1、Designation: F 1471 93 (Reapproved 2001)Standard Test Method forAir Cleaning Performance of a High-Efficiency ParticulateAir Filter System1This standard is issued under the fixed designation F 1471; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of revision, the year 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 procedure and equipmentfor measuring the penetration of test
3、particles through high-efficiency particulate air (HEPA) filter systems using a laseraerosol spectrometer (LAS). This test method provides thecapability of evaluating the overall effectiveness of HEPAfiltersystems consisting of one or two filter stages.1.2 The aerosols used for testing have a hetero
4、disperse sizedistribution in the submicrometer diameter range from 0.1 to1.0 m.1.3 The purpose for conducting in-place filter testing by thistest method is in the ability to determine penetration ofmulti-stage installations, without individual stage tests. Particlepenetration as low as 108can be mea
5、sured by this test method.Also, the LAS provides a measure of penetration for discreteparticle sizes.1.4 Maximum penetration for an installed HEPA filtersystem is 5 3 104for one filter stage, and 2.5 3 107for twostages in series is recommended.NOTE 1Acceptance penetration criteria must be specified
6、in theprogram, or owners specifications. The penetration criteria suggested inthis test method is referenced in Ref (1).21.5 The values stated in SI units are to be regarded as thestandard.1.6 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is
7、 theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in 9.6.2. Referenced Documents2.1 ASTM Standards:3F 328 Practice for Calibration
8、 of an Airborne ParticleCounter Using Monodisperse Spherical Particles2.2 Military Standard:MIL-STD 282 Military Standard Filter Units, ProtectiveClothing, Gas Mask Components, and Related Products:Performance Test Method43. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 diluter
9、a device used to reduce the aerosol particleconcentration to eliminate coincidence counting is in the LAS.3.1.2 dilution ratiothe ratio of the undiluted aerosolparticle concentration entering the diluter to the diluted portionof the particle concentration. Because diluters have inherentparticle loss
10、es that may vary according to the particle size, thedilution ratio may not be constant with respect to size.3.1.3 laser aerosol spectrometer (LAS)a precision particledetector that allows single particle counting and sizing by theamount of scattered light from individual particles, where thesignals c
11、an be grouped into categories corresponding to par-ticle size.3.1.4 penetrationthe number of particles passing throughthe filter stage, to the number of particles challenging theupstream side of the filter stage. The penetration, or thechallenge aerosol, may be associated for each particle size ofin
12、terest.4. Summary of Test Method4.1 A challenge aerosol produced by Di(2-Ethylhexyl) Se-bacate (DOS) or Di(2-Ethylhexyl) Phthalate (DOP) is injectedupstream of the filter system and allowed to mix with theairstream. Using a LAS, samples of the aerosol are collectedfrom the airstream through probes,
13、both upstream and down-stream of the filter system. With this test method, the penetra-tion of the filter system can be calculated either as a functionof particle size, or in a particular size of interest. Due to highparticle concentrations that may be required to evaluate theperformance of HEPA fil
14、ter systems, it may become necessaryto dilute the upstream sample to avoid errors due to coinci-dence counting by the LAS.1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.05 on Indoor Air.Current edition approved Feb
15、. 15, 1993. Published April 1993.2The boldface numbers in parentheses refer to a list of references at the end ofthis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information
16、, refer to the standards Document Summary page onthe ASTM website.4Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Un
17、ited States.4.2 If a diluter is required, the diluter system is calibratedusing lower particle counts of the same aerosol and using theLAS for the measurements (refer to Annex A1 for calibration).4.3 Heterodisperse submicrometer aerosols spanning thediameter range from 0.1 to 1.0 m are used in the t
18、esting.5. Significance and Use5.1 This test method describes a procedure for determiningthe penetration of aerosols through a one- or twostage HEPAfilter installation. Testing multiple filter stages as a single uniteliminates the need for: installation of auxiliary aerosol bypassducts, installation
19、of aerosol injection manifolds between filterstages, and entry of test personnel into contaminated areas. Itprovides for filter testing without interruption of plant pro-cesses and operation of ventilation systems.5.2 The procedure is applicable for measuring penetrationsrequiring sensitivities to 0
20、.1 m.5.3 Achallenge concentration of 2.5 3 105particles/cm3(p/cm3), is required for evaluation of one-filter stage, and 2 3 106p/cm3, or about 30 g/L (assuming unit density), is required toproperly evaluate a two-stage HEPA filter system as one unit.5.4 This test method can determine the penetration
21、 of HEPAfilters in the particle-size range from 0.1 to 0.2 m where thegreatest penetration of particles is likely to occur.6. Apparatus6.1 LAS5The LAS is a particle detector for the purpose ofsizing and counting single particles in a gas stream. Up to 3000particles per second (p/s) can be counted wi
22、th less than 10 %coincidence, or electronic loss at its maximum flow rate. Thequantitative particle size distribution shall be a distribution bynumber, not mass, volume, or surface area.6.2 The test aerosol should be in the diameter range from0.1 to 1.0 m.6.3 The primary particle-size calibration of
23、 the LAS by themanufacturer shall be based on at least three sizes of mono-disperse polystyrene latex spheres (PSLs), covering the dy-namic range of the LAS. Calibration standards must betraceable to the National Institute of Standards and Technology(NIST).6.4 Sample flow accuracy through the LAS of
24、 65% isrequired, based on the manufacturers specifications. (Refer tomanufacturers guide for altitude adjustments of the samplevolume.)6.5 The LAS must have the capability for producing alisting of the particle size distribution over the LAS range. Astandard RS-232C interface signal for line printer
25、s, taperecorders, and computers is usually provided with the instru-ment.6.6 For calibration aerosol having a median size two timesthe minimum detectable size of the LAS, the relative standarddeviation of the particle size distribution indicated by the LAS,shall not be increased more than 10 % over
26、the actual relativestandard deviation of the calibration aerosol.6.7 An aerosol diluter6is required to reduce the number ofparticles of the upstream sample to avoid significant coinci-dence counting losses in the LAS. The diluter must haveminimum particle losses over the size range of interest and t
27、hatthe losses are constant with particle size. Calibration of thediluter is done with the LAS. The diluter calibration procedureis indicated inAnnexA2.Aschematic diagram of the diluter incalibration mode is shown in Fig. A2.1. The diluter calibrationplot is presented in Fig.A2.2.Atypical diluter wit
28、h dimensionsis illustrated in Fig. A2.3.6.8 Aerosol Generation7It is required that the generatorproduce a particle-size distribution covering the diameter rangefrom 0.1 to 1.0 m. It must have the capability of achieving upto 3000 p/s in gas streams when testing multiple-stage HEPAfilter systems.6.9
29、For streams where large volumes of aerosol are notrequired, an air-operated or small gas-thermal generator maybe used.6.10 Injection ports, or manifolds, must be provided fordistributing the aerosol uniformly with the gas stream. Up-stream and downstream probes are required to extract aerosolsamples
30、 from inside the filter housing.The location of injectionports and sample collection probes or manifolds must belocated in accordance with the requirements in Annex A3.6.11 It is recommended that sample lines between the LAS,diluter, and the upstream and downstream probes be the samesize and materia
31、l, and the same length as practicable.7. Reagent and Materials7.1 DOP or DOS8is used as the liquid material to form testaerosols.7.2 Polystyrene Latex Spheres.98. Calibration and Standardization8.1 Perform the primary calibration of the LAS by theinstrument manufacturer or by qualified personnel usi
32、ng ac-ceptable standard methods in accordance with Ref (2). Performcalibrations at regular twelve-month intervals and followingany repair or modification of the instrument. Place a labelshowing the due date of the next calibration on the instrument.8.2 A check calibration by the operator is recommen
33、dedperiodically if the instrument is used continuously or is movedto a new test location requiring vehicle transportation or roughhandling. The calibration check consists of testing the LASwith at least two sizes of PSLs. The LAS must correctly sizethe calibration aerosols and reproduce the spectral
34、 peak towithin 0.05 m. If the instrument cannot be adjusted to withinthose calibration limits, then it must be returned to the5Laser aerosol spectrometers are available from the following sources: ParticleMeasuring Systems, Inc., 1815 South 57th Court, Boulder, CO 80301, TSIIncorporated Particle Ins
35、truments Group, P.O. Box 64394, St. Paul, MN 55164, andMet One, Inc., 481 California Avenue, Grants Pass, OR 97526.6Available fromTSI Incorporated Particle Instrument Group, P.O. Box 64394 St.Paul, MN 55164.7Aerosol generators are available from the following sources: Air TechniquesDivision of Hamil
36、ton Associates, Inc., Baltimore, MD 21207, Particle Measure-ments Systems, Inc., 1815 South 57th Court, Boulder, CO 80301 (Calibration), andNuclear Consulting Services, Inc., P.O. Box 29151, Columbus, OH 43229.8Di(2-Ethylhexyl) Phthalate (DOP) and Sebacate (DOS) are available from C.P.Hall Co., Chic
37、ago, IL 60635, and Nuclear Consulting Services, Inc., P.O. Box29151, Columbus, OH 43229.9Available from Duke Scientific Corp., Palo Alto, CA 94303.F 1471 93 (2001)2manufacturer for service and calibration.AnnexA1 describes aprocedure for calibration of the LAS.8.3 Aerosol DiluterIt is recommended th
38、at the sameaerosol used in the in-place testing be used for diluter calibra-tion. If more than one dilution stage is required, each stagemust be calibrated independently. A procedure for calibrationof the diluter using the LAS is outlined in Annex A2.9. Procedure9.1 An example of an in-place filter
39、test system and sam-pling arrangement is illustrated in Fig. 1. Components includethe gas-flow duct, filter housing with filters, the LAS, diluter,and aerosol generator.9.2 Aerosol Mixing Uniformity Tests Conduct these testsupon completion of initial installation and after any modifica-tions or repa
40、ir to the filter system. It is not required to conductthese tests each time the in-place test is performed. However,if aerosol mixing and sampling parameters are changed, thennew air aerosol mixing uniformity tests are required. Refer toAnnex A3 for procedure.9.3 Measure the airflow of the test gas
41、stream and theresistance across the filter stage following the procedureoutlined in Annex A3.9.4 Establish the arrangement of sample lines between theprobes, the diluter, and LAS. Make the upstream and down-stream sample lines as equal in length as practicable.9.5 Because of expected low particle co
42、unts that can pen-etrate HEPA filter systems, it is necessary to measure thenon-test particles in the gas stream to serve as backgroundsamples. With no aerosol generation and no sample dilution,use the LAS to sample the gas stream from the downstreamsample probe only. Collect samples at this locatio
43、n for thesame duration as will be required for the test aerosol. Thebackground particle counts may vary depending on externalleaks to the filter housing, but should not exceed 30 % of theexpected test aerosol. If higher background particles are foundthan those suggested and if leaks in the filter ho
44、using aresuspected, they must be plugged before testing can continue.9.6 Generate the challenge aerosol at the suggested particleconcentration, see 5.3(WarningAvoid unnecessary loadingof the filters by the test aerosols by injecting the aerosols onlywhen ready to perform penetration measurements).9.
45、7 Collect samples from the upstream probe and establishthe challenge particle count. This is accomplished by switchingthe sample line from the LAS to the diluter. Sampling periodsare usually 20 s, refer to Annex A2.9.8 Purge the sample collection system and zero the LASbefore proceeding to the next
46、step in the procedure. Thepurging procedure is described in A2.1.2 of Annex A2.9.9 Accumulate two successive samples from the down-stream location. Sampling time periods should be selected toyield net particle counts over background of at least 100.A10-min sampling period is usually sufficient. The
47、differencebetween each set of samples shall not exceed 5 % of the largercount. If penetration of only one filter stage is being measured,shorter sampling times may be used because of higher particlecounts. If significant penetration is experienced downstream ofone-filter stage and coincidence counti
48、ng is suspected in theLAS, then the diluter must be used in the sample line. See 6.1and 6.7.)10. Calculation10.1 Calculate the penetration of the filter system for eachdiscrete particle-size. The equation holds for each specific sizeparticle diameter as:P 5Cd2 CbCuD(1)where:P = penetration,Cd= parti
49、cle counts downstream,Cb= particle counts of background,Cu= particle counts upstream, andD = dilution ratio.10.2 To calculate the uncertainty of the upstream anddownstream penetration measurements, a theoretical value wasused in the following equation. The value is based on standardpropagation-of-error techniques neglecting covariance termsand using Poisson statistics to estimate uncertainties. Theequation is as follows:FIG. 1 Schematic Diagram of the In-Place Test ArrangementF 1471 93 (2001)3CVp5 PNTd!211 D/NTu! 1 CVD2#1/2(2)where:CVp= coefficient of vari
