Designation:D7971−20StandardGuideforMeasuringRoundnessofGlassSpheresUsingaFlowingStreamDigitalImageAnalyzer1ThisstandardisissuedunderthefixeddesignationD7971;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisguidecoversthedeterminationoftheroundnessofglassspheresusedinpavementmarkingsystemsusingaflowingstreamdigitalanalyzer.Typicalgradationsforpave-mentmarkingsystemsaredefinedinrangesfromType0through5inAASHTOM247.1.2Thisguideprovidesforthepresentationofroundnessdatainavarietyofformatstotherequirementoftheagencypavementmarkingmaterialspecification.Formostspecifica-tionsthestandardformatistopresenttheroundnessdataasPercentTrueSpheresrelativetoaseriesofstandardASTMsievesizes.1.3ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.5Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2B215PracticesforSamplingMetalPowders2.2AASHTOStandard:3AASHTOM247StandardGlassBeadsUsedinTrafficMarkings2.3ISOStandards:4ISO9276–6Representationofresultsofparticlesizeanaly-sis—Part6:DescriptiveandquantitativerepresentationofparticleshapeandmorphologyISO13322–1Particlesizeanalysis—Imageanalysismeth-ods—Part1:Staticimageanalysismethods3.Terminology3.1FlowingStreamDigitalAnalyzer:3.1.1Acomputercontrolle...
