1、Designation: E 1258 88 (Reapproved 2008)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 onASHRAE 51/AMCA 210, and an optionalprocedure based on a nonstandard airflow measurement tech-nique, commonly used by manufacturers of fan pressurizationdevices, but which has not been compared with standardairflow
6、 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 limitations prio
7、r to use.2. Referenced Documents2.1 ASTM Standards:2E 631 Terminology of Building ConstructionsE 779 Test Method for Determining Air Leakage Rate byFan Pressurization2.2 American Society of Heating, Refrigerating, and Air-Conditioning Engineers Standard:3ASHRAE 51/AMCA 210 Laboratory Methods for Tes
8、tingFans 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 Specific to This St
9、andard: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 expected to encount
10、er 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 the fan outlet ope
11、ning 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 conditioners. The other
12、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 measuring system, and a
13、 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 the static pressure
14、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 Buildings and is the direct responsibility of Subcommittee E06.41on Ai
15、r Leakage and Ventilation Performance.Current edition approved April 1, 2008. Published May 2008. Originallyapproved in 1988. Last previous edition approved in 2003 as E 1258 88 (2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceast
16、m.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, http:/www.ashrae.org.4Avail
17、able from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.10 flow conditioners, na comb
18、ination of screens orperforated plates 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, n
19、static 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 diameter, ndiameter of nozzle dis-charge end expressed in square metres.3.2.14 nozzle throat pressure difference, nstatic pressuredifference across
20、 the nozzle in a duct measured with 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
21、chamber expressed in pascals.3.2.17 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 tha
22、n 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 duct (see Fig. 4).4. Summary of Test Method4.1 This test method contains two procedures for calibratingfan pressurization devices, a preferred p
23、rocedure 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 measured b
24、y thesystem itself, 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
25、0.5 Dn6 0.005 Dn.NOTE 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 fre
26、e from burrs, nicks,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
27、Dngreater, but no lessthan 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
28、 shown above may be 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 (2008)2me
29、asurement 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. Other airflow rate measurementtechniques in a duct can be used such as orifice plates (ASMEMFC-3M) or constant injection tracer gas methods.5I
30、n orderfor an alternative 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-edge
31、d orificesinstalled 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 bu
32、ilding envelopes. Inorder 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
33、 pressurization techniques 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.
34、5 to 75 Pa) that is 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 Pressurizat
35、ion Devices,”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 dNOTEFor thin plates (b 0.02 d), there is no need for beveling theedge of
36、the orifice.FIG. 3 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 th
37、e test duct diameter.FIG. 5 Pitot Tube SpecificationsE 1258 88 (2008)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 variou
38、s 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 both directions. Such a single setup mayinvolve moving the fan pressurization system from one end ofthe chamber to the other, reversing the or
39、ientation 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 basictypes of fan pressurization systems in use, r/min doors andsignal doors.5.6 For fan pressurization systems that operate in multipleranges o
40、f airflow rate, the 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 certainparam
41、eters such as fan pressure 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
42、 The use of fan pressurization 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 obstruction
43、s.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 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
44、 knocked downor blown 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. Apparatu
45、s7.1 The calibration 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 l
46、east 2.4 m, and M is 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.
47、2.2.7.1.1.2 Flow ConditionersA 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 c
48、onditioners are provided 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 anunconf
49、ined 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 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 r
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