Designation:F328–98(Reapproved2003)StandardPracticeforCalibrationofanAirborneParticleCounterUsingMonodisperseSphericalParticles1ThisstandardisissuedunderthefixeddesignationF328;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversproceduresforcalibratinganddeterminingperformanceofanopticaldiscreteairbornepar-ticlecounter(DAPC)whenpresentedwithachallengeaerosolofnear-monodispersesphericalparticles.Thepracticeisdi-rectedtowardsdeterminationofaccuracyandresolutionoftheDAPCforparticleswhichhaveenteredthesamplinginletoftheDAPC.Considerationofinletsamplingefficiencyisnotpartofthispractice.1.2Theprocedurescoveredhereincludeinletsampleflowrate,zerocountlevel,particlesizingaccuracy,particlesizingresolution,particlecountingefficiency,andparticleconcentra-tionlimit.1.3Theparticlesizeparameterthatisreportedistheequivalentopticaldiameterbasedonprojectedareaofaparticleofknownrefractiveindexwhichissuspendedinair.TheminimumdiameterthatcanbereportedbyaDAPCisnormallyspecifiedbythemanufacturerandthemaximumdiameterthatcanbereportedforasinglesampleisdeterminedbythedynamicrangeoftheDAPCbeingused.Typicalminimumdiametersareintherangefromapproximately0.05µmto0.5µmandatypicaldynamicrangespecificationwillbebetween10to1and50to1.1.4ThecountingratecapabilityoftheDAPCislimitedbytemporalcoincidenceforthespecificinstrumentandbythemaximumcountingratecapabilityoftheelectronicsizingandcountingcircuitry.CoincidenceisdefinedasthesimultaneouspresenceofmorethanoneparticlewithintheDAPCopticallydefinedsensingzoneatanytime.Thecoincidencelimitisastatisticalfunctionoftheairborneparticleconcentrationandthesensingzonevolume(1).2Thislimitationmaybemodifiedbythepresenceofparticleswithdimensionsolargeastobeasignificantfractionofthesensingzonedimension(2).3Thesaturationlevelormaximum...
