1、Designation: E779 10Standard Test Method forDetermining Air Leakage Rate by Fan Pressurization1This standard is issued under the fixed designation E779; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method measures air-leakage rates through abuilding envelope under controlled pressurization and de-pressurization.1.2 This te
3、st method is applicable to small temperaturedifferentials and low-wind pressure differential, thereforestrong winds and large indoor-outdoor temperature differen-tials shall be avoided.1.3 This test method is intended to quantify the air tightnessof a building envelope. This test method does not mea
4、sure airchange rate or air leakage rate under normal weather conditionsand building operation.NOTE 1See Test Method E741 to directly measure air-change ratesusing the tracer gas dilution method1.4 This test method is intended to be used for measuringthe air tightness of building envelopes of single-
5、zone buildings.For the purpose of this test method, many multi-zone buildingscan be treated as single-zone buildings by opening interiordoors or by inducing equal pressures in adjacent zones.1.5 Only metric SI units of measurement are used in thisstandard. If a value for measurement is followed by a
6、 value inother units in parentheses, the second value may be approxi-mate. The first stated value is the requirement.1.6 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-priat
7、e safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements see Section 7.2. Referenced Documents2.1 ASTM Standards:2E631 Terminology of Building ConstructionsE741 Test Method for Determining Air Change in a SingleZone by Means
8、 of a Tracer Gas DilutionE1258 Test Method for Airflow Calibration of Fan Pressur-ization Devices3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology E631.3.2 Definitions of Terms Specific to This Standard: .3.2.1 air-change rate, nair-leakage rate in volume units
9、/hdivided by the building space volume with identical volumeunits, normally expressed as air changes/h, ACH.3.2.2 air-leakage, nthe movement/flow of air through thebuilding envelope, which is driven by either or both positive(infiltration) and negative (exfiltration) pressure differencesacross the e
10、nvelope.3.2.3 air-leakage graph, nthe graph that shows the rela-tionship of measured airflow rates to the corresponding mea-sured pressure differences, plotted on a log-log scale.3.2.4 air-leakage rate, nthe volume of air movement/unittime across the building envelope including airflow throughjoints
11、, cracks, and porous surfaces, or a combination thereofdriven by mechanical pressurization and de-pressurization,natural wind pressures, or air temperature differentials betweenthe building interior and the outdoors, or a combinationthereof.3.2.5 building envelope, nthe boundary or barrier sepa-rati
12、ng different environmental conditions within a building andfrom the outside environment.3.2.6 effective leakage area, nthe area of a hole, with adischarge coefficient of 1.0, which, witha4Papressuredifference, leaks the same as the building, also known as thesum of the unintentional openings in the
13、structure3.2.7 height, building, nthe vertical distance from gradeplane to the average height of the highest ceiling surface.3.2.8 interior volume, nconditioned space within a build-ing, generally not including attics and attached structures, forexample, garages, unless such spaces are connected to
14、theheating and air conditioning system, such as a crawl spaceplenum.3.2.9 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 including multi-room1This test method is under the jurisdiction of ASTM Co
15、mmittee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.41on Air Leakage and Ventilation Performance.Current edition approved Jan. 15, 2010. Published September 2010. Originallyapproved in 1981. Last previous edition approved in 2003 as E779 03. DOI:10.1520/E0779-
16、10.2For 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 International, 100 Barr Harbor Drive, PO B
17、ox C700, West Conshohocken, PA 19428-2959, United States.space that is interconnected within itself with door-sizedopenings through any partitions or floors where the fan airflowrate is less than 3 m3/s (6 3 103ft3/min).3.2.10 test pressure difference, nthe measured pressuredifference across the bui
18、lding envelope, expressed in Pascals(in. of water or pounds-force/ft2or in. of mercury).3.3 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 indoo
19、r-outdoor static pressuredifferences. From the relationship between the airflow ratesand pressure differences, the air leakage characteristics of abuilding envelope are determined.5. Significance and Use5.1 Air leakage accounts for a significant portion of thethermal space conditioning load. In addi
20、tion, it affects occupantcomfort and indoor air quality.5.2 In most commercial or industrial buildings, outdoor airis often introduced by design; however, air leakage is asignificant addition to the designed outdoor airflow. In mostresidential buildings, indoor-outdoor air exchange is attribut-able
21、primarily to air leakage through cracks and constructionjoints and is induced by pressure differences due to temperaturedifferences, wind, operation of auxiliary fans (for example,kitchen and bathroom exhausts), and the operation of combus-tion equipment in the building.5.3 The fan-pressurization me
22、thod is simpler than tracer gasmeasurements and is intended to characterize the air tightnessof the building envelope. It is used to compare the relative airtightness of several similar buildings to identify the leakagesources and rates of leakage from different components of thesame building envelo
23、pe, 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 requiredapparatus. Any
24、 arrangement of equipment using the sameprinciples and capable of performing the test procedure withinthe allowable tolerances shall be permitted.6.2 Major Components:6.2.1 Air-Moving EquipmentFan, blower, HVAC airmovement component or blower door assembly that is capableof moving air into and out o
25、f the conditioned space at requiredflow rates under a range of test pressure differences. Thesystem shall provide constant airflow at each incrementalpressure difference at fixed pressure for the period required toobtain readings of airflow rate.6.2.2 Pressure-Measuring DeviceManometer or pressurein
26、dicator to measure pressure difference with an accuracy of6 5 % of the measured pressure or 0.25 Pa (0.001 in. H2O),whichever is greater.6.2.3 Airflow Measuring SystemDevice to measure air-flow with an accuracy of 6 5 % of the measured flow. Theairflow measuring system shall be calibrated in accorda
27、ncewith Test Method E1258.6.2.4 Temperature-Measuring DeviceInstrument to mea-sure temperature with an accuracy of 6 1C (2F).7. Hazards7.1 Eye ProtectionGlass breakage at the building pressuredifferences normally applied to the test structure is uncommon:however, for added safety, adequate precautio
28、ns, such as theuse of eye protection shall 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 the fan or blower and topr
29、event accidental access to any moving parts of the equip-ment.7.4 Noise ProtectionExposure to the noise level generatedby fans can be hazardous to the hearing of involved personneland hearing protection is required.7.5 Debris and FumesThe blower or fan forces a largevolume of air into or out of a bu
30、ilding while in operation. Careshall be exercised to not to damage plants, pets, occupants, orinternal furnishings due to influx of cold or warm air. Cautionshall be exercised against sucking debris or exhaust gases fromfireplaces and flues into the interior of the building. Activecombustion devices
31、 shall be shut off or the safety determinedof conducting the test by a properly trained technician beforeconducting the test.8. Procedure8.1 To create a single zone for this test procedure, allinterconnecting doors in the conditioned space shall be opensuch that a uniform pressure shall be maintaine
32、d within theconditioned space to within 610 % of the measured inside/outside pressure difference. This condition shall be verified bydifferential pressure measurements at the highest pressure usedin the test. These measurements shall be taken at the highestceiling elevation and lowest floor elevatio
33、n of the building andon the windward and leeward sides.8.2 HVAC balancing dampers and registers shall not beadjusted. Fireplace and other operable dampers shall be closedunless they are used to pass air to pressurize or de-pressurizethe building.8.3 General observations of the condition of the build
34、ingshall be recorded, including appropriate observations of thewindows, doors, opaque walls, roof, and floor.TABLE 1 Symbols and UnitsSymbol Quantity UnitE Elevation above sea level m ftQ Measured airflow rate m3/s cfmQoAir leakage rate m3/s cfmC Air leakage coefficient m3/(s Pan) cfm/Panr Air densi
35、ty 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 m2ft2E779 1028.4 Measure and record the indoor and outdoor tempera-tures at the beginning and th
36、e end of the test and average thevalues. If the product of the absolute value of the indoor/outdoor air temperature difference multiplied by the buildingheight, gives a result greater than 200 m C (1180 ft F), thetest shall not be performed, because the pressure differenceinduced by the stack effect
37、 is too large to allow accurateinterpretation of the results.8.5 Connect the air duct or blower door assembly to thebuilding envelope, using a window, door, or vent opening. Sealor tape openings to avoid air leakage at these points.8.6 If a damper is used to control airflow, it shall be in afully cl
38、osed position for the zero flow pressure measurements.8.7 Installing the Envelope Pressure Sensor(s)Install thepressure measuring device across the building envelope.Where possible, locate the pressure tap at the bottom of theleeward wall. When wind causes adverse pressure fluctuationsit may be adva
39、ntageous to average the pressures measured atmultiple locations, for example, one across each facade. Fig. 1illustrates preferred locations that avoid extremes of exteriorpressures. A good location avoids exterior corners and shouldbe close to the middle (horizontally) of the exterior wall.Beware of
40、 direct sunlight hitting pressure tubing, especiallyvertical sections.8.8 Measure zero flow pressures with the fan openingblocked. These zero flow envelope pressures shall be measuredbefore and after the flow measurements. The average over atleast a 10-s interval shall be used. These zero flow press
41、uresshall be subtracted from the envelope pressures measuredduring pressurization and depressurization.NOTE 2Some equipment may perform this step, or an equivalent step,automatically. Follow the manufacturers instructions accordingly.8.9 The range of the induced pressure difference shall befrom 10 t
42、o 60 Pa (0.04 to 0.24 in. H2O), depending on thecapacity of the air-moving equipment. Because the capacity ofthe air-moving equipment, the lack of tightness in the building,and the weather conditions affect leakage measurements, thefull range of the higher values may not be achievable. In suchcases,
43、 substitute a partial range encompassing at least five datapoints.NOTE 3It 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, windows, ordampers have not been forced op
44、en by the induced pressure.8.10 Use increments of 5 to 10 Pa (0.02 to 0.04 in. H2O) forthe full range of induced pressure differences.8.11 At each pressure difference, measure the airflow rateand the pressure differences across the envelope. After the fanand instrumentation have stabilized, the aver
45、age over at least a10-s interval shall be used.8.12 For each test, collect data for both pressurization andde-pressurization.8.13 Determine the elevation of the measurement site, E (mor ft), above mean sea level within 100 m (330 ft).9. Data Analysis and Calculations9.1 Unless the airflow measuring
46、system gives volumetricflows at the barometric pressure and the temperatures of the airflowing through the flowmeter during the test, these readingsshall be converted using information obtained from the manu-facturer for the change in calibration with these parameters.The barometric pressure or air
47、density, if used in the conver-sions, may be calculated using equations from Appendix X1.9.2 Convert the readings of the airflow measuring system(corrected as in 9.1, if necessary) to volumetric air flows at thetemperature and barometric pressure of the outside air fordepressurization tests or of th
48、e inside air for pressurization tests(see Appendix X1, Eq X1.1 through X1.4 for determiningindoor and outdoor air densities). To convert the airflow rate toair leakage rate for depressurization, use the following equa-tion:FIG. 1 Recommended Locations for Exterior Pressures (Plan Views of Buildings“
49、X” Within Circles Mark Pressure Tap Locations)E779 103Qo5 QSrinroutD(1)where:rin= the indoor air density, in kg/m3(lb/ft3), androut= the 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 each pressure stationto determine the corrected envelope pressures.9.4 Plot the me
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