Designation:C931/C931M–04e1StandardSpecificationforExteriorGypsumSoffitBoard1ThisstandardisissuedunderthefixeddesignationC931/C931M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.e1NOTE—Thewordrating(s)wasaddedtothetermfireresistancethroughouteditoriallyOctober2004.1.Scope*1.1Thisspecificationcoversexteriorgypsumsoffitboard,designedtobeusedforexteriorsoffitsandcarportceilingsthatarecompletelyprotectedfromcontactwithliquidwater.NOTE1—SpecificationC840containsapplicationproceduresforexte-riorgypsumsoffitboard.1.2Thevaluesstatedineitherinch-poundunitsorSI(metric)aretoberegardedseparatelyasthestandard.Withinthetext,theSIunitsareshowninbrackets.Thevaluesstatedineachsystemshallbeusedindependentlyoftheother.Valuesfromthetwosystemsshallnotbecombined.1.3Thetextofthisstandardreferencesnotesandfootnotesthatprovideexplanatorymaterial.Thesenotesandfootnotes(excludingthoseintablesandfigures)shallnotbeconsideredasrequirementsofthestandard.2.ReferencedDocuments2.1ASTMStandards:2C11TerminologyRelatingtoGypsumandRelatedBuild-ingMaterialsandSystemsC473TestMethodsforPhysicalTestingofGypsumPanelProductsC645SpecificationforNonstructuralSteelFramingMem-bersC840SpecificationforApplicationandFinishingofGyp-sumBoardC1264SpecificationforSampling,Inspection,Rejection,Certification,Packaging,Marking,Shipping,Handling,andStorageofGypsumBoardE84TestMethodforSurfaceBurningCharacteristicsofBuildingMaterialsE119TestMethodsforFireTestsofBuildingConstructionandMaterials3.Terminology3.1DefinitionsoftermsshallbeinaccordancewithTermi-nologyC11.4.MaterialsandManufacture4.1Gypsumsoffitboardshallconsistofanoncombustiblecore,essentiallygypsum,surfacedwithpaperbondedtothecore.4.2Exteriorgypsumsoffitboard,typeX(specialfire-resistant...
