ASTM E779-2003 Standard Test Method for Determining Air Leakage Rate by Fan Pressurization《用风扇增压法测定空气泄漏率的标准试验方法》.pdf

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1、Designation: E 779 03Standard Test Method forDetermining Air Leakage Rate by Fan Pressurization1This standard is issued under the fixed designation E 779; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A

2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a standardized technique formeasuring air-leakage rates through a building envelope undercontrolled pressuriz

3、ation and de-pressurization.1.2 This test method is applicable to small temperaturedifferentials and low-wind pressure conditions. For tests con-ducted in the field, it must be recognized that field conditionsmay be less than ideal. Nevertheless, strong winds and largeindoor-outdoor temperature diff

4、erentials should be avoided.1.3 This test method is intended to produce a measure of airtightness of a building envelope. This test method does notmeasure air leakage rates under normal conditions of weatherand building operation.To measure air-change rate directly, usethe tracer gas dilution method

5、 (see Test Method E 741).1.4 This test method is intended for the measurement of theairtightness of building envelopes of single-zone buildings. Forthe purpose of this test method, many multi-zone buildings canbe treated as single-zone buildings by opening interior doors orby inducing equal pressure

6、s in adjacent zones.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to

7、 use. For specific hazardstatements see Section 7.2. Referenced Documents2.1 ASTM Standards:2E 741 Test Method for DeterminingAir Change in a SingleZone by Means of a Tracer Gas Dilution.E 1258 Test Method forAirflow Calibration of Fan Pressur-ization Devices3. Terminology3.1 Definitions of Terms Sp

8、ecific to This Standard:3.1.1 air-change rate, nair-leakage rate in volume units/hdivided by the building space volume with identical volumeunits, normally expressed as air changes/h, ACT.3.1.2 air-leakage graph, nthe graph that shows the rela-tionship of measured airflow rates to the corresponding

9、mea-sured pressure differences, usually plotted on a log-log scale.3.1.3 air-leakage rate, nthe volume of air movement/unittime across the building envelope.3.1.3.1 DiscussionThis movement includes flow throughjoints, cracks, and porous surfaces, or a combination thereof.The driving force for such a

10、n air leakage, in service can beeither mechanical pressurization and de-pressurization, naturalwind pressures, or air temperature differentials between thebuilding interior and the outdoors, or a combination thereof.3.1.4 building envelope, nthe boundary or barrier sepa-rating the interior volume of

11、 a building from the outsideenvironment.3.1.4.1 DiscussionFor the purpose of this test method, theinterior volume is the deliberately conditioned space within abuilding, generally not including attics, basements, and at-tached structures, for example, garages, unless such spaces areconnected to the

12、heating and air conditioning system, such asa crawl space plenum.3.1.5 single zone, na space in which the pressure differ-ences between any two places, differ by no more than 5 % ofthe inside to outside pressure difference.3.1.5.1 DiscussionA multi-room space that is intercon-nected within itself wi

13、th door-sized openings through anypartitions or floors is likely to satisfy this criterion if the fanairflow rate is less than 3 m3/s 6 3 103ft3/min).3.1.6 test pressure difference, nthe measured pressuredifference across the building envelope, expressed in Pascals(in. of water or pounds-force/ft2or

14、 in. of mercury).3.2 Symbols and UnitsSee Table 1.4. Summary of Test Method4.1 This test method consists of mechanical pressurizationor de-pressurization of a building and measurements of theresulting airflow rates at given indoor-outdoor static pressuredifferences. From the relationship between the

15、 airflow rates1This test method is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.41on Air Leakage and Ventilation.Current edition approved Oct. 1, 2003. Published November 2003. Originallyapproved in 1981. Last previous e

16、dition approved in 1999 as E 779 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM Internati

17、onal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.and pressure differences, the air leakage characteristics of abuilding envelope can be evaluated.5. Significance and Use5.1 Air leakage accounts for a significant portion of thethermal space conditioning load.

18、In addition, it can affectoccupant comfort and indoor air quality.5.2 In most commercial or industrial buildings, outdoor airoften is introduced by design; however, air leakage can be asignificant addition to the designed outdoor airflow. In mostresidential buildings, indoor-outdoor air exchange is

19、attribut-able primarily to air leakage through cracks and constructionjoints and can be induced by pressure differences due totemperature differences, wind, operation of auxiliary fans, forexample, kitchen and bathroom exhausts, and the operation ofcombustion equipment in the building.5.3 The fan-pr

20、essurization method is simpler than tracer gasmeasurements and is intended to characterize the air tightnessof the building envelope. It can be used to compare the relativeair tightness of several similar buildings, to identify the leakagesources and rates of leakage from different components of the

21、same building envelope, and to determine the air leakagereduction for individual retrofit measures applied incrementallyto an existing building, and to determine ventilation rates whencombined with weather and leak location information.6. Apparatus6.1 The following is a general description of the re

22、quiredapparatus. Any arrangement of equipment using the sameprinciples and capable of performing the test procedure withinthe allowable tolerances is permitted.6.2 Major Components:6.2.1 Air-Moving EquipmentA fan, blower, or blowerdoor assembly that is capable of moving air into and out of thecondit

23、ioned space at required flow rates under a range of testpressure differences. The system shall provide constant airflowat each incremental pressure difference at fixed pressure for theperiod required to obtain readings of airflow rate. Whereapplicable, the HVAC system of the building may be used inp

24、lace of the fan or blower.6.2.2 Pressure-Measuring DeviceA manometer or pres-sure indicator to measure pressure difference with an accuracyof 65 % of measured pressure.6.2.3 Airflow Measuring SystemA device to measureairflow with an accuracy of 65 % of the measured flow. Theairflow measuring system

25、shall be calibrated in accordancewith Test Method E 12586.2.4 Temperature-Measuring DeviceAn instrument tomeasure temperature with an accuracy of 61C (2F).6.2.5 Wind Speed-Measuring Device (Optional)A deviceto give an accuracy within 60.25 m/s (0.56 mph) at 2.5 m/s(5.6 mph). Perform wind speed measu

26、rements at a distancethree to five building heights away from the buildings, wherepractical. List the height above ground at which wind speed ismeasured.7. Hazards7.1 Eye ProtectionGlass should not break at the buildingpressure differences normally applied to the test structure:however, for added sa

27、fety, adequate precautions, such as theuse of eye protection should be taken to protect the personnel.7.2 Safety ClothingUse safety equipment required forgeneral field work, including safety shoes, and hard hats.7.3 Equipment GuardsThe air-moving equipment shallhave a proper guard or cage to house t

28、he fan or blower and toprevent accidental access to any moving parts of the equip-ment.7.4 Noise ProtectionMake hearing protection availablefor personnel who must be close to the noise that may begenerated by the fan.7.5 Debris and FumesThe blower or fan forces a largevolume of air into or out of a

29、building while in operation.Exercise care not to damage plants, pets, occupants, or internalfurnishings due to influx of cold or warm air. Exercise similarcautions against sucking debris or exhaust gases from fire-places and flues into the interior of the building. Activecombustion devices require a

30、 properly trained technician toshut them off or to determine the safety of conducting the test.8. Procedure8.1 To create a single zone for this test procedure, allinterconnecting doors, except for closets, which should beclosed, in the conditioned space should be opened such that auniform pressure w

31、ill be maintained within the conditionedspace to within 610 % of the measured inside/outside pressuredifference. Verify this condition by differential pressure mea-surements at the highest pressure used in the test. Make thesemeasurements at the highest and lowest level of the buildingand on the win

32、dward and leeward sides.8.2 HVAC balancing dampers and registers should not beadjusted. Fireplace and other operable dampers should beclosed unless they are used to pass air to pressurize orde-pressurize the building.8.3 Make general observations of the condition of thebuilding. Take notes on the wi

33、ndows, doors, opaque walls,roof, and floor.8.4 Measure and record the indoor and outdoor tempera-tures at the beginning and the end of the test so that theiraverage values can be estimated. If the product of the absolutevalue of the indoor/outdoor air temperature difference multi-plied by the buildi

34、ng height, gives a result greater than 200mC (1180 ftF), do not perform the test, because the pressuredifference induced by the stack effect is too large to allowaccurate interpretation of the results.TABLE 1 Symbols and UnitsSymbol Quantity UnitE Elevation above sea level m ftQ Measured airflow rat

35、e m3/s cfmQoAir leakage rate m3/s cfmC Air leakage coefficient m3/(s Pan) cfm/Panr Air density kg/m3lb/ft3T Temperature C Fn Pressure exponent . . .P Pressure Pa lb/ft2dP Induced pressure difference Pa lb/ft2dPrReference pressure difference Pa lb/ft2 Dynamic air viscosity kg/(ms) lb/(fth)A Area m2ft

36、2E7790328.5 If the wind speed is to be part of the measurementrecord, use a wind-measuring device or obtain readings from anearby weather bureau. Preferred test conditions are windspeed of 0 to 2 m/s (0 to 4 mph) and an outside temperaturefrom 5 to 35C (41 to 95F).8.6 Connect the air duct or blower

37、door assembly to thebuilding envelope, using a window, door, or vent opening. Sealor tape openings to avoid leakage at these points.8.7 If a damper is used to control airflow, it should be in afully closed position for the zero flow pressure measurements.8.8 Installing the Envelope Pressure Sensor(s

38、)Install thepressure measuring device across the building envelope. It isgood practice to use more than one location across the buildingenvelope for pressure measurement, for example, one acrosseach facade. Fig. 1 illustrates preferred locations for exteriorpressure measurement locations that avoid

39、extremes of exteriorpressures (at exterior corners). A good location avoids exteriorcorners and complex architectural features and should be closeto the middle of the exterior wall. In addition, buildings morethan three stories, or 7.5 m (25.5 ft), high shall have exteriorpressures measured at more

40、than one height on the exteriorwalls. The pressures from each location should be averaged,typically using a manifold. Average the pressures over at leasta 10-s time period.8.9 Measure zero flow pressures with the fan openingblocked. These zero flow envelope pressures are measuredbefore and after the

41、 flow measurements. These zero flowpressures are to be subtracted from the envelope pressuresmeasured during pressurization and depressurization.NOTE 1Some equipment may perform this step, or an equivalent step,automatically. Follow the manufacturers instructions accordingly.8.10 The range of the in

42、duced pressure difference shall befrom 10 to 60 Pa (0.04 to 0.24 in. H2O) depending on thecapacity of the air-handling equipment. Because the capacityof the air handling equipment, the tightness of the building, andthe weather conditions affect leakage measurements, the fullrange of the higher value

43、s may not be achievable. In suchcases, substitute a partial range encompassing at least five datapoints.NOTE 2It is advisable to check that the condition of the buildingenvelope has not changed after each pressure reading, for example, thatsealed openings have not become unsealed or that doors, wind

44、ows, ordampers have not been forced open by the induced pressure.8.11 Use increments of 5 to 10 Pa (0.02 to 0.04 in. H2O) forthe full range of induced pressure differences.8.12 At each pressure difference, measure the airflow rateand the pressure differences across the envelope. After the fanand ins

45、trumentation have stabilized, the average over at least a10-s interval should be used.8.13 For each test, collect data for both pressurization andde-pressurization.8.14 Determine the elevation of the measurement site, E (mor ft), above mean sea level within 100 m (330 ft).9. Data Analysis and Calcul

46、ations9.1 Unless the airflow measuring system gives volumetricflows at the pressure and the temperatures of the air flowingthrough the flowmeter during the test, these readings must beconverted using information obtained from the manufacturerfor the change in calibration with these parameters.9.2 Co

47、nvert the readings of the airflow measuring system(corrected as in 9.1, if necessary) to volumetric air flows at thetemperature and barometric pressure, due to elevation changesonly, of the outside air for depressurization tests or of the insideair for pressurization tests (see Appendix X1). To conv

48、ert theairflow rate to air leakage rate for depressurization, use thefollowing equation:Qo5 QSrinroutD(1)where:rin= the indoor air density, in kg/m3(lb/ft3), andFIG. 1 Recommended Locations for Exterior Pressures (Plan Views of Buildings“X” Within Circles Mark Pressure Tap Locations)E779033pout= the

49、 outdoor air density, in kg/m3(lb/ft3).9.2.1 To convert the airflow rate to air leakage rate forpressurization, use the following equation:Qo5 QSroutrinD(2)9.3 Average the zero flow envelope pressures measuredbefore and after the flow measurements. Subtract the averagefrom the measured envelope pressures at such pressure stationto determine the corrected envelope pressures.9.4 Plot the measured air leakage against the correctedpressure differences on a log-log plot to complete the airleakage graph for both pressurization a