Designation:D4549−15(Reapproved2021)StandardClassificationSystemandBasisforSpecificationforPolystyreneandRubber-ModifiedPolystyreneMoldingandExtrusionMaterials(PS)1ThisstandardisissuedunderthefixeddesignationD4549;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thisclassificationsystemcoverspolystyrenematerials,bothcrystalandrubbermodified,suitableformoldingandextrusion.1.2Thisclassificationsystemandsubsequentlinecallout(specification)areintendedtobeameansofcallingoutplasticmaterialsusedinthefabricationofenditemsorparts.Itisnotintendedfortheselectionofmaterials.Materialselectioncanbemadebythosehavingexpertiseintheplasticsfieldaftercarefulconsiderationofthedesignandtheperformancerequiredofthepart,theenvironmenttowhichitwillbeexposed,thefabricationprocesstobeemployed,theinherentpropertiesofthematerialotherthanthosecoveredbythisspecification,andtheeconomics.1.3Thepropertiesincludedinthisspecificationarethoserequiredtoidentifythecompositionscovered.Otherrequire-mentsnecessarytoidentifyparticularcharacteristicsimportanttospecializedapplicationsaretobespecifiedusingthesuffixesasgiveninSection5.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.NOTE1—ThisstandardcombineselementsfromISO1622-1-2andISO2897-1-2,butisnotequivalenttoeitherISOstandard.1.5Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2D256TestMethodsforDeterminingtheIzodPendulumImpactResistanceofPlastic...
