1、Designation: E1258 88 (Reapproved 2012)Standard Test Method forAirflow Calibration of Fan Pressurization Devices1This standard is issued under the fixed designation E1258; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 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 covers the airflow measurement cali-bration techniques for fan pressurization systems used formeasur
3、ing air leakage rates through building envelopes.1.2 This test method is applicable to systems used for airleakage measurement as described in Practice E779.1.3 This test method involves the installation of the fanpressurization system in a calibration chamber. Use of the fanpressurization system in
4、 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 measurem
5、ent.1.5 This standard includes two basic procedures, a preferredprocedure, based onASHRAE 51/AMCA 210, and an optionalprocedure based on a nonstandard airflow measurementtechnique, commonly used by manufacturers of fan pressur-ization devices, but which has not been compared withstandard airflow mea
6、surement techniques.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.7 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 standa
7、rd to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E631 Terminology of Building ConstructionsE779 Test Method for DeterminingAir Leakage Rate by FanPressurization2.2 American Soci
8、ety of Heating, Refrigerating, and Air-Conditioning Engineers Standard:3ASHRAE 51/AMCA 210 Laboratory 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 De
9、finitionsFor definitions used in this test method,see Terminology E631.3.2 Definitions of Terms Specific 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 r
10、ectangular or circularcross section to simulate the entrance and exit conditions thatthe fan is expected 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 expres
11、sed in cubic metres per second.3.2.5 fan outlet area, ngross inside area measured in theplane of 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 describ
12、ed in Fig. 1. One station islocated within the chamber between the fan and the nearestflow conditioners. 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
13、the building interior. Thesystem includes controllable air-moving equipment, an airflowrate measuring system, and a device for measuring the pressure1This test method is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.41on
14、Air Leakage and Ventilation Performance.Current edition approved Oct. 1, 2012. Published October 2012. Originallyapproved in 1988. Last previous edition approved in 2008 as E1258 88 (2008).DOI: 10.1520/E1258-88R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM C
15、ustomer 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, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA30329
16、, http:/www.ashrae.org.4Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1diffe
17、rence 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 the static pressure differenceacross a constriction that is
18、 integral to the system.3.2.9 fan speed, nspeed of rotation of the fan impellerexpressed in inverse seconds.3.2.10 flow conditioners, na combination of screens orperforated plates located within the calibration chamber toreduce pressure disturbances within the chamber.3.2.11 nozzle, na gradually tap
19、ered constriction, of veryprecise elliptical shape, used in airflow rate measurement (seeFig. 2).3.2.12 nozzle chamber pressure difference, nstatic pres-sure difference measured across a nozzle or bank of nozzleswhen nozzles are installed in a chamber expressed in pascals.3.2.13 nozzle throat diamet
20、er, 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 throat tapsexpressed in pascals (see Fig. 2).3.2.15 orifice, na sharp-edged circular constriction used inairflow measuremen
21、t (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 revolution-per-minute (r/min) door, na fan pressur-ization system with a calibration that relates the fan airflow rateto th
22、e 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 piece, nan element to connect aduct with a measuring station to a fan when the fan connectionis a different size than the duc
23、t (see Fig. 4).FIG. 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.NOTE 2Nozzle shall have elliptical section as shown. Two and three radii approximations to the e
24、lliptical 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,or roundings.NOTE 3The nozzle throat shall be measured (to an accuracy of 0.001 Dn) at the mi
25、nor 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 lessthan the mean at the nozzle exit.NOTE 4The nozzle surface shall fair smoothly so that a str
26、aightedge 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 used. Where a nozzle discharges directly to a duct, nozzleswith throat taps shall be used, an
27、d 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 SpecificationsE1258 88 (2012)24. Summary of Test Method4.1 This test method contains two procedures for calibratingfan pressurization devices, a p
28、referred procedure based onASHRAE 51/AMCA 210, and an optional procedure employ-ing 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
29、measured by thesystem itself, and the airflow rate measured in the calibrationfacility. In the preferred procedure, three modes of airflowmeasurement are acceptable: (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. Ot
30、her airflow rate measurementtechniques in a duct can be used such as orifice plates (ASMEMFC-3M) or constant injection tracer gas methods.5In orderfor an alternative airflow rate measurement technique to beincluded as a preferred procedure, the errors introduced by theprocedure must be demonstrated
31、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 in the wall of the chamber.4.4 The calibration must include measurement points thatcover a specific range in both fan pressure difference an
32、d fanairflow rate.5. Significance and Use5.1 The fan pressurization procedure provides a relativelyfast evaluation of the airtightness of building envelopes. Inorder for the accuracy of the test results to be known, theairflow rate measurement technique of the fan pressurizationsystem must be calibr
33、ated.5.2 This test method is applicable to fan pressurizationsystems that are installed in an opening in the buildingenvelope, as opposed to pressurization techniques involvingthe mechanical ventilation system of the building.5Persily, A. K., “Air Flow Calibration of Building Pressurization Devices,
34、”NBSIR 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 dNOTE 1For thin plates (b 0.02 d), there is no need for beveling theedge of the orific
35、e.FIG. 3 Sharp-Edged Orifice DesignFIG. 4 Transformation PieceNOTE 1Surface finish shall be 1 m or better. The static orifices maynot exceed 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 d
36、uct diameter.FIG. 5 Pitot Tube SpecificationsE1258 88 (2012)35.3 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 induc
37、edduring 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.5.4 The fan pressurization system must be calibrated in bothdirections of airflow used
38、to pressurize and depressurize abuilding if the system airflow direction is reversible. These twocalibrations can be conducted using the various setups de-scribed in this test method; however some of the setups can becombined such that a single calibration facility can be used tocalibrate the fan in
39、 both directions. Such a single setup mayinvolve moving the fan pressurization system from one end ofthe chamber to the other, reversing the orientation of thesystem 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 b
40、asictypes 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 system must be calibrated in eachrange.5.7 The calibration technique is intended to provide acomplete calibration of a fan pressurization
41、 system. Aftercalibrating several systems of an identical or similar design, thefan airflow rate may be found to be independent of certainparameters such as fan pressure difference. Other simplifyingrelations between fan airflow rate and fan speed or fan signalmay be observed. If these relations are
42、 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 pressurization systems in actual buildingsintroduces additional factors that may cause errors in theairflow rate measurement that are not acc
43、ounted for by thecalibration. These factors include operator and weather effectsand interference from internal partitions and other obstructions.6. Hazards6.1 Provide secure guards and cages for fans and motors toprevent accidental contact with any moving parts of theequipment.6.2 When the calibrati
44、on 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 blown around the test area.6.3 Noise may be generated by the moving air. Makehearing protection equipment available for personnel involvedin
45、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 calibration facility must include the followingcomponents:7.1.1 Preferred Procedure:7.1.1.1 ChamberAn enclosure of rectangular or circularcross sect
46、ion 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 is given by =4HW/.In the case of a circular cross section, the chamber diametershall be at least 2.5 m and M is equal to the chamber diamet
47、er.When multiple nozzles are used in a chamber, the chambermust be large enough to accommodate all the nozzles asdescribed in 7.1.2.1 and 7.1.2.2.7.1.1.2 Flow ConditionersA combination of screens orperforated plates located in the chamber to reduce pressuredisturbances within the enclosure. These ai
48、r 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 provided to ensure a substantiallyuniform flow ahead of the measuring plane. Where a measur-ing plane is located upstream of the flow conditio
49、ners, 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 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
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