Designation:D720/D720M−22StandardTestMethodforFree-SwellingIndexofCoal1ThisstandardisissuedunderthefixeddesignationD720/D720M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thistestmethod2isasmall-scale,empiricaltestforobtaininginformationregardingthefree-swellingpropertiesofacoal.Theresultsmaybeusedasanindicationofthecakingcharacteristicofthecoalwhenburnedasafuel.Thistestisnotrecommendedasamethodforthedeterminationofexpansionofcoalsincokeovens.1.2Units—ThevaluesstatedineitherSIunitsornon-SIunitsaretoberegardedseparatelyasstandard.Thevaluesstatedineachsystemarenotnecessarilyexactequivalents;therefore,toensureconformancewiththestandard,eachsystemshallbeusedindependentlyoftheother,andvaluesfromthetwosystemsshallnotbecombined.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.4Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:3D2013/D2013MPracticeforPreparingCoalSamplesforAnalysisE691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethod3.SignificanceandUse3.1Thistestmethod,inadditiontoindicatingthecakingpropertiesofacoalwhenburnedasafuel,canbeusedtogiveabroadindicationofthedegreeofoxidationofacoal.4.Apparatus4.1Thistestmethodcanbeperformedusingeitherelectricorgasheating.Whenusingelec...
