Designation:D388−19aStandardClassificationofCoalsbyRank1ThisstandardisissuedunderthefixeddesignationD388;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisstandardcoverstheclassificationofcoalsbyrank,thatis,accordingtotheirdegreeofmetamorphism,orprogres-sivealteration,inthenaturalseriesfromlignitetoanthracite.1.2Thisclassificationisapplicabletocoalsthatarecom-posedmainlyofvitrinite.NOTE1—Coalsrichininertiniteorliptinite(exinite),orboth,cannotbeproperlyclassifiedbecause,inthosemacerals,thepropertiesthatdeter-minerank(calorificvalue,volatilematter,andagglomeratingcharacter)differgreatlyfromthoseofvitriniteinthesamecoal.Often,suchcoalscanberecognizedbymegascopicexamination.InNorthAmerica,thesecoalsaremostlynonbandedvarietiesthatcontainonlyasmallproportionofvitrainandconsistmainlyofattritalmaterials.Thedegreeofmetamor-phismofnonbandedandothervitrinite-poorcoalscanbeestimatedbydeterminingtheclassificationpropertiesofisolatedorconcentratedvitrinitefractions,orbydeterminingthereflectanceofthevitrinite(seeTestMethodD2798andAppendixX1ofthisclassification).However,intheuseofthesevitrinite-poorcoals,somepropertiesnormallyassociatedwithrank,suchasrheology,combustibility,hardness,andgrindability(aswellastherankdeterminingproperties)maydiffersubstantiallyfromthoseofvitrinite-richcoalsofthesamedegreeofmetamorphism.1.3Theaccuracyoftheclassificationofimpurecoalmaybeimpairedbytheeffectoflargeamountsofmineralmatteronthedeterminationofvolatilematterandcalorificvalue,andontheircalculationtothemineral-matter-freebasis.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Thevaluesgiveninparenthesesareforinformationonly.1.4.1Exception—ThevaluesstatedinBritishthermalunitsperpound(Btu/lb)aretoberegardedasthestandard.TheSIequivalentsofBtu/lbareprovidedforinformationonly...
