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LL 02: Pressurisation - Infiltration Correlation: Measurements

AIVC, 2001
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Bibliographic info: LL 02
Languages: English

Pressurisation - Infiltration Correlation: Measurements


#NO 3442 Methods for measuring air leakage in high-rise appartments.

AUTHOR Shaw C Y, Gasparetto S, Reardon J T

BIBINF Canada, NRC, Institute for Research in Construction, [1989] 6 figs, 1 ref. #DATE 00:00:1989 in English

ABSTRACT In this booklet the method for measuring the overall air leakage and the wall air leakage of an apartment unit simultaneously, using two sets of fan pressurization apparatus, is considered. The methods used to measure the air infiltration rates, and the test results of the two apartment towers are then discussed.

KEYWORDS air leakage, apartment building, fan pressurization, air tightness, air infiltration

#NO 3555 Wind and pressure requirements for the validation of a multizone air air infiltration program.

AUTHOR Furbringer J M, Compagnon R, Roulet C A, Gadilhe A

BIBINF in: UK, 10th AIVC Conference Proceedings Volume 1, held Espoo, Finland, 25-28 September 1989, published February 1990, pp181-202, 12 figs, 11 tabs, 19 refs. #DATE 00:02:1990 in English

ABSTRACT In order to be validated, the computer programs simulating the air flows in multizone buildings need several measured data sets to be compared with. Such a set was measured on the LESO, a mid-sized administrative building. This set contains: a) The permeability coefficients (C,n) of the building obtained by guarded zone pressurization b) Pressure coefficients Cp measured in windtunnel and on the real building c) Tracer gas air flows measurements d) Corresponding weather data for two periods of 10 days on the non inhabited building. This set is being used to validate some multi-zone air infiltration programs using permeability values and weather data as input data and comparing the tracer gas measurements with the output data. An overview on this procedure used on an example will be presented and commented. Guidelines for the use of the data set will also be given.

KEYWORDS wind, validation, multizone air infiltration, low energy house

#NO 3581 Comparison of air infiltration rate and air leakage tests under reductive sealing for an industrial building.

AUTHOR Jones P J, Powell G

BIBINF in:UK, AIVC, 10th AIVC Conference, held at Espoo, Finland, 25-28 September 1989, Volume 2, February 1990, pp131-152, 14 figs, 5 tabs, 2 refs. #DATE 00:02:1990 in English

ABSTRACT The paper compares air infiltration rate measurements with air leakage measurements in a modern industrial building. In each case the tests have been performed firstly with the building "as-built", and then with the major leakage components sealed. The building investigated was of a cladding wall construction with U-values of 0.6 W.m-2.K-1 for both the walls and roof. It had a floor area of 466 m2. The volume was 3050 m3. Tracer decay tests and constant concentration methods (both using N2O) were performed in the building to establish the air infiltration rates. The air leakage of the building was determined by the fan pressurisation method. The paper presents the results of the measurements and the discussion focuses on the variations of the air infiltration rate due to changes in internal and external conditions. The results from the three different techniques used are compared. The results show that there was good agreement between the tracer decay and constant concentration methods when determining the air infiltration rate. There was also good agreement under reductive sealing between the reductions in measured air infiltration rate and measured air leakages. The paper is a result from research work funded by the Building Research Establishment to investigate air infiltration rates and air leakage rates in industrial buildings.

KEYWORDS industrial building, infiltration rate, air leakage, retrifitting, fan pressurisation

#NO 3619 Field investigation of residential infiltration and heating duct leakage.

AUTHOR Robinson D H, Lambert L A

BIBINF Preprint, USA, ASHRAE Transactions, Vol.95, Pt.2, 1989, 9 pp, 7 figs, 9 tabs, 3 refs. #DATE 00:00:1989 in English

ABSTRACT Field investigation and repair of residential ducted forced-air heating systems was conducted on more than 20 recent vintage homes. Fan pressurization, tracer gas, and flow hood measurements were made to quantify pre-and post-repair duct leakage. The homes studied were participants in theResidential Standards Demonstration Program (RSDP). Most of the homes represented the "current practice" control group. Results showed: - variability of duct leakage is high. About 10% of homes showed little leakage;10% showed severe leakage. - duct leakage added about 10% to house leakiness,measured by fan pressurization (4 Pa ELA and 50 Pa air exchange). - flow hood tests showed return duct leakage about twice that of supply ducts during normal furnace fan operation. this typically results in net pressurization of the house. - tracer gas tests showed that fan-driven losses dominate infiltration while the furnace fan operates, causing an increase of about one-half air exchange per hour. - duct leakage was only moderately repairable on a retrofit basis. Repairs reduced leakage by about one fourth. - engineering estimates indicated an average of 12% loss of heating system efficiency through air loss caused by duct leaks. - estimates of energy saving from duct repairs averaged 375 kWh per year. Such repairs would have a simple payback of about four years.

KEYWORDS duct, air leakage, heating system, tracer gas measurements, fan pressurization

#NO 3620 Effects of ducted forced-air heating systems on residential air leakage and heating energy use.

AUTHOR Lambert L A, Robinson D H

BIBINF Preprint, USA, ASHRAE Transactions, Vol.95, Pt.2, 1989, 8 pp, 5 figs, 2 tabs, 13 refs. #DATE 00:00:1989 in English

ABSTRACT Whole-house leakage and heating energy use of electric forced air and room heater equipped homes in the Northwest are compared. More than 800 homes were tested to study energy savings from a proposed code. Air leakage was measured using fan pressurization and tracer gas. Energy use was submetered; inside-to-ambient temperature differential was monitored. Two home groups were tested: energy-efficient "MCS" homes and a "control" group of current practice homes. Ducted and unducted heating systems were compared within homogeneous subsets of homes. Air leakages were compared using 4 Pascal air infiltration, effective leakage area, specific leakage area, and 50 Pascal ach. Heating energy was compared using specific K factor (Btu/h.0F.ft2). Ducted forced-air homes were leakier and used more heat than unducted homes. Ducted control homes were 26% leakier than unducted controls and used 40% more heating energy. Ducted MCS homes were 22% leakier and used 13% more heating energy than unducted MCS homes.

KEYWORDS heating system, air leakage, fan pressurisation, tracer gas

#NO 3705 AIM 2: The Alberta air infiltration model.

AUTHOR Walker I S, Wilson D J

BIBINF USA, University of Alberta, Department of Mechanical Engineering. Report 71, January 1990, 40 pp, 8 figs, 7 tabs, 12 refs. #DATE 00:01:1990 in English

ABSTRACT This report presents the relevant equations for a complete single zone air infiltration model (AIM-2), and validates the model by comparing its predictions to measured infiltration rates in test houses. The relation ship for the building envelope is described using a pressure flow law whose coefficients are determined by fan pressurization testing. Unlike other simple models the furnace flue is treated as a separate leakage site. Wind and stack effects are determined separately, then superimposed as a sum of pressures, with a correction term that accounts for the interaction of wind and stack induced pressure. This wind and stack effect interaction term includes the only empirical constant in AIM-2 determined by fitting tomeasured data. The results indicate that treating the furnace flue as a separate leakage site significantly improves model predictions. Because the flue leakage is at a different height for stack effect AIM-2's predictions have about 5% error and the other model errors range from about 20% to 50%. The flue top has its own wind pressure coefficient, and is allowed to have different shelter than the rest of the building. For a sheltered building with a flue AIM-2's error is about 16% with the other models ranging from about 40% to 90%. For an unsheltered building with a flue AIM-2 has an error of about 12% with the other models ranging from about 20% to 26%. These errors are the approximate sum of the bias and scatter in each case. The measurements also show that the orifice flow assumption used in some models is a significant source of error, and the power law pressure-flow relationship, used in AIM-2, is more appropriate as it reduces the scatter error for a housewith no flue from 18% for an orifice flow model to 3% for AIM-2.

KEYWORDS mathematical model, flue

#NO 3899 Evaluation of multizone air flow simulation codes using measured data. Validation de programmes de calcul des echanges d'air a l'aide de mesures experimentales.

AUTHOR Furbringer J M, Roulet C-A, Compagnon R, Scartezzini J-L

BIBINF Switzerland, LESO-EPFL, Research programme "Energy aspects of air flow in buildings", Projet NEFF 339.1, Final report, April 1990. #DATE 00:04:1990 in English, French

ABSTRACT Any simulation program and especially a multizone infiltration simulation code shall be evaluated in such a way that its application limits are known. This document reports on the work done to make possible such an evaluation. The evaluation process follows several phases, which are described in the report: validation of the individual routines and of their assembly, sensitivity analysis of the code,empirical validation and evaluation of the user-friendliness, and finally statistical evaluation. Most of the work is however experimental. The aim is to measure a set of high quality data needed for the empirical validation, which is the comparison of the results of simulations with data measured on a real building. In this work, the LESO is the building in consideration. Appropriate instruments were developed for that scope, namely a guarded zone pressurization system and a multi-tracer air flow rate measuring instrument. The resulting data set is presented partly in an annex to the present report and partly in an MS-DOS floppy disk.

KEYWORDS validation, multizone air flow simulation

#NO 4349 Measurement of airtightness, air infiltration and indoor air quality in ten detached houses in Sendai, Japan.

AUTHOR Yoshino H, Nagatomo M, Yamamoto Y, Matsumoto H, Utsumi Y

BIBINF USA, ASTM, reprinted from Standard Technical Publication STP 1067, "Air change rate and airtightness in buildings", 1990, pp249-266, 10 figs, 5 tabs, 10 refs. #DATE 00:00:1990 in English

ABSTRACT Airtightness, indoor air quality, and air infiltration were measured in ten occupied, detached, two-story houses of wooden construction in the winter of 1986-1987. The floor area of the houses was 120 to 160 m2. The houses had various types of heating systems. Seven of the houses had exhaust fan units for ventilating living rooms with air-to-air heat exchangers. Airtightness was measured by the fan pressurization method. Equivalent leakage area per floor area was 1.9 to 5.7 cm2/m2. The concentration of CO2, NO2, and suspended particles were measured. CO2 and NO2 concentrations in the houses where unvented oil heaters were used were higher than in the other houses. The airtightness and indoor air quality measured during this period were compared with measured results obtained for 13 detached houses during the winter of 1984-5. Air infiltration was measured by the concentration decay method using SF6 as atracer gas and was compared with the calculated value on the basis of equivalent leakage area.

KEYWORDS measurement technique, air tightness, indoor air quality, detached house

#NO 4383 The northwest residential infiltration survey: description and summary of results.

AUTHOR Palmiter L, Brown I

BIBINF USA, Proceedings of the ASHRAE/DOE/BTECC/CIBSE Conference, "Thermal Performance of the Exterior Envelopes of Buildings IV, December 4-7, 1989, Orlando, Florida, pp 445-457, 3 figs, 6 tabs, refs. #DATE 00:12:1989 in English

ABSTRACT This paper summarizes results from a regional infiltration survey in which statistical and scientific validity received special emphasis. Tracer gas and house pressurization methods were used to estimate the heating season infiltration rate in a true random sample of 134 new all-electric homes in the Pacific Northwest. Regional average heating season infiltration rates were estimated to be 0.40 air changes per hour (ACH) using the gas tracer method, and 0.45 ACH using the Sherman-Grimsrud (LBL) infiltration model. Infiltration and leakage rates varied considerably, with standard deviations around 50% of the mean. Evaluated by ASHRAE Standard 119 (ASHRAE 1989), 17% of the homes failed to meet conditions for ventilation tightness, and 35% failed to meet ASHRAE Standard 62-1981 (ASHRAE 1981) for minimal ventilation rates. Homes with forced-air heating systems had infiltration air change rates that were 35% to 45% greater than homes with baseboards or wall heaters. Differences in building height, indoor temperature, and duct leakage appear to accountfor half the measured difference.

KEYWORDS air infiltration, tracer gas, pressurisation

#NO 4787 Airtightness in buildings.

Permeabilite a l'air des batiments.

AUTHOR Riberon J, Bienfait D, Chandellier J

BIBINF "Ventilation et Renouvellement d'Air dans les Batiments", AIVC/AFME Workshop, held 18-22 March 1991, Lyon, France, 10pp, 5 figs, refs. #DATE 00:03:1991 in French

ABSTRACT Air leakage through a building envelope can disrupt the intended operation of heating and ventilating. In view of the high stakes, research work was conducted at the CSTB into air infiltration in buildings. They involved improvement in heat loss calculation due to cross ventilation and development of air leakage measurement methods. Using computer code which includes climatic data, a new way of calculating cross ventilation flow rate was derived. Cross ventilation heat losses do not only depend on flow rate through the building envelope (air leakage and air inlets) but also on flow rate due to ventilation system operation. They are decreasing when the negative pressure inside the building, caused by the operation of the ventilation system, is increasing. A guideline which describes how to determine the airtightness of a building by using the fan pressurisation method has been carried out. The test method is suitable for research work or field investigations. In order to extend its field of application to building inspection, a simplified method has been added. Studies have also been undertaken in order to get a better understanding of thetechnical basis which are aimed at reducing air leakage in dwellings, specifying air-tightness levels and assessing the technical implementations with regard to these levels.

KEYWORDS air tightness, air leakage, cross ventilation, measurement technique

#NO 4915 Determination of leakages in the building envelope using pressurization test measurements.

AUTHOR Jensen L

BIBINF Air Infiltration Review, Vol 7, No 4, August 1986, pp 6-8, 3 figs, 2 tabs, 1 ref. #DATE 00:08:1986 in English

ABSTRACT There are several methods by which the airtightness of a building can be measured. One method involves the use of a fan to pressurize or depressurize the building. This creates a known pressure difference across the building envelope. Thecorresponding air flow through the fan is measured and this is an indication of the airtightness of the building. This air flow rate can be expressed as the number of building air changes per hour, a useful unit when comparing buildings of different volumes. So far only simple methods have been employed to analyse this condition. However, it is possible to use a morestrict scientific approach based on mathematical models and known parameter identification methods. These techniques are described in this article.

KEYWORDS air leakage, building envelope, pressurisation

#NO 4916 The determination of leakages by simultaneous use of tracer gas and pressurization equipment.

AUTHOR Wouters P, L'Heureux D, Voordecker P

BIBINF Air Infiltration Review, Vol 8, No 1, November 1986, p4, 2 figs, 1 tab. #DATE 00:11:1986 in English

ABSTRACT The air leakage distribution in a building is, in certain circumstances, difficult to determine. One example of this is the ceiling of the dwelling illustrated in figure 1 and 2. It is almost impossible to make the ceiling perfectly airtight; thismeans that a measurement by difference is impossible. The inclined roof is not airtight at all. A rather simple and easy technique is to perform measurements using tracer gas and pressurisation equipment at the same time.

KEYWORDS air leakage, tracer gas, pressurisation

#NO 4926 AC pressurisation model tests.

AUTHOR Sutcliffe H, Waters J R

BIBINF Air Infiltration Review, Vol 9, No 4, August 1988, pp 12-15, 6 figs, 1 tab, 2 refs. #DATE 00:08:1988 in English

ABSTRACT Leakage area measurement by fan pressurisation becomes more difficult as the volume of a building is increased. The equipment becomes bulky, and measurements of air flow through the fan and the resulting pressure differential require more care. AC pressurisation offers an attractive alternative. However, in the case of large industrial buildings, the exterior envelope is often constructed of thin flexible sheet material, and also industrial leakage paths may have a much larger area than is found in, say, typical domestic construction. Thus the inertance effect described by Card et al (1) and the flexing constant described by Sherman (2) may be particularly important. In order to explore these problems, tests are being carried out on a laboratory model. This note reports the results of the first sets of measurements.

KEYWORDS pressurisation, testing chamber

#NO 4931 The design and testing of a calibration chamber used in the development of an AC pressurization apparatus.

AUTHOR Alkhaddar R M, Dewsbury J, Orlowski R

BIBINF Air Infiltration Review, Vol 11, No 2, March 1990, pp 7-9, 2 figs, 3 tabs. #DATE 00:03:1990 in English

ABSTRACT AC pressurisation is a method for measuring the airtightness of buildings. This technique, which is also called the infrasonic method, employs a reciprocating piston or bellows to impose a sinusoidal small change in volume inside the building being tested at a frequency in the range of 0.1-10Hz. A fluctuation in the internal pressure is produced. From these two factors, the frequency and the pressure reading, a measure of the airtightness of the building can be deduced. With AC pressurisation it should be possible to measure airtightness at lower pressure differences than with fan pressurization, as there should be less interference by wind and stack effects. The aim of this paper is to describe the design and testing of acalibration chamber for use in the development of an AC pressurisation instrument. The instrument will subject the test rig to pressure fluctuations of around 1-10Pa, at frequencies of the order of 0.1-10Hz.

KEYWORDS testing chamber, pressurisation

#NO 4976 Northwest residential infiltration survey (NORIS) technical reference field manual.

AUTHOR Parker G B, Hadley D L

BIBINF USA, Battelle Pacific Northwest Laboratories, July 1988. #DATE 00:07:1988 in English

ABSTRACT This document is intended to serve as a standard technical reference manual for field specialists performing data collection for the Northwest Residential Infiltration Survey (NORIS). It is also intended as a training aid and as project documentation of data collection principles, procedures, and protocols for the field measurements portion of the project. The primary purpose of this manual is to ensure that the data collected in NORIS participant homes is meaningful and defensible, and that it is collected efficiently, with minimal disturbance to the occupants of those homes. The procedures documented in this manual include those for acquiring data on structure leakage using a one-time fan pressurization (blower door) measurement, information on structure and occupant characteristics, a two- to three-week ventilation measurement using a perfluorocarbon tracer (PFT) technique, temperature andwind speed data, and records of significant occupant activities during the PFT measurement period.

KEYWORDS air infiltration, questionnaire, residential building

#NO 4978 Air infiltration and building factors: comparison of measurement methods.

AUTHOR Nagda N L, Fortmann R C, Koontz M D, Rector H E

BIBINF USA, proceedings of the 79th Annual Meeting of the Air Pollution Control Association, Pittsburgh, Pennsylvania, June 22-27, 1986, 15pp, 4 figs, 11 tabs, 12 refs. #DATE 00:06:1986 in English

ABSTRACT As part of an indoor air quality survey that GEOMET Technologies, Inc., conducted in Texas during the 1984-1985 heating season, air exchange was measured in residences using a pressurization technique and two different tracer-gas techniques. Selected questions were posed to occupants to quantify building factors and ventilation practices. In this paper, the measurement methods are described and empirical relationships derived from measurement results are presented.

KEYWORDS air infiltration, measurement technique, pressurisation, tracer gas

#NO 4996 Air-permeability measurements in multizone buildings.

AUTHOR Feustel H E

BIBINF USA, California, Lawrence Berkeley Laboratory, Applied Science Division, June 1988, 33pp, 5 figs, 4 tabs, 28 refs. #DATE 00:06: 1988 in English

ABSTRACT The fan pressurization technique is widely used to determine the air permeability of single-family detached houses. This technique uses a large door-mounted fan to blow air into or suck air out of a building to determine the air flow at various pressure differences across the building's shell. Whereas the technique to measure the leakage characteristics is already available for single-zone structures, for multizone buildings, with their internal air flow paths, these techniques are just being developed. This paper focuses on the comparison of two techniques to obtain leakage data for multizone buildings needed as input for multizone infiltration models, using standard equipment designed of single-zone applications.

KEYWORDS permeability, multizone, measurement technique

#NO 5258 The simulation of infiltration rates and air movement in a naturally ventilated industrial building.

AUTHOR Jones P, Alexander D, Powell G

BIBINF UK, AIVC 12th Conference, "Air Movement and Ventilation Control within Buildings", held 24-27 September 1991, Ottawa, Canada, proceedings published September 1991, Volume 1, pp 273-284. #DATE 00:09:1991 in English

ABSTRACT This paper describes the application of numerical models to predict the ventilation rate and internal air movement patterns for a naturally ventilated industrial building and compares the results with measured data. Two modelling techniques have been employed. Firstly, a zonal network model (HTBVent), using leakage area data derived from fan pressurisation measurements, was used to predict the time varying ventilation rate in response to variations in wind velocity and internal-external air temperature difference. The results compare well with measurement data (obtained using constant concentration tracer gas techniques) over a wide range of ventilation rates. Theresults demonstrate the use of zonal models to estimate thethermal benefits of applying sealing measures to building components. Secondly, a computational fluid dynamics (CFD) model (DFS-AIR) was used to predict the ventilation rates and also the internal air movement resulting from natural ventilation, for selected external conditions. The predicted ventilation rates again agree well with measurement data. The resulting air movement patterns can be used to indicate the effectiveness of natural ventilation and the implications for comfort throughoutthe occupied space. The general conclusion was that these modelling techniques, having been successfully tested against measurement data, can be used in the design of naturally ventilated buildings.

KEYWORDS infiltration rate, air movement, natural ventilation, industrial building, simulation

#NO 5263 Wind shelter effects on air infiltration for a row of houses.

AUTHOR Wilson D, Walker I

BIBINF UK, AIVC 12th Conference, "Air Movement and Ventilation Control within Buildings", held 24-27 September 1991, Ottawa, Canada, proceedings published September 1991, Volume 1, pp 335-346. #DATE 00:09:1991 in English

ABSTRACT Once the flow-pressurization characteristics of a building are known, the largest uncertainty in predicting air infiltration is the effect of wind shelter from nearby buildings. To study the effects of wind sheltering a large data set of hourly air infiltration and meteorological measurements were made for a rowof test houses located on an exposed rural site. This configuration produces strong variations in wind shelter as the wind direction shifts from along the row to perpendicular to it. A simple harmonic function is proposed for interpolating between highly sheltered and unsheltered wind directions for a building. Measurements show that the effect of strong wind shelter can change air infiltration rates by a factor of four, and strongly influence pressures that determine flow rates through passive ventilation intake and exhaust points.Measurements for buildings with varying leakage distributions are correlated to determine appropriate values for wind shelter coefficients.

KEYWORDS wind effect, shielding, test house

#NO 5325 Integrated forced-air heating and ventilation systems: evaluation and design considerations.

AUTHOR Jackson M

BIBINF UK, AIVC 12th Conference, "Air Movement and Ventilation Control within Buildings", held 24-27 September 1991, Ottawa, Canada, proceedings published September 1991, Volume 3, pp 319-326. #DATE 00:09:1991 in English

ABSTRACT Mechanical systems which use common ducts for combined heating and ventilating functions are becoming popular in the Pacific Northwest (U.S.). These systems range from simple fresh-air inlets ducted to the return side of a forced air heating system to more complex heat recovery ventilation systems utilizing the heating ducts for air distribution. Typical integrated systems do not have heat recovery capability. Several approaches to integrating and controlling non-heat recovery ventilation and forced air heating systems were evaluated as part of the Residential Construction Demonstration Project (RCDP). The houses tested for this study were built under Bonneville Power Administration sponsored energy-efficiency programs. Fan pressurization tests were performed to assess the envelope leakage characteristics, and tracer gas decay tests were used to measure infiltration and mechanical ventilation rates. Large variations in envelope tightness and mechanical ventilation rates were encountered. In most cases, the amount of accidental air leakage through ducts and air handlers exceeds the amount of fresh air intentionally supplied to the system. Systems which are properly designed, installed, and operated work well, but the potential for problems is large.

KEYWORDS air heating, ventilation system, fan pressurization

#NO 5694 Air permeability of building envelopes.

Permeabilite (la) a l'air des enveloppes.

AUTHOR Richalet V, Gibert J P

BIBINF Promoclim, Vol 20, No 1, January-February 1989, pp 19-31. #DATE 00:01:1989 in French

ABSTRACT Description of an experimental procedure for pressurisation. Measurements of losses and pressure differential were used to determine the level of air permeability of buildings (particularly the envelopes) and to detect air infiltration. Also presents test carried out on different buildings.

KEYWORDS building envelope, permeability, pressure differential

#NO 5834 Air infiltration instrumentation and measuring techniques. 1st AIC Conference.

AUTHOR Air Infiltration and Ventilation Centre

BIBINF UK, Air Infiltration and Ventilation Centre, 1st AIC Conference Proceeding, held Cumberland Lodge, Windsor Great Park, Berkshire, UK, 6-8 October 1980, 371pp. #DATE 00:10:1980 inEnglish

ABSTRACT The proceedings of the first AIVC Conference are divided into five sessions: Alternative measurement procedures; Automatic monitoring using tracer gas techniques; Pressurization test methods; Correlation of tracer gas and pressurization measurements; Other measurements.

KEYWORDS air infiltration, instrumentation, measurement technique

#NO 5840 5th AIC Conference: The implementation and effectiveness of air infiltration standards in buildings: Proceedings.

AUTHOR Air Infiltration and Ventilation Centre

BIBINF UK, Air Infiltration and Ventilation Centre, 5th AIC Conference Proceedings, held Harrah's Hotel, Reno, Nevada, USA, 1-4 October, 1984. #DATE 00:10:1984 in English

ABSTRACT Twenty one papers presented at the fifth AIVC Conference as follows: Review of building airtightness and ventilation standards; IEA Annex IX Minimum ventilation rates - Survey and outlook; A standard for minimum ventilation; Airtightness standards for buildings - the Canadian experience and future plans; Better airtightness: Better or worse ventilation?; Energy performance standards regarding air infiltration of buildings in Switzerland; Description of ASHRAE's proposed airtightness standard; Air quality issues in ventilation standards; Air leakage or controlled ventilation?; Development of occupancy-related ventilation control for Brunel University library; Performance of passive ventilation systems in atwo-storey house; Implications and analysis of airtightness and ventilation standards; The influence of climate and ventilation system on airtightness requirements; A consequence analysis of new Norwegian building regulations on air infiltration; Measured and building code values of air change rates in residential buildings; Constancy of airtightness in buildings; Baseline data: Health and comfort in modern office buildings; First-phase occupant reaction to well-sealed indoor environments; Contaminant build-up in houses; Verification of calculation models of air infiltration using three types of test houses; Air flow calibration of building pressurization devices.

KEYWORDS standard, air infiltration

#NO 5845 9th AIVC Conference: Effective ventilation: Proceedings Volume 1.

AUTHOR Air Infiltration and Ventilation Centre

BIBINF UK, Air Infiltration and Ventilation Centre, 9th AIVC Conference proceedings Vol.1, held Novotel Hotel, Gent, Belgium, 12-15 September, 1988, 439pp. #DATE 00:09:1988 in English

ABSTRACT Twenty three papers form the ninth AIVC Conference, titles as follows: Keynote speech: Air Infiltration and Ventilation; Natural airflows between roof, subfloor and living spaces; Experimental analysis of air diffusion in large space; Determination of ventilation efficiency based upon short termtests; Ventilation strategies in the case of polluted outdoor air situations; Ventilation generated by a fluctuating pressure differential; Air motion in the vicinity of air-supply devices for displacement ventilation; Integral mass balances and pulse injection tracer-techniques; Commercial building ventilation measurements using multiple tracer gases; Constant concentration measurement with 2 tracers; Extended testing of a multifamily building using constant concentration and PFT methods; Analysis of errors for a fan-pressurization technique for measuring inter-zonal air leakage; The use of a guarded zone pressurization technique to measure air flow permeabilities of amulti-zone building; Air leakage between apartments; Air infiltration induced by heating appliances; Indoor formaldehyde levels in energy-efficient homes with mechanical ventilation systems; Recirculation of air in dwellings; Effective ventilation in offices - the occupant's perspective; Aventilation concept for future dwelling-houses; Natural ventilation for a Crown court: developing statistical assessment techniques at the design stage; Market analysis of sensors for the use in demand controlled ventilating systems; Ventilation design for a bus station; Ventilation and air quality in Belgian buildings: a state of the art.

KEYWORDS ventilation effectiveness, ventilation system

#NO 5970 Improved ventilation combined with energy efficiency in naturally ventilated houses.

AUTHOR Blomsterberg A

BIBINF UK, Air Infiltration and Ventilation Centre, 13th AIVC Conference, proceedings, held Hotel Plaza Concorde, Nice, France, 15-18 September 1992. #DATE 15:09:1992 in English

ABSTRACT Modern one-family houses in Scandinavia built before 1980 are often naturally ventilated and heated by electric baseboard heaters. The overall supply of fresh air is often inadequate during the heating season in many of these houses. Long periods of time individual rooms might get too little fresh air. The performance of a natural ventilation system is very much dependent upon the overall airtightness and the distribution of the airtightness of the building and the weather. This paper examines the performance of six modern one-family houses before and after the ventilation system was improved. Different means of improving ventilation are described. The constant concentration tracer gas technique was used to examine the supply of fresh air. Fan pressurization combined with infrared photography were employed to characterize the air leakage of the building. A simplified theoretical model was used to further evaluate the measurements. It is obvious from the tested houses that the overall ventilation and the ventilation of individual rooms were improved. The ventilation losses were increased and therefore energy conserving measures had to be taken. The overall costs were high compared with the energy savings obtained.

KEYWORDS natural ventilation, residential building, air tightness, constant concentration, fan pressurization

#NO 6003 A combined pressurisation and tracer gas technique for air flow measurements.

AUTHOR Shao L, Kula H-G R, Sharples S, Ward I C

BIBINF UK, Air Infiltration and Ventilation Centre, 13th AIVC Conference, proceedings, held Hotel Plaza Concorde, Nice, France, 15-18 September 1992. #DATE 15:09:1992 in English

ABSTRACT Building air flow is directly related to the building energy consumption and indoor air quality. As buildings become increasingly air tight, air flow through building background cracks becomes more important, and can account for up to half of the total building air infiltration. However, background leakage is not well understood, due to the lack of appropriate measurement methods. The multi-fan guarding zone or deduction technique provides a means for testing background leakage distributions, an important parameter for characterising the background leakage. However, its reliable application in buildings is limited either due to practical constraints or due to the presence of certain types of air leakage paths, namely the branched paths. In this paper an alternative method, for measuring background leakage distributions, which does not have such problems, has been examined. This method is based on the simultaneous use of the pressurisation and tracer gas technique and termed in short the combined technique. It potentially suffers from all the accuracy problems associated with tracer gas technique, which could be made more serious by the high pressurisation flows. To counter this problem, mixing fans, among other measures, were utilised. The validity of this measure was examined and its effectiveness tested by applying the combined technique to one single and several multi-zone set-ups. Results showed that the technique is of good accuracy with relative errors consistently below 10%.

KEYWORDS pressurization, tracer gas, air flow, measurement technique

#NO 6004 An analytical study of branched connections: its implications to multizone air flow measurements.

AUTHOR Shao L, Sharples S, Ward I C, Kula H-G R

BIBINF UK, Air Infiltration and Ventilation Centre, 13th AIVC Conference, proceedings, held Hotel Plaza Concorde, Nice, France, 15-18 September 1992. #DATE 15:09:1992 in English

ABSTRACT A branched connection is a single flow passage connecting more than two zones. Its existence in a building has not been a critical issue for the measurement of air flows of single zones, as far as the validity or accuracy of the measurement techniques is concerned. However, with the ever increasing sophistication of building air flow measurement techniques - which include tracer gas and multifan pressurisation techniques - and the ever increasing use of them in multizones, it becomes increasingly desirable to examine the effect of branched connections. This paper presents an analytical study of the validity of the multizone air flow measurement techniques, as they are applied to buildings containing branched connections. It is found that the multifan pressurisation techniques have embedded inadequacies, which could lead to large flow rate measurement errors, if the techniques are applied to buildings containing branched connections. It is also found that all tracer gas techniques are valid regardless of the types of connections present. However, the interpretation of their results is much more restricted than in the case where only direct connections exist in the tested building.

KEYWORDS multizone, air flow, measurement technique

#NO 7007 Ventilation rates and air tightness levels in the Swedish housing stock.

AUTHOR Kronvall J, Boman C-A

BIBINF UK, Air Infiltration and Ventilation Centre, 14th AIVC Conference, "Energy Impact of Ventilation and Air Infiltration", held Copenhagen, Denmark, 21-23 September 1993, proceedings, pp1-10. #DATE 21:09:1993 in English

ABSTRACT This paper reports results from the ventilation and air tightness measurements in Swedish dwellings as part of the 1992 Swedish Energy and Indoor Climate Survey (the ELIB-study). The indoor climate in a random sample of 1200 single- and multi-family houses from the Swedish housing stock were investigated. Among different parameters the ventilation and the air-tightness of the houses were measured. The ventilation measurements were performed during one month in each house/flat by means of the so called PFT-method and the air tightness of a sub-sample of 90 buildings were measured by means of pressurisation technique. Main results are that the ventilation rate is lower than 0.35/(s, m2) or 0.5 ACH in more than 80% of all the single-family houses and more than 50% of all the multi-family houses. Expressed in1/(s,inhabitant) around 50% of all, both single- and multi-family houses, have a ventilation rate higher than 10 l/(s, inhabitant). The influence of age, construction year, ventilation system, renovation stratus and geographical region can be traced by means of a scheme of relative-differences correction factors. The investigation of the air tightness of the houses showed mainly that newer houses are less leaky than older ones and that the prescribed maximum n50-leakage value, asstated in the Swedish Building Code, is reached only by the newest multi-family houses.

KEYWORDS ventilation rate, air tightness, residential building

#NO 7058 Distributions of expected air infiltration and related energy use in buildings based on statistical methods with independent or correlated parameters.

AUTHOR Nielsen A

BIBINF UK, Air Infiltration and Ventilation Centre, 14th AIVC Conference, "Energy Impact of Ventilation and Air Infiltration", held Copenhagen, Denmark, 21-23 September 1993, proceedings, pp483-492. #DATE 21:09:1993 in English

ABSTRACT The equivalent leakage area algorithm is used to illustrate the use of statistical simulations to predict distributions of infiltration and energy loss for buildings. The important parameters in the model are: leakage at 50Pa pressurisation, indoor and outdoor temperature, leakage in the ceiling and the floor, wind speed, building height and shielding class. Most of these parameters are not known accurately.In the statistical method we assumed for each a distribution based on measurement or good guess. To find the resultant distribution of infiltration we make 1000 simulations with random values from the distributions of the parameters. This has been done with normal, uniform and/or Weibull distributions. We find that the infiltration energy loss for a house in Oslo in average is 7025 kWh/year (case 1) and 10% is above 10500 kWh.year and 10% is below 4200 kWh/year. The results are also given as mean air change for infiltration. Results from five other simulations are described. We normally assume that the parameters are uncorrelated, but it is easy to calculate what will happen, if we have a positive or negative correlation. We found, that in this case made correlation between some parameters practically no difference in the distributions. The simulation method can be used on more complicated and correct models to find out howuncertain knowledge of parameters will influence the finalresults.

KEYWORDS air infiltration, air leakage, simulation, energy losses

#NO 7472 Field comparison of alternative techniques for measuring air distribution system leakage.

AUTHOR Modera M P

BIBINF Paper submitted for ASTM Symposium on Airflow Performance of Building Envelopes, Components and Systems, October 10-11, 1993, Ft Worth, TX, USA, 16pp, 7 figs, 4 tabs, refs.#DATE 00:09:1993 in English

ABSTRACT ASTM has recently standardized a methodology for measuring the leakage of residential air distribution systems to unconditioned zones. The standard includes two alternative leakage measurement techniques, one of which requires only a blower door, whereas the second technique requires a flow-capture hood as well as a blower door. This paper reports on the results of field measurements in 30 houses using both measurement techniques, and analyzes the relative strengths and weaknesses of the two techniques. The repeatability of each of the techniques, as well as the comparability of the results from the two techniques, are examined. A key issue that is addressed in this paper is the importance of duct pressure measurements in each of the two techniques. Analyses show that the leakage measured with the blower-door-only technique would be negatively biased by 30-50% if the duct pressure was not incorporated into the measurements and analyses as is specifiedin the standard. Similarly, it is shown that supply leakage measurements with the flow-capture-hood technique would benegatively biased by 33% if the envelope pressure differential was used instead of the duct pressure differential.

KEYWORDS Duct, air leakage, fan pressurization, measurement technique, air infiltration.

#NO 7556 Infiltration: Just ACH 50 Divided by 20?

AUTHOR Meier A

BIBINF USA, Home Energy, January/February 1994, pp 35-37, 3 tabs.#DATE 00:01:1994 in English

ABSTRACT Many researchers have sought to develop a correlation between a one-time pressurization test and an annual infiltration rate.Translating blower door measurements into an average infiltration rate has bedeviled the retrofitter and researcher alike. The rate of air infiltration constantly varies, yet the pressurization test is typically a single measurement. Nevertheless, many researchers have sought to develop a correlation between a one-time pressurization test and an annual inflation rate.

KEYWORDS air infiltration, air change rate, measurement technique, residential building, pressurization testing

#NO 7970 Using pressure extension tests to improve radon protection of UK housing.

AUTHOR Bell P, Cripps A

BIBINF UK, Air Infiltration and Ventilation Centre, 1994, "The Role of Ventilation", proceedings of 15th AIVC Conference, held Buxton, UK, 27-30 September 1994, Volume 1, pp203-214.

ABSTRACT In order to demonstrate conformity with the current Building Regulations, many house builders are incorporating sumps beneath the ground floor construction of houses within the designated Radon Affected Areas. These sumps will allow for later depressurisation of the below ground floor construction and thereby prevent radon passage to the internal building environment. There are concerns regarding the costs of these measures and also the potential for these sumps to be used by vermin as nesting sites as well as their effectiveness. This paper reports on a ongoing study into the effect of different fill materials on sub-slab depressurization. In each test suction is applied at the centre of a floor slab and the resulting pressure field and flow rate is measured. These data give a good indication of the way in which a sump would be expected to perform. The results show that there is significant variation from fill materials described as being the same.

KEYWORDS (radon, pressurisation, building regulations)

#NO 7972 Air-tightness of US dwellings.

AUTHOR Sherman M, Dickerhoff D

BIBINF UK, Air Infiltration and Ventilation Centre, 1994, "The Role of Ventilation", proceedings of 15th AIVC Conference, held Buxton, UK, 27-30 September 1994, Volume 1, pp225-234.

ABSTRACT Blower Doors are used to measure the air tightness and air leakage of building envelopes. As existing dwellings in the United States are ventilated primarily through leaks in the building shell (i.e. infiltration) rather than by whole-house mechanical ventilation systems, qualification of airtightness data is critical in order to answer the following kind of questions: What is theConstruction Quality of the Building Envelope? Where are the Air Leakage Pathways? How Tight is the Building?How Much Ventilation Does the Air Leakage Supply? How Much Energy Does the Air Leakage Loose in this Building Too Tight? Is this Building Too Loose? When Should Mechanical Ventilation be Considered? Tens of thousands of unique fan pressurization measurements have been made of U.S. dwellings over the past decade: LBL has recently been collecting available data into its air leakage database containing over 12000 measurements. This report uses that data to determine the leakage characteristics of the U.S. housing stock in terms of region, age, construction type and quality. Results indicate thatU.S. dwellings tend to be quite leaky without respect toclimate.

KEYWORDS (air tightness, residential building, blower door)

#NO 7985 Effective ventilation strategies demand flexible system design.

AUTHOR Svensson A

BIBINF UK, Air Infiltration and Ventilation Centre, 1994, "The Role of Ventilation", proceedings of 15th AIVC Conference, held Buxton, UK, 27-30 September 1994, Volume 1, pp353-360.

ABSTRACT User experiences of the workings of a ventilation system have often been pretty disheartening. Draughty, too hot, noisy, too stuffy are some of the verdicts which in many cases have been confirmed by objective measurements. Often the complaints are due to the air flows not being appropriate to the room. This in turn can be due to adjustment difficulties or to the flow balance in different branches of the system being affected by residents tampering with the supply or exhaust air terminal device settings. In order to avoid these problems Stifab has developed a product - a self-acting regulator - which makes it possible to design more flexible systems. The pressure regulator makes it possible for a constant pressure to be maintained in the different branches of the ventilating system. This is practically independent of changes or influences elsewhere in the system. To guarantee perfect performance throughout the useful life of the ventilating system, the regulators are stationed at appropriate points in the distribution system. The paper describes examples of different system design in order to get: 1. a flexible demand controlled ventilating system 2. guaranteed air flow balance between supply and exhaust

KEYWORDS (ventilation strategy, pressurisation, demand controlled ventilation)

#NO 7990 Reducing air infiltration losses in naturally ventilated industrial buildings.

AUTHOR Jones P J, Powell G

BIBINF UK, Air Infiltration and Ventilation Centre, 1994, "The Role of Ventilation", proceedings of 15th AIVC Conference, held Buxton, UK, 27-30 September 1994, Volume 2, pp397-410.

ABSTRACT The UK factory stock is predominantly naturally ventilated. Measurements performed in this class of building have indicated that air infiltration rates infactories are usually excessive in relation to occupants' requirements for health and safety, resulting in an energy penalty. As part of a project to investigate construction options for energy efficient industrial buildings, three factories of different cladding construction types were designed and then built at Aberaman, South Wales. One of the primary aims of the project was to reduce air infiltration losses and increase air tightness. Attention has been paid to design details in order to achieve these aims. The construction process was observed in order to monitor site practice and workmanship. Tracer gas tests (primarily constant concentration) tests and air leakage (fan pressurisation) tests have been performed to determine the air infiltration rate and air leakage performance of the factories. A thermographic survey was used to assist the identification of the major air leakage sites. The results have shown that air infiltration rates have been reduced by the order of 40% for the three 'conventional'cladding constructions. Air leakage rates measured at 50 Pa are the lowest achieved in this class of building in the UK, based on published data. The major site for air leakage was found to be the eaves detail.

KEYWORDS (air infiltration, natural ventilation, industrial building, air tightness, tracer gas)


#NO 8009 Flow paths in a Swedish single family house - a case study.

AUTHOR Hedin B

BIBINF UK, Air Infiltration and Ventilation Centre, 1994, "The Role of Ventilation", proceedings of 15th AIVC Conference, held Buxton, UK, 27-30 September 1994, Volume 2, pp593-614.

ABSTRACT The ventilation of a Swedish single family house is investigated by means of tracer gas and pressurization techniques. The ventilation flow plays an important role in this house as it enters through a dynamic loft insulation and exits via the crawl space. This design is said to give preheated and clean supply air, warm floors and good energy efficiency. But to meet these promises, it is essential that the air really flows in the intended paths. A single tracer gas technique is used to determine the air flow rates. The measurements show that actually too much of the supply air by-passes the dynamic insulation by direct infiltration. The measurements also detect an unintended flow from the crawl space to the living area. If there exists radon in the ground such a flow must be avoided. Pressurization tests are used to build a pressure drop-flow model. This model describes intended flows, i.e. supply air through dynamic insulation, extract air to crawl space and exhaust air from crawl space to the outside, as well as the unintended flows, i.e. infiltration to living area and the two leakages from outside to crawl space and from crawl space to living area. The model is used to explain the present flows and then to tell how to change them. This is done by simulating the model when one of the parameters (e.g. a size of a leakage) is changing. One conclusion is that the crawl space must be made considerably more airtight.

KEYWORDS (air flow, residential building, tracer gas, pressurization, attic, insulation, crawlspace, air tightness)

#NO 8240 Estimation of design ventilation rates for buildings. 

AUTHOR Galbraith G H, McLean R C. 

BIBINF UK, Building Serv, Eng. Res. Technol; Vol 15, No 4, 1994, pp 199-203, 7 figs, 4 tabs, 10 refs. 

ABSTRACT Building fabric heat loads have decreased in recent years as standards of thermal insulation have improved. This in turn has led to an increase in the relative importance of the infiltration component of the total heat loss. The quantification of this component requires the accurate assessment of air infiltration rates under relevant environmental design conditions. Unfortunately, techniques for such assessments are much less well developed than those for calculating fabric heat loss and in many cases building services designers still rely upon the use of empirical estimates which are often unrealistic. This paper presents a case study in which a combined measurement and modelling procedure is applied to provide the designer with a more realistic estimate of air infiltration rates for an existing building. The basis of this work involves the use of the fan pressurisation measurement technique to determine actual leakage characteristics for the building envelope. This information provides real input data for a nodal airflow computer model, the results of which can then be used to estimate appropriate design ventilation rates. The case study involves application of the technique to a large secondary school undergoing refurbishment, and shows clearly that empirical estimates could have led to the installation of a severely undersized heating system. The measurements, in fact, highlighted a problem of excessive infiltration rates which required remedial action. The effectiveness of this remedial action was then confirmed by further measurements and remodelling was carried out to establish the final infiltration rates to be applied by the design engineers. 

KEYWORDS building design, ventilation rate

#NO 8345 Ventilation and airtightness in atria-full-scale measurements and analyses. 

AUTHOR Blomsterberg Ake, Wall Maria. 

BIBINF Poland, Silesian Technical University, 1994, proceedings of Roomvent '94: Air Distribution in Rooms, Fourth International Conference, held Krakow, Poland, June 15-17, 1994, Volume 2, pp 423-438. 

ABSTRACT Many modern office and residential buildings in Sweden include an atrium. The atria are often mechanically ventilated. Very little is known about the ventilation and air infiltration in built atria. The airtightness of the atria are mostly unknown. The airtightness and ventilation have therefore been tested in five different atria. One atrium is surrounded by an apartment building. There is no heating system in this atrium. The other four atria are surrounded by office buildings and are heated during the winter and cooled during the summer. The paper examines the air flows between the atrium and the surrounding building and between the atrium and the outside. The influence of the airtightness on the ventilation of the atrium is also examined. The different principles of ventilation in the examined buildings are discussed. Fan pressurization was employed to characterize the air leakage of the atrium. A multi-zone network model was used to evaluate the air flows. The roof of an atrium can be very leaky and therefore the exfiltration can be large. The walls between the atria and the surrounding buildings can also be very leaky and therefore the uncontrolled air flow through these walls can be large. Many ideas exist as to how to ventilate an atrium and how to couple its ventilation with the surrounding building. The knowledge concerning the real ventilation of atria and the surrounding buildings is insufficient. The size of the air flows between the different zones is of importance to the indoor climate and the energy use. 

KEYWORDS atrium, air tightness, mechanical ventilation

#NO 8422 Simulation and measurement of air infiltration and pollutant transport using a passive solar test house 

AUTHOR Yoshino H, Yun Z, Kobayashi H, Utsumi Y. 

BIBINF USA, ASHRAE, 1995, proceedings of ASHRAE Centennial Conference, held 28 January - 1 February 1995, Chicago, USA, 8pp, 12 figs, 2 tabs, refs. 

ABSTRACT This paper describes the measured and calculated results of air infiltration and decay profiles of tracer gas in a passive solar test house used to evaluate the simulation model COMIS for multizone air infiltration and pollutant transport. The interior leakage and exterior windows and wall leakage were measured by the fan pressurization method. Air infiltration was measured in three rooms under different conditions. The concentration decay method using three gases, N2O, SF6, and CHCI2F, was employed to find the air exchange rates and investigate indoor pollutant transport. The data, such as gas concentrations, temperatures, and wind, were measured in situ. In addition, the data from the measurements were used as simulation input data for air infiltration and pollutant concentrations, assuming tracer gases as the pollutant. The results of comparisons between measurement and simulation values of air exchange rates and tracer gas concentrations using the COMIS model are reasonable 

KEYWORDS simulation, air infiltration, pollutant, passive solar house

#NO 8848 A study of the air quality in classrooms 

AUTHOR Awbi A J. 

BIBINF Canada, proceedings Indoor Air Quality, Ventilation and Energy Conservation in Buildings , Second International Conference, held May 9-12, 1995, Montreal, edited by Fariborz Haghighat, Volume I, pp93-104. 

ABSTRACT Four naturally ventilated classrooms were studied to correlate the perceived high odour levels with infiltration rates. The classrooms were studied under controlled and uncontrolled conditions. The tests carried out were: pressurisation/depressurisation, tracer gas concentration decay and continuous carbon dioxide (CO2) concentration measurements. The air quality in the classrooms was found to be lower than the current guidelines and recommendations. To improve the indoor air quality, four factors were considered to determine the required ventilation rates: a) body odour control b) CO2 c) formaldehyde (HCHO) and d) moisture concentration levels (H2O) It is concluded that the required ventilation rate for each room should be determined by the need to control CO2 levels. However, accurate determination of ventilation rates can only be determined if all sources of pollution are considered, including occupants and furnishings. 

KEYWORDS school, indoor air quality, odour, natural ventilation, infiltration rate, carbon dioxide, formaldehyde

#NO 9054 Fan pressurization measurements by four protocols. 

AUTHOR Flanders S 

BIBINF UK, Air Infiltration and Ventilation Centre, 16th AIVC Conference Implementing the results of ventilation research , held Palm Springs, USA, 18 - 22 September, 1995, Proceedings Volume 1, pp 165-174. 

ABSTRACT Thirty-one independent fan pressurization measurement series were performed on seven apartments in three family housing buildings at Fort Riley, Kansas, using four protocols. The tests followed procedures in new or revised fan pressurization standards by the International Standards Organization (ISO), American Society for Testing and Materials (ASTM) and Canadian General Standards Board (CGSB). In addition, the effect of interzonal flow was considered. The three standards gave similar results. The tests during windy and calm conditions demonstrated that basic uncertainty calculations give a comparative indication of the quality of the results. The tests addressing interzonal flow did not show a strong influence on airtightness results, based on whether the adjacent units were open, closed, or pressurized at the same level. 

KEYWORDS fan pressurization, measurement technique

#NO 9060 Pressure simulation program. 

AUTHOR Knoll B, Phaff J C, de Gids W F 

BIBINF UK, Air Infiltration and Ventilation Centre, 16th AIVC Conference Implementing the results of ventilation research , held Palm Springs, USA, 18 - 22 September, 1995, Proceedings Volume 1, pp 233-242. 

ABSTRACT A computer program has been developed to predict the wind pressure coefficients Cp on facades and roofs of block shaped buildings. The program is based on fits of measured data, including wind shielding by obstacles and terrain roughness. Main advantages of the program are: * It needs no expertise of its users on wind pressures; * input is simple. It exists of building and obstacles co-ordinates and orientations; * generating Cp values for ventilation model calculations needs no separate action. By linking the pressure simulation program and the ventilation calculation program as well as their input, wider application of ventilation programs for non-experts becomes possible. The accuracy of the predicted wind pressures in the first version of the pressure simulation program are promising. Especially complex building shapes and surroundings have to be dealt with more carefully, as well as increasing wind velocities in small passages. Also detailed improvements are necessary, e.g. to account for sloped roofs and the position of ventilation provisions above roof level. Therefore, generation and implementation of additional wind tunnel data is planned, to improve the present version. 

KEYWORDS simulation, pressurization, wind pressure, wind barrier

#NO 9330 Radon reduction through solar ventilation: design and evaluation. 

AUTHOR Rhoads H E, Hoekje P L, Klein R J, Olson J A 

BIBINF USA, Energy Efficient Building Association, EEBA, 1995, proceedings of the 1995 Excellence in Housing conference, Innovations for Performance , held Minneapolis Hilton and Towers, Minnesota, USA, March 8-11, 1995, pp D12-D26. 

ABSTRACT Conventional residential energy conservation measures that limit air exchange rates between the indoors and outdoors have been shown to increase concentrations of radioactive radon decay products as well as other indoor air contaminants such as combustion by-products and off-gases from carpeting, furnishings, appliances, cleaning products, and building materials. The ventilation system under investigation seeks to combine the goals of energy efficiency and conservation with low-cost radon reduction and indoor air quality managements. Drawing on established radon mitigation techniques of ventilation, air supply and pressurisation, the Solar Radon Reduction System (SRRS) provides radon reduction at low energy costs due to solar preheating of supply air. Installation costs for the SRRS are also lower than conventional air-to-air heat exchanger and subslab suction radon mitigation options. Radon reduction and indoor air quality improvement are accomplished through dilution, reduced infiltration, and slight pressurisation of the dwelling through the induced-draft solar-heated outdoor air and the supply of combustion appliance make-up air. Installed in six test homes in Waterloo and Cedar Falls, Iowa, the SRRS was found to achieve significant radon reductions in all houses with elevated levels of up to 73% from background levels as high as 21.0 pCi/L. 

KEYWORDS radon, passive solar design, outdoor air

#NO 9847 Ventilation in houses with distributed heating systems.

Parent D, Stricker S, Fugler D

UK, Air Infiltration and Ventilation Centre (AIVC), 1996, proceedings of 17th AIVC Conference, "Optimum Ventilation and Air Flow Control in Buildings", Volume 1, held 17-20 September 1996, Gothenburg, Sweden, pp 185-195.

The LTEE laboratory of Hydro-Quebec, in collaboration with Canada Mortgage and Housing conducted an indoor air quality study involving 30 single family detached houses heated with electric baseboard heaters in the vicinity of Trois Rivieres during the 1993-94 heating season. The houses were selected according to the measured air leakage at 50 Pa. so as to have a sample distribution similar to the distribution of air leakage of houses in the province of Quebec. The "source strength" of several air pollutants were calculated from measurements of ambient pollutant levels and total ventilation during a one-week test. In addition, the indoor CO2 and humidity levels were recorded in eight of the houses continuously during the heating season. The level of CO2 in the master bedroom was found to follow fairly closely the CO2 level in other parts of the building including the basement (within about 200 ppm) except when the bedroom door was closed. With the room occupied and the door closed, CO2 levels in the bedroom increased steadily during the night until morning, when the door was opened, to levels in excess of 3 500 ppm with one person, and in excess of 4 500 ppm with two persons. Model studies using the measured pollutant source strengths and measured equivalent leakage areas of the buildings indicated that the recommended health guidelines for airborne respirable solid particles (RSP's), CO2 and formaldehyde are exceeded during periods of low total ventilation, coinciding with mild outdoor temperatures and low wind conditions. It was observed that kitchen and bathroom fans originally installed in some of these houses were not operated by the occupants for sufficiently long times to affect the quality of indoor air. Various different methods of ventilating some of the houses were tested, including quiet replacement exhaust fans, mixing fans for indoor air, and a fresh air intake and mixing system. The effects of operating various air handling systems were monitored by keeping track of indoor CO2 and relative humidity in the master bedroom, and occupancy in person-hours per day. Quiet replacement fans noticeably improved indoor air quality when these were operated over 50% to 100% of the time. An area of remaining concern is the fact that exhaust only systems accentuate the negative pressure in the basement by raising the level of the neutral pressure zone in the building, and may enhance the flow of soil gases into the basement. A system which mixed indoor air between the basement and the main floor also reduced the average level of indoor pollutants. The system was designed to create a pressure difference between the main floor and the basement, causing a slight pressurization of the basement. A system designed to introduce 5L/s of outdoor air and to mix it with 55L/s of indoor air for tempering was installed to draw air from the hallway and deliver the mixed air into each of three bedrooms. This system was capable of maintaining CO2 levels in the master bedroom below 1000 ppm with two occupants in the room and the door closed.

heating system, air leakage, pollutant, carbon dioxide, fan

#NO 9877 Evaluation of ventilation system in very low energy houses.

Pittomvils J, Hens H, van Bael F

UK, Air Infiltration and Ventilation Centre, (AIVC), 1996, proceedings of 17th AIVC Conference, "Optimum Ventilation and Air Flow Control in Buildings", Volume 2, held 17-20 September 1996, Gothenburg, Sweden, pp 513-520.

Since 1985 more than 170 very low energy houses, all of the same type and structure, were built in the Flemish Region, Belgium. Because conduction losses are very low, ventilation losses become very important, up to 45% of the heat losses if no heat recovery is utilised. Three of the houses were monitored in detail for energy consumption, energy and ventilation efficiency. All houses are equipped with the same ventilation system: balanced mechanical ventilation with heat recovery. Tracer gas measurements, pressurisation tests, multipoint temperature measurements and on site and laboratory tests of the heat recovery system, give us a complete scope of the ventilation system and its energy and ventilation efficiency. Pressurisation and depressurisation tests revealed the main air leaks in the construction: the different connections wall-floor and wall-roof, the window perimeter, even the sockets. Extra care in construction practice changed the n50-value from an average of 4.5 AC/h to 3.5AC/h, still high for a house with controlled ventilation. After testing the airtightness, we carried out tracer gas measurements in whole dwellings and between the different zones. Real ventilation rates and interzonal flows were derived. Questions like: Are the airflows in accordance with the design values? Do they match the requirements? How can we measure interzonal flows with one tracer? were answered. The paper gives a mathematical description of the tracer gas flow patterns (solution of the differential flow equations) and compares the results with the measured data. To complete the evaluation we carried out laboratory tests and field measurements on the heat recovery system. In laboratory the flat plate cross-flow heat exchanger showed a thermal efficiency up to 65% under specific climate conditions. In the dwellings, insulation and airtightness of the ducts appeared to be very important. The temperature efficiency decreased to values less than 45%. As a conclusion, one may stress that a global evaluation of the ventilation efficiency has to include different tests. The medium or poor airtightness has the greatest impact on the energy efficiency of heat recovery and on the ability to control the system. Detailed testing also showed some flaws in the ventilation system and in the building construction.

low energy house, ventilation system, mechanical ventilation, heat recovery

#NO 10105 Air leakage in the perspective of international standards.

Levin P A, Wilson D J, Ackerman M Y

in: Airflow performance of building envelopes, components and systems, USA, ASTM 1995, papers presented at a symposium held in Dallas, Texas, 10-11 October 1993, pp 231-247.

There exist a number of national standards and a draft international standard for the fan pressurization method for measuring air leakage. Although the standardized methods in principle are the same, the way of interpreting and presenting the results is different. In previous studies, houses that have a relatively large leakage area at a low pressure difference (4 to 10 Pa) can still seem comparatively airtight at a high pressure difference (50 Pa). This face is a consequence of differences in the flow exponent in the power-law equation, which is the normal equation used to fit to the data points, and can be a source of error when trying to compare the relative airtightness of houses. Extrapolating results from high pressure differences to low pressures, which are out of the measured range, can thus result in substantial errors. Air leakage testing of windows normally starts at 50 Pa which should be accounted for when trying to use these results as inputs in network air infiltration models. Measurement results on low pressure air leakage are discussed in the paper and compared with high pressure air leakage. Pressurization test date from 105 tests in one house at the Alberta Home Heating Research Facility are used for the study. The tests were made automatically over a seven-month period in low wind conditions. A wide range of pressure differences were tested and the results cover the test specifications for most standards. In addition to comparing standards, these tests were used to measure seasonal effects on air leakage in a wood-frame house with a plastic film air/vapor barrier. The results show some significant differences between the standards, and also a variation with month of test, indicating a seasonal variation in air leakage.

air leakage, measurement technique, fan, pressurisation, standard, wood frame, pressure difference

#NO 11538 Theoretical and field study of air change in industrial buildings.

Fleury E, Millet J R, Villenave J G, Veyrat O, Morisseau C

UK, Air Infiltration and Ventilation Centre, proceedings of "Ventilation Technologies in Urban Areas", 19th Annual Conference, held Oslo, Norway, 28-30 September 1998, pp 57-65.

The air leakages can have a large impact on heating needs and thermal comfort in industrial buildings. This is sometimes poorly taken into account, both due to the lack of theoretical approach and knowledge of air tightness. We present the application of the calculation code SIREN95 in this field and its validation against field measurements.

The field study concerns five average industrial buildings, in which different tasks have been carried out: air tightness measurements, using pressurisation method, two series of measurements of air change with a tracer gas method (decay), field measurements during a whole heating season.

Weekly energy balances were calculated using the results of field measurements - and the air changes calculated by SIREN95. They showed a good agreement between heat gains (internal and solar) and heat losses (through the envelope, air change).

calculation techniques

#NO 11579 Modern passive stack and ventilated schools - evaluation of ventilation and moisture conditions.

Blomsterberg A, Sikander E, Ruud S

UK, Air Infiltration and Ventilation Centre, proceedings of "Ventilation Technologies in Urban Areas", 19th Annual Conference, held Oslo, Norway, 28-30 September 1998, pp 450-457.

The aim has been to determine ventilation rates and risk of moisture damage in three modern schools with passive stack ventilation. The users are supposed to control the ventilation by using the lantern windows and the outdoor air is assumed to enter through an underground duct. The paper presents results, analysis and conclusions from the performed measurements and calculations. The ventilation rates are sometimes low and vary with the use of the windows in the facade and the lantern. It is, however, always possible to arrive at a sufficient ventilation rate. The supply air flow through the underground duct can, without a supply fan, be low and even go backwards during warm weather. To obtain desired ventilation rates and energy conservation the building must have a good airtightness. High relative humidities and even periods with condensation occur in the underground supply duct during spring and summer. Microbial growth has been found in two of the schools. Two important factors are choice of material and cleaning, where the knowledge is insufficient today. Moisture and microbial growth have been found in the roofs. The leakage paths, supply of moisture indoors and an interior pressurisation have contributed. In order to reduce the risks the building must have a good level of airtightness.

humidity, occupant control

#NO 11618 Evaluation of the COMIS model by comparing simulation and measurement of airflow and pollutant concentration.

Zhao Y, Yoshino H, Okuyama H

Indoor Air, No 8, 1998, pp 123-130, 9 figs, 2 tabs, 1 ref.

This paper describes the measured and calculated results of airflow rates and pollutant concentration profiles in an airtight test house, the aim being to evaluate the calculation model COMIS for multizone air infiltration and pollutant transport. Firstly, the leakage areas of internal doors, exterior walls and windows were measured by the fan pressurisation method. Secondly, two measurements were carried out, assuming that the test house consisted of ten zones. The concentrations and injection rate of SF6 were measured in order to determine the airflow rates by a system identification method. The boundary conditions, such as indoor and outdoor temperatures, wind speed and direction, and wind pressures were also recorded in situ and saved simultaneously on diskettes, using a computerised data acquisition system. Thirdly, the measured boundary data and leakage characteristics were used as input in the simulation of airflow using COMIS; initial concentrations, injection rate, along with the previous data were used for simulating pollutant transport, assuming tracer gas SF6 as a pollutant. Lastly, the comparisons between measurement and simulation results of airflow rates and pollutant concentrations were carried out by linear regression analysis. The correlation coefficient between the measured and calculated air change rates was 0.72, and that for pollutant concentration was 0.94.

air change rate, pollutant concentration

#NO 11734 Thermal insulation - determination of building airtightness - fan pressurization method. ISO 9972.

Anon

ISO, 1996, 10 pp.

The fan pressurization method produces a result that characterizes the airtightness of the building envelope or parts thereof. It can be used: to compare the relative airtightness of several similar buildings or building components; to identify the leakage sources and rates of leakage from different components of the same building envelope; to determine the air leakage reduction for individual retrofit measures applied incrementally to an existing building or building component. This method does not measure the air infiltration rate of a building. The results of the fan pressurization test can be used to estimate the air infiltration by means of calculation. If a direct measurement of the air infiltration is desired, other methods must be used. It is better to use the fan pressurization method for diagnostic purposes and measure the absolute infiltration rate with the tracer dilution method.

standard

#NO 11887 Airtightness of US dwellings.

Sherman M H, Dickerhoff D J

USA, ASHRAE, 1998, in: the ASHRAE Transactions CD, proceedings of the 1998 ASHRAE Annual Meeting, held Toronto, Canada, June 1998, 8 pp, 6 figs, 3 tabs, refs.

Blower doors are used to measure the airtightness and air leakage of building envelopes. As existing dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems, quantification of airtightness data is critical in order to answer the following kinds of questions: What is the construction quality of the building envelope? Where are the air leakage pathways? How tight is the building? Tens of thousands of unique fan pressurization measurements have been made of U.S. dwellings over the past decade, and the available data have been collected into an air leakage database. The report documents what is in that database and then uses the data to determine relevant leakage characteristics in the U.S. housing stock in terms of region, age, construction type, and quality.

air tightness, residential building


 


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