Designation:D4651−14(Reapproved2020)StandardSpecificationforIsobutaneThermophysicalPropertyTables1ThisstandardisissuedunderthefixeddesignationD4651;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thethermophysicalpropertytablesforisobutaneareforuseinthecalculationofthepressure-volume-temperature(PVT),thermodynamic,andtransportpropertiesofisobutaneforprocessdesignandoperations.Twotablesprovideproper-tiesattheconditionsofliquid-vaporequilibrium(saturationproperties),oneforliquidandoneforvapor,attemperaturesbetween120Kandthecriticalpoint,407.81K.AthirdtableprovidespropertiesatselectedT,ppointsfortheequilibriumphaseattemperaturesbetween120Kand570Katpressuresto20MPa.ThetablesweredevelopedusingtheNationalInstituteofStandardsandTechnologyStandardReferenceDatabaseproductREFPROP,version9.1.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.4Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.Applicability2.1Thesetablesapplydirectlyonlytopureisobutane.Theymayalsobeusedinmathematicalmodelsandtablesforthethermophysicalpropertiesofmixturescontainingisobutane.3.Tables3.1Thesetableswereproducedbyequationsfromacom-puterpackage,“NISTStandardReferenceDatabase23;Ref-erenceFluidThermodynamicandTransportPropertiesData-base(REFPROP):V...
