Designation:D1657−12(Reapproved2017)ManualofPetroleumMeasurementStandards(MPMS),Chapter9.2StandardTestMethodforDensityorRelativeDensityofLightHydrocarbonsbyPressureHydrometer1ThisstandardisissuedunderthefixeddesignationD1657;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofthedensityorrelativedensityoflighthydrocarbonsincludingliquefiedpetroleumgases(LPG)havingReidvaporpressuresexceeding101.325kPa(14.696psi).1.2Theprescribedapparatusshouldnotbeusedformate-rialshavingvaporpressureshigherthan1.4MPa(200psi)atthetesttemperature.Thispressurelimitisdictatedbythetypeofequipment.Higherpressurescanapplytootherequipmentdesigns.1.3Theinitialpressurehydrometerreadingsobtainedareuncorrectedhydrometerreadingsandnotdensitymeasure-ments.Readingsaremeasuredonahydrometerateitherthereferencetemperatureoratanotherconvenienttemperature,andreadingsarecorrectedforthemeniscuseffect,thethermalglassexpansioneffect,alternatecalibrationtemperatureeffectsandtothereferencetemperaturebymeansofcalculationsandAdjuncttoD1250GuideforPetroleumMeasurementTables(APIMPMSChapter11.1)orAPIMPMSChapter11.2.4(GPATP-27),asapplicable.1.4ValuesdeterminedasdensityorrelativedensitycanbeconvertedtoequivalentvaluesintheotherunitsoralternativereferencetemperaturesbymeansofInterconversionProce-duresAPIMPMSChapter11.5,orAdjuncttoD1250GuideforPetroleumMeasurementTables(APIMPMSChapter11.1)orAPIMPMSChapter11.2.4(GPATP-27),asapplicable.1.5ThecalculationsrequiredinSection11shallbeappliedtotheinitialpressurehydrometerreadingwithobservationsandresultsreportedasrequiredbySection11priortouseinasubsequentcalculationprocedure(measurementticketcalculation,meterfactorcalculation,orbaseprovervolumedetermination).1.6AnnexA1containsaprocedureforverifyingorcertify-ingtheequipmentf...
