1、Designation: E 1258 88 (Reapproved 2003)Standard Test Method forAirflow Calibration of Fan Pressurization Devices1This standard is issued under the fixed designation E 1258; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、of last revision. A 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 the airflow measurement cali-bration techniques for fan pressurization systems used formea
3、suring air leakage rates through building envelopes.1.2 This test method is applicable to systems used for airleakage measurement as described in Practice E 779.1.3 This test method involves the installation of the fanpressurization system in a calibration chamber. Use of the fanpressurization syste
4、m in an actual building may introduceadditional errors in the airflow measurement due to operatorinfluence, interference of internal partitions and furnishings,weather effects, and other factors.1.4 The proper use of this test method requires a knowledgeof the principles of airflow and pressure meas
5、urement.1.5 This standard includes two basic procedures, a preferredprocedure, based on ASHRAE Standard 51/AMCA Standard210, and an optional procedure based on a nonstandard airflowmeasurement technique, commonly used by manufacturers offan pressurization devices, but which has not been comparedwith
6、 standard airflow measurement techniques.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-priate safety and health practices and determine the applica-bility of regulatory
7、 limitations prior to use.2. Referenced Documents2.1 ASTM Standards:E 631 Terminology of Building Constructions2E 779 Test Method for Determining Air Leakage Rate byFan Pressurization22.2 American Society of Heating, Refrigerating, and Air-Conditioning Engineers Standard:3ASHRAE 51/AMCA 210 Laborato
8、ry Methods for TestingFans for Rating2.3 American Society of Mechanical Engineers Standard:4ASME MFC-3M Standard Measurement of Fluid Flow inPipes Using Orifice, Nozzle, and Venturi3. Terminology3.1 DefinitionsFor definitions used in this test method,see Terminology E 631.3.2 Descriptions of Terms S
9、pecific to This Standard:3.2.1 ambient conditions, nconditions in the space fromwhich air is drawn into the calibration chamber and into whichthe chamber air is expelled.3.2.2 chamber, nan enclosure of rectangular or circularcross section to simulate the entrance and exit conditions thatthe fan is e
10、xpected to encounter in service.3.2.3 fan air density, ndensity of air at the fan inletexpressed in kilograms per cubic metre.3.2.4 fan airflow rate, nvolumetric airflow rate at the fanair density expressed in cubic metres per second.3.2.5 fan outlet area, ngross inside area measured in theplane of
11、the fan outlet opening expressed in square metres.3.2.6 fan pressure difference, nthe static pressure differ-ence between two stations expressed in pascals, measuredusing the static pressure taps described in Fig. 1. One station islocated within the chamber between the fan and the nearestflow condit
12、ioners. The other station is outside the chamber.3.2.7 fan pressurization system, na device for measuringthe air leakage rate of a building envelope under controlledpressurization or depressurization of the building interior. Thesystem includes controllable air-moving equipment, an airflowrate measu
13、ring system, and a device for measuring the pressuredifference across the building envelope. Such a system is oftenreferred to as a blower door.3.2.8 fan signal, nan output from a fan pressurizationsystem (other than fan speed) that is related to fan airflow rateby the system calibration, such as th
14、e static pressure differenceacross a constriction that is integral to the system.3.2.9 fan speed, nspeed of rotation of the fan impellerexpressed in inverse seconds.1This test method is under the jurisdiction of ASTM Committee E06 onPerformance of Building Constructions and is the direct responsibil
15、ity of Subcom-mittee E06.41 on Infiltration Performances.Current edition approved Oct. 1, 2003. Published October 2003. Originallyapproved in 1988. Last previous edition approved in 1998 as E 1258 88 (1998).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
16、 Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Society of Heating, Refrigerating, and Air-Conditioning Engineers, 1791 Tullie Circle NE, Atlanta, GA 30329.4Available from Ameri
17、can Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.10 flow conditioners, na combination of screens orperforated pla
18、tes located within the calibration chamber toreduce pressure disturbances within the chamber.3.2.11 nozzle, na gradually tapered constriction, of veryprecise elliptical shape, used in airflow rate measurement (seeFig. 2).3.2.12 nozzle chamber pressure difference, nstatic pres-sure difference measure
19、d across a nozzle or bank of nozzleswhen nozzles are installed in a chamber expressed in pascals.3.2.13 nozzle throat diameter, ndiameter of nozzle dis-charge end expressed in square metres.3.2.14 nozzle throat pressure difference, nstatic pressuredifference across the nozzle in a duct measured with
20、 throat tapsexpressed in pascals (see Fig. 2).3.2.15 orifice, na sharp-edged circular constriction usedin airflow measurement (see Fig. 3).3.2.16 orifice pressure difference, nstatic pressure differ-ence measured across an orifice when the orifice is installed ina chamber expressed in pascals.3.2.17
21、 revolution-per-minute (r/min) door, na fan pres-surization system with a calibration that relates the fan airflowrate to the fan speed.3.2.18 signal door, na fan pressurization system with acalibration that relates the fan airflow rate to an output signalother than fan speed.3.2.19 transformation p
22、iece, nan element to connect aduct with a measuring station to a fan when the fan connectionis a different size than the duct (see Fig. 4).4. Summary of Test Method4.1 This test method contains two procedures for calibratingfan pressurization devices, a preferred procedure based onASHRAE Standard 51
23、/AMCA Standard 210, and an optionalprocedure employing an orifice in a chamber.4.2 Both procedures involve the installation of the fanpressurization system in a chamber.4.3 The calibration consists of a comparison of the airflowrate through the fan pressurization system measured by thesystem itself,
24、 and the airflow rate measured in the calibrationfacility. In the preferred procedure, three modes of airflowFIG. 1 Static Pressure Tap SpecificationsNozzle with throat taps Nozzle without throat tapsNOTE 1Nozzle throat dimension L shall be either 0.6 Dn6 0.005 Dn(recommended) or 0.5 Dn6 0.005 Dn.NO
25、TE 2Nozzle shall have elliptical section as shown. Two and three radii approximations to the elliptical form that do not differ at any point in thenormal direction more than 1.5 % Dnfrom the elliptical form may be used. The outlet edge of the nozzle shall be square, sharp, and free from burrs, nicks
26、,or roundings.NOTE 3The nozzle throat shall be measured (to an accuracy of 0.001 Dn) at the minor axis of the ellipse and the nozzle exit. At each place, fourdiameters, approximately 45 apart must be within 60.002 Dnof the mean. At the entrance to the throat the mean may be 0.002 Dngreater, but no l
27、essthan the mean at the nozzle exit.NOTE 4The nozzle surface shall fair smoothly so that a straightedge may be rocked over the surface without clicking and the surface waves shallnot be greater than 0.001 Dnpeak to peak.NOTE 5When nozzles are used in a chamber, either of the types shown above may be
28、 used. Where a nozzle discharges directly to a duct, nozzleswith throat taps shall be used, and the nozzle outlet should be flanged.NOTE 6Throat tap nozzles shall have four static pressure taps 90 apart connected to a piezometer ring.FIG. 2 Nozzle SpecificationsE 1258 88 (2003)2measurement are accep
29、table: (1) a nozzle or bank of nozzles inthe chamber, (2) a traverse in a duct using a pitot tube (see Fig.5), and (3) a nozzle in a duct. Other airflow rate measurementtechniques in a duct can be used such as orifice plates (ASMEMFC-3M) or constant injection tracer gas methods.5In orderfor an alter
30、native airflow rate measurement technique to beincluded as a preferred procedure, the errors introduced by theprocedure must be demonstrated not to exceed those intro-duced by a nozzle or pitot traverse. In the optional procedure,the airflow is measured with a series of sharp-edged orificesinstalled
31、 in the wall of the chamber.4.4 The calibration must include measurement points thatcover a specific range in both fan pressure difference and fanairflow rate.5. Significance and Use5.1 The fan pressurization procedure provides a relativelyfast evaluation of the airtightness of building envelopes. I
32、norder for the accuracy of the test results to be known, theairflow rate measurement technique of the fan pressurizationsystem must be calibrated.5.2 This test method is applicable to fan pressurizationsystems that are installed in an opening in the buildingenvelope, as opposed to pressurization tec
33、hniques involvingthe mechanical ventilation system of the building.5.3 The technique of pressurization testing of buildings putsspecific requirements on the calibration of fan pressurizationsystems. The calibration must cover the range of fan pressuredifferences (approximately 12.5 to 75 Pa) that is
34、 inducedduring pressurization tests. The calibration must also cover arange in fan airflow rates corresponding to the range inbuilding size and airtightness that the fan pressurization systemwill encounter in the field.5Persily, A. K., “Air Flow Calibration of Building Pressurization Devices,”NBSIR
35、84-2849, National Bureau of Standards, 1984.Recommended Plate Thickness, b1.5mmford up to 150 mm2.5mmford up to 300 mm3.2mmford up to 600 mm4.5mmford up to 1200 mmRecommended Edge Thickness, aLess than 0.02 dNOTEFor thin plates (b 0.02 d), there is no need for beveling theedge of the orifice.FIG. 3
36、Sharp-Edged Orifice DesignFIG. 4 Transformation PieceNOTESurface finish shall be 1 m or better. The static orifices may notexceed 1 mm in diameter. The minimum pitot tube stem diameterrecognized under this standard shall be 2.5 mm. In no case shall the stemdiameter exceed130 of the test duct diamete
37、r.FIG. 5 Pitot Tube SpecificationsE 1258 88 (2003)35.4 The fan pressurization system must be calibrated in bothdirections of airflow used to pressurize and depressurize abuilding if the system airflow direction is reversible. These twocalibrations can be conducted using the various setups de-scribed
38、 in this test method; however some of the setups can becombined such that a single calibration facility can be used tocalibrate the fan in both directions. Such a single setup mayinvolve moving the fan pressurization system from one end ofthe chamber to the other, reversing the orientation of thesys
39、tem at the same end of the chamber, or it may not requiremoving the system at all.5.5 The calibration technique is applicable to the two basictypes of fan pressurization systems in use, r/min doors andsignal doors.5.6 For fan pressurization systems that operate in multipleranges of airflow rate, the
40、 system must be calibrated in eachrange.5.7 The calibration technique is intended to provide acomplete calibration of a fan pressurization system. Aftercalibrating several systems of an identical or similar design, thefan airflow rate may be found to be independent of certainparameters such as fan p
41、ressure difference. Other simplifyingrelations between fan airflow rate and fan speed or fan signalmay be observed. If these relations are observed, a manufac-turer or other calibrator may choose to simplify the calibrationprocedure by reducing the number of calibration points.5.8 The use of fan pre
42、ssurization systems in actual buildingsintroduces additional factors that may cause errors in theairflow rate measurement that are not accounted for by thecalibration. These factors include operator and weather effectsand interference from internal partitions and other obstructions.6. Hazards6.1 Pro
43、vide secure guards and cages for fans and motors toprevent accidental contact with any moving parts of theequipment.6.2 When the calibration is being conducted, a large volumeof air is being drawn into and forced out of the apparatus.Exercise care to prevent any objects from being knocked downor blo
44、wn around the test area.6.3 Noise may be generated by the moving air. Makehearing protection equipment available for personnel involvedin the testing.6.4 Design the ducts, chamber, and other equipment utilizedto withstand the pressure and other forces to be encountered.7. Apparatus7.1 The calibratio
45、n facility must include the followingcomponents:7.1.1 Preferred Procedure:7.1.1.1 ChamberAn enclosure of rectangular or circularcross section with characteristic dimension, M. In the case of arectangular cross section, the height H shall be at least 2.1 m,the width W shall be at least 2.4 m, and M i
46、s given by=4HW/p. In the case of a circular cross section, the chamberdiameter shall be at least 2.5 m and M is equal to the chamberdiameter. When multiple nozzles are used in a chamber, thechamber must be large enough to accommodate all the nozzlesas described in 7.1.2.1 and 7.1.2.2.7.1.1.2 Flow Co
47、nditionersA combination of screens orperforated plates located in the chamber to reduce pressuredisturbances within the enclosure. These air to be locatedwithin the chamber in accordance with 7.1.2. Where a mea-suring plane is located downstream of the flow conditioners,the flow conditioners are pro
48、vided to ensure a substantiallyuniform flow ahead of the measuring plane. Where a measur-ing plane is located upstream of the flow conditioners, thepurpose of these screens is to absorb some of the kinetic energyof the upstream jet, and allow its normal expansion as if in anunconfined space. Screens
49、 of square-mesh round wire withopen areas of 50 to 60 % are suggested and several will usuallybe needed. Any combination of screens or perforated platesthat provide this flow conditioning may be used.7.1.1.3 Airflow Rate Measurement System, for measuringthe fan airflow rate. Acceptable systems include a nozzle orbank of nozzles within the chamber, a nozzle in a duct, or apitot traverse in a duct in accordance with 7.1.2.7.1.1.4 Flow Straighteners, for straightening the flow up-stream of the measuring stations when the airflow rate mea-surement syst
