Designation:D1921−18StandardTestMethodsforParticleSize(SieveAnalysis)ofPlasticMaterials1ThisstandardisissuedunderthefixeddesignationD1921;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Thesetestmethodscoverthemeasurementoftheparticlesizeofplasticmaterialsinthepowdered,granular,orpelletedformsinwhichtheyarecommonlysupplied.Asthesetestmethodsutilizedrysieving,thelowerlimitofmeasure-mentisconsideredtobeabout38µm(No.400sieve).Forsmallerparticlesizes,sedimentationtestmethodsarerecom-mended.1.2Twotestmethodsaredescribed:1.2.1TestMethodA—Thistestmethodusesmultiplesievesselectedtospantheparticlesizeofthematerial.Thismethodisusedtodeterminethemeanparticlediameterandparticlesizedistribution.1.2.2TestMethodB—ThistestmethodisanabbreviatedversionofTestMethodAconductedwithafewspecificsieves.Thistestmethoddetermines“percentpassing”or“percentretained”onagivensieve.TestMethodBisapplicabletomaterialswhichdonothaveanormalparticlesizedistributionsuchaspelletsandcubes.1.3ThevaluesstatedinSIunitsaretoberegardedasstandardfordimensionsofthewireclothopeningsandthediameterofthewiresusedinthewirecloth.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.NOTE1—ThereisnoknownISOequivalentforthistestmethod.1.5Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.Referenc...
