfusion is also provided in the histograms. (orig.)

  8. Solar chimney: A sustainable approach for ventilation and building space conditioning

    Directory of Open Access Journals (Sweden)

    Lal, S.,

    2013-03-01

    Full Text Available The residential and commercial buildings demand increase with rapidly growing population. It leads to the vertical growth of the buildings and needs proper ventilation and day-lighting. The natural air ventilation system is not significantly works in conventional structure, so fans and air conditioners are mandatory to meet the proper ventilation and space conditioning. Globally building sector consumed largest energy and utmost consumed in heating, ventilation and space conditioning. This load can be reduced by application of solar chimney and integrated approaches in buildings for heating, ventilation and space conditioning. It is a sustainable approach for these applications in buildings. The authors are reviewed the concept, various method of evaluation, modelings and performance of solar chimney variables, applications and integrated approaches.

  9. Assessing the potential of residential HVAC systems for demand-side management

    NARCIS (Netherlands)

    van der Klauw, Thijs; Hoogsteen, Gerwin; Gerards, Marco Egbertus Theodorus; Hurink, Johann L.; Feng, Xianyong; Hebner, Robert E.

    This paper investigates the potential of residential heating, ventilation and air conditioning systems to contribute to dynamic demand-side management. Thermal models for seven houses in Austin, Texas are developed with the goal of using them in a planning based demand-side management methodology.

  10. A Case Study in Market Transformation for Residential Energy Efficiency Programs

    Energy Technology Data Exchange (ETDEWEB)

    Building Technologies Office

    2017-09-01

    This case study describes how the Midwest Energy Efficiency Alliance (MEEA) partnered with gas and electric utilities in Iowa to establish the Iowa residential heating, ventilation, and air conditioning System Adjustment and Verified Efficiency (HVAC SAVE) program, taking it to scale improving the performance and energy efficiency of HVAC systems, growing businesses, and gaining consumer trust.

  11. 77 FR 40530 - Energy Conservation Standards for Residential Furnace Fans: Public Meeting and Availability of...

    Science.gov (United States)

    2012-07-10

    ... heating, ventilation, and air-conditioning (HVAC) systems for the purpose of circulating air through duct... INFORMATION: Table of Contents I. Authority II. History of Energy Conservation Standards Rulemaking for... circulating air through duct work, hereinafter referred to as ``residential furnace fans'' or simply ``furnace...

  12. Residential and Light Commercial HVAC. Teacher Edition and Student Edition. Second Edition.

    Science.gov (United States)

    Stephenson, David

    This package contains teacher and student editions of a residential and light commercial heating, ventilation, and air conditioning (HVAC) course of study. The teacher edition contains information on the following: using the publication; national competencies; competency profile; related academic and workplace skills list; tools, equipment, and…

  13. Optimization of Occupancy Based Demand Controlled Ventilation in Residences

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig; Walker, Iain; Sherman, Max

    2011-01-01

    Although it has been used for many years in commercial buildings, the application of demand controlled ventilation in residences is limited. In this study we used occupant exposure to pollutants integrated over time (referred to as "dose") as the metric to evaluate the effectiveness and air quality...... implications of demand controlled ventilation in residences. We looked at air quality for two situations. The first is that typically used in ventilation standards: the exposure over a long term. The second is to look at peak exposures that are associated with time variations in ventilation rates and pollutant...... when occupied. We used analytical solutions to the continuity equation to determine the ventilation effectiveness and the long-term chronic dose and peak acute exposure for a representative range of occupancy periods, pollutant generation rates and airflow rates. The results of the study showed that we...

  14. Clinical challenges in mechanical ventilation.

    Science.gov (United States)

    Goligher, Ewan C; Ferguson, Niall D; Brochard, Laurent J

    2016-04-30

    Mechanical ventilation supports gas exchange and alleviates the work of breathing when the respiratory muscles are overwhelmed by an acute pulmonary or systemic insult. Although mechanical ventilation is not generally considered a treatment for acute respiratory failure per se, ventilator management warrants close attention because inappropriate ventilation can result in injury to the lungs or respiratory muscles and worsen morbidity and mortality. Key clinical challenges include averting intubation in patients with respiratory failure with non-invasive techniques for respiratory support; delivering lung-protective ventilation to prevent ventilator-induced lung injury; maintaining adequate gas exchange in severely hypoxaemic patients; avoiding the development of ventilator-induced diaphragm dysfunction; and diagnosing and treating the many pathophysiological mechanisms that impair liberation from mechanical ventilation. Personalisation of mechanical ventilation based on individual physiological characteristics and responses to therapy can further improve outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Evaluation of Mechanical Ventilator Use with Liquid Oxygen Systems

    Science.gov (United States)

    2017-02-22

    Endotracheal tubes, high-volume, low-pressure, tracheal wall injury 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF...ventilators to the LOX devices. Ventilator settings were as follows : respiratory rate 35 breaths/min, inspiratory time 0.8 seconds, tidal volume 450 mL

  16. The growing role of noninvasive ventilation in patients requiring prolonged mechanical ventilation.

    Science.gov (United States)

    Hess, Dean R

    2012-06-01

    For many patients with chronic respiratory failure requiring ventilator support, noninvasive ventilation (NIV) is preferable to invasive support by tracheostomy. Currently available evidence does not support the use of nocturnal NIV in unselected patients with stable COPD. Several European studies have reported benefit for high intensity NIV, in which setting of inspiratory pressure and respiratory rate are selected to achieve normocapnia. There have also been studies reporting benefit for the use of NIV as an adjunct to exercise training. NIV may be useful as an adjunct to airway clearance techniques in patients with cystic fibrosis. Accumulating evidence supports the use of NIV in patients with obesity hypoventilation syndrome. There is considerable observational evidence supporting the use of NIV in patients with chronic respiratory failure related to neuromuscular disease, and one randomized controlled trial reported that the use of NIV was life-prolonging in patients with amyotrophic lateral sclerosis. A variety of interfaces can be used to provide NIV in patients with stable chronic respiratory failure. The mouthpiece is an interface that is unique in this patient population, and has been used with success in patients with neuromuscular disease. Bi-level pressure ventilators are commonly used for NIV, although there are now a new generation of intermediate ventilators that are portable, have a long battery life, and can be used for NIV and invasive applications. Pressure support ventilation, pressure controlled ventilation, and volume controlled ventilation have been used successfully for chronic applications of NIV. New modes have recently become available, but their benefits await evidence to support their widespread use. The success of NIV in a given patient population depends on selection of an appropriate patient, selection of an appropriate interface, selection of an appropriate ventilator and ventilator settings, the skills of the clinician, the

  17. The Impact of Roof Pitch and Ceiling Insulation on Cooling Load of Naturally-Ventilated Attics

    Directory of Open Access Journals (Sweden)

    Linxia Gu

    2012-07-01

    Full Text Available A 2D unsteady computational fluid dynamics (CFD model is employed to simulate buoyancy-driven turbulent ventilation in attics with different pitch values and ceiling insulation levels under summer conditions. The impacts of roof pitch and ceiling insulation on the cooling load of gable-roof residential buildings are investigated based on the simulation of turbulent air flow and natural convection heat transfer in attic spaces with roof pitches from 3/12 to 18/12 combined with ceiling insulation levels from R-1.2 to R-40. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively insensitive to the investigated variations of roof pitch and ceiling insulation. Furthermore, it is predicted that the ceiling insulation plays a control role on the attic cooling load and that an increase of roof pitch from 3/12 to 8/12 results in a decrease in the cooling load by around 9% in the investigated cases. The results suggest that the increase of roof pitch alone, without changing other design parameters, has limited impact on attics cooling load and airflow pattern. The research results also suggest both the predicted ventilating mass flow rate and attic cooling load can be satisfactorily correlated by simple relationships in terms of appropriately defined Rayleigh and Nusselt numbers.

  18. Consumer Decision Rules and Residential Finance.

    Science.gov (United States)

    Brandt, Jeanette A.; Jaffe, Austin J.

    1979-01-01

    As guidelines for residential financing, the authors compare different approaches to understanding and figuring the costs of home ownership: the relation of income to house price and housing costs, interest rate, and mortgage term. Instead of the traditional method, they recommend the time value of money approach. (MF)

  19. Correlation between air flow rate and pollutant concentrations during two-stage oak log combustion in a 25 KW residential boiler

    Directory of Open Access Journals (Sweden)

    Juszczak Marek

    2016-09-01

    Full Text Available It can be expected that there is a considerable correlation between combustion air flow rate and the concentrations of carbon monoxide, hydrocarbons and nitrogen oxide in the flue gas. The influence of temperature and oxygen concentration in the combustion zone on the concentrations of carbon monoxide, hydrocarbons and nitrogen oxide in the flue gas, for high and low combustion air flow, was analysed. Oxygen concentration for which the concentration of carbon monoxide is the lowest was determined, as well as the mutual relation between carbon monoxide and nitrogen oxide concentration.

  20. On the calculation of air flow rates to ventilate closed-type stations in subway with the double-track tunnel

    Science.gov (United States)

    Kiyanitsa, LA

    2018-03-01

    Metro is not only the most promising kind of public transport but also an important part of infrastructure in a modern city. As a place where large groups of people gather, subway is to ensure the required air exchange at the passenger platforms of the stations. The air flow rate for airing the stations is also determined based on the required temperature, humidity and MAC of gases. The present study estimates the required air flow rate at the passenger platform of the closed-type subway station with the double-track tunnel given the standard air temperature, humidity and gas concentration, as well as based on the condition of the specified air flow feed and air changes per hour. The article proposes the scheme of air recirculation from the double-track tunnel to the station.

  1. Incidence of the geometric parameters and of flow in the primary ventilation rate and of carbon monoxide emissions in burning atmospherics of medium and high pressure

    International Nuclear Information System (INIS)

    Amell A, Andres; Hernandez V, Jaime; Cortes T, Jaime

    2000-01-01

    In this kind of atmospheric burners, high-pressure gas supply and Venturi geometry guarantee a good primary air entrance for combustion. In this project we analyze the most important burner geometric parameters (outlet diameter, injection diameter and mixer geometry) and gas flux conditions (supply pressure) that have an influence over primary aeration rate. The results of this investigation will contribute with the methodology design improvement, focused to use this kind of burners in our country

  2. Natural ventilation for the prevention of airborne contagion.

    Science.gov (United States)

    Escombe, A Roderick; Oeser, Clarissa C; Gilman, Robert H; Navincopa, Marcos; Ticona, Eduardo; Pan, William; Martínez, Carlos; Chacaltana, Jesus; Rodríguez, Richard; Moore, David A J; Friedland, Jon S; Evans, Carlton A

    2007-02-01

    Institutional transmission of airborne infections such as tuberculosis (TB) is an important public health problem, especially in resource-limited settings where protective measures such as negative-pressure isolation rooms are difficult to implement. Natural ventilation may offer a low-cost alternative. Our objective was to investigate the rates, determinants, and effects of natural ventilation in health care settings. The study was carried out in eight hospitals in Lima, Peru; five were hospitals of "old-fashioned" design built pre-1950, and three of "modern" design, built 1970-1990. In these hospitals 70 naturally ventilated clinical rooms where infectious patients are likely to be encountered were studied. These included respiratory isolation rooms, TB wards, respiratory wards, general medical wards, outpatient consulting rooms, waiting rooms, and emergency departments. These rooms were compared with 12 mechanically ventilated negative-pressure respiratory isolation rooms built post-2000. Ventilation was measured using a carbon dioxide tracer gas technique in 368 experiments. Architectural and environmental variables were measured. For each experiment, infection risk was estimated for TB exposure using the Wells-Riley model of airborne infection. We found that opening windows and doors provided median ventilation of 28 air changes/hour (ACH), more than double that of mechanically ventilated negative-pressure rooms ventilated at the 12 ACH recommended for high-risk areas, and 18 times that with windows and doors closed (p ventilation than modern naturally ventilated rooms (40 versus 17 ACH; p natural ventilation exceeded mechanical (p ventilated rooms 39% of susceptible individuals would become infected following 24 h of exposure to untreated TB patients of infectiousness characterised in a well-documented outbreak. This infection rate compared with 33% in modern and 11% in pre-1950 naturally ventilated facilities with windows and doors open. Opening windows and

  3. Implementation of a real-time compliance dashboard to help reduce SICU ventilator-associated pneumonia with the ventilator bundle.

    Science.gov (United States)

    Zaydfudim, Victor; Dossett, Lesly A; Starmer, John M; Arbogast, Patrick G; Feurer, Irene D; Ray, Wayne A; May, Addison K; Pinson, C Wright

    2009-07-01

    Ventilator-associated pneumonia (VAP) causes significant morbidity and mortality in critically ill surgical patients. Recent studies suggest that the success of preventive measures is dependent on compliance with ventilator bundle parameters. Implementation of an electronic dashboard will improve compliance with the bundle parameters and reduce rates of VAP in our surgical intensive care unit (SICU). Time series analysis of VAP rates between January 2005 and July 2008, with dashboard implementation in July 2007. Multidisciplinary SICU at a tertiary-care referral center with a stable case mix during the study period. Patients admitted to the SICU between January 2005 and July 2008. Infection control data were used to establish rates of VAP and total ventilator days. For the time series analysis, VAP rates were calculated as quarterly VAP events per 1000 ventilator days. Ventilator bundle compliance was analyzed after dashboard implementation. Differences between expected and observed VAP rates based on time series analysis were used to estimate the effect of intervention. Average compliance with the ventilator bundle improved from 39% in August 2007 to 89% in July 2008 (P dashboard (P = .01). Quarterly VAP rates were significantly reduced in the November 2007 through January 2008 and February through April 2008 periods (P dashboard improved compliance with ventilator bundle measures and is associated with reduced rates of VAP in our SICU.

  4. Family ties and residential locations

    NARCIS (Netherlands)

    Mulder, C.H.; Cooke, T.J.

    2009-01-01

    In this paper, and in the Special Issue it introduces, the focus is on the role of family ties in residential location choice and, conversely, the role of residential locations in maintaining family ties. Not only do events in the nuclear family trigger residential relocations, but nearby family

  5. Ventilation of radioactive enclosures

    International Nuclear Information System (INIS)

    Caminade, F.; Laurent, H.

    1957-01-01

    Mechanical, physical and chemical manipulations on radioactive products must be carried out in properly ventilated enclosed places. The air extracted can only be discharged into the atmosphere after a correct filtration. The power of the ventilation systems is a function of the dimensions and purpose of the enclosure? The choice of types of filter is determined by the physical state and chemical nature of the radioactive materials to be manipulated. This study deals with the individual equipment of small installations: glove boxes, manipulation boxes with outside control and, if necessary, production chambers (maximum useful volume: 5 m 3 ). The performances of three types of 'ventilators', and the modifications provided by the addition of filters, are measured and compared. (author) [fr

  6. Mechanical ventilation strategies.

    Science.gov (United States)

    Keszler, Martin

    2017-08-01

    Although only a small proportion of full term and late preterm infants require invasive respiratory support, they are not immune from ventilator-associated lung injury. The process of lung damage from mechanical ventilation is multifactorial and cannot be linked to any single variable. Atelectrauma and volutrauma have been identified as the most important and potentially preventable elements of lung injury. Respiratory support strategies for full term and late preterm infants have not been as thoroughly studied as those for preterm infants; consequently, a strong evidence base on which to make recommendations is lacking. The choice of modalities of support and ventilation strategies should be guided by the specific underlying pathophysiologic considerations and the ventilatory approach must be individualized for each patient based on the predominant pathophysiology at the time. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. [Ventilator associated pneumonia].

    Science.gov (United States)

    Bellani, S; Nesci, M; Celotto, S; Lampati, L; Lucchini, A

    2003-04-01

    Ventilator associated pneumonia (VAP) is a nosocomial lower respiratory tract infection that ensues in critically ill patients undergoing mechanical ventilation. The reported incidence of VAP varies between 9% and 68% with a mortality ranging between 33% and 71%. Two key factors are implicated in the pathogenesis of VAP: bacterial colonization of the upper digestive-respiratory tract and aspiration of oral secretions into the trachea. Preventive measurements are advocated to reduce the incidence of VAP, such as selective decontamination of the digestive tract (SDD), supraglottic aspiration and positioning. Prompt recognition and treatment of established VAP has also been demostrated to affect outcome. Therefore, the knowledge of risk factors associated with the development of VAP and the implementation of strategies to prevent, diagnose and treat VAP are mainstems in the nursing of mechanically ventilated patients.

  8. CFD and Ventilation Research

    DEFF Research Database (Denmark)

    Li, Y.; Nielsen, Peter V.

    2011-01-01

    There has been a rapid growth of scientific literature on the application of computational fluid dynamics (CFD) in the research of ventilation and indoor air science. With a 1000–10,000 times increase in computer hardware capability in the past 20 years, CFD has become an integral part...... of scientific research and engineering development of complex air distribution and ventilation systems in buildings. This review discusses the major and specific challenges of CFD in terms of turbulence modelling, numerical approximation, and boundary conditions relevant to building ventilation. We emphasize...... the growing need for CFD verification and validation, suggest on-going needs for analytical and experimental methods to support the numerical solutions, and discuss the growing capacity of CFD in opening up new research areas. We suggest that CFD has not become a replacement for experiment and theoretical...

  9. Auxiliary mine ventilation manual

    International Nuclear Information System (INIS)

    Workplace Safety North

    2010-01-01

    An adequate ventilation system is needed for air quality and handling in a mine and is comprised of many different pieces of equipment for removing contaminated air and supplying fresh air and thereby provide a satisfactory working environment. This manual highlights auxiliary ventilation systems made up of small fans, ducts, tubes, air movers, deflectors and additional air flow controls which distribute fresh air delivered by the primary system to all areas. A review of auxiliary ventilation is provided. Design, operation and management issues are discussed and guidelines are furnished. This manual is limited to underground hard rock operations and does not address directly other, specific auxiliary systems, either in underground coal mines or uranium mines.

  10. Auxiliary mine ventilation manual

    Energy Technology Data Exchange (ETDEWEB)

    Workplace Safety North

    2010-07-01

    An adequate ventilation system is needed for air quality and handling in a mine and is comprised of many different pieces of equipment for removing contaminated air and supplying fresh air and thereby provide a satisfactory working environment. This manual highlights auxiliary ventilation systems made up of small fans, ducts, tubes, air movers, deflectors and additional air flow controls which distribute fresh air delivered by the primary system to all areas. A review of auxiliary ventilation is provided. Design, operation and management issues are discussed and guidelines are furnished. This manual is limited to underground hard rock operations and does not address directly other, specific auxiliary systems, either in underground coal mines or uranium mines.

  11. Heliox Improves Carbon Dioxide Removal during Lung Protective Mechanical Ventilation.

    Science.gov (United States)

    Beurskens, Charlotte J; Brevoord, Daniel; Lagrand, Wim K; van den Bergh, Walter M; Vroom, Margreeth B; Preckel, Benedikt; Horn, Janneke; Juffermans, Nicole P

    2014-01-01

    Introduction. Helium is a noble gas with low density and increased carbon dioxide (CO2) diffusion capacity. This allows lower driving pressures in mechanical ventilation and increased CO2 diffusion. We hypothesized that heliox facilitates ventilation in patients during lung-protective mechanical ventilation using low tidal volumes. Methods. This is an observational cohort substudy of a single arm intervention study. Twenty-four ICU patients were included, who were admitted after a cardiac arrest and mechanically ventilated for 3 hours with heliox (50% helium; 50% oxygen). A fixed protective ventilation protocol (6 mL/kg) was used, with prospective observation for changes in lung mechanics and gas exchange. Statistics was by Bonferroni post-hoc correction with statistical significance set at P ventilation, respiratory rate decreased (25 ± 4 versus 23 ± 5 breaths min(-1), P = 0.010). Minute volume ventilation showed a trend to decrease compared to baseline (11.1 ± 1.9 versus 9.9 ± 2.1 L min(-1), P = 0.026), while reducing PaCO2 levels (5.0 ± 0.6 versus 4.5 ± 0.6 kPa, P = 0.011) and peak pressures (21.1 ± 3.3 versus 19.8 ± 3.2 cm H2O, P = 0.024). Conclusions. Heliox improved CO2 elimination while allowing reduced minute volume ventilation in adult patients during protective mechanical ventilation.

  12. GREEN RETROFITTING RESIDENTIAL BUILDINGS

    Science.gov (United States)

    When compared with the rest of the world, the United States consumes a disproportionately large amount of energy and is a major source of greenhouse gases from fossil fuel combustion. As much as two thirds of U.S. electricity production is consumed by residential and commerci...

  13. Residential Mechanical Precooling

    Energy Technology Data Exchange (ETDEWEB)

    German, a. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States); Hoeschele, M. [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

    2014-12-01

    This research conducted by the Alliance for Residential Building Innovation team evaluated mechanical air conditioner pre-cooling strategies in homes throughout the United States. EnergyPlus modeling evaluated two homes with different performance characteristics in seven climates. Results are applicable to new construction homes and most existing homes built in the last 10 years, as well as fairly efficient retrofitted homes.

  14. Assessment of Adaptive Rate Response Provided by Accelerometer, Minute Ventilation and Dual Sensor Compared with Normal Sinus Rhythm During Exercise: A Self-controlled Study in Chronotropically Competent Subjects

    Directory of Open Access Journals (Sweden)

    Yuanyuan Cao

    2015-01-01

    Full Text Available Background: Dual sensor (DS for rate adaption was supposed to be more physiological. To evaluate its superiority, the DS (accelerometer [ACC] and minute ventilation [MV] and normal sinus rate response were compared in a self-controlled way during exercise treadmill testing. Methods: This self-controlled study was performed in atrioventricular block patients with normal sinus function who met the indications of pacemaker implant. Twenty-one patients came to the 1-month follow-up visit. Patients performed a treadmill test 1-month post implant while programmed in DDDR and sensor passive mode. For these patients, sensor response factors were left at default settings (ACC = 8, MV = 3 and sensor indicated rates (SIRs for DS, ACC and MV sensor were retrieved from the pacemaker memories, along with measured sinus node (SN rates from the beginning to 1-minute after the end of the treadmill test, and compared among study groups. Repeated measures analysis of variance and profile analysis, as well as variance analysis of randomized block designs, were used for statistical analysis. Results: Fifteen patients (15/21 were determined to be chronotropically competent. The mean differences between DS SIRs and intrinsic sinus rates during treadmill testing were smaller than those for ACC and MV sensor (mean difference between SIR and SN rate: ACC vs. SN, MV vs. SN, DS vs. SN, respectively, 34.84, 17.60, 16.15 beats/min, though no sensors could mimic sinus rates under the default settings for sensor response factor (ACC vs. SN P-adjusted < 0.001; MV vs. SN P-adjusted = 0.002; DS vs. SN P-adjusted = 0.005. However, both in the range of 1 st minute and first 3 minutes of exercise, only the DS SIR profile did not differ from sinus rates (P-adjusted = 0.09, 0.90, respectively. Conclusions: The DS under default settings provides more physiological rate response during physical activity than the corresponding single sensors (ACC or MV sensor. Further study is needed to

  15. Ventilation with heat recovery

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Svendsen, Svend

    2005-01-01

    This paper presents the experiences from the use of ventilation with heat recovery in several experimental single-family houses developed and built within the last four years to meet the new Danish energy requirements of 2005. Included are descriptions of the ventilation system components...... and the main functional demands as well as measurements of the thermal efficiency, electricity consumptions and building air tightness. The paper addresses the aspects of minimizing the heat loss from the duct system and the heat recovery unit (when placed in an unheated attic space) in order to obtain...

  16. Behovstyret ventilation til enfamiliehuse

    DEFF Research Database (Denmark)

    Nielsen, Toke Rammer; Drivsholm, Christian; Hansen, Mads Peter Rudolph

    Muligheden for behovsstyret ventilation i enfamiliehuse er undersøgt. To strategier er afprøvet i praksis: En relativ simpel og billig strategi og en relativ avanceret og dyr strategi. Den simple strategi regulerer luftskiftet ensartet for alle rum mellem et lavt eller højt niveau. Den avancerede...... ventilation efter gældende krav. Desuden kræver den simple regulering kun få sensorer og er således væsentlig billigere og enklere at implementere end den avancerede strategi....

  17. Ventilation Systems Operating Experience Review for Fusion Applications

    International Nuclear Information System (INIS)

    Cadwallader, L.C.

    1999-01-01

    This report is a collection and review of system operation and failure experiences for air ventilation systems in nuclear facilities. These experiences are applicable for magnetic and inertial fusion facilities since air ventilation systems are support systems that can be considered generic to nuclear facilities. The report contains descriptions of ventilation system components, operating experiences with these systems, component failure rates, and component repair times. Since ventilation systems have a role in mitigating accident releases in nuclear facilities, these data are useful in safety analysis and risk assessment of public safety. An effort has also been given to identifying any safety issues with personnel operating or maintaining ventilation systems. Finally, the recommended failure data were compared to an independent data set to determine the accuracy of individual values. This comparison is useful for the International Energy Agency task on fusion component failure rate data collection

  18. Ventilator associated pneumonia and infection control

    NARCIS (Netherlands)

    Alp, E.; Voss, A.

    2006-01-01

    Ventilator associated pneumonia (VAP) is the leading cause of morbidity and mortality in intensive care units. The incidence of VAP varies from 7% to 70% in different studies and the mortality rates are 20-75% according to the study population. Aspiration of colonized pathogenic microorganisms on

  19. Boundary conditions for natural supply ventilation

    NARCIS (Netherlands)

    Jansen, D.W.L.; Loomans, M.G.L.C.; Wit, de M.H.; Zeiler, W.; Seppänen, O.; Säteri, J.

    2007-01-01

    The development of an air jet from a controlled natural ventilation grill for different outdoor conditions is studied. Extensive laboratory measurements are taken in different situations, while the air flow rate through the grill is kept constant. The grill setting and supply temperature are varied.

  20. Energy Performance of Three Residential College Buildings in University of Malaya Campus, Kuala Lumpur

    Directory of Open Access Journals (Sweden)

    Adi Ainurzaman Jamaludin

    2011-12-01

    Full Text Available Three residential colleges located in Kuala Lumpur, Malaysia, were selected for energy performance analysis in regards to its implementation of bioclimatic design strategies. Specifically, passive design strategies on daylighting and natural ventilation were examined. In Malaysia, the residential college or hostel is a multi-residential building providing accommodation to university students. The three residential colleges in this study, namely C1, C2 and C3, were built in different years with different designs and forms, particularly with regards to enclosure and facade design, solar control devices, passive daylight concepts, and natural ventilation strategies. The building designs were carefully studied and an electric consumption analysis was carried out in each residential college. This study revealed that the wide-scale implementation of bioclimatic design strategies in college C2 help reduced the annual energy consumption. The building bioclimatic design features that are accountable to reduce energy consumption are the internal courtyard and balconies on each unit of floor area, as shown in C3.Results from this study highly recommend internal courtyard and balcony building combination for multi residential building design, especially in tropical urban regions.

  1. Protective ventilation of preterm lambs exposed to acute chorioamnionitis does not reduce ventilation-induced lung or brain injury.

    Science.gov (United States)

    Barton, Samantha K; Moss, Timothy J M; Hooper, Stuart B; Crossley, Kelly J; Gill, Andrew W; Kluckow, Martin; Zahra, Valerie; Wong, Flora Y; Pichler, Gerhard; Galinsky, Robert; Miller, Suzanne L; Tolcos, Mary; Polglase, Graeme R

    2014-01-01

    The onset of mechanical ventilation is a critical time for the initiation of cerebral white matter (WM) injury in preterm neonates, particularly if they are inadvertently exposed to high tidal volumes (VT) in the delivery room. Protective ventilation strategies at birth reduce ventilation-induced lung and brain inflammation and injury, however its efficacy in a compromised newborn is not known. Chorioamnionitis is a common antecedent of preterm birth, and increases the risk and severity of WM injury. We investigated the effects of high VT ventilation, after chorioamnionitis, on preterm lung and WM inflammation and injury, and whether a protective ventilation strategy could mitigate the response. Pregnant ewes (n = 18) received intra-amniotic lipopolysaccharide (LPS) 2 days before delivery, instrumentation and ventilation at 127±1 days gestation. Lambs were either immediately euthanased and used as unventilated controls (LPSUVC; n = 6), or were ventilated using an injurious high VT strategy (LPSINJ; n = 5) or a protective ventilation strategy (LPSPROT; n = 7) for a total of 90 min. Mean arterial pressure, heart rate and cerebral haemodynamics and oxygenation were measured continuously. Lungs and brains underwent molecular and histological assessment of inflammation and injury. LPSINJ lambs had poorer oxygenation than LPSPROT lambs. Ventilation requirements and cardiopulmonary and systemic haemodynamics were not different between ventilation strategies. Compared to unventilated lambs, LPSINJ and LPSPROT lambs had increases in pro-inflammatory cytokine expression within the lungs and brain, and increased astrogliosis (pVentilation after acute chorioamnionitis, irrespective of strategy used, increases haemodynamic instability and lung and cerebral inflammation and injury. Mechanical ventilation is a potential contributor to WM injury in infants exposed to chorioamnionitis.

  2. Ventilation system for 99Mo production apparatus

    International Nuclear Information System (INIS)

    Izumo, Mishiroku; Okane, Shougo; Sorita, Takami; Aoyama, Saburou

    1978-04-01

    In production of 20 Ci 99 Mo from 235 U fission, about 120 Ci of radioiodine ( 131 I, 132 I, and 133 I) is involved. To remove airborne radioiodine from the exhaust air from production apparatus and minimize radioiodine release to the atmosphere, the ventilation system is equipped with 2 units of Model-FD charcoal filter (KI 3 -Impregnated charcoal 2 inch thick of Barnebey-Cheney Co.). From September 1976 to December 1977, 21 runs of 99 Mo production involving airborne radioiodine were carried out. The ventilation system was operated continuously for the whole 15 months period; variation in removal efficiency of airborne radioiodine from the exhaust air stream was observed. In the runs valuable experiences were gained in operation and maintenance of the ventilation system including activated charcoal filter and health-physics management of such facility. Following are the results: (1) Airborne radioiodine from 99 Mo production apparatus is reduced to 10 -3 % of the original quantity. (2) When the ventilation system is operated at a maximum air flow rate through the filter, the average efficiency during 15 months is over 98%. (3) Airborne radioiodine released from 99 Mo production apparatus to the ventilation system is less than 5% particulate iodine and alkyl iodines and more than 95% inorganic iodine. (4) Airborne radioiodine released from the stack is less than 28 μCi/run, which is below the limit in regulations on Radioisotope Production Laboratory. (auth.)

  3. Demand controlled ventilation; Behovsstyrt ventilasjon

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Henning Holm

    2006-07-01

    The terms CAV and VAV have been known terms for many years in the ventilation business. The terms are also included in building regulations, but the time is now right to focus on demand controlled ventilation (DCV). The new building regulations and the accompanying energy framework underline the need for a more nuanced thinking when it comes to controlling ventilation systems. Descriptions and further details of the ventilation systems are provided (ml)

  4. Flow measurement in mechanical ventilation: a review.

    Science.gov (United States)

    Schena, Emiliano; Massaroni, Carlo; Saccomandi, Paola; Cecchini, Stefano

    2015-03-01

    Accurate monitoring of flow rate and volume exchanges is essential to minimize ventilator-induced lung injury. Mechanical ventilators employ flowmeters to estimate the amount of gases delivered to patients and use the flow signal as a feedback to adjust the desired amount of gas to be delivered. Since flowmeters play a crucial role in this field, they are required to fulfill strict criteria in terms of dynamic and static characteristics. Therefore, mechanical ventilators are equipped with only the following kinds of flowmeters: linear pneumotachographs, fixed and variable orifice meters, hot wire anemometers, and ultrasonic flowmeters. This paper provides an overview of these sensors. Their working principles are described together with their relevant advantages and disadvantages. Furthermore, the most promising emerging approaches for flowmeters design (i.e., fiber optic technology and three dimensional micro-fabrication) are briefly reviewed showing their potential for this application. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  5. Battery life of portable home ventilators: effects of ventilator settings.

    Science.gov (United States)

    Falaize, Line; Leroux, Karl; Prigent, Hélène; Louis, Bruno; Khirani, Sonia; Orlikowski, David; Fauroux, Brigitte; Lofaso, Frédéric

    2014-07-01

    The battery life (BL) of portable home ventilator batteries is reported by manufacturers. The aim of this study was to evaluate the effects of ventilator mode, breathing frequency, PEEP, and leaks on the BL of 5 commercially available portable ventilators. The effects of the ventilator mode (volume controlled-continuous mandatory ventilation [VC-CMV] vs pressure support ventilation [PSV]), PEEP 5 cm H2O, breathing frequency (10, 15, and 20 breaths/min), and leaks during both volume-targeted ventilation and PSV on the BL of 5 ventilators (Elisée 150, Monnal T50, PB560, Vivo 50, and Trilogy 100) were evaluated. Each ventilator was ventilated with a test lung at a tidal volume of 700 ml and an inspiratory time of 1.2 s in the absence of leaks. Switching from PSV to VC-CMV or the addition of PEEP did not significantly change ventilator BL. The increase in breathing frequency from 10 to 20 breaths/min decreased the BL by 18 ± 11% (P = .005). Leaks were associated with an increase in BL during the VC-CMV mode (18 ± 20%, P = .04) but a decrease in BL during the PSV mode (-13 ± 15%, P = .04). The BL of home ventilators depends on the ventilator settings. BL is not affected by the ventilator mode (VC-CMV or PSV) or the addition of PEEP. BL decreases with an increase in breathing frequency and during leaks with a PSV mode, whereas leaks increase the duration of ventilator BL during VC-CMV. Copyright © 2014 by Daedalus Enterprises.

  6. Hybrid Ventilation Air Flow Process

    DEFF Research Database (Denmark)

    Heiselberg, Per Kvols

    The scope of this annex is therefore to obtain better knowledge of the use of hybrid ventilation technologies. The annex focus on development of control strategies for hybrid ventilation, on development of methods to predict hybrid ventilation performance in office buildings and on implementation...

  7. Ventilator and viral induced inflammation

    NARCIS (Netherlands)

    Hennus, M.P.

    2013-01-01

    This thesis expands current knowledge on ventilator induced lung injury and provides insights on the immunological effects of mechanical ventilation during viral respiratory infections. The experimental studies in the first part of this thesis improve our understanding of how mechanical ventilation

  8. How to Plan Ventilation Systems.

    Science.gov (United States)

    Clarke, John H.

    1963-01-01

    Ventilation systems for factory safety demand careful planning. The increased heat loads and new processes of industry have introduced complex ventilation problems in--(1) ventilation supply, (2) duct work design, (3) space requirements, (4) hood face velocities, (5) discharge stacks, and (6) building eddies. This article describes and diagrams…

  9. Risk factors associated with development of ventilator associated pneumonia.

    Science.gov (United States)

    Noor, Ahmed; Hussain, Syed Fayyaz

    2005-02-01

    To assess the risk factors associated with development of ventilator associated pneumonia (VAP). A case control study. Intensive Care Unit (ICU) at the Aga Khan University Hospital, Karachi, between January 1999 and June 2000. All patients with assisted mechanical ventilation were assessed for the development of VAP. Risk factors associated with development of VAP were determined. Adult patients who developed pneumonia, 48 hours after ventilation, were called cases while those who did not develop pneumonia were called controls. Seventy (28%) out of 250 mechanically ventilated patients developed VAP (rate of VAP was 26 cases per 1000 ventilator days). Shock during first 48 hours of ventilation (odds ratio (OR), 5.95; 95% confidence interval (CI), 2.83-12.52), transport out of ICU during mechanical ventilation (OR, 6.0; 95% CI, 2.92-12.37), re-intubation (OR, 4.23; 95% CI, 2.53-9.85), prior episode of aspiration of gastric content (OR, 3.07; 95% CI, 1.35-7.01), and use of antibiotics prior to intubation (OR,2.55; 95% CI, 1.20-5.41) were found to be independently associated with a higher risk of developing VAP. Gram negative organisms and Staphylococcus aureus were responsible for over 90% of cases. Patients with VAP had higher crude mortality rate (57.1%) compared with controls (32.2%). Ventilator associated pneumonia is associated with a high mortality. This study has identified risk factors associated with VAP.

  10. Omnidirectional ventilated acoustic barrier

    Science.gov (United States)

    Zhang, Hai-long; Zhu, Yi-fan; Liang, Bin; Yang, Jing; Yang, Jun; Cheng, Jian-chun

    2017-11-01

    As an important problem in acoustics, sound insulation finds applications in a great variety of situations. In the existing schemes, however, there has always been a trade-off between the thinness of sound-insulating devices and their ventilating capabilities, limiting their potentials in the control of low-frequency sound in high ventilation environments. Here, we design and experimentally implement an omnidirectional acoustic barrier with a planar profile, subwavelength thickness ( 0.18 λ ), yet high ventilation. The proposed mechanism is based on the interference between the resonant scattering of discrete states and the background scattering of continuous states which induces a Fano-like asymmetric transmission profile. Benefitting from the binary-structured design of the coiled unit and hollow pipe, it maximally simplifies the design and fabrication while ensuring the ventilation for all the non-resonant units with open tubes. The simulated and measured results agree well, showing the effectiveness of our proposed mechanism to block low frequency sound coming from various directions while allowing 63% of the air flow to pass. We anticipate our design to open routes to design sound insulators and to enable applications in traditionally unattainable cases such as those calling for noise reduction and cooling simultaneously.

  11. Mechanical ventilation of mice

    NARCIS (Netherlands)

    Schwarte, L. A.; Zuurbier, C. J.; Ince, C.

    2000-01-01

    Due to growing interest in murine functional genomics research, there is an increasing need for physiological stable in vivo murine models. Of special importance is support and control of ventilation by artificial respiration, which is difficult to execute as a consequence of the small size of the

  12. Lavt elforbrug til ventilation

    DEFF Research Database (Denmark)

    Jagemar, L.; Bergsøe, Niels Christian

    Rapporten giver gode råd om mulige energibesparelser og praktiske projekteringshensyn, som er forbundet med udformning af energieffektiv ventilation i ikke blot kontorbygninger, men i alle bygninger med komfortventilationsanlæg. I forbindelse med projektering af ventilationsanlæg har interessen...

  13. Understanding mechanical ventilators.

    Science.gov (United States)

    Chatburn, Robert L

    2010-12-01

    The respiratory care academic community has not yet adopted a standardized system for classifying and describing modes of ventilation. As a result, there is enough confusion that patient care, clinician education and even ventilator sales are all put at risk. This article summarizes a ventilator mode taxonomy that has been extensively published over the last 15 years. Specifically, the classification system has three components: a description of the control variables within breath; a description of the sequence of mandatory and spontaneous breaths; and a specification for the targeting scheme. This three-level specification provides scalability of detail to make the mode description appropriate for the particular need. At the bedside, we need only refer to a mode briefly using the first or perhaps first and second components. To distinguish between similar modes and brand names, we would need to include all components. This taxonomy uses the equation of motion for the respiratory system as the underlying theoretical framework. All terms relevant to describing modes of mechanical ventilation are defined in an extensive appendix.

  14. Human response to ductless personalized ventilation coupled with displacement ventilation

    DEFF Research Database (Denmark)

    Dalewski, Mariusz; Veselý, Michal; Melikov, Arsen K.

    2012-01-01

    A human subject experiment was carried out to investigate the extent to which ductless personalized ventilation (DPV) in conjunction with displacement ventilation can improve perceived air quality (PAQ) and thermal comfort at elevated room air temperature in comparison with displacement ventilation...... alone. The experimental conditions comprised displacement ventilation alone (room air temperature of 23 °C, 26 °C, 29 °C) and DPV with displacement ventilation (26 °C, 29 °C), both operating at supply air temperatures 3, 5 or 6K lower than room air temperature, as well as mixing ventilation (23 °C, 3 K......). During one hour exposure participants answered questionnaires regarding PAQ and thermal comfort. PAQ was significantly better with DPV than without DPV at the same background conditions. Thermal comfort improved when DPV was used. Combining DPV with displacement ventilation showed the potential...

  15. Employee influenza vaccination in residential care facilities.

    Science.gov (United States)

    Apenteng, Bettye A; Opoku, Samuel T

    2014-03-01

    The organizational literature on infection control in residential care facilities is limited. Using a nationally representative dataset, we examined the organizational factors associated with implementing at least 1 influenza-related employee vaccination policy/program, as well as the effect of vaccination policies on health care worker (HCW) influenza vaccine uptake in residential care facilities. The study was a cross-sectional study using data from the 2010 National Survey of Residential Care Facilities. Multivariate logistic regression analysis was used to address the study's objectives. Facility size, director's educational attainment, and having a written influenza pandemic preparedness plan were significantly associated with the implementation of at least 1 influenza-related employee vaccination policy/program, after controlling for other facility-level factors. Recommending vaccination to employees, providing vaccination on site, providing vaccinations to employees at no cost, and requiring vaccination as a condition of employment were associated with higher employee influenza vaccination rates. Residential care facilities can improve vaccination rates among employees by adopting effective employee vaccination policies. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  16. Interfaces and ventilator settings for long-term noninvasive ventilation in COPD patients

    Directory of Open Access Journals (Sweden)

    Callegari J

    2017-06-01

    Full Text Available Jens Callegari,1 Friederike Sophie Magnet,1 Steven Taubner,1 Melanie Berger,2 Sarah Bettina Schwarz,1 Wolfram Windisch,1 Jan Hendrik Storre3,4 1Department of Pneumology, Cologne-Merheim Hospital, Kliniken der Stadt Koeln, Witten/Herdecke University Hospital, 2Department of Pneumology, Malteser Hospital St Hildegardis, Cologne, 3Department of Pneumology, University Medical Hospital, Freiburg, 4Department of Intensive Care, Sleep Medicine and Mechanical Ventilation, Asklepios Fachkliniken Munich-Gauting, Gauting, Germany Introduction: The establishment of high-intensity (HI noninvasive ventilation (NIV that targets elevated PaCO2 has led to an increase in the use of long-term NIV to treat patients with chronic hypercapnic COPD. However, the role of the ventilation interface, especially in more aggressive ventilation strategies, has not been systematically assessed.Methods: Ventilator settings and NIV compliance were assessed in this prospective cross-sectional monocentric cohort study of COPD patients with pre-existing NIV. Daytime ­arterialized blood gas analyses and lung function testing were also performed. The primary end point was the distribution among study patients of interfaces (full-face masks [FFMs] vs nasal masks [NMs] in a real-life setting.Results: The majority of the 123 patients studied used an FFM (77%, while 23% used an NM. Ventilation settings were as follows: mean ± standard deviation (SD inspiratory positive airway pressure (IPAP was 23.2±4.6 mbar and mean ± SD breathing rate was 16.7±2.4/minute. Pressure support ventilation (PSV mode was used in 52.8% of patients, while assisted pressure-controlled ventilation (aPCV was used in 47.2% of patients. Higher IPAP levels were associated with an increased use of FFMs (IPAP <21 mbar: 73% vs IPAP >25 mbar: 84%. Mean compliance was 6.5 hours/day, with no differences between FFM (6.4 hours/day and NM (6.7 hours/day users. PaCO2 assessment of ventilation quality revealed

  17. Ammonia emissions in tunnel-ventilated broiler houses

    Directory of Open Access Journals (Sweden)

    KAO Lima

    2011-12-01

    Full Text Available Gas production in broiler houses and their emissions are closely related to the microclimate established inside the house according to air temperature, humidity, and velocity. Therefore, the internal house environment is influenced by building typology and ventilation system. The objective of the present study was to evaluate ammonia emission rates in broiler houses equipped with different ventilation systems (negative or positive pressure and litter conditions (new or built-up. The environment of six commercial broiler houses was evaluated internal and external NH3 concentrations. Ventilation rates were recorded to estimate ammonia emission rates. The efficiency of circulation and exhaust fans was assessed, and higher ventilation rates were determined in negative-pressure houses due to the higher flow of the fans. Houses with new litter increased ammonia emission rates along the rearing period, indicating the relationship between gas emissions, bird age and ventilation rates, and presented a typical curve of NH3 emission increase. Negative-pressure houses with built-up litter presented higher emission rates during the first rearing week due to the high NH3 concentration during the brooding period, when the ventilation rates required to maintain chick thermal comfort are low. Although the results of the present study indicate an advantage of the positive-pressure systems as to gas emissions, further research is needed reduce gas emissions in broiler houses with negative-pressure systems.

  18. Development of Smart Ventilation Control Algorithms for Humidity Control in High-Performance Homes in Humid U.S. Climates

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ticci, Sara [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-04-11

    Past field research and simulation studies have shown that high performance homes experience elevated indoor humidity levels for substantial portions of the year in humid climates. This is largely the result of lower sensible cooling loads, which reduces the moisture removed by the cooling system. These elevated humidity levels lead to concerns about occupant comfort, health and building durability. Use of mechanical ventilation at rates specified in ASHRAE Standard 62.2-2013 are often cited as an additional contributor to humidity problems in these homes. Past research has explored solutions, including supplemental dehumidification, cooling system operational enhancements and ventilation system design (e.g., ERV, supply, exhaust, etc.). This project’s goal is to develop and demonstrate (through simulations) smart ventilation strategies that can contribute to humidity control in high performance homes. These strategies must maintain IAQ via equivalence with ASHRAE Standard 62.2-2013. To be acceptable they must not result in excessive energy use. Smart controls will be compared with dehumidifier energy and moisture performance. This work explores the development and performance of smart algorithms for control of mechanical ventilation systems, with the objective of reducing high humidity in modern high performance residences. Simulations of DOE Zero-Energy Ready homes were performed using the REGCAP simulation tool. Control strategies were developed and tested using the Residential Integrated Ventilation (RIVEC) controller, which tracks pollutant exposure in real-time and controls ventilation to provide an equivalent exposure on an annual basis to homes meeting ASHRAE 62.2-2013. RIVEC is used to increase or decrease the real-time ventilation rate to reduce moisture transport into the home or increase moisture removal. This approach was implemented for no-, one- and two-sensor strategies, paired with a variety of control approaches in six humid climates (Miami

  19. Thermal plumes in ventilated rooms

    DEFF Research Database (Denmark)

    Kofoed, Peter; Nielsen, Peter V.

    1990-01-01

    The design of a displacement ventilation system involves determination of the flow rate in the thermal plumes. The flow rate in the plumes and the vertical temperature gradient influence each other, and they are influenced by many factors. This paper shows some descriptions of these effects. Free...... above a point heat source cannot be used. This is caused either by the way of generating the plume including a long intermediate region or by the environmental conditions where vertical temperature gradients are present. The flow has a larger angle of spread and the entrainment factor is greather than...... turbulent plumes from different heated bodies are investigated. The measurements have taken place in a full-scale test room where the vertical temperature gradient have been changed. The velocity and the temperature distribution in the plume are measured. Large scale plume axis wandering is taken...

  20. Ventilation of nuclear power plants

    International Nuclear Information System (INIS)

    Madoyan, A.A.; Vlasik, V.F.

    1984-01-01

    Foundations and calculation methods of ventilation of rooms with different degree of heat and gas release with the change of operation mode of NPP main equipment, as well as problems of NPP site and adjoining area aerodynamics, have been presented. Systems of air ventilation and conditioning, cooling equipment, are considered. The main points of designing are described and determination of economic efficiency of the ventilation systems are made. Technical characteristics of the ventilators, conditioners, filters and air heaters used, are presented. Organization of adjustment, tests, operation and maintenance of the ventilation systems of NPP with RBMK and WWER-type reactors, is described

  1. Increasing ventilation as an intervention in homes of asthmatic children

    DEFF Research Database (Denmark)

    Hogaard, Nina Viskum; Rubak, Sune Leisgaard Mørck; Halken, Susanne

    2016-01-01

    in children. We conducted a double-blind, placebo-controlled intervention study with 46 asthmatic, house dust mite allergic children. The aim was to investigate the association between indoor air quality in homes and severity of asthma, in particular the effect of increased ventilation rate and expected lower...... exposure to HDM on medication intake among these children. As a result of the intervention, the ventilation rate increased and the CO2 concentration fell significantly compared to baseline in the intervention group. The analyses of the effect of ventilation on health outcomes are being processed...

  2. Air quality Performance of Ductless Personalized Ventilation in Conjunction with Displacement Ventilation: Impact of Walking Person

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Lu, Pengfei; Melikov, Arsen Krikor

    2015-01-01

    The present experiment evaluates the impact of air disturbances from a walking person on inhaled air by ductless personalized ventilation (DPV) with displacement ventilation (DV), when a seated occupant is the source of pollution: bio-effluents and exhaled air. The measurements took place in a full...... and the DV supply. Pollution from feet and exhaled air by one manikin was simulated with tracer gases. Room temperature of 26 °C and 90 L/s DV supply flow rate were kept constant. Measurements under numerous combinations of DPV operation modes and supply flow rates were performed. Tracer gas concentrations...

  3. The Impacts of Elevated Carbondioxide (CO2 on Users’ Comfort in Residential Building at BawakSabo, Auchi, Nigeria

    Directory of Open Access Journals (Sweden)

    Clement Oluwole Folorunso

    2017-11-01

    Full Text Available This research work establishes the effects of CO2 on users’ comfort in residential building with specific residential neighborhood in Bawak Sabo as the study area. There is an existing complaint of sneezing, tiredness, sweating and headache at dawn from resident of this neighborhood documented in a medical report of a medical hospital within the community. The research is set to investigate the cause of these problems. The methodology adopted was the combination of experimental-field survey and review of existing literature. Measurement of CO2 concentration was conducted in a given 10% sample population (cases. Measurement was taken in tenement and bungalow accommodation of varied room sizes (9.0m 2 and 12.6 m 2 floor area, population (one to two occupants per room and window opening adjustment. Measurements were taken 8 hours day time and twilight with varied user activity and ventilation rate respectively. The results show that CO2 concentration was higher in rooms with larger numbers of persons. CO2 concentration was closely related to room size and density and increased rapidly when doors and windows were locked. Elevated carbondixoide was low in bungalow accommodation with more numbers of window openings in comparison with tenement accommodation. Differential levels of CO2 concentration have negative impacts on the users’ in ways such as shortness of breath, sneezing sweating and increased breath rate among others. It was concluded that CO2 concentration was responsible for the reported discomfort experienced by BawakSabo residents.

  4. Guidelines for residential commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Wray, Craig P.; Walker, Iain S.; Sherman, Max H.

    2003-01-31

    Currently, houses do not perform optimally or even as many codes and forecasts predict, largely because they are field assembled and there is no consistent process to identify problems or to correct them. Residential commissioning is a solution to this problem. This guide is the culmination of a 30-month project that began in September 1999. The ultimate objective of the project is to increase the number of houses that undergo commissioning, which will improve the quality, comfort, and safety of homes for California citizens. The project goal is to lay the groundwork for a residential commissioning industry in California focused on end-use energy and non-energy issues. As such, we intend this guide to be a beginning and not an end. Our intent is that the guide will lead to the programmatic integration of commissioning with other building industry processes, which in turn will provide more value to a single site visit for people such as home energy auditors and raters, home inspectors, and building performance contractors. Project work to support the development of this guide includes: a literature review and annotated bibliography, which facilitates access to 469 documents related to residential commissioning published over the past 20 years (Wray et al. 2000), an analysis of the potential benefits one can realistically expect from commissioning new and existing California houses (Matson et al. 2002), and an assessment of 107 diagnostic tools for evaluating residential commissioning metrics (Wray et al. 2002). In this guide, we describe the issues that non-experts should consider in developing a commissioning program to achieve the benefits we have identified. We do this by providing specific recommendations about: how to structure the commissioning process, which diagnostics to use, and how to use them to commission new and existing houses. Using examples, we also demonstrate the potential benefits of applying the recommended whole-house commissioning approach to

  5. Design Procedure for Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per; Tjelflaat, Per Olaf

    Mechanical and natural ventilation systems have developed separately during many years. The natural next step in this development is development of ventilation concepts that utilises and combines the best features from each system into a new type of ventilation system - Hybrid Ventilation....... Buildings with hybrid ventilation often include other sustainable technologies and an energy optimisation requires an integrated approach in the design of the building and its mechanical systems. Therefore, the hybrid ventilation design procedure differs from the design procedure for conventional HVAC....... The first ideas on a design procedure for hybrid ventilation is presented and the different types of design methods, that is needed in different phases of the design process, is discussed....

  6. Cost-benefit of ventilation and averted radon in dwellings

    International Nuclear Information System (INIS)

    Katona, T.; Kanyar, B.

    2003-01-01

    To assess an economically optimal ventilation rate we have introduced a cost-benefit analysis taking into account the cost of heating and benefit of averted dose due to ventilation. The cost of heating due to the elevated ventilation for mitigation of radon content in dwellings can be compensated by the monetary benefit of the averted dose, in case of higher (annually 3-10 mSv) exposure. During the heating season the economically optimal ventilation takes 0.1-0.5 h -1 , meanwhile the radon concentration in the indoor air decreases to 200-800 Bq/m 3 , depending on the exhalation of radon, number of persons living in the dwellings and other local parameters. Our results from the optimal planning correspond to the radon concentrations recommended by the international organizations as action levels. In general, the periodic ventilation in daytime provides a higher averted dose than the constant one in case of the same heating cost. (authors)

  7. Human Thermal Comfort In Residential House Buildings Of Jimma Town Southwest Ethiopia.

    Directory of Open Access Journals (Sweden)

    Chali Yadeta

    2015-08-01

    Full Text Available Indoor human thermal comfort is an important factor in indoor air quality assessment. Thermal comfort affects human health work efficiency and overall wellbeing. Thermal discomfort in indoors lowers the emotional and physical health of the occupants. This paper targets to explore human thermal comfort in residential house buildings of Jimma town and state some possible mechanisms to improve the existing thermal discomfort in large number the houses. For the study 303 structured questionnaires were distributed to the residential houses in thirteen places of the town based on predetermined criteria. The study reveals that human thermal discomfort in residential houses Jimma town are mainly from poor architectural design and improper use of heat generating appliances in indoors. The uses architectural design that suites the present climatic conditions and use of materials that facilitates ventilations will enhance the realization of the required human thermal comfort in residential houses of the study area.

  8. Residential electricity demand in Singapore

    International Nuclear Information System (INIS)

    Ang, B.W.; Goh, T.N.; Liu, X.Q.

    1992-01-01

    Residential electricity consumption in Singapore increased at a rate of 8.8% per year between 1972 and 1990. Estimates of the long-run income and price elasticities are 1.0 and -0.35, respectively. The energy-conservation campaigns that have been launched are found to have marginal effects on consumption. A statistical analysis shows that the consumption is sensitive to small changes in climatic variables, particularly the temperature, which is closely linked to the growing diffusion of electric appliances for environmental controls. There has been a temporal increase in the ownership levels of appliances associated with increasing household incomes. However, other factors were involved since the ownership levels would also increase over time after the elimination of the income effect. A large part of the future growth in electricity demand will arise from the growing need for air-conditioning, which will lead to increasingly large seasonal variations in electricity use. (author)

  9. Football Equipment Removal Improves Chest Compression and Ventilation Efficacy.

    Science.gov (United States)

    Mihalik, Jason P; Lynall, Robert C; Fraser, Melissa A; Decoster, Laura C; De Maio, Valerie J; Patel, Amar P; Swartz, Erik E

    2016-01-01

    Airway access recommendations in potential catastrophic spine injury scenarios advocate for facemask removal, while keeping the helmet and shoulder pads in place for ensuing emergency transport. The anecdotal evidence to support these recommendations assumes that maintaining the helmet and shoulder pads assists inline cervical stabilization and that facial access guarantees adequate airway access. Our objective was to determine the effect of football equipment interference on performing chest compressions and delivering adequate ventilations on patient simulators. We hypothesized that conditions with more football equipment would decrease chest compression and ventilation efficacy. Thirty-two certified athletic trainers were block randomized to participate in six different compression conditions and six different ventilation conditions using human patient simulators. Data for chest compression (mean compression depth, compression rate, percentage of correctly released compressions, and percentage of adequate compressions) and ventilation (total ventilations, mean ventilation volume, and percentage of ventilations delivering adequate volume) conditions were analyzed across all conditions. The fully equipped athlete resulted in the lowest mean compression depth (F5,154 = 22.82; P Emergency medical personnel should remove the helmet and shoulder pads from all football athletes who require cardiopulmonary resuscitation, while maintaining appropriate cervical spine stabilization when injury is suspected. Further research is needed to confirm our findings supporting full equipment removal for chest compression and ventilation delivery.

  10. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bergey, Daniel [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-02-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  11. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [Building Science Corporation, Somerville, MA (United States); Bergey, Daniel [Building Science Corporation, Somerville, MA (United States)

    2014-02-01

    In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. This was because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four system factor categories: balance, distribution, outside air source, and recirculation filtration. Recommended system factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  12. Analysis Thermal Comfort Condition in Complex Residential Building, Case Study: Chiangmai, Thailand

    Science.gov (United States)

    Juangjandee, Warangkana

    2017-10-01

    Due to the increasing need for complex residential buildings, it appears that people migrate into the high-density urban areas because the infrastructural facilities can be easily found in the modern metropolitan areas. Such rapid growth of urbanization creates congested residential buildings obstructing solar radiation and wind flow, whereas most urban residents spend 80-90% of their time indoor. Furthermore, the buildings were mostly built with average materials and construction detail. This causes high humidity condition for tenants that could promote mould growth. This study aims to analyse thermal comfort condition in complex residential building, Thailand for finding the passive solution to improve indoor air quality and respond to local conditions. The research methodology will be in two folds: 1) surveying on case study 2) analysis for finding the passive solution of reducing humidity indoor air The result of the survey indicated that the building need to find passive solution for solving humidity problem, that can be divided into two ways which raising ventilation and indoor temperature including increasing wind-flow ventilation and adjusting thermal temperature, for example; improving building design and stack driven ventilation. For raising indoor temperature or increasing mean radiant temperature, daylight can be passive solution for complex residential design for reducing humidity and enhance illumination indoor space simultaneous.

  13. Residential radon in Finland: sources, variation, modelling and dose comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Arvela, H

    1995-09-01

    The study deals with sources of indoor radon in Finland, seasonal variations in radon concentration, the effect of house construction and ventilation and also with the radiation dose from indoor radon and terrestrial gamma radiation. The results are based on radon measurements in approximately 4000 dwellings and on air exchange measurements in 250 dwellings as well as on model calculations. The results confirm that convective soil air flow is by far the most important source of indoor radon in Finnish low-rise residential housing. (97 refs., 61 figs., 30 tabs.).

  14. Residential radon in Finland: sources, variation, modelling and dose comparisons

    International Nuclear Information System (INIS)

    Arvela, H.

    1995-09-01

    The study deals with sources of indoor radon in Finland, seasonal variations in radon concentration, the effect of house construction and ventilation and also with the radiation dose from indoor radon and terrestrial gamma radiation. The results are based on radon measurements in approximately 4000 dwellings and on air exchange measurements in 250 dwellings as well as on model calculations. The results confirm that convective soil air flow is by far the most important source of indoor radon in Finnish low-rise residential housing. (97 refs., 61 figs., 30 tabs.)

  15. High Frequency Oscillatory Ventilation

    Directory of Open Access Journals (Sweden)

    AC Bryan

    1996-01-01

    Full Text Available High frequency oscillatory (HFO ventilation using low tidal volume and peak airway pressures is extremely efficient at eliminating carbon dioxide and raising pH in the newborn infant with acute respiratory failure. Improvement in oxygenation requires a strategy of sustained or repetitive inflations to 25 to 30 cm H2O in order to place the lung on the deflation limb of the pressure-volume curve. This strategy has also been shown to decrease the amount of secondary lung injury in animal models. Experience of the use of HFO ventilation as a rescue therapy as well as several published controlled trials have shown improved outcomes and a decrease in the use of extracorporeal membrane oxygenation when it has been used in newborns.

  16. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Yu, Tao; Heiselberg, Per Kvols

    cooling capacity, energy saving, low investment cost and low noise level; while the limitations include condensation risk and the limit on the room geometry. Furthermore, the crucial design parameters are summarized and their effects on the system performance are discussed. In addition to the stand...... is not well structured with this system. These become the motivations in developing the design guide. This design guide aims to establish a systematic understanding of diffuse ceiling ventilation and provide assistance in designing of such a system. The guide is targeted at design engineers, architects...... and manufacturers and the users of diffuse ceiling technology. The design guide introduces the principle and key characteristics of room air distribution with diffuse ceiling ventilation. It provides an overview of potential benefit and limitations of this technology. The benefits include high thermal comfort, high...

  17. Arterial oxygen tension and pulmonary ventilation in horses placed in the Anderson Sling suspension system after a period of lateral recumbency and anaesthetised with constant rate infusions of romifidine and ketamine.

    Science.gov (United States)

    François, I; Lalèyê, F-X; Micat, M; Benredouane, K; Portier, K

    2014-09-01

    Some controversy exists over whether or not horses' recovery and cardiopulmonary function are affected by suspension in slings. To measure arterial oxygen tension and pulmonary ventilation in anaesthetised horses placed in a standing position in an Anderson Sling (AS) after a period of right lateral recumbency (RLR). Randomised crossover experimental study. Six Standardbred horses were anaesthetised twice. Catheters were inserted into the right jugular vein and the left carotid artery. After premedication with romifidine, anaesthesia was induced with diazepam and ketamine. Following 50 min in RLR, horses were maintained in either RLR or AS for an additional 60 min through to recovery. Anaesthesia was maintained i.v. with a constant rate infusion of romifidine and ketamine. Heart rate, respiratory rate, mean arterial pressure, expiratory tidal volume, minute volumes and end tidal CO2 were monitored continuously. Venous and arterial bloods were sampled for lactate concentration, creatine kinase activity and blood gas analysis before premedication, after induction, every 20 min for 100 min, as soon as the horse was standing (TR), and 24 h later. The data were averaged within 2 anaesthetic periods: P1, 0-20 min; and P2, 40-100 min. During P2, horses in the RLR group had lower arterial oxygen tension (P = 0.001), higher alveolar-arterial oxygen tension gradient (P = 0.005), higher respiratory rate (P = 0.04) and higher minute volumes (P = 0.04) than horses in the AS group. Arterial CO2 tension and mean arterial pressure increased in the AS group during P2 (P = 0.01 and 0.02 respectively). The recoveries were judged better in the AS group than in the RLR group (P = 0.01). During TR, lactate were higher in the RLR group than in the AS group (P = 0.007). Creatine kinase activities were higher in the AS group at 24 h vs. TR (P = 0.02). Anderson Sling suspension after a period of recumbency improves cardiopulmonary function and recovery quality in horses and

  18. Harnessing natural ventilation benefits.

    Science.gov (United States)

    O'Leary, John

    2013-04-01

    Making sure that a healthcare establishment has a good supply of clean fresh air is an important factor in keeping patients, staff, and visitors, free from the negative effects of CO2 and other contaminants. John O'Leary of Trend Controls, a major international supplier of building energy management solutions (BEMS), examines the growing use of natural ventilation, and the health, energy-saving, and financial benefits, that it offers.

  19. Purge ventilation operability

    International Nuclear Information System (INIS)

    Marella, J.R.

    1995-01-01

    A determination of minimum requirements for purge exhaust ventilation system operability has been performed. HLWE and HLW Regulatory Program personnel have evaluated the various scenarios of equipment conditions and HLWE has developed the requirements for purge exhaust systems. This report is provided to document operability requirements to assist Tank Farm personnel to determine whether a system is operable/inoperable and to define required compensatory actions

  20. Ventilation i industrien

    DEFF Research Database (Denmark)

    Valbjørn, O.

    I en række afsnit belyses problemer med træk, kulde, varme, og luftforurening på industriens arbejdspladser, og hvordan man ved ventilation og bygningsudformning kan bekæmpe disse gener. Hvert afsnit kan i princippet læses for sig, og anvisningen kan derfor bruges som håndbog, både af de der er...

  1. Factors contributing to the fluctuations in residential construction in Iran

    Directory of Open Access Journals (Sweden)

    Hassan Gholipour Fereidouni

    2011-12-01

    Full Text Available Residential construction is one of the most important pillars of Iran’s economy. Although this sector had an increasing trend over the past two decades, however, the growth rate of residential construction was very volatile. The purpose of this paper is to empirically investigate those factors contributing to this fluctuation over the 1991:Q2-2008:Q4. By applying cointegration approach, the empirical results show that housing prices, construction costs, GDP and gold prices are important factors to explain swings in residential construction in Iran.

  2. Use of Ventilator Bundle and Staff Education to Decrease Ventilator-Associated Pneumonia in Intensive Care Patients.

    Science.gov (United States)

    Parisi, Maria; Gerovasili, Vasiliki; Dimopoulos, Stavros; Kampisiouli, Efstathia; Goga, Christina; Perivolioti, Efstathia; Argyropoulou, Athina; Routsi, Christina; Tsiodras, Sotirios; Nanas, Serafeim

    2016-10-01

    Ventilator-associated pneumonia (VAP), one of the most common hospital-acquired infections, has a high mortality rate. To evaluate the incidence of VAP in a multidisciplinary intensive care unit and to examine the effects of the implementation of ventilator bundles and staff education on its incidence. A 24-month-long before/after study was conducted, divided into baseline, intervention, and postintervention periods. VAP incidence and rate, the microbiological profile, duration of mechanical ventilation, and length of stay in the intensive care unit were recorded and compared between the periods. Of 1097 patients evaluated, 362 met the inclusion criteria. The baseline VAP rate was 21.6 per 1000 ventilator days. During the postintervention period, it decreased to 11.6 per 1000 ventilator days (P = .01). Length of stay in the intensive care unit decreased from 36 to 27 days (P = .04), and duration of mechanical ventilation decreased from 26 to 21 days (P = .06). VAP incidence was high in a general intensive care unit in a Greek hospital. However, implementation of a ventilator bundle and staff education has decreased both VAP incidence and length of stay in the unit. ©2016 American Association of Critical-Care Nurses.

  3. Noninvasive Ventilation in Premature Neonates.

    Science.gov (United States)

    Flanagan, Keri Ann

    2016-04-01

    The use of noninvasive ventilation is a constantly evolving treatment option for respiratory disease in the premature infant. The goals of these noninvasive ventilation techniques are to improve gas exchange in the premature infant's lungs and to minimize the need for intubation and invasive mechanical ventilation. The goals of this article are to consider various uses of nasal interfaces, discuss skin care and developmental positioning concerns faced by the bedside nurse, and discuss the medical management aimed to reduce morbidity and mortality. This article explores the nursing role, the advances in medical strategies for noninvasive ventilation, and the team approach to noninvasive ventilation use in this population. Search strategy included a literature review on medical databases, such as EBSCOhost, CINAHL, PubMed, and NeoReviews. Innovative products, nursing research on developmental positioning and skin care, and advanced medical management have led to better and safer outcomes for premature infants requiring noninvasive ventilation. The medical focus of avoiding long-term mechanical ventilation would not be possible without the technology to provide noninvasive ventilation to these premature infants and the watchful eye of the nurse in terms of careful positioning, preventing skin breakdown and facial scarring, and a proper seal to maximize ventilation accuracy. This article encourages nursing-based research to quantify some of the knowledge about skin care and positioning as well as research into most appropriate uses for noninvasive ventilation devices.

  4. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... quite well with the Epstein's formula ratio are presented. In some cases the measured airflow rates fit quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed....

  5. Re-thinking residential mobility

    Science.gov (United States)

    van Ham, Maarten; Findlay, Allan M.

    2015-01-01

    While researchers are increasingly re-conceptualizing international migration, far less attention has been devoted to re-thinking short-distance residential mobility and immobility. In this paper we harness the life course approach to propose a new conceptual framework for residential mobility research. We contend that residential mobility and immobility should be re-conceptualized as relational practices that link lives through time and space while connecting people to structural conditions. Re-thinking and re-assessing residential mobility by exploiting new developments in longitudinal analysis will allow geographers to understand, critique and address pressing societal challenges. PMID:27330243

  6. Large-Scale Residential Demolition

    Science.gov (United States)

    The EPA provides resources for handling residential demolitions or renovations. This includes planning, handling harmful materials, recycling, funding, compliance assistance, good practices and regulations.

  7. Health impacts due to personal exposure to fine particles caused by insulation of residential buildings in Europe

    Science.gov (United States)

    Gens, Alexandra; Hurley, J. Fintan; Tuomisto, Jouni T.; Friedrich, Rainer

    2014-02-01

    The insulation of residential buildings affects human exposure to fine particles. According to current EU guidelines, insulation is regulated for energy saving reasons. As buildings become tighter, the air exchange rate is reduced and, thus, the indoor concentration of pollutants is increased if there are significant indoor sources. While usually the effects of heat insulation and increase of the air-tightness of buildings on greenhouse gas emissions are highlighted, the negative impacts on human health due to higher indoor concentrations are not addressed. Thus, we investigated these impacts using scenarios in three European countries, i. e. Czech Republic, Switzerland and Greece. The assessment was based on modelling the human exposure to fine particles originating from sources of particles within outdoor and indoor air, including environmental tobacco smoke. Exposure response relationships were derived to link (adverse) health effects to the exposure. Furthermore, probable values for the parameters influencing the infiltration of fine particles into residential buildings were modelled. Results show that the insulation and increase of the air-tightness of residential buildings leads to an overall increase of the mean population exposure - and consequently adverse health effects - in all considered countries (ranging for health effects from 0.4% in Czech Republic to 11.8% in Greece for 100% insulated buildings) due to an accumulation of particles indoors, especially from environmental tobacco smoke. Considering only the emission reductions in outdoor air (omitting changes in infiltration parameters) leads to a decrease of adverse health effects. This study highlights the importance of ensuring a sufficient air exchange rate when insulating buildings, e. g. by prescribing heat ventilation and air conditioning systems in new buildings and information campaigns on good airing practice in renovated buildings. It also shows that assessing policy measures based on the

  8. Design Principles for Natural and Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per

    For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system- Hybrid Ventilation. ....... The hybrid ventilation concepts, design challenges and principles are discussed and illustrated by four building examples.......For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system- Hybrid Ventilation...

  9. Nuclear waste repository ventilation system studies

    International Nuclear Information System (INIS)

    Smith, P.R.; Hensel, E.C.; Leslie, I.H.; Schultheis, T.M.; Walls, J.R.; Gregory, W.S.

    1993-01-01

    Ventilation studies of the Waste Isolation Pilot Plant described in this article were performed by personnel from New Mexico State University in collaboration with Sandia National Laboratories, Los Alamos National Laboratory, and Westinghouse Corporation. The following research tasks were performed: 1) High-efficiency particulate air filters of the type used at the Waste Isolation Pilot Plant were loaded with salt aerosol from the site, 2) Filter resistance as a function of salt mass and flow rate was established for later use in computer simulations, 3) Filter efficiency was measured during the loading tests to establish a relation between efficiency and salt loading, 4) The structural strength of the salt-loaded high-efficiency filters was investigated by subjecting the filters to pressure transients of the types expected from fires, explosions and tornados, 5) Computer codes, obtained from Los Alamos National Laboratory, were used to model the ventilation systems and study their response to accident-induced pressure transients and heat fluxes, 6) Partial verification of the computer simulations was obtained by comparing normal operation of the ventilation systems to predicted normal operation, 7) A feasibility study using model-based control of the ventilation systems was initiated and will be completed during the second year of the project. (author) 12 figs., 16 refs

  10. Aerosol delivery in intubated, mechanically ventilated patients

    International Nuclear Information System (INIS)

    MacIntyre, N.R.; Silver, R.M.; Miller, C.W.; Schuler, F.; Coleman, R.E.

    1985-01-01

    To study the effects of respiratory failure and mechanical ventilation on aerosol delivery to the lungs, nuclear scans were performed after aerosolization of 5 to 9 mCi of Tc-99m diethylenetriamine pentaacetic acid in seven stable, intubated, and mechanically ventilated patients. The radioactivity reaching the lungs was 2.9 +/- .7% (mean +/- SD) of the administered dose, an amount significantly less than that in three healthy nonintubated subjects and also less than what would be expected in nonintubated subjects from other published reports. A subsequent study was performed in 15 additional mechanically ventilated patients who were receiving aerosolized bronchodilators through their endotracheal tube. In these patients, heart rate and lung mechanical function values before and after treatment were not significantly different. It is concluded from these studies that aerosol delivery in mechanically ventilated patients is significantly reduced and that this is probably due to a combination of suboptimal breathing pattern, intrinsic airway disease, and the endotracheal tube functioning as both a site for aerosol deposition through impaction as well as a barrier to gastrointestinal absorption

  11. Ventilators in ICU: A boon or burden

    Directory of Open Access Journals (Sweden)

    Man Mohan Mehndiratta

    2016-01-01

    Full Text Available Background and Aims: Ventilator-associated pneumonia (VAP is a major challenge in intensive care units (ICUs. This challenge is even more discernible in a neurological setting owing to the predispositions of patients. Data on VAP in the neurology and neurosurgery ICUs (NNICUs are scanty in developing countries. This study was conducted to find out the occurrence of VAP, its risk factors, microbiological profile, and antibiotic resistance in patients admitted to the NNICU of a tertiary care institute in India. Materials and Methods: Endotracheal aspirate and blood samples were collected from 100 patients admitted to the NNICU. Complete blood count, microscopic examination, culture and sensitivity testing of aspirate were done. Chest x-ray was also performed to aid in the diagnosis of VAP. Results: Incidence rate of VAP was found to be 24%. Acinetobacter baumannii was the most common pathogen (24.3% isolated from patients with VAP, and all of these isolates were sensitive to meropenem. Duration of mechanical ventilation (P < 0.0001 and associated comorbid illness (P = 0.005 were found to be significantly associated with VAP, and the duration of mechanical ventilation was found to be the only independent risk factor (P < 0.0001. Conclusions: This study highlights the risks and microbiological perspective of ventilator use among neurology patients so that adequate preventive strategies can be adopted on time.

  12. Ventilation in Sewers Quantified by Measurements of CO2

    DEFF Research Database (Denmark)

    Fuglsang, Emil Dietz; Vollertsen, Jes; Nielsen, Asbjørn Haaning

    2012-01-01

    Understanding and quantifying ventilation in sewer systems is a prerequisite to predict transport of odorous and corrosive gasses within the system as well as their interaction with the urban atmosphere. This paper studies ventilation in sewer systems quantified by measurements of the natural...... occurring compound CO2. Most often Danish wastewater is supersaturated with CO2 and hence a potential for stripping is present. A novel model was built based on the kinetics behind the stripping process. It was applied to simulate ventilation rates from field measurements of wastewater temperature, p...

  13. Mechanical ventilation in neurosurgical patients

    Directory of Open Access Journals (Sweden)

    Keshav Goyal

    2013-01-01

    Full Text Available Mechanical ventilation significantly affects cerebral oxygenation and cerebral blood flow through changes in arterial carbon dioxide levels. Neurosurgical patients might require mechanical ventilation for correction and maintenance of changes in the pulmonary system that occur either due to neurosurgical pathology or following surgery during the acute phase. This review discusses the basics of mechanical ventilation relevant to the neurosurgeon in the day-to-day management of neurosurgical patient requiring artificial support of the respiration.

  14. Mechanical Ventilation and Bronchopulmonary Dysplasia.

    Science.gov (United States)

    Keszler, Martin; Sant'Anna, Guilherme

    2015-12-01

    Mechanical ventilation is an important potentially modifiable risk factor for the development of bronchopulmonary dysplasia. Effective use of noninvasive respiratory support reduces the risk of lung injury. Lung volume recruitment and avoidance of excessive tidal volume are key elements of lung-protective ventilation strategies. Avoidance of oxidative stress, less invasive methods of surfactant administration, and high-frequency ventilation are also important factors in lung injury prevention. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. What does built-in software of home ventilators tell us? An observational study of 150 patients on home ventilation.

    Science.gov (United States)

    Pasquina, Patrick; Adler, Dan; Farr, Pamela; Bourqui, Pascale; Bridevaux, Pierre Olivier; Janssens, Jean-Paul

    2012-01-01

    Recent home ventilators are equipped with built-in software which provides data such as compliance, estimations of leaks, tidal volume, minute ventilation, respiratory rate, apnea and apnea-hypopnea indexes, and percentage of inspirations triggered by the patient (or ventilator). However, for many of these variables, there is neither consensus nor documentation as to what is to be expected in a population of stable patients under noninvasive ventilation (NIV). To document the values and distribution of specific items downloaded from ventilator monitoring software, by diagnostic category. Analysis of data downloaded from home ventilators in clinically stable patients under long-term NIV, during elective home visits by specialized nurses. Data were collected from home ventilators of 150 patients with chronic obstructive pulmonary disease (n = 32), overlap syndrome (n = 29), obesity-hypoventilation (n = 38), neuromuscular disorders (n = 19), restrictive disorders (n = 21), and central sleep apnea syndrome (n = 11). On average, leaks were low, being lowest in patients with facial masks (vs. nasal masks), and increased with older age. Compliance was excellent in all groups. Patients with neuromuscular diseases triggered their ventilators less and tended to be 'captured', while other groups triggered at least half of inspiratory cycles. Most patients had a respiratory rate just slightly above the back-up rate. Residual apneas and hypopneas were highest in patients with central apneas. Built-in software of home ventilators provides the clinician with new parameters, some of which are a useful adjunct to recommended tools for monitoring NIV and may contribute to a better understanding of residual hypoventilation and/or desaturations. However, an independent validation of the accuracy of this information is mandatory. Copyright © 2011 S. Karger AG, Basel.

  16. Design Principles for Natural and Hybrid Ventilation

    OpenAIRE

    Heiselberg, Per

    2000-01-01

    For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system- Hybrid Ventilation. The hybrid ventilation concepts, design challenges and principles are discussed and illustrated by four building examples.

  17. 46 CFR 42.15-45 - Ventilators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Ventilators. 42.15-45 Section 42.15-45 Shipping COAST... Conditions of Assignment of Freeboard § 42.15-45 Ventilators. (a) Ventilators in position 1 or 2 to spaces... any ventilator exceeds 351/2 inches in height it shall be specially supported. (b) Ventilators passing...

  18. Synchronized mechanical ventilation for respiratory support in newborn infants.

    Science.gov (United States)

    Greenough, Anne; Murthy, Vadivelam; Milner, Anthony D; Rossor, Thomas E; Sundaresan, Adesh

    2016-08-19

    During synchronised mechanical ventilation, positive airway pressure and spontaneous inspiration coincide. If synchronous ventilation is provoked, adequate gas exchange should be achieved at lower peak airway pressures, potentially reducing baro/volutrauma, air leak and bronchopulmonary dysplasia. Synchronous ventilation can potentially be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient-triggered ventilation. To compare the efficacy of:(i) synchronised mechanical ventilation, delivered as high-frequency positive pressure ventilation (HFPPV) or patient-triggered ventilation (assist control ventilation (ACV) and synchronous intermittent mandatory ventilation (SIMV)), with conventional ventilation or high-frequency oscillation (HFO);(ii) different types of triggered ventilation (ACV, SIMV, pressure-regulated volume control ventilation (PRVCV), SIMV with pressure support (PS) and pressure support ventilation (PSV)). We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 5), MEDLINE via PubMed (1966 to June 5 2016), EMBASE (1980 to June 5 2016), and CINAHL (1982 to June 5 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised or quasi-randomised clinical trials comparing synchronised ventilation delivered as HFPPV to CMV, or ACV/SIMV to CMV or HFO in neonates. Randomised trials comparing different triggered ventilation modes (ACV, SIMV, SIMV plus PS, PRVCV and PSV) in neonates. Data were collected regarding clinical outcomes including mortality, air leaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intraventricular haemorrhage (grades 3 and 4), bronchopulmonary dysplasia (BPD) (oxygen dependency beyond 28 days), moderate/severe BPD (oxygen

  19. Comparison of two modes of ventilation after fast-track cardiac surgery: Adaptive support ventilation versus synchronized intermittent mandatory ventilation

    International Nuclear Information System (INIS)

    Aghadavoudi, O.

    2012-01-01

    Objective: There is substantial debate regarding the appropriate protocol for ventilatory management in fast-track cardiac anesthesia (FTCA). This study was carried out to assess and compare the risks and benefits of respiratory weaning based on adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation (SIMV) after uncomplicated cardiac surgery. Methodology: In a randomized clinical trial, after receiving approval of the Department Research Committee and informed consent from study subjects, 100 patients undergoing elective coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB) were enrolled during a 4-month period at a university-based hospital. After surgery and admission to the intensive care unit (ICU), patients were randomized to ASV and SIMV groups. Arterial blood gas (ABG) and hemodynamic variables, respiratory and ventilator characteristics including lung compliance, rapid shallow breathing index (RSBI), tidal volume (TV), respiratory rate (RR), peak inspiratory pressure (P peak), mean airway pressure (p mean), Pao2/FIo2, duration of mechanical ventilation and tracheal intubation, and length of ICU stay were recorded and compared between the two groups. The data were analyzed in 82 patients after considering the exclusion criteria. Results: There were no differences between ASV and SIMV groups in demographics and preoperative characteristics. The duration of tracheal intubation and the length of ICU stay were similar in both groups. There were no statistically and clinically relevant differences between the two groups in ABG, hemodynamic changes, and respiratory and ventilator characteristics during ICU stay. Conclusion: Although ASV may facilitate postoperative respiratory management in FTCA, both ASV and SIMV provide similarly safe and practicable respiratory weaning in the cardiac ICU. The evaluation of potential advantages in patient outcomes and resource utilization of respiratory weaning based on ASV

  20. New Air Cleaning Strategies for Reduced Commercial Building Ventilation Energy

    Energy Technology Data Exchange (ETDEWEB)

    Sidheswaran, Meera; Destaillats, Hugo; Sullivan, Douglas P.; Fisk, William J.

    2010-10-27

    Approximately ten percent of the energy consumed in U.S. commercial buildings is used by HVAC systems to condition outdoor ventilation air. Reducing ventilation rates would be a simple and broadly-applicable energy retrofit option, if practical counter measures were available that maintained acceptable concentrations of indoor-generated air pollutants. The two general categories of countermeasures are: 1) indoor pollutant source control, and 2) air cleaning. Although pollutant source control should be used to the degree possible, source control is complicated by the large number and changing nature of indoor pollutant sources. Particle air cleaning is already routinely applied in commercial buildings. Previous calculations indicate that particle filtration consumes only 10percent to 25percent of the energy that would otherwise be required to achieve an equivalent amount of particle removal with ventilation. If cost-effective air cleaning technologies for volatile organic compounds (VOCs) were also available, outdoor air ventilation rates could be reduced substantially and broadly in the commercial building stock to save energy. The research carried out in this project focuses on developing novel VOC air cleaning technologies needed to enable energy-saving reductions in ventilation rates. The minimum required VOC removal efficiency to counteract a 50percent reduction in ventilation rate for air cleaning systems installed in the HVAC supply airstream is modest (generally 20percent or less).

  1. Modeling ventilation and radon in new dutch dwellings

    International Nuclear Information System (INIS)

    Janssen, M.P.M.

    2003-01-01

    Indoor radon concentrations were estimated for various ventilation conditions, the differences being mainly related to the airtightness of the dwelling and the ventilation behavior of its occupants. The estimations were aimed at describing the variation in air change rates and radon concentrations to be expected in the representative newly built Dutch dwellings and identifying the most important parameters determining air change rate and indoor radon concentration. The model estimations were compared with measurements. Most of the air was predicted to enter the model dwelling through leaks in the building shell, independent of the ventilation conditions of the dwelling. Opening the air inlets was shown to be an efficient way to increase infiltration and thus to decrease radon concentration. The effect of increasing the mechanical ventilation rate was considerably less than opening the air inlets. The mechanical ventilation sets the lower limit to the air change rate of the dwelling, and is effective in reducing the radon concentration when natural infiltration is low. Opening inside doors proved to be effective in preventing peak concentrations in poorly ventilated rooms. As the airtightness of newly built dwellings is still being improved, higher radon concentrations are to be expected in the near future and the effect of occupant behavior on indoor radon concentrations is likely to increase. According to the model estimations soil-borne radon played a moderate role, which is in line with measurements. (au)

  2. Residential energy demand in Brazil

    International Nuclear Information System (INIS)

    Arouca, M.; Gomes, F.M.; Rosa, L.P.

    1981-01-01

    The energy demand in Brazilian residential sector is studied, discussing the methodology for analyzing this demand from some ideas suggested, for developing an adequate method to brazilian characteristics. The residential energy consumption of several fuels in Brazil is also presented, including a comparative evaluation with the United States and France. (author)

  3. Potential of Natural Ventilation in Cold Conditions Countries

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan; Østergaard, Poul Alberg

    2014-01-01

    The objective of this article is to investigate the energy performance of natural ventilation as a passive cooling method of buildings within houses located in temperate countries using Denmark as a case study. The method consists in running simulations with a thermal-airflow program of a household...... the simulations are validated with measured data, and by applying a new assessment method presented in this article as the cooling rate due to natural ventilation instead of a constant mechanical ventilation rate in the thermal balance within the dwelling, the energy saving is calculated. Results show...... ventilation rather mechanical one on large-scale scenarios located in temperate conditions. Finally, as a practical implication example, an assessment for Denmark is carried out....

  4. Perceived decisional responsibility for mechanical ventilation and weaning

    DEFF Research Database (Denmark)

    Haugdahl, Hege S; Storli, Sissel; Rose, Louise

    2014-01-01

    AIM: To explore variability in perceptions of nurse managers and physician directors regarding roles, responsibilities and clinical-decision making related to mechanical ventilator weaning in Norwegian intensive care units (ICUs). BACKGROUND: Effective teamwork is crucial for providing optimal...... patient care in ICU. More knowledge on nurses' and physicians' perceptions of responsibility in clinical decision-making for mechanical ventilation is needed. METHODS: Self-administered survey of mechanical ventilation and weaning responsibilities was sent to nurse managers and physician directors...... of Norwegian adult ICUs. Nurses' decisional influence and autonomy were estimated on a numeric rating scale (NRS) from 0 to 10 (least to most). RESULTS: Response rate was 38/60 (63%) nurses and 38/52 (73%) physicians. On the NRS nurse managers perceived the autonomy and influence of nurses' ventilator...

  5. Solar Air Collectors for Space Heating and Ventilation Applications—Performance and Case Studies under Romanian Climatic Conditions

    Directory of Open Access Journals (Sweden)

    Sanda Budea

    2014-06-01

    Full Text Available Solar air collectors have various applications: on the one hand, they can be used for air heating in cold seasons; on the other hand they can be used in summer to evacuate the warm and polluted air from residential, offices, industrial, and commercial buildings. The paper presents experimental results of a solar collector air, under the climatic conditions of the Southeastern Europe. The relationships between the direct solar irradiation, the resulting heat flow, the air velocity at the outlet, the air flow rate, the nominal regime of the collector and the efficiency of conversion of solar energy into thermal energy are all highlighted. Thus, it was shown that after a maximum 50 min, solar air collectors, with baffles and double air passage can reach over 50% efficiency for solar irradiation of 900–1000 W/m2. The article also presents a mathematical model and the results of a computational program that allows sizing solar collectors for the transfer of air, with the purpose of improving the natural ventilation of buildings. The article is completed with case studies, sizing the area to be covered with solar collectors, to ensure ventilation of a house with two floors or for an office building. In addition, the ACH (air change per hour coefficient was calculated and compared.

  6. The air quality in ventilation installations. Practical guidelines; Qualite de l'air dans les installations aerauliques. Guide pratique

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, L. [France Air, 91 - Chilly Mazarin (France); Bianchina, M. [Unelvent, 93 - Le Bourget (France); Blazy, M. [Anjos, 01 - Torcieu (France); Boulanger, X. [Aldes, 21 - Chenove (France); Chiesa, M. [Atlantic (France); Duclos, M. [Groupe Titanair, 69 - Lyon (France); Hubert, D.; Kridorian, O. [Groupe Astato, Blanc Mesnil (France); Josserand, O. [Carrier (Belgium); Lancieux, C. [Camfil, 60 - Saint Martin Longueau (France); Lemaire, J.C. [Agence de l' Environnement et de la Maitrise de l' Energie, ADEME, 75 - Paris (France); Petit, Ph. [Compagnie Industrielle d' Applications Thermiques ( CIAT ), 75 - Paris (France); Ribot, B. [Electricite de France (EDF), 75 - Paris (France); Tokarek, S. [Gaz de France (GDF), 75 - Paris (France); Bernard, A.M.; Tissot, A. [Centre Technique des Industries Aerauliques et Thermiques (CETIAT), 69 - Villeurbanne (France)

    2004-07-01

    The present guide aims to provide design departments, maintenance companies and builders with practical guidelines and recommendations for the installation of ventilation and air-conditioning systems. The objective is to ensure good Indoor Air Quality (IAQ) and to safeguard the health and well-being of the occupants. The guide deals with aspects of design, dimensioning, installation and servicing, all of which play a major role in guaranteeing IAQ and duct-work hygiene. These steps are reviewed for the principal ventilation systems met in both residential and commercial premises. The first part presents the system and draws the attention of the user to specific points which require particular care in term of IAQ. The second part details recommended practice component by component, in respect of design, installation and servicing. Application of these simple guidelines during the various project stages is essential, in order to ensure a good IAQ in ventilation systems. Content: introduction; good ventilation; systems: exhaust ventilation, balanced ventilation, air handling unit, terminal ventilation units, impact of systems on indoor air quality, components: air inlet, air filter, heat recovery unit, heating or cooling coil, humidifier, mechanical fan unit, cowl and hybrid ventilation fan, mixing box, ventilation duct-work, air outlet and air terminal device; references.

  7. Dependence of radon level on ventilation systems in residences

    International Nuclear Information System (INIS)

    Kokotti, H.

    1995-01-01

    The concentration of indoor radon and radon entry from soil into a house are expected to increase with increasing radon concentration in soil pores, and indoor radon concentration is expected to decrease with increasing ventilation rate. Depressurization, which can be caused by the stack effect, by wind and by unbalanced ventilation, creates different pressure conditions in a house and in the soil beneath it. To reveal the possible differences in radon removal and entry resulting from different ventilation systems, radon concentrations were determined in three similar slab-on-grade buildings provided with mechanical supply and exhaust ventilation, mechanical exhaust or natural ventilation. To limitate the effect of differences in soil parameters, the houses were constructed on the same gravel esker in Kuopio. Thus, the variation in radon entry as a result of different depressurisation of the houses (caused by unbalanced mechanical ventilation systems) could also be observed. In addition, the effect of pressurisation on living rooms could be determined in five slab-on-grade houses constructed on the same esker in Hollola. Mechanical supply and exhaust ventilation system controlled by measured indoor-outdoor pressure difference, was installed in the six houses. The seasonal variation with and without controlled pressure conditions were followed in a slab-on-grade house constructed on a gravel esker in Rekola. Long-term radon concentrations were observed to correlate negatively with air exchange rates. However, the removal effect of ventilation was found to be disturbed by negative pressure due to the stack effect and/or to unbalanced mechanical ventilation. (91 refs., 17 figs., 10 tabs.)

  8. Effect of flashlight guidance on manual ventilation performance in cardiopulmonary resuscitation: A randomized controlled simulation study.

    Science.gov (United States)

    Kim, Ji Hoon; Beom, Jin Ho; You, Je Sung; Cho, Junho; Min, In Kyung; Chung, Hyun Soo

    2018-01-01

    Several auditory-based feedback devices have been developed to improve the quality of ventilation performance during cardiopulmonary resuscitation (CPR), but their effectiveness has not been proven in actual CPR situations. In the present study, we investigated the effectiveness of visual flashlight guidance in maintaining high-quality ventilation performance. We conducted a simulation-based, randomized, parallel trial including 121 senior medical students. All participants were randomized to perform ventilation during 2 minutes of CPR with or without flashlight guidance. For each participant, we measured mean ventilation rate as a primary outcome and ventilation volume, inspiration velocity, and ventilation interval as secondary outcomes using a computerized device system. Mean ventilation rate did not significantly differ between flashlight guidance and control groups (P = 0.159), but participants in the flashlight guidance group exhibited significantly less variation in ventilation rate than participants in the control group (Pguidance group. Our results demonstrate that flashlight guidance is effective in maintaining a constant ventilation rate and interval. If confirmed by further studies in clinical practice, flashlight guidance could be expected to improve the quality of ventilation performed during CPR.

  9. The performance of Dräger Oxylog ventilators at simulated altitude.

    Science.gov (United States)

    Flynn, J G; Singh, B

    2008-07-01

    Ventilated patients frequently require transport by air in a hypobaric environment. Previous studies have demonstrated significant changes in the performance of ventilators with changes in cabin pressure (altitude) but no studies have been published on the function of modem ventilators at altitude. This experiment set out to evaluate ventilatory parameters (tidal volume and respiratory rate) of three commonly used transport ventilators (the Dräger Oxylog 1000, 2000 and 3000) in a simulated hypobaric environment. Ventilators were assessed using either air-mix (60% oxygen) or 100% oxygen and tested against models simulating a normal lung, a low compliance (Acute Respiratory Distress Syndrome) lung and a high-resistance (asthma) lung. Ventilators were tested at a range of simulated altitudes between sea level and 3048 m. Over this range, tidal volume delivered by the Oxylog 1000 increased by 68% and respiratory rate decreased by 28%. Tidal volume delivered by the Oxylog 2000 ventilator increased by 29% over the same range of altitudes but there was no significant change in respiratory rate. Tidal volume and respiratory rate remained constant with the Oxylog 3000 over the same range of altitudes. Changes were consistent with each ventilator regardless of oxygen content or lung model. It is important that clinicians involved in critical care transport in a hypobaric environment are aware that individual ventilators perform differently at altitude and that they are aware of the characteristics of the particular ventilator that they are using.

  10. Smaller self-inflating bags produce greater guideline consistent ventilation in simulated cardiopulmonary resuscitation.

    Science.gov (United States)

    Nehme, Ziad; Boyle, Malcolm J

    2009-02-20

    Suboptimal bag ventilation in cardiopulmonary resuscitation (CPR) has demonstrated detrimental physiological outcomes for cardiac arrest patients. In light of recent guideline changes for resuscitation, there is a need to identify the efficacy of bag ventilation by prehospital care providers. The objective of this study was to evaluate bag ventilation in relation to operator ability to achieve guideline consistent ventilation rate, tidal volume and minute volume when using two different capacity self-inflating bags in an undergraduate paramedic cohort. An experimental study using a mechanical lung model and a simulated adult cardiac arrest to assess the ventilation ability of third year Monash University undergraduate paramedic students. Participants were instructed to ventilate using 1600 ml and 1000 ml bags for a length of two minutes at the correct rate and tidal volume for a patient undergoing CPR with an advanced airway. Ventilation rate and tidal volume were recorded using an analogue scale with mean values calculated. Ethics approval was granted. Suboptimal ventilation with the use of conventional 1600 ml bag was common, with 77% and 97% of participants unable to achieve guideline consistent ventilation rates and tidal volumes respectively. Reduced levels of suboptimal ventilation arouse from the use of the smaller bag with a 27% reduction in suboptimal tidal volumes (p = 0.015) and 23% reduction in suboptimal minute volumes (p = 0.045). Smaller self-inflating bags reduce the incidence of suboptimal tidal volumes and minute volumes and produce greater guideline consistent results for cardiac arrest patients.

  11. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Li, Zhigang

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed....

  12. Ventilation air conditioner for a reactor container

    International Nuclear Information System (INIS)

    Ikegame, Noboru; Nakagawa, Takeshi.

    1980-01-01

    Purpose: To suppress the variations in the internal pressure of a reactor container and smoothly ventilate the reactor container. Constitution: The air conditioner provides an air-flow-rate-control damper, a purge-air supply fan, and a filter device in the air-supply pipe of a reactor container. Furthermore, it provides a pressure difference detector at a part of the container. The air-flow-rate-control damper is connected electrically through a position-modulator-comparison amplifier to the pressure difference detector. When the filtration becomes insufficient by clogging of the filter device and the internal pressure increased abruptly in the container, the pressure-difference detector can detect it, and the damper is operated by a pressure regulator and the comparator so as to control the air flow to the container. Thus, the internal pressure variation is controlled so as to easily ventilate the container. (J.P.N.)

  13. Naturlig ventilation i enfamiliehuse

    DEFF Research Database (Denmark)

    Bergsøe, N.C.

    Meddelelsen beskriver resultaterne af en række beregninger foretaget ved anvendelse af et computerprogram. Beregningerne har til formål at belyse forskellige parametres indvirkning på funktionen af et naturligt ventilationssystem. Blandt andet belyses systemets afhængighed af aftrækskanalernes di...... dimension, udeluftventilarealet og placeringen af aftrækskanalernes udmunding i tagfladen. Derudover gengives i kortfattet form de væsentligste konklusioner af udvalgte publikationer, som behandler særlige forhold vedrørende naturlig ventilation i praksis....

  14. Radioaerosol ventilation imaging in ventilator-dependent patients. Technical considerations

    International Nuclear Information System (INIS)

    Vezina, W.; Chamberlain, M.; Vinitski, S.; King, M.; Nicholson, R.; Morgan, W.K.

    1985-01-01

    The differentiation of pulmonary embolism (PE) from regional ventilatory abnormalities accompanied by reduced perfusion requires contemporary perfusion and ventilation studies. Distinguishing these conditions in ventilator-dependent patients is aided by administering a Tc-99m aerosol to characterize regional ventilation, and by performing a conventional Tc-99m MAA perfusion study. The technique uses a simple in-house constructed apparatus. Simple photographic techniques suffice, but computer subtraction of perfusion from the combined perfusion-ventilation image renders interpretation easier if aerosol administration follows perfusion imaging. Multiple defects can be examined in a single study. Excluding normal or near-normal perfusion studies, PE was thought to be present in eight of 16 patients after perfusion imaging alone, but in only one of eight after added aerosol imaging. Angiography confirmed the diagnosis in that patient. Of the eight patients who had abnormal perfusion but were thought unlikely to have PE from the perfusion study alone, two had normal ventilation, and subsequently were shown to have PE by angiography. Because angiography was only performed on patients who were thought to have a high probability of PE on sequential perfusion-ventilation imaging, the true incidence of PE may have been higher. Aerosol ventilation imaging is a useful adjunct to perfusion imaging in patients on ventilators. It requires an efficient delivery system, particularly if aerosol administration follows perfusion imaging, as it does in this study

  15. Plane Stratified Flow in a Room Ventilated by Displacement Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm; Nickel, J.; Baron, D. J. G.

    2004-01-01

    The air movement in the occupied zone of a room ventilated by displacement ventilation exists as a stratified flow along the floor. This flow can be radial or plane according to the number of wall-mounted diffusers and the room geometry. The paper addresses the situations where plane flow...

  16. SU-F-J-219: Predicting Ventilation Change Due to Radiation Therapy: Dependency On Pre-RT Ventilation and Effort Correction

    Energy Technology Data Exchange (ETDEWEB)

    Patton, T; Du, K; Bayouth, J [University of Wisconsin, Madison, WI (United States); Christensen, G; Reinhardt, J [University of Iowa, Iowa City, IA (United States)

    2016-06-15

    Purpose: Ventilation change caused by radiation therapy (RT) can be predicted using four-dimensional computed tomography (4DCT) and image registration. This study tested the dependency of predicted post-RT ventilation on effort correction and pre-RT lung function. Methods: Pre-RT and 3 month post-RT 4DCT images were obtained for 13 patients. The 4DCT images were used to create ventilation maps using a deformable image registration based Jacobian expansion calculation. The post-RT ventilation maps were predicted in four different ways using the dose delivered, pre-RT ventilation, and effort correction. The pre-RT ventilation and effort correction were toggled to determine dependency. The four different predicted ventilation maps were compared to the post-RT ventilation map calculated from image registration to establish the best prediction method. Gamma pass rates were used to compare the different maps with the criteria of 2mm distance-to-agreement and 6% ventilation difference. Paired t-tests of gamma pass rates were used to determine significant differences between the maps. Additional gamma pass rates were calculated using only voxels receiving over 20 Gy. Results: The predicted post-RT ventilation maps were in agreement with the actual post-RT maps in the following percentage of voxels averaged over all subjects: 71% with pre-RT ventilation and effort correction, 69% with no pre-RT ventilation and effort correction, 60% with pre-RT ventilation and no effort correction, and 58% with no pre-RT ventilation and no effort correction. When analyzing only voxels receiving over 20 Gy, the gamma pass rates were respectively 74%, 69%, 65%, and 55%. The prediction including both pre- RT ventilation and effort correction was the only prediction with significant improvement over using no prediction (p<0.02). Conclusion: Post-RT ventilation is best predicted using both pre-RT ventilation and effort correction. This is the only prediction that provided a significant

  17. Particle loading rates for HVAC filters, heat exchangers, and ducts.

    Science.gov (United States)

    Waring, M S; Siegel, J A

    2008-06-01

    The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

  18. Occupant Interactions and Effectiveness of Natural Ventilation Strategies in Contemporary New Housing in Scotland, UK.

    Science.gov (United States)

    Sharpe, Tim; Farren, Paul; Howieson, Stirling; Tuohy, Paul; McQuillan, Jonathan

    2015-07-21

    The need to reduce carbon emissions and fuel poverty has led to increased building envelope air tightness, intended to reduce uncontrolled ventilation heat losses. Ventilation strategies in dwellings still allow the use of trickle ventilators in window frames for background ventilation. The extent to which this results in "healthy" Indoor Air Quality (IAQ) in recently constructed dwellings was a concern of regulators in Scotland. This paper describes research to explore this. First a review of literature was conducted, then data on occupant interactions with ventilation provisions (windows, doors, trickle vents) gathered through an interview-based survey of 200 recently constructed dwellings, and measurements made on a sample of 40 of these. The main measured parameter discussed here is CO2 concentration. It was concluded after the literature review that 1000 ppm absolute was a reasonable threshold to use for "adequate" ventilation. The occupant survey found that there was very little occupant interaction with the trickle ventilators e.g., in bedrooms 63% were always closed, 28% always open, and in only 9% of cases occupants intervened to make occasional adjustments. In the measured dwellings average bedroom CO2 levels of 1520 ppm during occupied (night time) hours were observed. Where windows were open the average bedroom CO2 levels were 972 ppm. With windows closed, the combination of "trickle ventilators open plus doors open" gave an average of 1021 ppm. "Trickle ventilators open" gave an average of 1571 ppm. All other combinations gave averages of 1550 to 2000 ppm. Ventilation rates and air change rates were estimated from measured CO2 levels, for all dwellings calculated ventilation rate was less than 8 L/s/p, in 42% of cases calculated air change rate was less than 0.5 ach. It was concluded that trickle ventilation as installed and used is ineffective in meeting desired ventilation rates, evidenced by high CO2 levels reported across the sampled dwellings

  19. [Lung protective ventilation. Ventilatory modes and ventilator parameters].

    Science.gov (United States)

    Schädler, Dirk; Weiler, Norbert

    2008-06-01

    Mechanical ventilation has a considerable potential for injuring the lung tissue. Therefore, attention has to be paid to the proper choice of ventilatory mode and settings to secure lung-protective ventilation whenever possible. Such ventilator strategy should account for low tidal volume ventilation (6 ml/kg PBW), limited plateau pressure (30 to 35 cm H2O) and positive end-expiratory pressure (PEEP). It is unclear whether pressure controlled or volume controlled ventilation with square flow profile is beneficial. The adjustment of inspiration and expiration time should consider the actual breathing mechanics and anticipate the generation of intrinsic PEEP. Ventilatory modes with the possibility of supporting spontaneous breathing should be used as soon as possible.

  20. Characterization of natural ventilation in wastewater collection systems.

    Science.gov (United States)

    Ward, Matthew; Corsi, Richard; Morton, Robert; Knapp, Tom; Apgar, Dirk; Quigley, Chris; Easter, Chris; Witherspoon, Jay; Pramanik, Amit; Parker, Wayne

    2011-03-01

    The purpose of the study was to characterize natural ventilation in full-scale gravity collection system components while measuring other parameters related to ventilation. Experiments were completed at four different locations in the wastewater collection systems of Los Angeles County Sanitation Districts, Los Angeles, California, and the King County Wastewater Treatment District, Seattle, Washington. The subject components were concrete gravity pipes ranging in diameter from 0.8 to 2.4 m (33 to 96 in.). Air velocity was measured in each pipe using a carbon-monoxide pulse tracer method. Air velocity was measured entering or exiting the components at vents using a standpipe and hotwire anemometer arrangement. Ambient wind speed, temperature, and relative humidity; headspace temperature and relative humidity; and wastewater flow and temperature were measured. The field experiments resulted in a large database of measured ventilation and related parameters characterizing ventilation in full-scale gravity sewers. Measured ventilation rates ranged from 23 to 840 L/s. The experimental data was used to evaluate existing ventilation models. Three models that were based upon empirical extrapolation, computational fluid dynamics, and thermodynamics, respectively, were evaluated based on predictive accuracy compared to the measured data. Strengths and weaknesses in each model were found and these observations were used to propose a concept for an improved ventilation model.

  1. Ventilation System Type and the Resulting Classroom Temperature and Air Quality During Heating Season

    DEFF Research Database (Denmark)

    Gao, Jie; Wargocki, Pawel; Wang, Yi

    2014-01-01

    The present study investigated how different ventilation system types influence classroom temperature and air quality. Five classrooms were selected in the same school. They were ventilated by manually operable windows, manually operable windows with exhaust fan, automatically operable windows...... with and without exhaust fan and by mechanical ventilation system. Temperature, relative humidity, carbon dioxide (CO2) concentration and opening of windows were continuously monitored for one month during heating season in 2012. Classroom with manually operable windows had the highest carbon dioxide concentration...... levels so that the estimated ventilation rate was the lowest compared with the classrooms ventilated with other systems. Temperatures were slightly lower in classroom ventilated by manually operable windows with exhaust fan. Windows were opened seldom even in the classroom ventilated by manually operable...

  2. Improved Performance With Ventilation

    Science.gov (United States)

    Kawakami, Ellison; Lee, Seung Jae; Karn, Ashish; Hong, Jiarong; Arndt, Roger

    2013-11-01

    Drag reduction and/or speed augmentation of marine vehicles by means of supercavitation is a topic of great interest. During the initial launch of a supercavitating vehicle, ventilation is required to supply an artificial cavity until conditions at which a natural supercavity can be sustained are reached. Various aspects of the flow physics of a supercavitating vehicle have been under investigation for several years at Saint Anthony Falls Laboratory. Both steady flow and simulated flow below a wave train have been studied. Using a high speed camera and the proper software, it is possible to synchronize cavity dimensions with pressure measurements taken inside the cavity to permit an in-depth study of unsteadiness. It was found that flow unsteadiness caused a decrease in the overall length of the supercavity while having only a minimal effect on the maximum diameter. Results regarding supercavity shape, ventilation demand, cavitation parameters and closure methods are reviewed in light of new studies that focused on various closure mechanisms. Sponsored by ONR.

  3. Ventilator-associated pneumonia.

    Science.gov (United States)

    Shaw, Michael Jan

    2005-05-01

    This review summarises some of the notable papers on ventilator-associated pneumonia (VAP) from January 2003 to October 2004. Ventilator-associated pneumonia remains an important drain on hospital resources. All population groups are affected, but patients with VAP are more likely to be older, sicker, and male, with invasive medical devices in situ. Early VAP diagnosis is desirable to reduce VAP mortality and to retard emergence of multidrug-resistant microbes. This may be possible using preliminary culture results or intracellular organism in polymorphonuclear cells. In most intensive care units, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii are the commonest organisms isolated in VAP. However, causative organisms vary between and within hospitals. Consequently, individual intensive care units should develop empirical antibiotic policies to target the pathogenic bacteria prevalent in their patient populations. Preventative strategies aimed at reducing aerodigestive tract colonisation by pathogenic organisms, and also their subsequent aspiration, are becoming increasingly important. Educating medical staff about these simple measures is therefore pertinent. To reduce the occurrence of multidrug-resistant organisms, limiting the duration of antibiotic treatment to 8 days and antimicrobial rotation should be contemplated. Empirical therapy with antipseudomonal penicillins plus beta-lactamase inhibitors should be considered. If methicillin-resistant Staphylococcus aureus VAP is a possibility, linezolid may be better than vancomycin. Prevention remains the key to reducing VAP prevalence.

  4. Medida da freqüência respiratória e do volume corrente para prever a falha na extubação de recém-nascidos de muito baixo peso em ventilação mecânica Evaluation of respiratory rate and tidal volume to predict extubation failure in mechanically ventilated very low birth weight infants

    Directory of Open Access Journals (Sweden)

    Josy Davidson

    2008-03-01

    Full Text Available OBJETIVO: Verificar se a freqüência respiratória (FR, o volume corrente (VC e a relação FR/VC poderiam prever a falha na extubação em recém-nascidos de muito baixo peso submetidos à ventilação mecânica. MÉTODOS: Estudo prospectivo, observacional, de recém-nascidos com idade gestacional OBJECTIVE: To verify if respiratory rate (RR, tidal volume (TV and respiratory rate and tidal volume ratio (RR/TV could predict extubation failure in very low birth weight infants submitted to mechanical ventilation. METHODS: This prospective observational study enrolled newborn infants with gestational age <37 weeks and birth weight <1,500g, mechanically ventilated from birth during 48 hours to 30 days and thought to be ready for extubation. As soon as the physicians decided for extubation, the neonates received endotracheal continuous positive airway pressure (CPAP for 10 minutes while spontaneous RR, TV and RR/TV were measured using a fixed-orifice pneumotachograph positioned between the endotracheal tube and the ventilator circuit. Thereafter, the neonates were extubated to nasal CPAP. Extubation failure was defined as the need for reintubation within 48 hours. RESULTS: Of the 35 studied infants, 20 (57% were successfully extubated and 15 (43% required reintubation. RR and RR/TV before extubation had a trend to be higher in unsuccessfully extubated infants. TV was similar in both groups. Sensitivity and specificity of these parameters as predictors of extubation failure were 50 and 67% respectively for RR, 40 and 67% for TV and 40 and 73% for RR/TV. CONCLUSIONS: RR, TV and RR/TV showed low sensitivity and specificity to predict extubation failure in mechanically ventilated very low birth weight infants.

  5. A Review on Natural Ventilation-enabling Façade Noise Control Devices for Congested High-Rise Cities

    Directory of Open Access Journals (Sweden)

    Shiu-Keung Tang

    2017-02-01

    Full Text Available This review summarizes the current status of the research and development of natural ventilation-enabling noise control devices for use on the façades of high-rise residential buildings in congested cities. These devices are important for a sustainable urbanized city, as they are supposed to offer good acoustical protection to citizens, allowing for an acceptable level of natural ventilation inside residential units; energy for mechanical ventilation can then be saved. From the information presented in the existing literature, it is concluded that protrusive devices, such as lintels and balconies, are not effective noise screening devices, even if they are installed with sound absorbers and/or reflectors, under the effect of city reverberation. On the contrary, plenum windows and similar structures, which are plenum structures with a staggered air inlet and outlet, are interesting alternatives that are worth rigorous considerations.

  6. Energy efficient residential house wall system

    International Nuclear Information System (INIS)

    Aldawi, Fayez; Date, Abhijit; Alam, Firoz; Khan, Iftekhar; Alghamdi, Mohammed

    2013-01-01

    The energy consumption and greenhouse gas emission by the residential housing sector are considered to be one of the largest in economically developed countries. The larger energy consumption and greenhouse gas emission not only put additional pressure on finite fossil fuel resources but also cause global warming and climate change. Additionally, the residential housing sector will be consuming more energy as the house demand and average house floor area are progressively increasing. With currently used residential house wall systems, it is hard to reduce energy consumption for ongoing house space heating and cooling. A smart house wall envelope with optimal thermal masses and insulation materials is vital for reducing our increasing energy consumption. The major aim of this study is to investigate thermal performance and energy saving potential of a new house wall system for variable climate conditions. The thermal performance modelling was carried out using commercially developed software AccuRate ® . The findings indicate that a notable energy savings can be accomplished if a smart house wall system is used. -- Highlights: • Smart house wall system. • Thermal performance modelling and star energy rating. • Energy savings and greenhouse gas reduction

  7. FACTOR ANALYSIS OF MULTISTOREY RESIDENTIAL BUILDINGS ZONE

    Directory of Open Access Journals (Sweden)

    Петр Матвеевич Мазуркин

    2016-02-01

    Full Text Available According to the UN classification of 11 classes of soil cover, the first three are grass, trees and shrubs and forests. In the city they correspond to the three elements of vegetation: lawns, tree plantings (trees and shrubs. We have adopted zoning for city-building to identify statistical regularities. Map dimensions in GIS "Map 2011" Yoshkar-Ola was allocated to "residential zone" and "Area of construction of multi-storey residential buildings (cadastral 58 quart crystals". The parameters of the elements of the vegetation cover have been considered: the number of elements of different levels, area and perimeter, the absolute and relative form, and activity of vegetation. As the result, we have obtained equations of binomial rank distributions, conducted the ratings and selected the best of cadastral quarter on environmental conditions.

  8. Residential indoor air quality guideline : ozone

    International Nuclear Information System (INIS)

    2010-01-01

    Ozone (O 3 ) is a colourless gas that reacts rapidly on surfaces and with other constituents in the air. Sources of indoor O 3 include devices sold as home air cleaners, and some types of office equipment. Outdoor O 3 is also an important contributor to indoor levels of O 3 , depending on the air exchange rate with indoor environments. This residential indoor air quality guideline examined factors that affect the introduction, dispersion and removal of O 3 indoors. The health effects of prolonged exposure to O 3 were discussed, and studies conducted to evaluate the population health impacts of O 3 were reviewed. The studies demonstrated that there is a significant association between ambient O 3 and adverse health impacts. Exposure guidelines for residential indoor air quality were discussed. 14 refs.

  9. Free Convection Personalized Ventilation (FCPV)

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    Normally we supply fresh air to a room with a diffuser, and this air is distributed in the room according to different principles as: mixing ventilation, displacement ventilation etc. That means we have to supply a very large amount of air to the whole room, although a person in the room totally ...

  10. Innovation in home mechanical ventilation

    NARCIS (Netherlands)

    Hazenberg, Andrea

    2017-01-01

    Patients on home mechanical ventilation (HMV) are ventilator dependent, usually for the rest of their lives. In the past decades, the number of patients on HMV increased to nearly 3,000 in 2016 in the Netherlands. Current indications for HMV are patients diagnosed with either neuromuscular disease,

  11. Reverse ventilation--perfusion mismatch

    International Nuclear Information System (INIS)

    Palmaz, J.C.; Barnett, C.A.; Reich, S.B.; Krumpe, P.E.; Farrer, P.A.

    1984-01-01

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients

  12. Evaluation of the user interface simplicity in the modern generation of mechanical ventilators.

    Science.gov (United States)

    Uzawa, Yoshihiro; Yamada, Yoshitsugu; Suzukawa, Masayuki

    2008-03-01

    We designed this study to evaluate the simplicity of the user interface in modern-generation mechanical ventilators. We hypothesized that different designs in the user interface could result in different rates of operational failures. A laboratory in a tertiary teaching hospital. Crossover design. Twenty-one medical resident physicians who did not possess operating experience with any of the selected ventilators. Four modern mechanical ventilators were selected: Dräger Evita XL, Maquet Servo-i, Newport e500, and Puritan Bennett 840. Each subject was requested to perform 8 tasks on each ventilator. Two objective variables (the number of successfully completed tasks without operational failures and the operational time) and the overall subjective rating of the ease of use, measured with a 100-mm visual analog scale were recorded. The total percentage of operational failures made for all subjects, for all tasks, was 23%. There were significant differences in the rates of operational failures and operational time among the 4 ventilators. Subjects made more operational failures in setting up the ventilators and in making ventilator-setting changes than in reacting to alarms. The subjective feeling of the ease of use was also significantly different among the ventilators. The design of the user interface is relevant to the occurrence of operational failures. Our data indicate that ventilator designers could optimize the user-interface design to reduce the operational failures; therefore, basic user interface should be standardized among the clinically used mechanical ventilators.

  13. Residential Energy Performance Metrics

    Directory of Open Access Journals (Sweden)

    Christopher Wright

    2010-06-01

    Full Text Available Techniques for residential energy monitoring are an emerging field that is currently drawing significant attention. This paper is a description of the current efforts to monitor and compare the performance of three solar powered homes built at Missouri University of Science and Technology. The homes are outfitted with an array of sensors and a data logger system to measure and record electricity production, system energy use, internal home temperature and humidity, hot water production, and exterior ambient conditions the houses are experiencing. Data is being collected to measure the performance of the houses, compare to energy modeling programs, design and develop cost effective sensor systems for energy monitoring, and produce a cost effective home control system.

  14. Feasibility of Protective Ventilation During Elective Supratentorial Neurosurgery: A Randomized, Crossover, Clinical Trial.

    Science.gov (United States)

    Ruggieri, Francesco; Beretta, Luigi; Corno, Laura; Testa, Valentina; Martino, Enrico A; Gemma, Marco

    2017-06-30

    Traditional ventilation approaches, providing high tidal volumes (Vt), produce excessive alveolar distention and lung injury. Protective ventilation, employing lower Vt and positive end-expiratory pressure (PEEP), is an attractive alternative also for neuroanesthesia, when prolonged mechanical ventilation is needed. Nevertheless, protective ventilation during intracranial surgery may exert dangerous effects on intracranial pressure (ICP). We tested the feasibility of a protective ventilation strategy in neurosurgery. Our monocentric, double-blind, 1:1 randomized, 2×2 crossover study aimed at studying the effect size and variability of ICP in patients undergoing elective supratentorial brain tumor removal and alternatively ventilated with Vt 9 mL/kg-PEEP 0 mm Hg and Vt 7 mL/kg-PEEP 5 mm Hg. Respiratory rate was adjusted to maintain comparable end-tidal carbon dioxide between ventilation modes. ICP was measured through a subdural catheter inserted before dural opening. Forty patients were enrolled; 8 (15%) were excluded after enrollment. ICP did not differ between traditional and protective ventilation (11.28±5.37, 11 [7 to 14.5] vs. 11.90±5.86, 11 [8 to 15] mm Hg; P=0.541). End-tidal carbon dioxide (28.91±2.28, 29 [28 to 30] vs. 28.00±2.17, 28 [27 to 29] mm Hg; Pprotective ventilation. Blood pressure, heart rate, and body temperature did not differ between ventilation modes. Dural tension was "acceptable for surgery" in all cases. ICP differences between ventilation modes were not affected by ICP values under traditional ventilation (coefficient=0.067; 95% confidence interval, -0.278 to 0.144; P=0.523). Protective ventilation is a feasible alternative to traditional ventilation during elective neurosurgery.

  15. Effectiveness of ventilation improvements as a protective measure against radon

    International Nuclear Information System (INIS)

    Hoving, P.; Arvela, H.

    1993-01-01

    Radon reduction rates for ventilation improvement measures vary considerably. In 70% of the cases studied, further mitigation is needed to reach a level of 400 Bq/m 3 . Ventilation measures in crawl spaces and basements have resulted in reduction rates of up to 90%, though more typically 30-70%. Installing new mechanical systems in dwellings has resulted in 20-80% reduction rates. If fan use or fan efficiency is increased, radon levels can be reduced as much as when new systems are installed. Increasing fresh-air supply through vents or window gaps reduces radon concentrations 10-40%. Low ventilation rates, measured after mitigation using the passive per fluorocarbon tracer gas method, seem to be accompanied by also low radon reduction rates. Multiple zone tracer gas measurements were conducted in order to reveal radon entry from the soil and radon transport between zones. (orig.). (3 refs., 3 figs., 2 tabs.)

  16. Ventilation of an hydrofoil wake

    Science.gov (United States)

    Arndt, Roger; Lee, Seung Jae; Monson, Garrett

    2013-11-01

    Ventilation physics plays a role in a variety of important engineering applications. For example, hydroturbine ventilation is used for control of vibration and cavitation erosion and more recently for improving the dissolved oxygen content of the flow through the turbine. The latter technology has been the focus of an ongoing study involving the ventilation of an hydrofoil wake to determine the velocity and size distribution of bubbles in a bubbly wake. This was carried out by utilizing particle shadow velocimetry (PSV). This technique is a non-scattering approach that relies on direct in-line volume illumination by a pulsed source such as a light-emitting diode (LED). The data are compared with previous studies of ventilated flow. The theoretical results of Hinze suggest that a scaling relationship is possible that can lead to developing appropriate design parameters for a ventilation system. Sponsored by ONR and DOE.

  17. Natural ventilation for free stall dairy barns

    OpenAIRE

    Gay, Susan Wood

    2009-01-01

    Natural ventilation is a result of a combination good construction, correct temperature, humidity control, air exchange. This publication discusses how to achieve natural ventilation in your structure.

  18. Heliox Improves Carbon Dioxide Removal during Lung Protective Mechanical Ventilation

    Directory of Open Access Journals (Sweden)

    Charlotte J. Beurskens

    2014-01-01

    Full Text Available Introduction. Helium is a noble gas with low density and increased carbon dioxide (CO2 diffusion capacity. This allows lower driving pressures in mechanical ventilation and increased CO2 diffusion. We hypothesized that heliox facilitates ventilation in patients during lung-protective mechanical ventilation using low tidal volumes. Methods. This is an observational cohort substudy of a single arm intervention study. Twenty-four ICU patients were included, who were admitted after a cardiac arrest and mechanically ventilated for 3 hours with heliox (50% helium; 50% oxygen. A fixed protective ventilation protocol (6 mL/kg was used, with prospective observation for changes in lung mechanics and gas exchange. Statistics was by Bonferroni post-hoc correction with statistical significance set at P<0.017. Results. During heliox ventilation, respiratory rate decreased (25±4 versus 23±5 breaths min−1, P=0.010. Minute volume ventilation showed a trend to decrease compared to baseline (11.1±1.9 versus 9.9±2.1 L min−1, P=0.026, while reducing PaCO2 levels (5.0±0.6 versus 4.5±0.6 kPa, P=0.011 and peak pressures (21.1±3.3 versus 19.8±3.2 cm H2O, P=0.024. Conclusions. Heliox improved CO2 elimination while allowing reduced minute volume ventilation in adult patients during protective mechanical ventilation.

  19. Daytime Mouthpiece for Continuous Noninvasive Ventilation in Individuals With Amyotrophic Lateral Sclerosis.

    Science.gov (United States)

    Bédard, Marie-Eve; McKim, Douglas A

    2016-10-01

    Noninvasive ventilation (NIV) is commonly used to provide ventilatory support for individuals with amyotrophic lateral sclerosis (ALS). Once 24-h ventilation is required, the decision between invasive tracheostomy ventilation and palliation is often faced. This study describes the use and outcomes of daytime mouthpiece ventilation added to nighttime mask ventilation for continuous NIV in subjects with ALS as an effective alternative. This was a retrospective study of 39 subjects with ALS using daytime mouthpiece ventilation over a 17-y period. Thirty-one subjects were successful with mouthpiece ventilation, 2 were excluded, 2 stopped because of lack of motivation, and 4 with bulbar subscores of the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (b-ALSFRS-R) between 0 and 3 physically failed to use it consistently. No subject in the successful group had a b-ALSFRS-R score of NIV and mouthpiece ventilation were 648 (176-2,188) and 286 (41-1,769) d, respectively. Peak cough flow with lung-volume recruitment >180 L/min at initiation of mouthpiece ventilation was associated with a longer survival (637 ± 468 vs 240 ± 158 d (P = .01). Mouthpiece ventilation provides effective ventilation and prolonged survival for individuals with ALS requiring full-time ventilatory support and maintaining adequate bulbar function. Copyright © 2016 by Daedalus Enterprises.

  20. Ventilation of carbon monoxide from a biomass pellet storage tank--a study of the effects of variation of temperature and cross-ventilation on the efficiency of natural ventilation.

    Science.gov (United States)

    Emhofer, Waltraud; Lichtenegger, Klaus; Haslinger, Walter; Hofbauer, Hermann; Schmutzer-Roseneder, Irene; Aigenbauer, Stefan; Lienhard, Martin

    2015-01-01

    Wood pellets have been reported to emit toxic gaseous emissions during transport and storage. Carbon monoxide (CO) emission, due to the high toxicity of the gas and the possibility of it being present at high levels, is the most imminent threat to be considered before entering a pellet storage facility. For small-scale (ventilation, preferably natural ventilation utilizing already existing openings, has become the most favored solution to overcome the problem of high CO concentrations. However, there is little knowledge on the ventilation rates that can be reached and thus on the effectiveness of such measures. The aim of the study was to investigate ventilation rates for a specific small-scale pellet storage system depending on characteristic temperature differences. Furthermore, the influence of the implementation of a chimney and the influence of cross-ventilation on the ventilation rates were investigated. The air exchange rates observed in the experiments ranged between close to zero and up to 8 m(3) h(-1), depending largely on the existing temperature differences and the existence of cross-ventilation. The results demonstrate that implementing natural ventilation is a possible measure to enhance safety from CO emissions, but not one without limitations. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  1. Delivery of tidal volume from four anaesthesia ventilators during volume-controlled ventilation: a bench study.

    Science.gov (United States)

    Wallon, G; Bonnet, A; Guérin, C

    2013-06-01

    Tidal volume (V(T)) must be accurately delivered by anaesthesia ventilators in the volume-controlled ventilation mode in order for lung protective ventilation to be effective. However, the impact of fresh gas flow (FGF) and lung mechanics on delivery of V(T) by the newest anaesthesia ventilators has not been reported. We measured delivered V(T) (V(TI)) from four anaesthesia ventilators (Aisys™, Flow-i™, Primus™, and Zeus™) on a pneumatic test lung set with three combinations of lung compliance (C, ml cm H2O(-1)) and resistance (R, cm H2O litre(-1) s(-2)): C60R5, C30R5, C60R20. For each CR, three FGF rates (0.5, 3, 10 litre min(-1)) were investigated at three set V(T)s (300, 500, 800 ml) and two values of PEEP (0 and 10 cm H2O). The volume error = [(V(TI) - V(Tset))/V(Tset)] ×100 was computed in body temperature and pressure-saturated conditions and compared using analysis of variance. For each CR and each set V(T), the absolute value of the volume error significantly declined from Aisys™ to Flow-i™, Zeus™, and Primus™. For C60R5, these values were 12.5% for Aisys™, 5% for Flow-i™ and Zeus™, and 0% for Primus™. With an increase in FGF, absolute values of the volume error increased only for Aisys™ and Zeus™. However, in C30R5, the volume error was minimal at mid-FGF for Aisys™. The results were similar at PEEP 10 cm H2O. Under experimental conditions, the volume error differed significantly between the four new anaesthesia ventilators tested and was influenced by FGF, although this effect may not be clinically relevant.

  2. Design and operation of ventilation in low energy residences – A survey on code requirements and building reality from six European countries and China

    DEFF Research Database (Denmark)

    del Carmen Bocanegra-Yanez, Maria; Rojas, Gabriel; Zukowska-Tejsen, Daria

    involved in the Annex. There were two main objectives, firstly, to describe and analyse a transition between actual requirements (national building codes and standards) and current practice. Secondly, to investigate current barriers and challenges regarding installation of mechanical ventilation......One of the key objectives of the IEA Annex 68 research programme entitled “Indoor Air Quality Design and Control in Low Energy Residential Buildings” is to provide a generic guideline for the design and operation of ventilation in residential buildings. Modern and refurnished domestic buildings...

  3. Modeling the airborne survival of influenza virus in a residential setting: the impacts of home humidification

    Science.gov (United States)

    2010-01-01

    Background Laboratory research studies indicate that aerosolized influenza viruses survive for longer periods at low relative humidity (RH) conditions. Further analysis has shown that absolute humidity (AH) may be an improved predictor of virus survival in the environment. Maintaining airborne moisture levels that reduce survival of the virus in the air and on surfaces could be another tool for managing public health risks of influenza. Methods A multi-zone indoor air quality model was used to evaluate the ability of portable humidifiers to control moisture content of the air and the potential related benefit of decreasing survival of influenza viruses in single-family residences. We modeled indoor AH and influenza virus concentrations during winter months (Northeast US) using the CONTAM multi-zone indoor air quality model. A two-story residential template was used under two different ventilation conditions - forced hot air and radiant heating. Humidity was evaluated on a room-specific and whole house basis. Estimates of emission rates for influenza virus were particle-size specific and derived from published studies and included emissions during both tidal breathing and coughing events. The survival of the influenza virus was determined based on the established relationship between AH and virus survival. Results The presence of a portable humidifier with an output of 0.16 kg water per hour in the bedroom resulted in an increase in median sleeping hours AH/RH levels of 11 to 19% compared to periods without a humidifier present. The associated percent decrease in influenza virus survival was 17.5 - 31.6%. Distribution of water vapor through a residence was estimated to yield 3 to 12% increases in AH/RH and 7.8-13.9% reductions in influenza virus survival. Conclusion This modeling analysis demonstrates the potential benefit of portable residential humidifiers in reducing the survival of aerosolized influenza virus by controlling humidity indoors. PMID:20815876

  4. Modeling the airborne survival of influenza virus in a residential setting: the impacts of home humidification

    Directory of Open Access Journals (Sweden)

    Myatt Theodore A

    2010-09-01

    Full Text Available Abstract Background Laboratory research studies indicate that aerosolized influenza viruses survive for longer periods at low relative humidity (RH conditions. Further analysis has shown that absolute humidity (AH may be an improved predictor of virus survival in the environment. Maintaining airborne moisture levels that reduce survival of the virus in the air and on surfaces could be another tool for managing public health risks of influenza. Methods A multi-zone indoor air quality model was used to evaluate the ability of portable humidifiers to control moisture content of the air and the potential related benefit of decreasing survival of influenza viruses in single-family residences. We modeled indoor AH and influenza virus concentrations during winter months (Northeast US using the CONTAM multi-zone indoor air quality model. A two-story residential template was used under two different ventilation conditions - forced hot air and radiant heating. Humidity was evaluated on a room-specific and whole house basis. Estimates of emission rates for influenza virus were particle-size specific and derived from published studies and included emissions during both tidal breathing and coughing events. The survival of the influenza virus was determined based on the established relationship between AH and virus survival. Results The presence of a portable humidifier with an output of 0.16 kg water per hour in the bedroom resulted in an increase in median sleeping hours AH/RH levels of 11 to 19% compared to periods without a humidifier present. The associated percent decrease in influenza virus survival was 17.5 - 31.6%. Distribution of water vapor through a residence was estimated to yield 3 to 12% increases in AH/RH and 7.8-13.9% reductions in influenza virus survival. Conclusion This modeling analysis demonstrates the potential benefit of portable residential humidifiers in reducing the survival of aerosolized influenza virus by controlling humidity

  5. Costs of day hospital and community residential chemical dependency treatment.

    Science.gov (United States)

    Kaskutas, Lee Ann; Zavala, Silvana K; Parthasarathy, Sujaya; Witbrodt, Jane

    2008-03-01

    Patient placement criteria developed by the American Society of Addiction Medicine (ASAM) have identified a need for low-intensity residential treatment as an alternative to day hospital for patients with higher levels of severity. A recent clinical trial found similar outcomes at social model residential treatment and clinically-oriented day hospital programs, but did not report on costs. This paper addresses whether the similar outcomes in the recent trial were delivered with comparable costs, overall and within gender and ethnicity stratum. This paper reports on clients not at environmental risk who participated in a randomized trial conducted in three metropolitan areas served by a large pre-paid health plan. Cost data were collected using the Drug Abuse Treatment Cost Analysis Program (DATCAP). Costs per episode were calculated by multiplying DATCAP-derived program-specific costs by each client's length of stay. Differences in length of stay, and in per-episode costs, were compared between residential and day hospital subjects. Lengths of stay at residential treatment were significantly longer than at day hospital, in the sample overall and in disaggregated analyses. This difference was especially marked among non-Whites. The average cost per week was USD 575 per week at day hospital, versus USD 370 per week at the residential programs. However, because of the longer stays in residential, per-episode costs were significantly higher in the sample overall and among non-Whites (and marginally higher for men). These cost results must be considered in light of the null findings comparing outcomes between subjects randomized to residential versus day hospital programs. The longer stays in the sample overall and for non-White clients at residential programs came at higher costs but did not lead to better rates of abstinence. The short stays in day hospital among non-Whites call into question the attractiveness of day hospital for minority clients. Outcomes and costs

  6. Ventilator-associated pneumonia: clinical significance and implications for nursing.

    Science.gov (United States)

    Grap, M J; Munro, C L

    1997-01-01

    Pneumonia is the second most common nosocomial infection in the United States and the leading cause of death from nosocomial infections. Intubation and mechanical ventilation greatly increase the risk of bacterial pneumonia. Ventilator-associated pneumonia (VAP) occurs in a patient treated with mechanical ventilation, and it is neither present nor developing at the time of intubation; it is a serious problem--with significant morbidity and mortality rates. Aspiration of bacteria from the oropharynx, leakage of contaminated secretions around the endotracheal tube, patient position, and cross-contamination from respiratory equipment and health care providers are important factors in the development of VAP. Nurses caring for patients treated with mechanical ventilation must recognize risk factors and include strategies for reducing these factors as part of their nursing care. This article summarizes the literature related to VAP: its incidence, associated factors, diagnosis, and current therapies, with an emphasis on nursing implications in the care of these patients.

  7. Pseudomonas aeruginosa ventilator-associated pneumonia management

    Science.gov (United States)

    Ramírez-Estrada, Sergio; Borgatta, Bárbara; Rello, Jordi

    2016-01-01

    Ventilator-associated pneumonia is the most common infection in intensive care unit patients associated with high morbidity rates and elevated economic costs; Pseudomonas aeruginosa is one of the most frequent bacteria linked with this entity, with a high attributable mortality despite adequate treatment that is increased in the presence of multiresistant strains, a situation that is becoming more common in intensive care units. In this manuscript, we review the current management of ventilator-associated pneumonia due to P. aeruginosa, the most recent antipseudomonal agents, and new adjunctive therapies that are shifting the way we treat these infections. We support early initiation of broad-spectrum antipseudomonal antibiotics in present, followed by culture-guided monotherapy de-escalation when susceptibilities are available. Future management should be directed at blocking virulence; the role of alternative strategies such as new antibiotics, nebulized treatments, and vaccines is promising. PMID:26855594

  8. Ventilator associated pneumonia and infection control

    Directory of Open Access Journals (Sweden)

    Alp Emine

    2006-04-01

    Full Text Available Abstract Ventilator associated pneumonia (VAP is the leading cause of morbidity and mortality in intensive care units. The incidence of VAP varies from 7% to 70% in different studies and the mortality rates are 20–75% according to the study population. Aspiration of colonized pathogenic microorganisms on the oropharynx and gastrointestinal tract is the main route for the development of VAP. On the other hand, the major risk factor for VAP is intubation and the duration of mechanical ventilation. Diagnosis remains difficult, and studies showed the importance of early initiation of appropriate antibiotic for prognosis. VAP causes extra length of stay in hospital and intensive care units and increases hospital cost. Consequently, infection control policies are more rational and will save money.

  9. Ventilation techniques and radon in small houses

    International Nuclear Information System (INIS)

    Keskinen, J.; Graeffe, G.; Janka, K.

    1988-01-01

    Indoor radon is the main cause of radiation exposure in Finland. The National Board of Health set the recommended concentration limits in 1986: an action level of 800 Bq/m 3 and a planning value of 200 Bq/m 3 for new buildings. The 800 Bq/m 3 concentration is estimated to be exceeded in 1.4% of the housing. This rather high number has motivated a number of studies concerning countermeasures against radon in existing houses. The purpose of this study was to find out possible remedial actions against radon using standard ventilation techniques. The ventilation rates were not increased over 0.71/h in order to have a realistic view about the possibilities of the state-of-the-art techniques. Special attention was given to methods which would be generally applicable to a large number of dwellings already existing. Results are reported of a pilot study with six small houses with established high radon concentrations

  10. Inhaled Antibiotics for Ventilator-Associated Infections.

    Science.gov (United States)

    Palmer, Lucy B

    2017-09-01

    Multidrug-resistant organisms are creating a challenge for physicians treating the critically ill. As new antibiotics lag behind the emergence of worsening resistance, intensivists in countries with high rates of extensively drug-resistant bacteria are turning to inhaled antibiotics as adjunctive therapy. These drugs can provide high concentrations of drug in the lung that could not be achieved with intravenous antibiotics without significant systemic toxicity. This article summarizes current evidence describing the use of inhaled antibiotics for the treatment of bacterial ventilator-associated pneumonia and ventilator-associated tracheobronchitis. Preliminary data suggest aerosolized antimicrobials may effectively treat resistant pathogens with high minimum inhibitory concentrations. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. [Oesophagitis during mechanical ventilation].

    Science.gov (United States)

    Gastinne, H; Canard, J M; Pillegand, B; Voultoury, J C; Catanzano, A; Claude, R; Gay, R

    1982-10-16

    Twenty-one patients whose condition required mechanical ventilation with nasogastric intubation were investigated for oesophagitis before the 3rd day and on the 15th day of treatment, including endoscopy and biopsy. Lesions of oesophagitis were detected in 14 cases during the initial examination and in 19 cases on the second endoscopy. The course of the lesions varied from one patient to another and appeared to be unrelated to the course of the primary disease. Oesophagitis in these patients is probably due to frequent episodes of gastro-oesophageal reflux encouraged by cough, impaired consciousness and the presence of a tube. Reflux may also be the cause of inapparent and recurrent lung aspiration.

  12. Cardiac gated ventilation

    International Nuclear Information System (INIS)

    Hanson, C.W. III; Hoffman, E.A.

    1995-01-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart

  13. CFD Simulations to Improve Ventilation in Low-Income Housing

    Science.gov (United States)

    Ho, Rosemond; Gorle, Catherine

    2017-11-01

    Quality of housing plays an important role in public health. In Dhaka, Bangladesh, the leading causes of death include tuberculosis, lower respiratory infections, and chronic obstructive pulmonary disease, so improving home ventilation could potentially mitigate these negative health effects. The goal of this project is to use computational fluid dynamics (CFD) to predict the relative effectiveness of different ventilation strategies for Dhaka homes. A Reynolds-averaged Navier-Stokes CFD model of a standard Dhaka home with apertures of different sizes and locations was developed to predict air exchange rates. Our initial focus is on simulating ventilation driven by buoyancy-alone conditions, which is often considered the limiting case in natural ventilation design. We explore the relationship between ventilation rate and aperture area to determine the most promising configurations for optimal ventilation solutions. Future research will include the modeling of wind-driven conditions, and extensive uncertainty quantification studies to investigate the effect of variability in the layout of homes and neighborhoods, and in local wind and temperature conditions. The ultimate objective is to formulate robust design recommendations that can reduce risks of respiratory illness in low-income housing.

  14. Estimation of Lung Ventilation

    Science.gov (United States)

    Ding, Kai; Cao, Kunlin; Du, Kaifang; Amelon, Ryan; Christensen, Gary E.; Raghavan, Madhavan; Reinhardt, Joseph M.

    Since the primary function of the lung is gas exchange, ventilation can be interpreted as an index of lung function in addition to perfusion. Injury and disease processes can alter lung function on a global and/or a local level. MDCT can be used to acquire multiple static breath-hold CT images of the lung taken at different lung volumes, or with proper respiratory control, 4DCT images of the lung reconstructed at different respiratory phases. Image registration can be applied to this data to estimate a deformation field that transforms the lung from one volume configuration to the other. This deformation field can be analyzed to estimate local lung tissue expansion, calculate voxel-by-voxel intensity change, and make biomechanical measurements. The physiologic significance of the registration-based measures of respiratory function can be established by comparing to more conventional measurements, such as nuclear medicine or contrast wash-in/wash-out studies with CT or MR. An important emerging application of these methods is the detection of pulmonary function change in subjects undergoing radiation therapy (RT) for lung cancer. During RT, treatment is commonly limited to sub-therapeutic doses due to unintended toxicity to normal lung tissue. Measurement of pulmonary function may be useful as a planning tool during RT planning, may be useful for tracking the progression of toxicity to nearby normal tissue during RT, and can be used to evaluate the effectiveness of a treatment post-therapy. This chapter reviews the basic measures to estimate regional ventilation from image registration of CT images, the comparison of them to the existing golden standard and the application in radiation therapy.

  15. Energy Use Consequences of Ventilating a Net-Zero Energy House

    Science.gov (United States)

    Ng, Lisa C.; Payne, W. Vance

    2016-01-01

    A Net-Zero Energy Residential Test Facility (NZERTF) has been constructed at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland to demonstrate that a home similar in size, aesthetics, and amenities to those in the surrounding communities can achieve net-zero energy use over the course of a year while meeting the average electricity and water use needs of a family of four in the United States. The facility incorporates renewable energy and energy efficient technologies, including an air-to-air heat pump system, a solar photovoltaic system, a solar thermal domestic hot water system, and a heat recovery ventilation system sized to meet American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) Standard 62.2-2010 ventilation requirements. The largest energy end use within the home was space conditioning, which included heat loss through the building envelope, ventilation air supplied by the heat recovery ventilator (HRV), and internal loads. While HRVs are often described as being able to save energy when compared to ventilating without heat recovery, there have been no studies using a full year of measured data that determine the thermal load and energy impacts of HRV-based ventilation on the central heating and cooling system. Over the course of a year, continuous operation of the HRV at the NZERTF resulted in an annual savings of 7 % in heat pump energy use compared with the hypothetical case of ventilating without heat recovery. The heat pump electrical use varied from an increase of 5 % in the cooling months to 36 % savings in the heating months compared with ventilation without heat recovery. The increase in the cooling months occurred when the outdoor temperature was lower than the indoor temperature, during which the availability of an economizer mode would have been beneficial. Nevertheless, the fan energy required to operate the selected HRV at the NZERTF paid for itself in the heat pump energy saved

  16. Energy Use Consequences of Ventilating a Net-Zero Energy House.

    Science.gov (United States)

    Ng, Lisa C; Payne, W Vance

    2016-03-05

    A Net-Zero Energy Residential Test Facility (NZERTF) has been constructed at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland to demonstrate that a home similar in size, aesthetics, and amenities to those in the surrounding communities can achieve net-zero energy use over the course of a year while meeting the average electricity and water use needs of a family of four in the United States. The facility incorporates renewable energy and energy efficient technologies, including an air-to-air heat pump system, a solar photovoltaic system, a solar thermal domestic hot water system, and a heat recovery ventilation system sized to meet American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) Standard 62.2-2010 ventilation requirements. The largest energy end use within the home was space conditioning, which included heat loss through the building envelope, ventilation air supplied by the heat recovery ventilator (HRV), and internal loads. While HRVs are often described as being able to save energy when compared to ventilating without heat recovery, there have been no studies using a full year of measured data that determine the thermal load and energy impacts of HRV-based ventilation on the central heating and cooling system. Over the course of a year, continuous operation of the HRV at the NZERTF resulted in an annual savings of 7 % in heat pump energy use compared with the hypothetical case of ventilating without heat recovery. The heat pump electrical use varied from an increase of 5 % in the cooling months to 36 % savings in the heating months compared with ventilation without heat recovery. The increase in the cooling months occurred when the outdoor temperature was lower than the indoor temperature, during which the availability of an economizer mode would have been beneficial. Nevertheless, the fan energy required to operate the selected HRV at the NZERTF paid for itself in the heat pump energy saved

  17. Mitigating residential exposure to secondhand tobacco smoke

    Science.gov (United States)

    Klepeis, Neil E.; Nazaroff, William W.

    In a companion paper, we used a simulation model to explore secondhand tobacco smoke (SHS) exposures for typical conditions in residences. In the current paper, we extend this analysis to evaluate the effectiveness of physical mitigation approaches in reducing nonsmokers' exposure to airborne SHS particulate matter in a hypothetical 6-zone house. Measures investigated included closing doors or opening windows in response to smoking activity, modifying location patterns to segregate the nonsmoker and the active smoker, and operating particle filtration devices. We first performed 24 scripted simulation trials using hypothetical patterns of occupant location. We then performed cohort simulation trials across 25 mitigation scenarios using over 1000 pairs of nonsmoker and smoker time-location patterns that were selected from a survey of human activity patterns in US homes. We limited cohort pairs to cases where more than 10 cigarettes were smoked indoors at home each day and the nonsmoker was at home for more than two thirds of the day. We evaluated the effectiveness of each mitigation approach by examining its impact on the simulated frequency distribution of residential SHS particle exposure. The two most effective strategies were the isolation of the smoker in a closed room with an open window, and a ban on smoking whenever the nonsmoker was at home. The use of open windows to supply local or cross ventilation, or the operation of portable filtration devices in smoking rooms, provided moderate exposure reductions. Closed doors, by themselves, were not effective.

  18. Fractal ventilation enhances respiratory sinus arrhythmia

    Directory of Open Access Journals (Sweden)

    Girling Linda G

    2005-05-01

    Full Text Available Abstract Background Programming a mechanical ventilator with a biologically variable or fractal breathing pattern (an example of 1/f noise improves gas exchange and respiratory mechanics. Here we show that fractal ventilation increases respiratory sinus arrhythmia (RSA – a mechanism known to improve ventilation/perfusion matching. Methods Pigs were anaesthetised with propofol/ketamine, paralysed with doxacurium, and ventilated in either control mode (CV or in fractal mode (FV at baseline and then following infusion of oleic acid to result in lung injury. Results Mean RSA and mean positive RSA were nearly double with FV, both at baseline and following oleic acid. At baseline, mean RSA = 18.6 msec with CV and 36.8 msec with FV (n = 10; p = 0.043; post oleic acid, mean RSA = 11.1 msec with CV and 21.8 msec with FV (n = 9, p = 0.028; at baseline, mean positive RSA = 20.8 msec with CV and 38.1 msec with FV (p = 0.047; post oleic acid, mean positive RSA = 13.2 msec with CV and 24.4 msec with FV (p = 0.026. Heart rate variability was also greater with FV. At baseline the coefficient of variation for heart rate was 2.2% during CV and 4.0% during FV. Following oleic acid the variation was 2.1 vs. 5.6% respectively. Conclusion These findings suggest FV enhances physiological entrainment between respiratory, brain stem and cardiac nonlinear oscillators, further supporting the concept that RSA itself reflects cardiorespiratory interaction. In addition, these results provide another mechanism whereby FV may be superior to conventional CV.

  19. Residential outage cost estimation: Hong Kong

    International Nuclear Information System (INIS)

    Woo, C.K.; Ho, T.; Shiu, A.; Cheng, Y.S.; Horowitz, I.; Wang, J.

    2014-01-01

    Hong Kong has almost perfect electricity reliability, the result of substantial investments ultimately financed by electricity consumers who may be willing to accept lower reliability in exchange for lower bills. But consumers with high outage costs are likely to reject the reliability reduction. Our ordered-logit regression analysis of the responses by 1876 households to a telephone survey conducted in June 2013 indicates that Hong Kong residents exhibit a statistically-significant preference for their existing service reliability and rate. Moreover, the average residential cost estimate for a 1-h outage is US$45 (HK$350), topping the estimates reported in 10 of the 11 studies published in the last 10 years. The policy implication is that absent additional compelling evidence, Hong Kong should not reduce its service reliability. - Highlights: • Use a contingent valuation survey to obtain residential preferences for reliability. • Use an ordered logit analysis to estimate Hong Kong's residential outage costs. • Find high outage cost estimates that imply high reliability requirements. • Conclude that sans new evidence, Hong Kong should not reduce its reliability

  20. Mechanical ventilation in abdominal surgery.

    Science.gov (United States)

    Futier, E; Godet, T; Millot, A; Constantin, J-M; Jaber, S

    2014-01-01

    One of the key challenges in perioperative care is to reduce postoperative morbidity and mortality. Patients who develop postoperative morbidity but survive to leave hospital have often reduced functional independence and long-term survival. Mechanical ventilation provides a specific example that may help us to shift thinking from treatment to prevention of postoperative complications. Mechanical ventilation in patients undergoing surgery has long been considered only as a modality to ensure gas exchange while allowing maintenance of anesthesia with delivery of inhaled anesthetics. Evidence is accumulating, however, suggesting an association between intraoperative mechanical ventilation strategy and postoperative pulmonary function and clinical outcome in patients undergoing abdominal surgery. Non-protective ventilator settings, especially high tidal volume (VT) (>10-12mL/kg) and the use of very low level of positive end-expiratory pressure (PEEP) (PEEPventilator-associated lung injury in patients with healthy lungs. Stimulated by previous findings in patients with acute respiratory distress syndrome, the use of lower tidal volume ventilation is becoming increasingly more common in the operating room. However, lowering tidal volume, though important, is only part of the overall multifaceted approach of lung protective mechanical ventilation. In this review, we aimed at providing the most recent and relevant clinical evidence regarding the use of mechanical ventilation in patients undergoing abdominal surgery. Copyright © 2014 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier SAS. All rights reserved.