Designation:D5797−21StandardSpecificationforMethanolFuelBlends(M51–M85)forMethanol-CapableAutomotiveSpark-IgnitionEngines1ThisstandardisissuedunderthefixeddesignationD5797;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thisspecificationcoverstherequirementsforautomo-tivefuelblendsofmethanolandgasolineforuseingroundvehiclesequippedwithmethanol-capableflexible-fuel,anddedicatedmethanolspark-ignitionengines.Fuelproducedtothisspecificationcontains51%to85%byvolumemethanol.Thisfuelissometimesreferredtoatretailas“M85.”AppendixX1discussesthesignificanceofthepropertiesspecified.AppendixX2presentsthecurrentstatusinthedevelopmentofaluminositytestprocedure(flamevisibility)formethanolfuelblends(M51–M85).1.2Thevaporpressureofmethanolfuelblendsisvariedforseasonalclimaticchanges.Vaporpressureisincreasedatlowertemperaturestoensureadequatevehicleoperabilityandsafety.Methanolcontentandselectionofgasolineblendstocksareadjustedbytheblendertomeetthesevaporpressurerequire-ments.1.3TheUnitedStatesgovernmenthasestablishedvariousprogramsforalternativefuels.Manyofthedefinitionsofalternativefuelusedbytheseprogramscanbemoreorlessrestrictivethantherequirementsofthisspecification.SeeAnnexA1foradditionalinformationonalternativefuelscontainingmethanol.1.4ThevaluesstatedinSIunitsaretoberegardedasthestandard.1.4.1Exception—Non-SIunitsareprovidedforinformationonly.Inmostcases,U.S.federalregulationsspecifynon-SIunits.1.5Thefollowingprecautionarycaveatpertainsonlytothetestmethodportions–AppendixX2ofthisspecification.Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafety,health,andenvironmentalpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.1.6Thisintern...
