Designation:D1142−95(Reapproved2021)StandardTestMethodforWaterVaporContentofGaseousFuelsbyMeasurementofDew-PointTemperature1ThisstandardisissuedunderthefixeddesignationD1142;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thistestmethodcoversthedeterminationofthewatervaporcontentofgaseousfuelsbymeasurementofthedew-pointtemperatureandthecalculationtherefromofthewatervaporcontent.NOTE1—Somegaseousfuelscontainvaporsofhydrocarbonsorothercomponentsthateasilycondenseintoliquidandsometimesinterferewithormaskthewaterdewpoint.Whenthisoccurs,itissometimesveryhelpfultosupplementtheapparatusinFig.1withanopticalattachmentthatuniformlyilluminatesthedew–pointmirrorandalsomagnifiesthecondensateonthemirror.Withthisattachmentitispossible,insomecases,toobserveseparatecondensationpointsofwatervapor,hydrocarbons,andglycolaminesaswellasicepoints.However,ifthedewpointofthecondensablehydrocarbonsishigherthanthewatervapordewpoint,whensuchhydrocarbonsarepresentinlargeamounts,theymayfloodthemirrorandobscureorwashoffthewaterdewpoint.Bestresultsindistinguishingmultiplecomponentdewpointsareobtainedwhentheyarenottoocloselyspaced.NOTE2—Condensationofwatervaporonthedew-pointmirrormayappearasliquidwaterattemperaturesaslowas0to−10°F(−18to−23°C).Atlowertemperaturesanicepointratherthanawaterdewpointlikelywillbeobserved.Theminimumdewpointofanyvaporthatcanbeobservedislimitedbythemechanicalpartsoftheequipment.Mirrortemperaturesaslowas−150°F(−100°C)havebeenmeasured,usingliquidnitrogenasthecoolantwithathermocoupleattachedtothemirror,insteadofathermometerwell.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-p...
