Designation:C22/C22M−00(Reapproved2015)StandardSpecificationforGypsum1ThisstandardisissuedunderthefixeddesignationC22/C22M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisspecificationcoversgypsum,calciumsulfatecom-binedwithtwomoleculesofwaterincrystallineformandhavingtheapproximatechemicalformulaCaSO4·2H2O.1.2Thevaluesstatedineitherinch-poundunitsorSI(metric)aretoberegardedseparatelyasthestandard.Withinthetext,theSIunitsareshowninbrackets.Thevaluesstatedineachsystemshallbeusedindependentlyoftheother.Valuesfromthetwosystemsshallnotbecombined.1.3Thetextofthisspecificationreferencesnotesandfootnoteswhichprovideexplanatorymaterial.Thesenotesandfootnotes(excludingthoseintablesandfigures)shallnotbeconsideredasrequirementsofthespecification.2.ReferencedDocuments2.1ASTMStandards:2C11TerminologyRelatingtoGypsumandRelatedBuildingMaterialsandSystemsC471MTestMethodsforChemicalAnalysisofGypsumandGypsumProducts(Metric)C472TestMethodsforPhysicalTestingofGypsum,Gyp-sumPlastersandGypsumConcrete3.Terminology3.1Definitions—DefinitionsshallbeinaccordancewithTerminologyC11.4.ChemicalComposition4.1Gypsumshallcontainnotlessthan70.0weightpercentCaSO4·2H2O.4.2Thechemicalcomposition,withinthelimitsprescribedby4.1,shallbespecifiedinthepurchaseorderorcontract.5.PhysicalProperties5.1Size—Ifnecessary,gypsumshallbecrushedorground,orboth,tothesizespecifiedinthepurchaseorder.6.Sampling6.1Bulk—Whengypsumisshippedinbulk,samplesofapproximately5lb[2kg]eachshallbetakenatregularintervalsduringthecompleteloadingorunloadingofthecarrier,insuchawayastoaccumulatenotlessthan200lb[90kg]ofmaterialandtorepresentcorrectlythepercentagesofboththecoarseparticlesandthefinesintheshipment.Thismaterialshallbebrokentopassa1-in.[25.0-mm]sieve,thoroughlymixed,andreducedbyquarteringtoprovidenotle...
