ASTM E779-2019 Standard Test Method for Determining Air Leakage Rate by Fan Pressurization.pdf

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1、Designation: E779 10 (Reapproved 2018)E779 19Standard 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 y

2、ear of last revision. A number 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 a building envelope under controlled pressurization and de-

3、pressurization.1.2 This test method is applicable to small temperature differentials and low-wind pressure differential, therefore strong windsand large indoor-outdoor temperature differentials shall be avoided.1.3 This test method is intended to quantify the air tightness of a building envelope. Th

4、is test method does not measure airchange rate or air leakage rate under normal weather conditions and building operation.NOTE 1See Test Method E741 to directly measure air-change rates using the tracer gas dilution method.1.4 This test method is intended to be used for measuring the air tightness o

5、f building envelopes of single-zone buildings. Forthe purpose of this test method, many multi-zone buildings can be treated as single-zone buildings by opening interior doors orby inducing equal pressures in adjacent zones.1.5 Only metric SI units of measurement are used in this standard. If a value

6、 for measurement is followed by a value in otherunits in parentheses, the second value may be approximate. The first stated value is the requirement.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this

7、standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulatory limitations prior to use. For specific hazard statements see Section 7.1.7 This international standard was developed in accordance with internationally recognized principles on

8、standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E631 Terminology of Building ConstructionsE

9、741 Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas DilutionE1258 Test Method for Airflow Calibration of Fan Pressurization Devices3. Terminology3.1 For definitions of terms used in this test method, refer to Terminology E631.3.2 Definitions of Terms Specific to This

10、 Standard:3.2.1 air-change rate, nair-leakage rate in volume units/h divided by the building space volume with identical volume units,normally expressed as air changes/h, ACH.3.2.2 air-leakage, nthe movement/flow of air through the building envelope, which is driven by either or both positive(infilt

11、ration) and negative (exfiltration) pressure differences across the envelope.3.2.3 air-leakage graph, nthe graph that shows the relationship of measured airflow rates to the corresponding measuredpressure differences, plotted on a log-log scale.1 This test method is under the jurisdiction ofASTM Com

12、mittee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.41 on Air Leakageand Ventilation Performance.Current edition approved July 15, 2018Jan. 1, 2019. Published July 2018January 2019. Originally approved in 1981. Last previous edition approved in 20102018 asE779

13、 10.E77910 (2018). DOI: 10.1520/E0779-10R18.10.1520/E077919.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.T

14、his document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior edit

15、ions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.4 air-leakage rate, nthe volume of air moveme

16、nt/unit time across the building envelope including airflow through joints,cracks, and porous surfaces, or a combination thereof driven by mechanical pressurization and de-pressurization, natural windpressures, or air temperature differentials between the building interior and the outdoors, or a com

17、bination thereof.3.2.5 building envelope, nthe boundary or barrier separating different environmental conditions within a building and fromthe outside environment.3.2.6 effective leakage area, nthe area of a hole, with a discharge coefficient of 1.0, which, with a 4 Pa pressure difference,leaks the

18、same as the building, also known as the sum of the unintentional openings in the structure.3.2.7 height, building, nthe vertical distance from grade plane to the average height of the highest ceiling surface.3.2.8 interior volume, ndeliberately conditioned space within a building, generally not incl

19、uding attics and attached structures,for example, garages, unless such spaces are connected to the heating and air conditioning system, such as a crawl space plenum.3.2.9 single zone, na space in which the pressure differences between any two places, differ by no more than 5 % of the insideto outsid

20、e pressure difference including multi-room space that is interconnected within itself with door-sized openings through anypartitions or floors where the fan airflow rate is less than 3 m3/s (6 103 ft3/min).3.2.10 test pressure difference, nthe measured pressure difference across the building envelop

21、e, expressed in Pascals (in. ofwater or pounds-force/ft2 or in. of mercury).3.3 Symbols and UnitsSee Table 1.4. Summary of Test Method4.1 This test method consists of mechanical pressurization or de-pressurization of a building and measurements of the resultingairflow rates at given indoor-outdoor s

22、tatic pressure differences. From the relationship between the airflow rates and pressuredifferences, the air leakage characteristics of a building envelope are determined.5. Significance and Use5.1 Air leakage accounts for a significant portion of the thermal space conditioning load. In addition, it

23、 affects occupant comfortand indoor air quality.5.2 In most commercial or industrial buildings, outdoor air is often introduced by design; however, air leakage is a significantaddition to the designed outdoor airflow. In most residential buildings, indoor-outdoor air exchange is attributable primari

24、ly to airleakage through cracks and construction joints and is induced by pressure differences due to temperature differences, wind,operation of auxiliary fans (for example, kitchen and bathroom exhausts), and the operation of combustion equipment in thebuilding.5.3 The fan-pressurization method is

25、simpler than tracer gas measurements and is intended to characterize the air tightness ofthe building envelope. It is used to compare the relative air tightness of several similar buildings to identify the leakage sourcesand rates of leakage from different components of the same building envelope, a

26、nd to determine the air leakage reduction forindividual retrofit measures applied incrementally to an existing building, and to determine ventilation rates when combined withweather and leak location information.6. Apparatus6.1 The following is a general description of the required apparatus. Any ar

27、rangement of equipment using the same principlesand capable of performing the test procedure within the allowable tolerances shall be permitted.6.2 Major Components:TABLE 1 Symbols and UnitsSymbol Quantity UnitE Elevation above sea level m ftQ Measured airflow rate m3 /s cfmQo Air leakage rate m3 /s

28、 cfmC Air leakage coefficient m3 /(s Pan) cfm/Pan Air density kg/m3 lb/ft3T Temperature C Fn Pressure exponent . . .P Pressure Pa lb/ft2dP Induced pressure difference Pa lb/ft2dPr Reference pressure difference Pa lb/ft2 Dynamic air viscosity kg/(ms) lb/(fth)A Area m2 ft2E779 1926.2.1 Air-Moving Equi

29、pmentFan, blower, HVAC air movement component or blower door assembly that is capable of movingair into and out of the conditioned space at required flow rates under a range of test pressure differences. The system shall provideconstant airflow at each incremental pressure difference at fixed pressu

30、re for the period required to obtain readings of airflow rate.6.2.2 Pressure-Measuring DeviceManometer or pressure indicator to measure pressure difference with an accuracy of 65 %of the measured pressure or 0.25 Pa (0.001 in. H2O), whichever is greater.6.2.3 Airflow Measuring SystemDevice to measur

31、e airflow with an accuracy of 65 % of the measured flow. The airflowmeasuring system shall be calibrated in accordance with Test Method E1258.6.2.4 Temperature-Measuring DeviceInstrument to measure temperature with an accuracy of 61 C (2 F).7. Hazards7.1 Eye ProtectionGlass breakage at the building

32、pressure differences normally applied to the test structure is uncommon:however, for added safety, adequate precautions, such as the use of eye protection shall be taken to protect the personnel.7.2 Safety ClothingUse safety equipment required for general field work, including safety shoes, and hard

33、 hats.7.3 Equipment GuardsThe air-moving equipment shall have a proper guard or cage to house the fan or blower and to preventaccidental access to any moving parts of the equipment.7.4 Noise ProtectionExposure to the noise level generated by fans can be hazardous to the hearing of involved personnel

34、 andhearing protection is required.7.5 Debris and FumesThe blower or fan forces a large volume of air into or out of a building while in operation. Care shallbe exercised to not to damage plants, pets, occupants, or internal furnishings due to influx of cold or warm air. Caution shall beexercised ag

35、ainst sucking debris or exhaust gases from fireplaces and flues into the interior of the building. Active combustiondevices shall be shut off or the safety determined of conducting the test by a properly trained technician before conducting the test.8. Procedure8.1 To create a single zone for this t

36、est procedure, all interconnecting doors in the conditioned space shall be open such thata uniform pressure shall be maintained within the conditioned space to within 610 % of the measured inside/outside pressuredifference. This condition shall be verified by differential pressure measurements at th

37、e highest pressure used in the test. Thesemeasurements shall be taken at the highest ceiling elevation and lowest floor elevation of the building and on the windward andleeward sides.8.2 HVAC balancing dampers and registers shall not be adjusted. Fireplace and other operable dampers shall be closed

38、unlessthey are used to pass air to pressurize or de-pressurize the building.8.3 General observations of the condition of the building shall be recorded, including appropriate observations of the windows,doors, opaque walls, roof, and floor.8.4 Measure and record the indoor and outdoor temperatures a

39、t the beginning and the end of the test and average the values.If the product of the absolute value of the indoor/outdoor air temperature difference multiplied by the building height, gives a resultgreater than 200 m C (1180 ft F), the test shall not be performed, because the pressure difference ind

40、uced by the stack effect istoo large to allow accurate interpretation of the results.8.5 Connect the air duct or blower door assembly to the building envelope, using a window, door, or vent opening. Seal or tapeopenings to avoid air leakage at these points.8.6 If a damper is used to control airflow,

41、 it shall be in a fully closed position for the zero flow pressure measurements.8.7 Installing the Envelope Pressure Sensor(s)Install the pressure measuring device across the building envelope. Wherepossible, locate the pressure tap at the bottom of the leeward wall. When wind causes adverse pressur

42、e fluctuations it may beadvantageous to average the pressures measured at multiple locations, for example, one across each facade. Fig. 1 illustratespreferred locations that avoid extremes of exterior pressures. A good location avoids exterior corners and should be close to themiddle (horizontally)

43、of the exterior wall. Beware of direct sunlight hitting pressure tubing, especially vertical sections.8.8 Measure zero flow pressures with the fan opening blocked. These zero flow envelope pressures shall be measured beforeand after the flow measurements. The average over at least a 10-s interval sh

44、all be used. These zero flow pressures shall besubtracted from the envelope pressures measured during 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 p

45、ressure difference shall be from 10 to 60 Pa (0.04 to 0.24 in. H2O), depending on the capacityof the air-moving equipment. Because the capacity of the air-moving equipment, the lack of tightness in the building, and theweather conditions affect leakage measurements, the full range of the higher valu

46、es may not be achievable. In such cases, substitutea partial range encompassing at least five data points.NOTE 3It is advisable to check that the condition of the building envelope has not changed after each pressure reading, for example, that sealedopenings have not become unsealed or that doors, w

47、indows, or dampers have not been forced open by the induced pressure.E779 1938.10 Use increments of 5 to 10 Pa (0.02 to 0.04 in. H2O) for the full range of induced pressure differences.8.11 At each pressure difference, measure the airflow rate and the pressure differences across the envelope. After

48、the fan andinstrumentation have stabilized, the average over at least a 10-s interval shall be used.8.12 For each test, collect data for both pressurization and de-pressurization.8.13 Determine the elevation of the measurement site, E (m or ft), above mean sea level within 100 m (330 ft).9. Data Ana

49、lysis and Calculations9.1 Unless the airflow measuring system gives volumetric flows at the barometric pressure and the temperatures of the airflowing through the flowmeter during the test, these readings shall be converted using information obtained from the manufacturerfor the change in calibration with these parameters. The barometric pressure or air density, if used in the conversions, may becalculated using equations from Appendix X1.9.2 Convert the readings of the airflow measuring system (corrected as in 9.1,