Bibliographic info:
LL 15

Identification of air leakage paths
#NO 288 Analysis of infiltration by tracer gas technique, pressurization tests and infrared scans.
AUTHOR Stewart M.B. Jacob T.R. Winston J.G.
BIBINF Proceedings ASHRAE/DOE Conference "Thermal performance of the exterior envelopes of buildings" Florida December 3-5th 1979 10 figs, 3 tabs, 3 refs. #DATE 03:12:1979 in English
ABSTRACT Reports the investigation of the natural ventilation of three test houses. Describes the houses which were of standard design. Natural ventilation rates were measured using sulphur hexafluoride as a tracer gas. An energy audit was also performed using a fan to pressurize and depressurize the house and an infrared scanner to detect the leakage paths. The tracer gas measurements were converted to a format similar to thepressurization results by using a previously developed model. Gives results in the form of graphs. Finds that the two methods placed the houses in the same relative ranking in terms of leakiness, but the pressurization technique indicated much smaller differences than the tracer gas technique.
KEYWORDS air infiltration, tracer gas, sulphur hexafluoride thermography, house, pressurization correlation
#NO 314 Estimated rate of pressurization and depressurization of buildings.
BIBINF ASHRAE trans. vol 86. part 1. 2 refs. #DATE 01:01:1980 in English
ABSTRACT States that the calculation of transient pressures in buildings requires the estimation of the rate of air leakage through various paths. Gives an expression for infiltration through a wall component. Gives formulae for calculating pressure transients inside a building under forced ventilation with air leaking out of the building under various conditions. Theseformulae also apply when air is leaking into the building. Discusses practical applications and the practical problems for which the formulae are useful.
KEYWORDS air infiltration, pressure distribution,
#NO 339 The thermal performance of a two-bedroom mobile home
AUTHOR Tietsma G.J. Peavy B.A.
BIBINF National Bureau of Standards Building Science Series 102. 55p. 56 figs 2 refs. #DATE 01:02:1978 in English
ABSTRACT Reports tests made on a mobile home to evaluate its thermal performance. Describes home, instrumentation and test procedure. Gives energy consumption as a function of indoor-outdoor temperature difference. Finds that oversized heating plant resulted in low seasonal operating efficiency. Air infiltration was measured using pressurization technique and SF6 as a tracer gas. The latter showed that operation of the heating plant induced higher air infiltration rates. Reports thermographic survey of interior surfaces which showed air paths formed by wrinkles in the surface insulation. Separate tests identified places in the mobile home envelope with high condensation potential.
KEYWORDS mobile home, air infiltration, heat loss, pressurization, tracer gas, sulphur hexafluoride, thermography, component leakage
#NO 372 Ventilation heat loss outside in.
BIBINF London and Southern Junior gas association 21p. 4 figs 26 refs. = Gas Engng. and Management November 1979. #DATE 20:04:1979 in English
ABSTRACT Outlines the problem of assessing the rate of heat loss from dwellings due to ventilation. Discusses the mechanisms and pathways of ventilation and ways of controlling air infiltration. Reviews methods of measuring ventilation using tracer gases. Discusses qualities of ideal tracer gas and three automated measuring systems. Reviews some experimental results obtained from the SEGAS test house. Describes house and measurement method. Finds sealing house reduced ventilation rates by between 30 and 45 per cent.
KEYWORDS air infiltration, heat loss, tracer gas,. automatic equipment, component leakage,
#NO 398 Air leakage characteristics of low-income housing and the effectiveness of weatherization techniques for reducing air infiltration
AUTHOR Grot R.A. Clark R.E.
BIBINF Proceedings ASHRAE/DOE Conference "Thermal performance of the exterior envelopes of buildings" Kissimmee, Florida 3-5 December 1979. 8 tabs 10figs 5 refs. #DATE 03:12:1979 in English
ABSTRACT Reports measurements of air change rates made on approximately 250 dwellings, occupied by low income households in 14 cities, in all major climatic zones of the United States. Two types of measurements were used : a tracer-gas decay technique using air sample bags and a fan depressurization test that measures induced air exchange rates. Shows that for this group of dwellings natural air infiltration rates have an approximate lognormal distribution. Finds little correlation between natural air infiltration rates and induced air exchange rates unless buildings are divided into classes of similar buildings.Mentions important use of fan depressurization as a diagnostic tool to find air leakage paths. Presents preliminary estimates of reduction in induced air change rates from weatherization techniques.
KEYWORDS air infiltration, house, retrofit, pressurization correlation, fan, tracer gas, sulphur hexafluoride, weatherstripping,
#NO 403 The influence of window design on the air flow through cracks.
Der Einfluss der Fensterbauart auf den Luftdurchgang
AUTHOR Cammerer J.S. Hirschbold F.X.
BIBINF Gesundh. Ing. vol.61 no 29 p393-9, 6 tabs #DATE 01:01:1938 in German
ABSTRACT Reports investigation of air leakage through windows. Gives tables of air leakage of various types of windows with their dimensions, crack length, number of corners and length of air paths within cracks. Suggest that this information can be used to calculate the heat flow through windows.
KEYWORDS window, air leakage
#NO 490 The need for improved airtightness in buildings.
AUTHOR Handegard G.O.
BIBINF National Research Council of Canada. Division of Building Research. note. no. 151 7p 7 refs = Engineering Foundation Conference on "Ventilation vs. energy conservation" Henniker July 1977. pub. N.B.S. #DATE 01:11:1979 in English
ABSTRACT Outlines causes of air infiltration. Discusses the air leakage paths of openings and measures that can be taken to reduce air leakage. Concludes that air infiltration should never be relied upon for ventilation but efforts should be made to make the building envelope more airtight, and a mechanical ventilation system should be installed.
KEYWORDS air infiltration,
#NO 500 Infrasonic measurement of building air leakage-a progress report.
AUTHOR Card W.H. Sallman A. Graham R.W. Drucker E.E.
BIBINF Proceedings ASTM, ASHRAE, NBS, DOE Symposium on Air infiltration measurements Washington D.C. March 13, 1978. Department of Electrical and Computer Engineering, Syracuse University, Technical Report TR-78-5. 13 figs 4 refs. #DATE 01:03:1978 in English
ABSTRACT Describes infrasonic method of measuring the air leakage of a house or apartment. Describes apparatus, consisting of a motor driven source of known output a sensitive pressure pickup and anelectronic signal processor. A low frequency (about one cycle per second) alternating air flow of known magnitude is applied to the interior of the building, and the alternating component of inside pressure that results is measured. The pressure response is a function of the type and size of leakage paths. Describes measurements made on three interior rooms and gives sample results. Concludes that the accuracy of the present system is rather low and that interpretation is difficult but that the system is easier to set up than a blower.
KEYWORDS air leakage, alternating pressure,
#NO 509 Air leakage measurements in three apartment houses in the Chicago area.
AUTHOR Hunt C.M. Porterfield J.M. Ondris P.
BIBINF National Bureau of Standards Interagency report NBSIR 78-1475 24p. 12 figs. 9 refs. #DATE 01:06:1978 in English #AIC 205
ABSTRACT Describes air infiltration measurements made in three apartment houses in the Chicago area using SF6 as a tracer gas. Two were in tenement districts and one was suburban. Data were collected in selected apartments in each building, andthese data were used to estimate the infiltration rate for the whole building. Whole building estimates of 0.94 and 1.2 air changes per hour were obtained under the conditions of tests in the tenement apartments, and 0.82 air changesper hour in the suburban apartment. Comparisons of the air tightness of individual dwelling units by fan pressurization-depressurization techniques were also made. The suburban apartment was found to be much tighter than the other two apartments. The difference was much greater than predicted by the tracer tests. Analysis of the ASHRAE crack method suggests that it understimates the number of leakage paths, but in applying the method results may be obtained which are plausible or even too high, if pressure difference across the cracks is overestimated.
KEYWORDS air infiltration, tracer gas, pressurization, flat, residential building, crack, sulphur hexafluoride,
#NO 556 Design principles
AUTHOR Handegard G.D.
BIBINF In "Construction details for air tightness". NRCC DBR. Proceedings no.3. p1-5 3 refs. #DATE 01:04:1980 in English #AIC 226.
ABSTRACT Outlines forces causing air leakage through openings in a building. Discusses likely leakage paths and states importance of identifying these and improving the air tightness of walls, windows, floors and roofs.
KEYWORDS air leakage, building design,
#NO 589 A computer technique for predicting smoke movement in tall buildings.
AUTHOR Barrett R.E. Locklin P.W.
BIBINF A.S.S.E. Jnl. vol.16 no.1 p.8-14 Jan. 1971 8 figs. 1 tab. 9 refs. #DATE 01:01:1971 in English #AIC 271
ABSTRACT Describes a computer technique for analysing air movement resulting from stack effect in a tall building. Describes the method which determines the air flows for all possible paths through exterior walls and within the building. The building is divided into multi-storey zones based on the design of the building and the HVAC system. Gives an example of the method applied to a building under two different climatic conditions. Considers the problem of thedifficulty in opening doors due to excess pressure across the door. Method requires knowledge of wall and window leakage and the effective crack areas of internal doors.
KEYWORDS stack effect, computer, high rise building, air flow,
#NO 613 Conventional buildings for reactor containment.
AUTHOR Koontz R.L. et al.
BIBINF Atomics International, California NAA-SR-10100; available from National Technical Information Service, U.S. Dept. of Commerce. 1965 418p. figs. bibliog. #DATE 01:05:1965 in english #AICR US1
ABSTRACT Reports measurements of air leakage rates through structural components of conventional metal-panel and concrete buildings which may serve as containment for nuclear reactors. The component measurements included structural penetrations such as doors and louvres as well as caulking compounds, gaskets and paints. Specimens were sealed inside test vessels and pressure differentials generated across the specimen with each component installed in the manner of typical construction techniques. After the major leak paths were determined, additional tests were made with improved methods of construction. Presents detailed descriptions and results of each completed test.< Presents analytic expressions, using the empirical constants from the tests, for predicting the flow rates through building components as a function of size, method af construction and pressure difference. Gives equations for calculating the total leak rate of a building of any size for any excess pressure. Describes methods for estimating leak rates, locating leak paths and measuring the leakage rates of completed structures.
KEYWORDS air leakage, concrete wall, door, caulking, paint, joint, air flow, pressurization
#NO 627 Airtightness of buildings: Results from airtightness measurements in new Norwegian houses.
Boligers lufttethet: Resultater fra lufttethetsmalinger av nyere norske boliger.
AUTHOR Brunsell J.T. Uvslokk S.
BIBINF Norges Byggforskningsinstitutt report no.31 1980 ISBN:82-536-0125-5< =A.I.C. translation no.7 #DATE 01:01:1980 in english, norwegian #AIC 278
ABSTRACT Presents the results from a major airtightness survey carried out in Norwegian dwellings. 61 detached houses and 34 flats were pressure tested. In 14 of the detached houses and 6 of the flats, leakage paths were traced using thermography. Gives tables of results. Lists most common leakage paths located by thermography. Occupants of the dwellings were interviewed about draught problems, but there was no clear correlation between occupant dissatisfaction and leakage rate. Notes a considerable variation in leakage between the houses.
KEYWORDS house, flat, pressurization, thermography, air leakage,
#NO 628 Ventilation with open windows.
AUTHOR Dickson D.J.
BIBINF Electricity Council Research Centre, Capenhurst M 1329 April 1980 49p. 21 figs. #DATE 01:04:1980 in english #AIC 242
ABSTRACT The ventilation rate and energy consumption of one of the ECRC test houses was monitored continuously during one heating season, with one bedroom window open by various amounts. Results show that a very small window opening issufficient to satisfy ventilation requirements most of the time. Finds that air flow paths in and out of the house are mainly determined by wind direction, but that air flow between rooms is temperature induced and a very large interchange takes place even for temperature differences of one or two degrees.< The energy cost of ventilation can be calculated provided that the temperature of the air leaving the house is known. This will usually be the bedroom temperature. The measured ventilation rates could be related to the measured house leakage only by assuming that stack effect ventilation took place mainly through openings into the basement and loft, while wind induced ventilation took place through other openings in the front and back of the house.
KEYWORDS air flow, open window, air change rate, house, tracer gas, smoke, carbon dioxide, nitrous oxide
#NO 650 Air flows in building components.
AUTHOR Kronvall J.
BIBINF Division of Building Technology, Lund Institute of Technology. report TVBH-1002 1980 194p. figs. #DATE 10:11:1980 in English #AICR SE16
ABSTRACT Treats different aspects of air movements in building components. Shows to what degree the concepts of fluid mechanics can be applied to problems concerning air flows in building components. Presents the applicable parts of fluid mechanics and outlines routines to make it possible to handle complex flow and pressure distribution problems.< Reports experimental investigation concerning the determination of surface roughness of plates. A test device for this purpose was designed and tested on a number of building materials. Also the magnitude of contraction and bendloss factors were investigated experimentally.< Investigates the influence of fluctuating pressure differences on the flowrate across building components. Finds that rapid fluctuations influence theflow rate only a little and if the fluctuations are slow it is possible to calculate the flow rate as if the problem were a steady state one, using time-averaged pressure difference values.< Reviews leakage characteristics of different building components and discusses the air leakage of whole building envelopes. Suggests an addition to pressurization tests taking the form of the leakage rate-pressure difference curve into account. Such a procedure could imply a new possibility of detecting large, and maybe hidden flow paths giving rise to substantial contributions to the total leakage rate of a building.< Includes some tables covering surface roughness, permeability and porosity data of different building materials.
KEYWORDS air flow, crack, theoretical modelling, pressurization, building material, permeability
#NO 683 Listening for air leaks - How to spot infiltration with your ears.
BIBINF Popular Science February 1981 p38,40 #DATE 01:02:1981 in English #AIC 332
ABSTRACT Describes use of an acoustic method developed by Keast to detect air leaks. A loud source of sound is placed inside the building and a microphone, stethoscope, rubber hose or sound meter is used to detect places where anincrease in sound indicates air leakage. Finds method is effective in detecting simple leaks but will not spot complex paths through walls.
KEYWORDS sound, air leakage, house,
#NO 766 Experimental thermal calibration of houses.
AUTHOR Siviour J.B.
BIBINF Proceedings International Colloquium "Comparative experimentation of low energy houses" Liege, 6-8 May 1981 paper V. 13p. 10 figs. 11 refs. #DATE 06:05:1981 in English AIC.
ABSTRACT Describes a procedure for measuring the transmission and ventilation heat losses of unoccupied houses and their solar heat gain. Internal temperatures, ventilation rate and weather data are measured. An infrared camera is used todetect both local areas of high transmission heat loss and, together with a slight pressurization of the house, air leakage paths. Gives graphs for calculating the effective solar heating. Notes that results obtained from the tests depend very much on the skill of the people operating the equipment.
KEYWORDS heat loss, house, measurement technique,
#NO 1221 Variation of airtightness with time.
Tathetens tidsberoende.
AUTHOR Hedberg H.O.
BIBINF Unpublished report Tyrens Foretagsgrupp AB Stockholm 1982 40pp. #DATE 01:01:1982 in Swedish
ABSTRACT Subjects 11 private dwellings at Taby and 5 at Brunna (all 2-3 yrs old) to repeated airtightness tests over a period of two years. Finds the largest leakage is 2.5 ach and the mean leakage is 1.6 ach. Immediately after its completion, the air tightness of a building undergoes a certain deterioration, after which it stabilizes. Over the 2yr. measuring period the changes are small, and could all be attributed to occupancy effects. Leakage paths occurat the junctions of wall and ceiling and wall and floor, and at service entries. In order that airtightness behaviour should be fully measured,tightness measurements should be repeated after 3-5 yrs.
KEYWORDS tight house, pressurization, residential building, ageing,
#NO 1285 The project measurement of building tightness is completed, but many open questions remain.
Rakkenustentiiviystutkimus valmis - avoimia kysymyskia riittaa viela.
AUTHOR Railio J.
BIBINF LVI vol.35 no.8 1983 p.22 5 figs. 1 tab. 9 refs. #DATE 01:08:1983 in English
ABSTRACT Reports conclusions from projects investigating the tightness of buildings sponsored by the Ministry of Trade and Industry. Describes factors influencing ventilation such as size and shape of building, location, distribution of leakage points, interior air flow paths and the design and control of ventilation. Wind condition and temperature difference are the only driving forces in natural ventilation, in mechanical ventilation the temperature has only a limited influence but the wind may cause considerable draught in an untight building. Points out that mechanical ventilation seems to be the right solution to air quality problems in tight houses.
KEYWORDS natural ventilation, tight house, mechanical ventilation,
#NO 1356 Parameters affecting air infiltration and air tightness in 31 east Tennessee homes.
AUTHOR Gammage R.B. Hawthorne A.R. White D.A.
BIBINF Preprint ASTM Symposium on measured air leakage performance of buildings Philadelphia USA April 2-3 1984 13 pp. 2 tabs. #DATE 02:04:1984 in English
ABSTRACT A major pathway for loss of conditioned air in east Tennessee homes with externally located HVAC systems is leakage in the ductwork. The effect on infiltration rates, as measured by Freon-12 tracer gas dilution, becomes marked if the central duct fan is operating. Duct fan on and duct fan off measurements of the rate of air exchange gave mean values of 0.41 and 0.78 ach respectively in a total of 31 homes. Specific leakage areas measured using a pressurization technique are affected to a lesser extent by inclusion of the ductwork volume within the total volume of the house being pressurized. A subset of 7 of the study homes were measured using this technique - the average increment in the specific leakage area was 15%.
KEYWORDS mechanical ventilation, air leakage, pressurization, component leakage, tracer gas, decay rate, fan, duct,
#NO 1649 Parameters affecting air leakage in East Tennessee homes.
AUTHOR Gammage R B. et al.
BIBINF Indoor Air. Vol 5. Buildings, Ventilation and Thermal Climate. Edited by B Berglund, T Lindvall, J Sundell. Swedish Council for Building Research, 1984. 429-434, 2 tabs, 6 refs. #DATE 00:00:1984 in English AIVC bk,
ABSTRACT A major pathway for loss of conditioned air in East Tennessee homes with externally located heating, ventilation, and air-conditioning (HVAC) systems is leakage in the ductwork. The average infiltration rate, as measured by Freon-12 tracer gas dilution, nearly doubles if the central duct fan is operating: duct fan on and duct fan off measurements of the rate of air exchange gave mean values of 0.78 and 0.44 h to the -1, respectively, in a total of 31 homes. Specific leakage areas measured by the blower-door, pressurization-depressurization technique are affected to a lesser extent by inclusion of the ductwork volume within the total volume of the house that is being pressurized: the average increment in the specific leakage area for asubset of 7 of the study homes is about 15%. For homes that have central HVAC systems, weatherization and energy conservation programs should be cognizant of the seriousness of air and energy losses that can be caused by leaking ductwork.
KEYWORDS component leakage, air infiltration, tracer gas, freon, pressurization
#NO 1677 Infiltration models for multicellular structures - a literature review.
AUTHOR Feustel H E, Kendon V M.
BIBINF Energy and Buildings, 1985, Vol 8, p123-136. 1 fig, 8 tabs, 39 refs. #DATE 11:12:1984 in English
ABSTRACT Infiltration models are used to simulate the rates of incoming and outgoing air flows for a building with known leakage under given weather and shielding conditions. Additional information about the flow paths and air-mass flows inside the building can only be made available by using multichamber infiltration models. This review of the literature revealed the existence of 15 multichamber infiltration models, all developed between 1966 and 1983 and differing significantly in the number of cells they can handle, depending on the date of their development. In terms of the flow equations these programmes use, they are very similar: most of the differences between them are in the description of the building and the algorithm provided for solving the set of nonlinear equations. In this literature review, it was found that only a few of the 15 models are able to describe and simulate the ventilation system and the interrelation of mechanical and natural ventilation.
KEYWORDS mathematical modelling, multi-chamber, air infiltration, mechanical ventilation
#NO 1678 Thermal effects of air leakages on the thermal performance of building structures.
AUTHOR Kohonen R, Virtanen M.
BIBINF Espoo, Finland:Technical Research Centre of Finland, Laboratory of Heating and Ventilating, 1985. 21p. 17 figs. #DATE 00:00:1985 in English
ABSTRACT Simulation of the thermal performance of a building to take account of uncontrolled infiltration shows that infiltrating air on a leakage path is efficiently warmed up, especially if infiltration flow rates are low. For allowable infiltration flow rates with respect to thermal comfort, (0.5 -0.7 dm3/sm), the heating is 25 - 60 per cent of the temperature difference between the outside and inside air. For the longest leakage path, the incoming air is even near to the room air temperature. The warming up of infiltrating air depends on the infiltration flow rate and the length of the leakage path, as well as the thermal properties of the structure around the crack. The calculation method presented can be used to study the principle of the warming up of infiltrating air, and of leakage from inside to outside.
KEYWORDS air infiltration, crack, ventilation heat loss, theoretical modelling
#NO 1698 Air infiltration - modelling and practical results.
AUTHOR Railio J, Saarnio P.
BIBINF Unpublished paper, Technical Research Centre of Finland, 1985, 11 figs, 4 tabs, 5 refs. #DATE 00:00:1985 in English
ABSTRACT A steady state multi-cell calculation model has been developed in order to predict the interconnection between airtightness and ventilation rates. The model has been tested with measured leakage data of a detached house. It is applicable also for other types of buildings provided with natural ventilation systems. The model is being used - combined with field measurements on airtightness, air flows, pressure conditions and air change rates - to help to solve various practical problems on ventilation. Some examples of calculation results are presented. The airtightness of various leakage paths is measured with the collector chamber method. To measure local air change rates and ventilation efficiency in various rooms, a ten-point measurement equipment with N2O tracer gas is used. For practical purposes, methods for airtightness measurements in larger buildings have been developed. Results from measurements in residential buildings are presented. Observed comfort or air quality problems are less related to air infiltration than to insufficient total or local air change rates, which occur in airtight buildings without supply air arrangements, with natural ventilation or mechanical exhaust.
KEYWORDS mathematical modelling, air tightness, air change rate, multi-chamber, detached house, natural ventilation, tracer gas, nitrous oxide, residential building, ventilation efficiency
#NO 1755 Smoke control in VA hospitals.
BIBINF ASHRAE Journal, April 1985, p42-45, 1 fig, 2 tabs, 8 refs. #DATE 00:04:1985 in English
ABSTRACT Smoke control makes use of mechanical fans to produce airflows and pressure differences to control smoke movement. Describes one day of tests of the smoke control systems at the 6-storey VA hospital, San Diego, California. Each floor is divided into a number of zones separated by fire walls and fire doors. Theeffectiveness of these barriers depends on the leakage paths in the barrier and on the pressure differences across the barrier. The pressure difference was found to be considerably below the desired minimum pressure difference of 25 Pa. It was hypothesized that this poor performance was due to exceptionally high leakage from the outside to the wing tested, resulting in exhaust air being pulled directly from the outside rather than through the core of the building. Evident leakage areas in the gaps around the 6 exterior doors were sealed, and pressure difference was found to have increased from 10 to 12 Pa.Blocking outside vents in the interstitial space resulted in a pressure difference of 15 Pa.
KEYWORDS air leakage, performance test, pressure difference, smoke, hospital, high rise building
#NO 1796 Improving the accuracy of a constant concentration tracer gas system.
AUTHOR Bohac D L, Harrje D T
BIBINF 6th AIC Conference "Ventilation Strategies and Measurement Techniques", Het Meerdal Park, Netherlands, 16-19 September 1985. Bracknell, UK: Air Infiltration Centre, 1985. p25.1-25.23. 10 figs, 20 refs. #DATE 00:09:1985 inEnglish AIVC bk
ABSTRACT Air infiltration flows into different zones of a building can be measured with the constant concentration technique by injecting a metered amount of tracer gas to hold the concentration of the gas constant. The control and estimation algorithm used to calculate the injection rate is designed using classical transform and optimal estimation methods. The ability of the control algorithm to keep the concentration constant and to accurately measure time varying infiltration flows is demonstrated using digital computer simulations and laboratory experiments. Field demonstrations then complete the confirmation that all components of the total system are performing as designed, and that the desired accuracy targets have been achieved. The details of how constant concentration system accuracy targets were attained in the Princeton constant concentration tracer gas measurement system are outlined in this paper. Before the total system accuracy goals could be achieved it was necessary to focus attention on the commercial SF6 detection unit based upon the principles of gas chromatography and electron capture. Gas flow paths, sequencing and critical times in a given sample analysis all directly impinge on the total system function and ultimate accuracy. Some of the points discussed are: internal air leakage, valve switching, and calibration of various subsystems.
KEYWORDS tracer gas, measurement technique, constant concentration, sulphur hexafluoride
#NO 1994 Skymark 1 Air Leakage Study. Final Report.
AUTHOR McGugan C A, Giannini D, Tyrcz E T
BIBINF Report No CNG R-82-03. Mississauga:Ontario Research Foundation, Department of Engineering and Metallurgy, Building Performance Centre, 1982. 64p. 20 figs, 25 tabs, 3 refs. Microfiche. #DATE 30:03:1982 in English
ABSTRACT A study was conducted to determine the air leakage rates in Skymark 1, a high rise condominium in Toronto, particularly air leakage rates of the exterior walls of "Florida Rooms" which were constructed by the enclosure of original open balconies. In addition, air leakage between suites was studied to attempt to identify internal leakage paths. The method used for measurement of the leakage rates was a modification of the pressurization method developed by NRC. Fans were used to pressurize the "Florida Rooms" and suites, and the air flow required to maintain various pressure differentials between inside and outside air was measured. The leakage rates measured for the Florida Room interior walls were in general higher than those measured for other high riseand apartment buildings. Leakage rates for the Florida Room exterior walls were close to those of the original balcony walls. The suites exhibited similar rates for overall leakage. Sealing of identified leak paths around ducts and pipes led to a small reduction in overall leakage.
KEYWORDS air leakage, pressurization, high rise building, flat, sealing
AUTHOR Keast, D. N.;
BIBINF RESEARCH.LOC = Cambridge, MA; RESEARCH.LOC = Brockton; TYPE = REPORT; #DATE 01:10:1978; VOLUME.TITLE = Brookhaven National Laboratory Report 50952; PAGES = 1-144; REPORT.NO = BNL 50952; PUBLISHER.NAME = National Technical Information Service U.S. Department of Commerce; PUBLISHER.CITY = Springfield, VA 22161; in English
ABSTRACT Unnecessary air infiltration ,draftiness, in buildings can be a major cause for excessive energy consumption. A method for using sound to locate, for subsequent sealing, the openings of air infiltration leakage paths in buildings has been investigated. The results of pertinent analytical studies, laboratory experiments, and field applications of this acoustic location method are reported, and a plan is provided to encourage national implementation of the method. Low-cost, readily available equipment and procedures are described whereby the average building contractor or homeowner can use acoustic leak location to pinpoint many of the air infiltration openings in a building.;
#NO 2336 Calculation model for airtightness and natural ventilation of buildings.
Rakennusten tiiviyden ja ilmanvaihdon laskentamalli.
AUTHOR Saarnio P
BIBINF Technical Research Centre of Finland, Research reports 242, November 1983, 82p, 24 figs, 3 tabs, 20 refs, + English summary.
#DATE 00:11:1983 in Finnish
ABSTRACT A multi-cell calculation model was developed for calculation of the interconnections between airtightness, air change rates, pressure conditions and energy consumption. The flow equation used in the model is quadratic, which can be used as well for a single leakage path as for a whole building envelope. For energy calculation the area of wind directions is divided into12 sectors (each 30 degrees) plus one sector for calm wind conditions. The mean values of wind speed and outside temperature applied to each wind sector are calculated from weather data of several years period. The momentary pressure fluctuations of wind are not taken into account in calculation. Steady-state flow equations are applied to each leakage path to solve the mass flow using the mean values of wind pressure coefficients for each wall area and wind sector. The physical realibility of the model is tested by comparing the results of calculations with the results of the measurements in an actual building. The airtightness of various leakage paths was measured with the collector chamber method. The total air tightness of the building envelope calculated with leakage data measures in an actual building agreed very well with the values measured with the pressure test at small pressure differences (<10 Pa) Good agreement between calculated and measured infiltration rates was also obtained in test conditions.
KEYWORDS mathematical model, air tightness, air flow, air change rate, leakage path
#NO 2592 Improved methods for air sealing residences.
BIBINF Proceedings, Fifth Annual Conference, Energy Efficient Buildings Association, Minneapolis, Minnesota, USA, April 1987, 10p, 15 figs, 10 refs. #DATE 00:04:1987 in English
ABSTRACT In the past decade, a large number of air sealing techniques for residences have been introduced. Using these techniques, builders have been able to reduce whole house leakage values to below 1.5 air changes per hour at 50pascals. A disadvantage of the techniques has been increased cost compared to conventional construction. In this paper a critical look is taken at research data on the location of common air leakage paths in residences, and some improved and simplified techniques for air sealing are suggested. The twodominant air leakage locations are the ceiling-interior partition joints and the foundation-sill area. To date, the most popular air sealing technique has been the use of a polyethylene vapour barrier which also serves as the air barrier for the structure. Generally, great care is taken in sealing all the joints in the polyethylene sheets. It is the author's contention that a substantial amount of the joint sealing with the polyethylene sheets is unnecessary, given that the gypsum board can serve as the air barrier. Improved details incorporating this approach are included in the paper.
KEYWORDS residential building, air leakage, vapour barrier, air barrier, joint, sealing
#NO 2679 Flow in an algorithm for calculating air infiltration into buildings.
BIBINF Third International Congress on Building Energy Management III Ventilation, air movement and air quality: field measurement and energy auditing, p5-12, 2figs, 1 tab, 10 refs. #DATE 00:00:1987 in English
ABSTRACT Many computer programs have been developed in order to calculate infiltration. However most models presently in use are either not within the public domain or are written as research tools, rather than for meeting the needs of dynamic building thermal models. In order to overcome this problem a computer program, called FLOW, has been developed. This code differs from previous calculation methods in that the wind pressure coefficients, and consequently the pressure distribution around the building, are determined internally, in doing so it accounts for the nature and roughness of the surrounding terrain and the consequent atmospheric boundary layer, the wind speed and direction, the building proportions and for any external shielding. The FLOW Program can be run using either a single cell approach, in which the interior of the building is assumed to be at single uniform pressure, or a multi-cell model. In the latter case, the interior is subdivided into zones of differing pressure interconnected by leakage paths. The change from single cell model, or vice-versa, is controlled by simple alteration to the input data.
KEYWORDS mathematical modelling, calculation techniques, computer
#NO 2851 Air flow through cracks.
AUTHOR Baker P H, Sharples S, Ward I C
BIBINF Bldg & Environ, Vol.22, No.4, 1987, p293-304, 12 figs, 4 tabs, 13 refs. #DATE 00:00:1987 in English
ABSTRACT The pressure flow characteristics of a number of full-scale model cracks, representative of real leakage paths, have been measured. The crack flow equations developed by Etheridge have been verified over a wider range of parameters. The authors suggest a quadratic relationship which follows from the same theory as the Etheridge solution, to replace the ubiquitous power law as a practical fit to pressurisation data. Unlike the power law, the quadratic coefficients A and B can be directly related to crack parameters, and a simplegraphical method is given to enable the prediction of crack leakage areas.
KEYWORDS air flow, crack, mathematical model, pressurization
#NO 2981 The calculation of wind effect on ventilation.
AUTHOR Liddament M W
BIBINF Preprint: Ashrae Transactions, Vol 94, Pt 2, 1988, 15 pp, 8 figs, 1 tab, 17 refs. #DATE 00:00:1988 in English
ABSTRACT Natural ventilation is governed by the overall leakage characterstics of a building (accidental and purposely provided) and by the driving forces of wind and temperature. As greater control is influenced over airtightness design, the reliable prediction of naturally driven air change becomes increasingly dependent on the quality of climatic data. The influence of wind is particularly difficult to quantify, since its behaviour is dramatically influenced by surrounding terrain and shielding conditions. This paper seeks to review and address the relevance of wind pressure as a driving mechanism. A simple multi-flow path simulation model is introduced and is used to illustrate the effects of wind on air change rate. The model is specifically used to illustrate the sensitivity of results to variations in surface wind pressure coefficients and to differing shielding and terrain roughness conditions. Model results are also used to discuss the significance of both temperature differences and mechanical ventilation on the impact of wind.
KEYWORDS calculation techniques, wind effect, ventilation, modelling
#NO 3117 Natural airflows between roof, subfloor and living spaces.
AUTHOR Bassett M R
BIBINF in: " Effective Ventilation", 9th AIVC Conference, Gent, Belgium, 12-15 September, 1988. #DATE 00:09:1988 in English
ABSTRACT This paper is concerned with natural air flows between major construction cavities in New Zealand houses. A two tracer technique was developed to measure infiltration rates in the subfloor (crawl space), the living space and roof space, together with air flow rates connecting these zones. Five experimental houses were chosen to represent expected extremes in air flow resistance between sub floor and roof space. Two were clad in brick veneer over timber frame walls, allowing possible air leakage paths through the wall cavities, and the other three were clad in weatherboards with little likelihood of air leakage paths through the wall cavities. Subfloor to roof space air flows of around 30% of the roof space ventilation rate were measured in the brick clad houses while in the weatherboard examples it was only 7%. Air flows connecting subfloor and roof space with living space were generally in the range 1-30m3/h with a general tendency for upward flows to exceed downward flows. Interzone flows involving the living space were not obviously dependent on the type of building or on wind speed and zone temperature differences.
KEYWORDS air flow, cavity, residential building, tracer gas, crawlspace, infiltration rate
#NO 3296 Instrumentation for the measurement of air infiltration - an annotated bibliography.
AUTHOR Manning S
BIBINF UK, AIC, Technical Note 4, 1981. #DATE 00:00:1981 in English
ABSTRACT An annotated bibliography containing 89 references to papers selected from the AIC's library and intended to be selective rather than comprehensive. Includes references only to papers entirely or substantially concerned with instrumentation of containing information about a particular measurement technique. References are divided into three sections according to subject: tracer gas methods, pressure tests, and other associated techniques such as thermography and acoustic detection of leakage paths.(Out of Print)
KEYWORDS measurement technique
#NO 3494 The Poly Air Dam: A new plastic gasket to improve airtightness.
BIBINF Alberta Municipal Affairs, Nov 15 1987, pp 1-85, 6 tabs, 32 figs. #DATE 00:00:1989 in English
ABSTRACT This booklet describes a project whose purpose was to develop an effective, inexpensive, simple product and technique to seal three pathways which are some of the major air leakage pathways occurring in houses. The pathways considered were: 1) Bottom plates/subfloor junction, 2) Rim joist/top of foundation wall junction and 3) Wall framing/window (door) jamb junction.
KEYWORDS air leakage, sealant, wall, window
#NO 3562 Ventilation and airtightness in energy balance analyses
AUTHOR Blomsterberg A
BIBINF in:UK, AIVC, 10th AIVC Conference, held at Espoo, Finland, 25-28 September 1989, Volume 1, February 1990, pp305-324, 4 tabs, 3 refs. #DATE 00:02:1990 in English
ABSTRACT Ventilation in buildings occurs as a consequence of natural air infiltration and through the use of purpose provided ventilation. The air infiltration part of ventilation is often difficult to determine for different boundary conditions. The influence of ventilation on the energy balance of a residential building is therefore usually determined as a remainder together with internal gains from people and the sun or given a constant value. This paper summarizes a report, on one-family houses, on: - the influence of ventilation and airtightness on the energy balance - methods of separating out the ventilation losses from the energy balance - the performance of different ventilation systems. The results are based on performance monitoring and evaluation during two years of four modern one-family houses with different ventilation systems. Two of the houses are equipped with mechanical exhaust-supply ventilation and two with mechanical exhaust ventilation. The ventilation systems were studied during several one-week periods using the constant concentration tracer gas technique. The airtightness of the houses was examined using the fan pressurization technique. The ventilation was predicted with a simplified theoretical one-zone model (the LBL-model) and a multi-zone network model (MOVECOMP). The energy balance was simulated with a dynamic simulation model (STAWAD). The following conclusions are valid for the examined houses. A simplified theoretical one-zone model can be useful and make accurate estimations of the air infiltration in tight houses with mechanical ventilation. This is also a very straightforward kind of model to employ. For less tight houses a multi-zone network model can be useful. There are however two problems with a multi-zone network model; it is time-consuming to put together all the inputs needed and there isn't enough data as to wind pressure and the location of leakage paths available.
KEYWORDS energy balance, mechanical ventilation, constant concentration, fan pressurisation
#NO 3797 Ventilation and the leakage characteristics of dwellings.
AUTHOR Galbraith G H, McLean R C, Stephen R
BIBINF UK, Building Serv. Eng. Res. Technol., Vol 10, No 3, 1989, pp115-122. #DATE 00:00:1989 in English
ABSTRACT As fabric heat losses decrease with improved thermal insulation, ventilation heat losses, as a fraction of the total, become relatively more important. Thus, further effective energy savings may best be achieved by reducing energy losses associated with excessive ventilation. However, a means of measuring ventilation levels, or the magnitude of the air leakage paths through which ventilation takes place, is required to ensure that sealing of some openings does not result in unacceptably low ventilation rates and the accompanying risks of condensation, mould and poor indoor air quality. The fan-pressurisation technique does not measure ventilation rate directly, but air leakage data may be used for comparisons between houses and to predict ventilation rates which would occur under natural conditions. Air leakage data for a sample of 32 traditionally constructed Scottish dwellings are presented and discussed. The mean air leakage rate in these dwellings was found to be 60% higher than that found in a sample of 100 dwellings throughout the UK. It is concluded that there is considerable scope for reducing air leakage rates,and therefore ventilation heat loss, in many Scottish dwellings.
KEYWORDS ventilation heat loss, leakage path, condensation, fan pressurisation
#NO 3880 Infiltration and leakage paths in single family houses - a multizone infiltration case study.
AUTHOR Bassett M
BIBINF UK, Coventry, AIVC, Technical Note 27, February 1990, 59pp. #DATE 00:02:1990 in English
ABSTRACT This document describes preliminary work towards validating models that predict air flow rates between several zones. It is preliminary in the sense that it examines the quality and definition of physical data needed for a more testing and thorough validation. The exercise has used a version of the multi-zone computer model developed by Walton at the National Bureau of Standards with some modifications to the treatment of wind pressure coefficients. The experimental data consisted of air flows between the subfloor, living space, and roof space zones for five single storey houses, together with air leakage rates from outside. There were approximately 300 data points supported with climatic data measured on site, and individual zone air tightness data. Satisfactory agreement was generally achieved between measured and calculated infiltration rates in each of the three zone types. The most uncertain components of input data were the wind pressure coefficients and the distribution of leakage openings to different parts of the building. Literature values for pressure coefficients and a simple area-based rule for allocating leakage openings to different surfaces was followed. In many cases, calculated inter-zone air flows were similar to measured air flows and in others, better definition of inter-zone air flow characteristics was clearly necessary.
KEYWORDS leakage path, multizone infiltration, validation, model
#NO 3895 Leakage distribution in buildings - an annotated bibliography. La distribution des fuites d'air dans les immeubles - une bibliographie commentee.
AUTHOR Allen C (translator: Emery J-P)
BIBINF Switzerland, Dubendorf, EMPA, Translation of AIVC Technical Note 16, Translated March 1987, 39pp. #DATE 00:03:1987 in French
ABSTRACT Examines those factors which can influence leakage distribution, including building style, construction quality, materials, ageing, pressure and variations in humidity.
KEYWORDS air leakage, humidity, leakage path
#NO 4039 Criteria for the air leakage characteristics of building envelopes: Final report.
AUTHOR Trow, Inc
BIBINF Canada, Canada Mortgage and Housing Corporation, Project B-03499-A, December 30, 1989. #DATE 00:12:1989 in English
ABSTRACT A procedure for estimating the moisture accumulation in building envelopes due to air leakage has been developed. It is based on the calculated, steady state thermal conditions resulting from anticipated, incremental changes in the indoor to outdoor temperature difference for a given locality. Monthly "bin" data, at two degree Celsius intervals, are utilized in a computer program to calculate the thermal conditions within a particular envelope for specific indoor conditions, and the amount of condensation expected to accumulate in the envelope is determined on the basis of the psychrometric processes involved and the physical arrangement and moisture absorption characteristics of the materials involved. The calculation procedure is based on the assumption that the air flowing through the envelope comes into thermal and moisture equilibrium with the surfaces that it contacts. This represents the condition when the maximum amount of moisture will be condensed from the air and absorbed by the surface, and hence is appropriate as a basis for establishing limiting criteria. If the air was assumed to flow through the envelope more rapidly, or by means of a shorter, more direct path, it would not be cooled as much, less moisture would be condensed, and less time would be available for absorption of the moisture by thematerials involved. The program calculates the coincident, maximum stack effect pressure difference, acting over a unit storey height, to determine the rate of air flow through the envelope for each temperature "bin". When applied to the actual number of storeys, this also represents a maximum condition insofar as stack effect is concerned. It is suggested that the less predictable effects of wind, air leakage of internal separations, the distribution of leakage openings, and exhaust fan operation tend to offset each other, and need be considered except as a subsequent modifier in considering specific buildings. The limit chosen to establish the maximum leakage opening area criteria is based on a material within an envelope reaching a critical moisture content above which deterioration or degradation occurs. A Delphi technique was employed to obtain the collective opinion of a panel of selected experts as to appropriate coefficients to be used in the program and the critical moisture content levels for a number of current building materials. Using these values, the procedure was employed to determine the applicable, limiting leakage opening areas for four representative wall constructions for seven climate regions of Canada.
KEYWORDS air leakage, building envelope, moisture
#NO 4837 Structure of models for the prediction of airflow and contaminant dispersal in buildings.
AUTHOR Grot R A, Axley J A
BIBINF UK, AIVC 11th Conference, "Ventilation System Performance", held 18-21 September 1990, Belgirate, Italy, Proceedings published March 1990, Volume 1, pp 223-266, 19 figs, 13 refs. #DATE 00:03: 1991 in English
ABSTRACT This paper treats the structure of models for predicting interzonal airflow and contaminant dispersal in buildings. It will discuss the mathematical structure of such models, the use of modern data structures, the application of structured program techniques and the use of object-oriented structures for the development of users interfaces and building description processes. Two computer models developed at National Institute of Standards and Technology (NIST) will be used as examples of how these techniques can be applied to air flow analysis and contaminant dispersal: NBSAVIS - a building description processor for multizone buildings, and CONTAM88 - an interzonal airflow and contaminant dispersal analysis program. NBSAVIS treats the building as a collection of physical objects which have flow and leakage characteristics and creates a building idealization (flow paths, zones and contaminant source data) from the physical description of the building. It will be demonstrated that with the proper data structure, general interfaces which are both user-friendly and physically correct can be developed. CONTAM88 combines previously developed interzonal airflow and contaminant dispersal analysis programs AIRMOV, CONTAM86 and CONTAM87 into one model which includes such features as contaminant reactions, pressure induced contaminant sources for modeling radon entry and plateout and disposition of contaminants onto surfaces. An example is presented on the use of these programs for airflow and contaminant dispersal analysis in a large apartment building.
KEYWORDS modelling, prediction, air flow, contaminant
#NO 4883 Technique for measuring the indoor 222Rn source potential of soil.
AUTHOR Nazaroff W W, Sextro R G
BIBINF USA, Environmental Science and Technology, Vol 23, April 1989, pp 451-457, 5 figs, 2 tabs, 23 refs. #DATE 00:04:1989 in English
ABSTRACT Elevated indoor 222Rn concentrations are often caused by high rates of entry from soil. The 222Rn source potential of soil depends on two parameters: the release rate of 222Rn into the soil pores and the volume of soil that can contribute itsemanated 222Rn to indoor air. These parameters are characterized, respectively, by the soil's 222Rn generation rate and its permeability. By measuring two quantities associated with air extracted from a soil probe-the 222Rn concentration and the flow rate associated with a specified dynamic pressure difference-both characteristics may be determined from a single procedure. A means of interpreting results from the probe technique to predict 222Rn entry potential into a basement with a perimeter leakage path is provided. In a field test of the technique, the measured 222Rn source potential in soils adjacentto a sample of four houses correlates well with measured indoor 222Rn concentrations.
KEYWORDS radon, soil, measurement technique
#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 theinertance 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 4994 A survey of air flow models for multizone structures.
AUTHOR Feustel H E, Dieris J
BIBINF USA, California, Lawrence Berkeley Laboratory, Applied Science Division, March 1991, 49pp, 2 figs, 1 tab, 27 refs. #DATE 00:03: 1991 in English
ABSTRACT Air flow models are used to simulate the rates of incoming and outgoing air flows for a building with known leakage under given weather and shielding conditions. Additional information about the flow paths and air-mass flows inside the building can only be made by using multizone air flow models. In order to obtain more information on multizone air flow models, a literature review was performed in 1984 [1]. A second literature review and a questionnaire survey performed in 1989, revealed the existence of 50 multizone air flow models, all developed since 1966, two of which are still under development. All these programs use similar flow equations for crack flow, but differ in the versatility to describe the full range of flow phenomena and the algorithm provided for solving the set of nonlinear equations. This literature review has found that newer models are able to describe and simulate the ventilation systems and interrelation of mechanical and natural ventilation.
KEYWORDS air flow, modelling, multizone
#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 5318 Estimation of air leakage in high-rise residential buildings.
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 251-252. #DATE 00:09:1991 in English
ABSTRACT A simplified air infiltration estimation procedure has been developed primarily based on equivalent air leakage area and local net pressure distribution. The pressure difference at a given location depends on the infiltration driving forces (stack, wind and mechanical ventilation) and the characteristics of the opening in the building envelope. A simplified network of air-flow paths can be established using the following information: climate and exposure, building types, building form, building dimensions, surface to volume ratios, shafts, and envelope types, windows and doors, envelope crack lengths, openings, and make-up air strategies. The algebraic sum of air-flow through these paths must always be equaled to zero. By applying the mass balance equation, component of air infiltration which would be occurring during the peak winter condition can be determined. This air-flow is responsible forthe space heating load due to uncontrolled infiltration. Any reduction in this infiltration flow should decrease the heating requirements for the building.
KEYWORDS air leakage, high rise building, cold climate
#NO 5378 Building technology and air flow control in housing.
BIBINF Sweden, Swedish Council for Building Research, Document D16:1991, 133pp. #DATE 00:00:1991 in English
ABSTRACT The objective of this thesis is to examine the importance of building technology on air leakage for mainly new Swedish multi-family buildings. Air leakage in buildings can be divided into external air leakage through the building envelope andinternal air leakage which occurs within a building. The different consequences of these two types of air leakage are examined in the thesis. Basic equations for different air flow paths have been reviewed and compared with measurement results.Fan Pressurization test results should be used with great care outside the measured pressure range as air flow characteristics, for some types of air leakage paths, were found to vary with pressure difference. Important air leakage paths in buildings are described. Many examples of building construction details and recommended solutions for airtightness are discussed. Careful planning and control at the building site is important for achieving airtight buildings. The choice of building system and assembly details must be selected for simplicity of on-site construction. The number of penetrations should be minimized. Air change rates measured in three apartments were found to be constant and close to the fan-controlled air flows. The airtightness in these building envelopes was between 0.8 and 1.0ach/h at 50 Pa, and that seems to be sufficient in terms of controlling the overall air change rates. Internal air leakage between apartments measured by Fan Pressurization has been foundto account for between 12 and 50 per cent of the total air leakage. High pressure differences are easily obtained in new Swedish apartment buildings. When applying forced kitchen extract ventilation, measured pressure differences between the inside andoutside of buildings were found to be between about 0 to 100 Pa. As a result of this, internal air leakages up to 12 m3 /h between apartments were found. Depending on conditions in adjacent apartments, these air flows may cause occasional odour and pollutant problems. Ventilation systems and means of forcing the kitchen air flow that do not cause big pressure differences shouldbe favoured.
KEYWORDS air flow, air leakage, air change rate, pressure difference
#NO 5693 Airtightness and air quality in preserved wood foundations.
AUTHOR Buchan, Lawton, Parent Limited
BIBINF Canada Mortgage and Housing Corporation, February 1992, 22pp. #DATE 00:02:1992 in English
ABSTRACT Infiltration of soil gas into basements is a cause of indoor air quality problems. Very little research has been conducted on air quality concerns that specifically relate to preserved wood foundations (PWF). This report documents the findings of a field study that examined the air leakage characteristics of preserved wood foundations. The study also investigated the level of "off-gassing" from the chemicals used for wood preservation in PWF basements. The field work involved four types of testing on fourteen homes. The highlight of this study was the development of a test protocol to determine the air leakage characteristics of the basement portion of a house. The test protocol was then modified to ascertain the leakage of specific cracks in the basement. Unfortunately the testing protocol could not be used to determine the level of below grade air infiltration because the majority of the air leakage into PWF basements was found to be around windows and headers. The basement wall cavity air was sampled and analyzed for volatile organic compounds. Chemicals encountered were compared to those used in the wood preserving process. All concentrations found were very low and well underthe Ontario Ministry of the Environment ambient air quality criteria. To determine likely below-grade air infiltration paths, samples of wall cavity air, basement air, and air from below sleeper floors were taken and analyzed for radon levels.
KEYWORDS air tightness, indoor air quality, wood, foundation
#NO 5742 Mad air on the rise.
BIBINF USA, Northern Building Science, January/February 1992, pp 8-9, 1 fig. #DATE 00:01:1992 in English
ABSTRACT John Tooley, from Natural Florida Retrofit, Inc. came to Anchorage in December to give weatherization crews a workshop on stopping what he has coined "MAD-AIR" and reducing duct leakage. Although Tooley began his research in warm climates evaluating the effect of air conditioner fans and duct leakage, he has since travelled throughout the U.S. and Canada and has foundthat MAD-AIR is a significant problem everywhere.
KEYWORDS duct, air infiltration, air flow, air leakage
#NO 5832 Air flow patterns within buildings: measurement techniques.
AUTHOR Roulet C-A, Vandaele L
BIBINF UK, Air Infiltration and Ventilation Centre, Technical Note AIVC 34, December 1991 (IEA Annex XX Final Report). #DATE 00:12:1991 in English
ABSTRACT This handbook is concerned with the measurement of those parameters which are important in gaining an understanding of air infiltration and ventilation. The handbook has been designed so that the material suited to your particular level of interest or current expertise, is readily accessible. The flow chart in Figure 1.1 illustrates the structure. The introduction provides a general overview of infiltration and ventilation in buildings. Ventilation studies are discussed and the aims of the handbook outlined. Part I defines the parameters which are important, presents the reasons why they should be measured and gives a guide to the selection of techniques for particular applications. Summaries of the main techniques available are presented, which are cross referenced with the main body of the handbook. Part II presents the theory and practice of measuring the airtightness of the building envelope and its components.Leakage location and leakage path distribution within the building is also examined. Part III presents the theory and practice of measuring air exchange rates and the related contaminant flow rates. Air exchange between a building and the external environment is examined, as is the air exchange between the various internal spaces of a building. Part IV presents some measurement methods which may be useful to qualify the indoor air and the efficiency of the ventilation system. Measurement of contaminant concentrations are however not described, since another book will be necessary to describe all the possible methods to analyze the thousands of possible contaminants. PartV describes measurement methods which are able to qualify a system, namely to measure the flow rates in the ventilation network and to control its airtightness.
KEYWORDS air flow, measurement technique, air leakage, ventilation system, energy efficiency
#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 6076 Impact of inter-space airflow on air humidity behaviour within buildings.
AUTHOR El Diasty R, Budaiwi I, Fazio P
BIBINF Japan, Society of Heating, Air Conditioning and Sanitary Engineers of Japan, 1992, proceedings of the International Symposium on Room Air Convection and Ventilation Effectiveness - ISRACVE, held at the University of Tokyo, 22-24 July, 1992, pp 584-605. #DATE 22:07:1992 in English
ABSTRACT Indoor spaces in a multi-space building are not dully separated since interconnecting elements such as doorways do exist. The presence of inter-space air-flow introduces additional physical characteristics that need to be addressed in order to accurately account for moisture transfer between interconnected spaces by air movement. The objective of this paper is to report the results of a recent study to model and analyse the effect of inter-space air movement within multi-space buildings on air humidity behaviour within each individual space. The influence of inter-space airflow paths characteristics, zonal arrangement, and the building envelope are examined. Moreover, the combined effect of air leakage through the building envelope are examined. Moreover, the combined effect of air leakage through the building envelope and the inter-space air movement on the space air humidity behaviour is analysed. Assuming known pressure in each space, the corresponding airflow rates were evaluated for the various building airflow elements. The mass balance concept is then utilised in conjunction with the airflow network modelling technique in order to obtain a set of nodal nonlinear algebraic equations representing the mass balance atdifferent spaces. The spatial pressures are evaluated by simultaneously solving the resulting mass balance equations. The air humidity behaviour in each space as well as the moisture interaction between different spaces are modelled via a system of differential equations which are solved simultaneously to determine air humidity conditions in each space. A case study is presented along with a parametric analysis to demonstrate the influence of each parameter as well as to show the advantage of the proposed model and thecomputation procedure. Air humidity behaviour showed significant difference when inter-space airflow was considered.
KEYWORDS humidity, moisture, air flow, building envelope
#NO 6671 The dynamic modelling of air humidity behaviour in a multi-zone space.
AUTHOR El Diasty R, Fazio P, Badaiwi I
BIBINF UK, Building and Environment, Vol 28, No 1, 1993, pp 33-51, 21 figs, 22 refs. #DATE 00:00:1993 in English
ABSTRACT Single-zone dynamic modelling of air humidity can fairly account for most moisture transfer processes in single-zone buildings. However, such models cannot truly represent air humidity behaviour in most buildings since they have distinct interior partitioning of their volumes. A dynamic model to describe the air humidity behaviour and to determine its variations in a multi-zone space is proposed. The model accounts for boundary conditions variation from one zone to another, the different zonal interaction with the outdoor environment and the individual zonal functional and physical characteristics. The model accounts for both diffuse moisture transfer and convective moisture transfer due to inter-zonal air movement. A multi-cell air flow model that accounts for individual zone air flow, air flow through the envelope in each zone and the interzonal air flow is incorporated. Air humidity within each zone is determined through a simultaneous solution of a set of linear algebraic equations using time dependent humidity parameters. A discrete time interval approach was used since most moisture transfer processes are not continuous in nature. A case study on a six-zone building space is presented to demonstrate the airhumidity behaviour in a multi-zone space as well as to examine the effect of the influencing parameters such as wind speed and direction, air leakage characteristics, indoor moisture generation, surface condensation, inter-zonal air temperature variation, and building materials absorption and desorption. The results also showed the uniqueness of individual zones air humidity behaviour and its dependence on its relative location along the building air humidity flow path.
KEYWORDS modelling, humidity, multizone
#NO 6832 Power demand and energy savings through air leakage control in high-rise residential buildings in cold climates.
BIBINF Paper presented at the Fifth Conference on Thermal Performance of the Exterior Envelopes of Buildings, Building Thermal Envelopes Co-ordinating Council, December 7-10, 1992, Clearwater, Florida, USA, 12pp, 7figs, 2tabs, refs. #DATE 00:12: 1992 in English
ABSTRACT The air leakage rate in high-rise residential buildings predominantly depends on the stack and wind forces acting on the envelope, the operation of mechanical equipment, and the characteristics of leakage paths. During peak cold weather conditions, air leakage in the buildings also peaks, putting an additional burden on the space-heating system. Air leakage control has the potential to reduce electric space-heating loads. A method has been developed to determine the air leakage rate for high-rise residential buildings. Visual inspection of air leakage paths, aided by simple field tests, and assigning components airtightness characteristics are important parts of the air leakage control assessment procedure (ALCAP). This assessment procedure was applied and field-demonstrated in two high-rise residential buildings. The field comparison was accomplished by undertaking proven whole-building air-tightness tests and monitoring energy and power demands. The results for two high-rise buildings can be summarized as follows: (1) air leakage control offered a reduction in peak space-heating demand by 4 to 7 w/m2 of floor space, depending on the location and building characteristics; (2) the air leakage assessment procedure was found to be reliable within 10% in predicting the potential reduction in peak space-heating demand; and (3) the indoor air quality tests performed before and after the airsealing showed that there was no negative impact on the general conditions of comfort and air quality in both buildings.
KEYWORDS high rise building, cold climate, energy saving, air leakage
#NO 6953 Power demand and energy savings through air leakage control in high-rise residential buildings in cold climates.
BIBINF Proceedings of the ASHRAE/DOE/BTECC Conference, December 7-10, 1992, 'Thermal Performance of the Exterior Envelopes of Buildings', Clearwater Beach, Florida. #DATE 00:12:1992 inEnglish
ABSTRACT The air leakage rate in high-rise residential buildings predominantly depends on the stack and wind forces acting on the envelope, the operation of mechanical equipment, and the characteristics of leakage paths. During peak cold weather conditions, air leakage in the buildings also peaks, putting an additional burden on the space-heating system. Air leakage control has the potential to reduce electric space-heating loads. A method has been developed to determine the air leakage rate for high-rise residential buildings. Visual inspection of air leakage paths, aided by simple field tests, and assigning components airtightness characteristics are important parts of the air leakage control assessment procedure (ALCAP). This assessment procedure was applied and field-demonstrated in two high-rise residential buildings. The field comparison was accomplished by undertaking proven whole-building airtightness tests and monitoring energy and power demands. The results for two high-rise buildings can be summarized as follows: (1) air leakage control offered a reduction in peak space-heating demand by 4 to 7 W/m2 of floor space, depending on the location and building characteristics; (2) the air leakage assessment procedure was found to be reliable within 10% in predicting the potential reduction in peak space-heating demand; and (3) the indoor air quality tests performed before and after the airsealing showed that there was no negative impact on the general conditions of comfort and air quality in both buildings.
KEYWORDS air leakage, high rise building, cold climate, energy saving
#NO 7063 Thermography: its applications for building air leakage measurements.
AUTHOR Roberts J W, Ward I C
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, pp533-542. #DATE 21:09:1993 in English
ABSTRACT Preliminary work has indicated that thermography can be used to determine air leakage pathways from or to buildings. Accurate measurements have now been taken using temperature controllable environmental chambers.These results reinforce the potential useof thermography for this application. In conjunction with the physical measurements a simulation has been carried out using computational fluid dynamics. The two sets of results are found to be in good agreement with each other thus validating the computer model, and give further proof of the adaptability of thermography for building air leakage measurements.
KEYWORDS thermography, air leakage, computational fluid dynamics
#NO 7272 Three surveys of subfloor moisture in New Zealand.
AUTHOR Trethowen H A.
BIBINF USA, Ashrae Transactions, Vol 100, Pt 1, 1994, (preprint), 11pp, 10 figs, 3 tabs, refs. #DATE 00:00:1994 in English
ABSTRACT This paper outlines three surveys relating to moisture in house crawl spaces in a cool temperate climate and conclusions drawn from them. The surveys were: - Atwo-year survey of 10 houses, monitoring moisture conditions in crawl spaces and roof spaces where the two were coupled by air leakage paths. Three different remedial treatments were tested, including covering the ground with polyethylene film. This ground cover was assessed later as at least 70% and possibly up to 95%effective. - A pilot study on measurement of subfloorground evaporation using lysimeters, leading to a one-year survey on ground evaporation under 60 houses inthree towns. Average evaporation was approximately 400 g/ (1.3 oz/ - A small survey on subfloor natural ventilation rates and the interchanges between the subfloor and other parts of the building. This survey showed that a NIST model correlated well with observed air exchange.
KEYWORDS survey, floor, moisture, crawlspace, ventilation rate.
#NO 7360 Modelling radon transport in multistory residential buildings.
AUTHOR Persily A K.
BIBINF USA, ASTM, authorized reprint from Standard Technical Publication 1205, 1993, pp 226-242, 8 figs, 6 tabs, 13 refs. #DATE 00:00:1993 in English
ABSTRACT Radon concentrations have been studied extensively in single-family residential buildings, but relatively little work has been done in large buildings, including multistory residential buildings. The phenomena of radon transport in multistory residential buildings is made more complicated by the multizone nature of the airflow system and the numerous interzone airflow paths that must be characterized in such a system. This paper presents the results of a computer simulation of airflow and radon transport in a twelve-story residential building. Interzone airflow rates and radon concentrations were predicted using the multizone airflow and contaminant dispersal program CONTAM88. Limited simulations were conducted to study the influence of two different radon source terms, indoor-outdoor temperature difference and exterior wall leakage values on radon transport and radon concentration distributions.
KEYWORDS radon, modelling, residential building, indoor air quality.
#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 8009 Flow paths in a Swedish single family house - a case study.
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 8017 Measuring subfloor ventilation rates.
AUTHOR Hartless R, White M K
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, pp687-696.
ABSTRACT This paper reports on ventilation measurements taken beneath a suspended floor of a BRE/DoE energy and environment test house. Sulphur hexafluoride was introduced into the subfloor void at a constant rate andthe resulting concentration measured. Wind speed, wind direction, and internal, external and subfloor temperatures were also recorded. A range of air brick locations were used for each run which lasted two to three days. Analysis of the data shows that subfloor ventilation rates in this test house fluctuated widely, ranging from about 3 air changes per hour (ach) to over 13 ach. Also, the subfloor ventilation rate for this house seems to be heavily influenced by the subfloor/external temperature difference rather than the wind speed, particularly when air bricks are located on sheltered subfloor walls. The main reason for this stack dependence is that there is a significant leakage path at the wall/floor junction with air moving from the subfloor void to the gap behind the plasterboard lining.
KEYWORDS (crawlspace, ventilation rate, measurement technique, floor, wall, air leakage)
#NO 8063 Blower door cruise control.
BIBINF USA, Home Energy, March/April 1994, pp 7-8.
ABSTRACT The use of pressure differential diagnostics to measure and interpret air leakage is changing the way blower-door users approach buildings. While measuring series leakage paths can give practitioners a better understanding of building dynamics, the techniques involved can sometimes be cumbersome. Technicians working for Mass-Save Incorporated have been using a new flow control system that simplifies the diagnostic process. This system maintains a consistent house pressure relative to the outside by automatically adjusting fan speed. As the technician moves throughout the building opening various size holes into zones, the pressure difference will automatically return to 50 Pa, or any other preset pressure.
KEYWORDS (blower door, air leakage)
#NO 8180 Design issues for natural ventilation in the UK: commercial and public buildings.
AUTHOR Perera MDAES, Gilham A V, Croome D J
BIBINF UK, CIBSE (Chartered Inst of Building Services Engineers), 1994, proceedings of CIBSE National Conference 1994, held Brighton Conference Centre, 2-4 October 1994, Volume 2,pp 83-89.
ABSTRACT The principle of good design for natural ventilation is to 'build tight - ventilate right'. That is, to minimise uncontrolled infiltration by making the building envelope airtight, and to provide the necessary ventilation with 'fresh' air in a controlled manner. It is necessary to emphasise that a building cannot be 'too tight' - but it can be underventilated. There is considerable scope for making UK buildings tighter. However, simpler techniques need to be developed (especially in large non-domestic buildings) to identify envelope tightness and associated leakage paths. Criteria relating to comfort, especially those associated with odour, metabolic CO2 and summer overheating need to be investigated. Guidelines observed in designing for natural ventilation may conflict with other design or climate-responsive strategies. This is the key issue which future work should address.
KEYWORDS (natural ventilation, commercial building, public building)
#NO 8916 The use of blower door data. 
AUTHOR Sherman M 
BIBINF Indoor Air, No 5, 1995, pp 215-224, 1 fig, 3 tabs, refs. 
ABSTRACT The role of ventilation in the housing stock is to provide fresh air and to dilute internally generated pollutants in order to assure adequate indoor air quality. 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, accurate understanding of the uses of blower-door data is critical. Blower doors can be used to answer the following questions: * What is the construction 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 lose? * Is this building too tight? * Is this building too loose? * When should mechanical ventilation be considered? Various ASHRAE Standards (e.g. 62, 119 and 136) are used to determine acceptable ventilation levels and energy requirements. 
KEYWORDS blower door, residential building, air tightness, air leakage, building envelope
#NO 9635 Natural ventilation in the United Kingdom: design issues for commercial and public buildings.
AUTHOR Perera M D A E S, Gilham A V, Clements-Croome T D J
BIBINF UK, Building Serv Eng Res Technol, Vol 17, No 1, 1996, pp 1-5, 2 figs, 15 refs.
ABSTRACT The principle of good design for natural ventilation is to "build tight - ventilate right". A building cannot be `too tight', but it may be under-ventilated. There is considerable scope for making UK buildings tighter. However, simpler techniques need to be developed (especially in large non domestic buildings) to identify envelope tightness and associated leakage paths. Also guidance needs to be provided on constructing tighter envelopes. Studies necessary to assess the implication of tighter buildings are described. Sufficient information is available on ventilation requirements necessary to satisfy safety and health criteria. However, criteria relating to comfort, especially those associated with odour, metabolic CO and summer overheating need to be investigated. The paper also discusses minimising the effects of tobacco smoke and controlling other internally generated pollutants. Guidelines for natural ventilation design may conflict with other design or climate-responsive strategies, future work should address this, and address issues such as ventilation openings (to provide both "background" and "rapid" ventilation) and design for deeper, naturally ventilated buildings.
KEYWORDS natural ventilation, commercial building, public building, air leakage
#NO 10123 Cardboard box demonstration of series leakage. The Energy Conservatory ACEEE '96.
USA, The Energy Conservatory, ACEEE '96, 1996.
A simple model consisting of a box on top of another box can be used to demonstrate the measurement of series leakage paths. Series leaks are leaks which are not directly connected to the outside, but pass through an intermediate zone (for example a crawl space, attic or garage) on their way into or out of a building. A number of simple pressure diagnostic techniques have been developed allowing us to estimate the leakage areas of series leaks.
air leakage

#NO 10265 Field comparison of design and diagnostic pathways for duct efficiency evaluation. 
Andrews J W 
USA, Washington DC, American Council for an Energy Efficient Economy (ACEEE), Proceedings of the 1996 Summer Study on Energy Efficiency in Buildings, "Profiting from Energy Efficiency". 
A new method of test for residential thermal distribution efficiency is currently being developed under the auspices of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). This test method will have three main approaches, or ``pathways,'' designated Design, Diagnostic, and Research. The Design Pathway uses builder's information to predict thermal distribution efficiency in new construction. The Diagnostic Pathway uses air-flow, temperature, and pressure-difference tests intended to take one to four hours_to evaluate thermal distribution efficiency in a completed house. For forced-air systems, three distinct techniques are being considered, one based on thermal inputs and outputs in the duct system, the second based on pressure and leakage-area measurements, and the third based on pressure differentials induced in the house by partial blockage of the return duct. This paper presents and discusses the results of Design Pathway calculations based on measured duct-system and floor-plan layouts and surface areas (in lieu of building plans) for fifteen residential duct systems in Long Island, New York. These are compared with measured Diagnostic Pathway efficiencies in eight of these homes. 
duct, energy efficiency, standard

#NO 10269 Diagnostics and measurements of infiltration and ventilation systems in high rise apartment buildings. 
Feustel H E, Diamond R C 
USA, Washington DC, American Council for an Energy Efficient Economy (ACEEE), Proceedings of the 1996 Summer Study on Energy Efficiency in Buildings, "Profiting from Energy Efficiency" 
The provision of ventilation air for high-rise multifamily housing has plagued retrofit practitioners and researchers alike. How does one determine whether sufficient levels of outdoor air are being provided to all apartments in a building? And how does one know whether the systems can be retrofit to improve their energy efficiency without compromising air quality? We have been studying the air flows and ventilation systems in high-rise buildings in Massachusetts and in California, and have seen all the horror stories of poorly functioning systems that are neither efficient nor deliver satisfactory ventilation. Frequent problems include the imbalance of supply and exhaust air, the lack of an unobstructed path for supply air, differences in ventilation rates between upper and lower floors and a change in air flow due to seasonal variations in temperature and wind. Based on our diagnostic tests of air flow and air leakage, which we use with our multi-zone airflow computer simulations, we have characterized some common problems and suggest strategies to improve the performance of these systems. 
apartment building, high rise building, outdoor air

#NO 11057 System effects on filtration efficiency.
Carlsson T, Blomsterberg A
USA, Washington DC, Healthy Buildings/IAQ '97, 1997, proceedings of a conference held Bethesda MD, USA, September 27 - October 2, 1997, Volume 3, pp 347-352, 3 figs, 2 tabs, 3 refs.
Allergies and over-sensitivity have become very common and are increasing. Every third child and every fourth adult is affected in Sweden. As we spend close to 90% of our life indoors, the quality of our dwellings is of crucial importance. Therefore, a block of flats adapted to the needs of allergic persons was build in Gotborg, Sweden. A technical evaluation was carried out from 1990 to 1996, covering the design, the construction and the handing over and occupation phases. A thorough examination of the particle content and of the indoor air was performed. Some outdoor air enters through leakage pathways in the building envelope. The size of this airflow depends on how leaky the envelope is and the balance of the airflow between exhaust and supply air. Another parameter that has an impact on filtration efficiency is how much air bypasses the filter cassette. Results show that a ventilation system installed with a class F7 filter gives a filtration efficiency corresponding to a class F6 filter, depending on leakage effects in the envelope and the system.
pollutant, allergies, filter
#NO 11101 Measured and modelled duct efficiency in manufactured homes: insights for standard 152P.
Francisco P W, Palmiter L
USA, Ashrae Transactions, Vol 104, Pt 1, 1998, 12pp, 7 figs, 9 tabs, refs.
Modeling of delivery efficiency was performed using three levels if combing measured and default input parameters and compared to measured data from seven manufactured homes. Using values based in all measured data provided modeled efficiency results that were closest to short-term coheat efficiency results. As individual measured parameters were replaced by estimated or default values suggested by the draft version of proposed ASHRAE Standard 152P, the agreement with measured efficiency results worsened. The primary parameters that were varied were the leakage to outdoors and the temperatures in the buffer spaces in which the ducts were located. All of the models gave results that were on average, within 8 percentage points of measured results. However, simple modifications to the way in which the estimated or default values were not used and that the comparisons were for a very simple type of house, as manufactured homes do not have return duct systems. Additional suggestions are made on ways to improve the determination of input parameters for modeling paths suggested by Standard 152P that were not compared to measured results in this paper.
duct, mobile home, standard
#NO 11228 Monitoring of the building envelope of a heritage house. A case study.
Said M N A, Brown W C, Shirtliffe C J, Maurenbrecher A H P
Germany, Fraunhofer Institute of Building Physics, proceedings of "Retrofitting in commercial and institutional buildings", an IEA Future Buildings Forum Workshop held in Stuttgart, Germany, April 28-30, 1997, pp 241-258, 10 figs, 1 tab.
The paper describes the long-term monitoring of the hygrothermal performance of the building envelope of a heritage house located in Ottawa. The house, once the residence of two of Canada's Prime Ministers, now serves as a museum. To preserve the historical artifacts within the building, the specified temperature and relative humidity for the indoor air are 21oC and 35% to 50% respectively. As the house must also be preserved, there was concern about the effect of the high indoor relative humidity (moisture) on the durability of the building structure. The main objective of the monitoring was to assess the effect of the conditioned air on the building envelope. Selected wall sections and a window were continuously monitored from March 1995 to August 1996. The monitoring included indoor and outdoor conditions and the attic environment. Temperature, relative humidity, surface wetting-drying cycles (from precipitation or condensation), and air pressure differential were monitored. This paper describes the monitoring approach and results. The results indicated that he brick walls are unlikely to experience internal condensation problems as long as they are subjected to negative air pressure difference. However, because the building is quite leaky, the negative pressure introduced too much cold dry air from the exterior. It caused localized cold spots with condensation and ice formation on interior of walls and ceiling. Negative air pressures difference are not a solution unless the leakage paths are reduced.
building envelope, retrofitting
#NO 11481 Air Flow Distribution in a High-Rise Residential Building
Feustel H E, Diamond R C
Sweden, Stockholm, KTH Building Services Engineering, 1998, proceedings of Roomvent 98: 6th International Conference on Air Distribution in Rooms, held June 14-17 1998 in Stockholm, Sweden, edited by Elisabeth Mundt and Tor-Goran Malmstrom, Volume 1, pp 29-36.
The provision of ventilation air for high-rise multifamily housing has plagued retrofit practitioners and researchers alike. We have been studying the air flows and ventilation systems in high-rise buildings in Massachusetts and in California, and have seen all the horror stories of poorly functioning systems that are neither efficient nor deliver satisfactory ventilation. Frequent problems include the imbalance of supply and exhaust air, the lack of an unobstructed path for supply air, differences in ventilation rates between upper and lower floors and a change in air flow due to seasonal variations in temperature and wind. Based on our diagnostic tests of air flow and air leakage, which we use with our multi-zone airflow computer simulations, we have characterized some common problems and suggest strategies to improve the performance of these systems.
air distribution, high rise building, ventilation performance
#NO 11534 Simulation of infiltration heat recovery. 
Buchanan C R, Sherman M H
UK, Air Infiltration and Ventilation Centre, proceedings of "Ventilation Technologies in Urban Areas", 19th Annual Conference, held Oslo, Norway, 28-30 September 1998, pp 17-26.
Infiltration has traditionally been assumed to affect the energy load of a building by an amount equal to the product of the infiltration flow rate and the enthalpy difference between inside and outside. Results from detailed computational fluid dynamics simulations of five wall geometries over a range of infiltration rates show that heat transfer between the infiltrating air and walls can be substantial, reducing the impact of infiltration. The classical method for determining the infiltration energy load was found to over-predict the amount by as much as 95 percent and by at least 10 percent. However, in order to achieve significant heat recovery, flow paths which are unlikely in adventitious leakage are required.
CFD, modelling, adventitious ventilation
#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 11887 Airtightness of U S 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
#NO 11923 Comparison of residential air infiltration rates predicted by single-zone and multizone models.
Musser A, Yuill G K
USA, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc (ASHRAE), 1999, in: the ASHRAE Transactions CD, proceedings of the 1999 ASHRAE Winter Meeting, held Chicago, USA, January 1999, 8 pp, 2 figs, 5 tabs, refs.
Residential air infiltration rates predicted by a detailed multizone computational model are compared with those predicted by a single-zone model. The multizone model is created using the public domain program CONTAM96, which allows the user to break the house into a number of zones connected to one another and the outdoors by leakage paths and user-defined characteristics. Actual floor plans for a ranch-style house and typical published leakage characteristics of residential building components are used to construct a very detailed model with roughly 2,000 zones and 7,000 leakage paths. The leakage path configuration of this multizone model is then validated by performing fan pressurization tests on two houses constructed according to the floor plan used to develop the computational model. At pressure differences typical of infiltration conditions, the leakage of the multizone model is in between that of the two identical houses. Infiltration rates computed by the multizone model for representative outdoor temperatures and wind speeds are then compared to those predicted by the single-zone LBL model. Four ventilation systems are modeled: no mechanical ventilation or exhaust, supply fan only, exhaust fan only, and balanced supply and exhaust fans. Comparisons are initially made based on the single-zone model predictions using typical assumptions,. The multizone computational model is then used to calculate more precise wind parameters and building leakage characteristics for use in the single-zone model, and the resulting infiltration is again compared with that predicted by the multizone model. These comparisons show that the predictions of both models are sensitive to the choice of wind-related parameters and that the assumption that leakage is evenly distributed throughout the building envelope has little effect on the predictions of the single-zone model. The predictions of the single-zone model most closely match those of the multizone model when flows are added using a quadrature method that takes into account the flow exponent obtained using the multizone model.
air infiltration rate, multizone model
#NO 12214 Comparison of modelled and measured tracer gas concentrations in a multizone building.
Sextro R G, Daisey J M, Feustel H E, Dickerhoff D J, Jump C
UK, Garston, BRE, 1999, proceedings of Indoor Air 99, the 8th International Conference on Indoor Air Quality and Climate, and the Air Infiltration and Ventilation Centre (AIVC) 20th Annual Conference, held Edinburgh, Scotland, 8-13 August 1999, Volume 1, pp 696-701.
Few detailed comparisons of modelled and measured pollutant concentrations in multizone buildings have been published. The COMIS air flow and contaminant transport model permits simulation of the effects of building and HVAC operation, as well as the influence of the local meteorology, on air flows within the building. We have recently used this model to simulate the release of a gas-phase tracer in a three-story, multi-room building located at Dugway Proving Ground, Utah, USA. Following detailed leakage and flow-path characterisation measurements of the building, experiments were conducted in which tracer gas concentrations were measured as a function of time in each room of the building. Comparison of the simulations with these detailed measurements showed reasonable-and in some cases, quite good - agreement. The paper describes some details of the experiments and modelling and discusses the differences between the observed and the predicted concentrations.
tracer gas, modelling, measurement technique, multizone building
#NO 12776 Analysis of wind-induced internal pressure in enclosures.
Miguel A F, Silva A M
Energy and Buildings, No 32, 2000, pp 101-107, 15 figs, 2 tabs, 13 refs.
A mathematical approach is developed for the dynamics of wind-induced pressures within enclosures. The model is based on the equations of mass conservation and motion, and the state equation of gases. It takes into account the characteristics of leakage paths of enclosure, the volume and flexibility of the enclosure envelop and objects within the enclosure. A sensitivity study is performed to examine the influence of these parameters on the dynamics of the internal pressure. 
pressure, dynamic response, opening; window, door, modelling
#NO 12790 Impact of added insulation on air leakage patterns.
Derome D, Fazio P, Desmarais G
Canada Mortgage and Housing Corporation, External Research Program Research Report, January 2000, 71 pp.
Adding insulation to exterior walls may worsen the original wall performance. Depending on the amount and geometry of air leakage in the original wall, added insulation may actually increase the potential for condensation, letting water accumulate in the wood structure and leading to rot.
An experiment was set up to compare the performance of different leaky walls and to investigate their behaviour with insulation added on one side or other of the wood studs. The experiment also maps the path of air leakage. The test conditions represented winter and late spring weather in Montreal,
It was found that the first measure to be considered remains the sealing and air tightening of the existing walls, with special care given to junctions and to punctures. If not sealed, leaky walls were found to accumulate moisture, especially when insulated on the outside. 
external insulation, air leakage, wall
#NO 13093 Air flow and thermal analysis of a forced air heating and ventilation system.
Levin P
UK, Air Infiltration and Ventilation Centre, proceedings of "Innovations in Ventilation Technology", 21st AIVC Annual Conference, held The Hague, Netherlands, 26-29 September 2000, paper 44.
The prediction of energy use, air flows and temperatures in different rooms of a building and at different climatic conditions is very important, especially when evaluating new concepts for heating and ventilation systems in combination with different building envelope constructions. A thorough system analysis considering coupled air flow and thermal calculations becomes very complex if e.g. thermal bridges and dynamic conditions are considered. The substance of this paper is to describe a relatively simple methodology for system analysis that has been applied to a house and to compare obtained results from measurements and calculations. 
The methodology consists of initial calculation of air flows using the multi-zone model IDA-MAE for different configurations and climatic conditions. The air flows are then included in a TSBI3 computer model for temperature and energy use calculations. 
User-friendly computer tools that combine multi-zone air flow and thermal calculations are desired to simplify a sensitivity analysis, and this will also increase the precision in the predictions. This development is in progress internationally. Further development of field methods to measure the air leakage characteristics of building components and individual air leakage paths would be useful to increase the knowledge of, in particular, interior air leakage paths in buildings.
The evaluated building concept, called TEEG, uses a heated crawlspace to distribute ventilation and heating air through gaps in the floors along the external walls. As the system relies on distribution of warm air through gaps in the floors, it becomes very sensitive to uncontrolled air leakage paths. Measurements of air leakage become an important quality control tool for buildings using this concept.
forced air heating, air flow, building envelope, multizone modelling, crawlspace
#NO 13109 Airtightness of French dwellings: results from field measurement studies.
Litvak A, Guillot K, Kilberger M, Boze D
UK, Air Infiltration and Ventilation Centre, proceedings of "Innovations in Ventilation Technology", 21st AIVC Annual Conference, held The Hague, Netherlands, 26-29 September 2000, paper 60.
A field measurement study of the airtightness of 73 - less than 5 year old - French dwellings was led between 1999 and 2000. Buildings have been selected and classified according to the construction structure, the thermal insulation and the occupancy mode. Using a fan-depressurization technique, we assessed the air leakage rate of each dwelling with two depressurization tests. Meanwhile quantifying air leakage rates, we observed qualitatively the most frequent locations of air leakage paths using a smoke detection method and infrared thermography. We assessed the ratio of the air leakage rate weighted by intrinsic dimensions of each construction, namely : the unheated surfaces and the heated volume. From our results, we compare the performances of the different types of dwellings and we assess the impact of the envelope airtightness on the building ventilation efficiency. We show that thermal performances of buildings can be dramatically affected according to the dwelling construction characteristics. Finally, we discuss the potentials for reducing indoor air infiltration with a view to improve the indoor air quality and the energy efficiency of buildings.
air tightness, residential building, field measurements, air infiltration, building envelope
#NO 13115 Evaluation of energy performance on nine identical row houses in Montreal.
Zmeureanu R G, Marceau M L, Payer J, Derome D
USA, Atlanta, American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), 1998, proceedings of "Thermal performance of the exterior envelopes of buildings VII" a conference held Sheraton Sand Key Hotel, Clearwater Beach, Florida, 6-10 December 1998, pp 81-86, 2 figs, 2 tabs, refs.
A detailed evaluation of the energy performance of nine identical row houses, built in 1994 on the same street by the same contractor, was performed in response to the homeowners' complaints. The energy audit was performed between January and March 1997 and covered both the house envelope and the heating system. This paper presents the process followed in this evaluation and the major problems noticed, such as leaky envelope, unexpected pathways for cold air, or closed dampers of the heat recovery unit. A comparison with some reference or target values is also presented. Finally the impact of some energy conservation measures is evaluated.
terraced house, energy audit, air leakage, building envelope
#NO 13121 EIFS hygrothermal performance due to initial construction moisture as a function of air leakage, interior cavity insulation, and climate conditions.
Salonvaara M H, Karagiozis A N
USA, Atlanta, American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), 1998, proceedings of "Thermal performance of the exterior envelopes of buildings VII" a conference held Sheraton Sand Key Hotel, Clearwater Beach, Florida, 6-10 December 1998, pp 179-188, 15 figs, 1 tab, refs.
The drying capability of an EIFS wall system with initial construction moisture critically depends on the climatic conditions in which it is placed. The drying rate mechanisms with which walls redistribute and transport moisture away from the envelope may affect the service life of the wall system. Potential moisture-inducted damage becomes important when the wall is not properly designed with adequate drying capacity.
This paper investigates the drying performance of a particular EIFS (exterior insulation and finish system) clad wall. A state-of-the-art two-dimensional hygrothermal model, developed by the authors, was employed to determine the hourly spatial temperatures, moisture content, and air velocity distributes within wall systems as a function of real climate conditions.
In the parametric investigation, the performance of a particular EIFS clad wall as a function of two stud cavity insulation materials was studied. Two cavity insulation walls were investigated: fiberglass and cellulose insulation. Two climatic conditions were chosen in the moisture analysis, representing cold and mild climates: these were Chicago, Illinois and Wilmington, North Carolina respectively.
The effect of wall drying and wetting in the presence of a particular air flow path (cracks) was investigated for all cases. The air leakage path was assumed to be present due to an electrical outlet close at the interior, an opening present between oriented strand panels, and a conduit in the stucco layer. Initial OSB moisture content was assumed to be very high. The influences of wind-driven rain, solar radiation and air movement were included in the simulation analysis on an hourly basis. 
Results showed that air leakage through a particular EIFS clad wall in Wilmington produced a net drying effect for a wall system with an initially wet OSB layer, while air leakage developed a net seasonal moisture accumulation in Chicago. The effect of stud cavity insulation was found to be critical, as the storage capacity for moisture increased in the cellulose case, compared to the fiberglass insulation case. The distinct effect is present when comparing the two insulation systems. The cellulose insulation case retained higher amounts of moisture. Solar driven moisture was also more critical in the cellulose insulation case than in the fiberglass case. The thermal and moisture results were then linked to a state-of-the-art mold growth model to assess the risk of moisture-induced damage. Results were developed in the form of mold growth indexes. Results showed the probable mold growth index as a potential as a function of climate conditions and as a function of cavity insulation. Higher risks of mold growth is present in the cellulose case than in the fiberglass case. If there is a high mold growth index and the underlying material is maintained at high moisture content, there is potential for developing decay (if the wood is already infected internally). Since boric acid is added in cellulose insulation as a treatment for fire, mold, insect and rodent control, as wet blown cellulose comes in contact with other materials, some of the chemical will treat these surfaces. For the same wall system, Wilmington exhibited slightly worse conditions that Chicago for mold growth. The development of mold growth indexes permits one to perform a moisture engineering analysis and extended current moisture assessment analysis of building envelopes' long-term performance.
hygrothermal performance, building construction, cavity insulation, air leakage
#NO 13147 The pressure response of buildings.
Lstiburek J W
USA, Atlanta, American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), 1998, proceedings of "Thermal performance of the exterior envelopes of buildings VII" a conference held Sheraton Sand Key Hotel, Clearwater Beach, Florida, 6-10 December 1998, pp 799-817, 21 figs, refs.
Airflow in buildings is one of the major factors that governs the interaction of the building structure with the mechanical system, climate, and occupants. If the airflow at any point within a building or building assembly can be determined or predicted, the temperature and moisture (hygrothermal and psychometric) conditions can also be determined or predicted. If the hygrothermal conditions of the building or building assembly are known, the performance of materials can also be determined or predicted. This paper shows that airflow in buildings is complex, time dependant and multidirectional. The understanding of airflow through and within buildings has been based on the requirement for continuity of mass and momentum caused by wind forces, thermal effects (stack action), and forces associated with the operation of mechanical cooling, heating, exhaust and other ventilation systems.
Interstitial airflow and interstitial air pressure fields are not often considered. Building analysis typically develops the building pressure field from the airflow field. In doing so, exterior and interior walls, floors, and roof assemblies are either considered as monolithic or having openings resulting in flow across the specific assemblies. 
This paper shows that many problems associated with pollutant transfer and the spread of smoke and fire cannot be explained by cross-assembly (one-dimensional) airflow as well as such moisture effects as microbial contamination, corrosion and biological decay. Even the analysis of energy consumption and comfort within buildings needs to be considered in terms of multidirectional airflow. This paper shows that buildings typically comprise multi-layer envelope assemblies with numerous air gaps or void spaces that are often connected to service chases. Complex three-dimensional flow paths and intricate air pressure relationships must be considered. 
This paper also introduces an alternative pattern of analysis: developing the flow field, the leakage areas, and the flow relationships from the measured building pressure field - the air pressure regime within and surrounding the building. This approach accounts for interstitial air pressure fields and resulting interstitial airflows. It provides a powerful diagnosis tool for solving many of the problems related to direct and indirect effects of airflows.
air flow
#NO 13372 Field measurement results of the airtightness of 64 French dwellings.
Litvak A, Kilberger M, Guillot K
UK, Oxford, Elsevier, 2000, proceedings of Roomvent 2000, "Air Distribution in Rooms: Ventilation for Health and Sustainable Environment", held 9-12 July 2000, Reading, UK, Volume 2, pp 1093-1098, 6 figs, 1 tab, refs.
This work presents a field measurement study, investigating the airtightness of 64 French dwellings less than ten years old. Buildings have been classified according to the type of construction (masonry or timber frame) and of occupancy mode (multi- or single-family). Using a fan-depressurisation technique, we assessed the air leakage rate of each dwelling, based on a theoretical flow model that relates the infiltration airflow rate to the differential pressure. Meanwhile quantifying air leakage rates, we also observed the locations of air leakage paths using a smoke detection method and infrared thermography. In order to compare the results obtained among the sample of dwellings, we assessed the ratio of the air leakage rates divided by intrinsic characteristics of each construction, namely the unheated surfaces and the heated volume. We compared the performance of the French dwellings measured in this study, as a function of the different building types. The results of this work show that construction characteristics can play a significant role on buildings' airtightness, as well as on the interpretation itself of the performance.
Airtightness, field measurements, dwellings, infiltration, ventilation, buildings, air leakages
#NO 13456 Mold, a poltergeist.
Wemhoff P
USA, Home Energy, January/February 2001, pp 19-23, 2 figs.
Case study of a severe mould-odour problem in the bedroom of a house in Jacksonville, Florida. The room had been sealed shut by the owners to prevent the odour penetrating the rest of the home. The remedy covered relocation of garden sprinklers, elimination of a negative indoor pressure caused by ductwork supply leaks, correction of the air flow, creation of return air pathways, correction of the refrigerant charge of the air conditioner, provision of constant air flow to the troubled rooms, and application of a brick coating to reduce the water absorbancy of the brick. The problems subsequently cleared up completely. 
mould, odour, moisture, wall, water leakage, ventilation strategy
#NO 13585 Draught and cold in industrial buildings.
Anttonen H
in: "Progress in Modern Ventilation", Proceedings of Ventilation 2000, Volume 2, proceedings of the 6th International Symposium on Ventilation for Contaminant Control, held Helsinki, Finland, 4-7 June 2000, Finnish Institute of Occupational Health, Helsinki, Finland, 2000, pp 14-16, 2 figs, 1 tab, 2 refs.
The study has measured thermal parameters in industrial halls to describe the seriousness of draught and main reasons for problems. Concludes that cold airflows through the doorways were remarkable and they effected large areas of the measured industrial halls. The supply and exhaust ventilation rates and the air leakage paths at the building envelope effect the pressure difference across the leakage paths and doorways and also the cooling of workers. For example effective air curtains are needed to prevent penetration of cold airflows in high traffic doorways.
draughts, industrial building