Designation:D2759−00(Reapproved2010)StandardPracticeforSamplingGasfromaTransformerUnderPositivePressure1ThisstandardisissuedunderthefixeddesignationD2759;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversthesamplingofgasabovetheinsulatingliquidofatransformer.Agassamplingbottlecollectsthegassamplefromthegasspacethatisatapositivepressure.1.2Representativesamplesofgasaretakenforanalysistodeterminetheircompositions.1.3ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.SignificanceandUse2.1Agassamplefromabovetheinsulatingliquidintransformersandotherelectricalpowerapparatuscanbeusedtogiveanearlyindicationofdevelopingfaultconditions.Combustiblegasesareformedfromthebreakdownoftheinsulatingmaterialsunderthermalandelectricalstress.Exces-siveconcentrationsofcombustiblegasesindicatetheneedtotakeappropriateaction.2.2Itisimportantthatgassamplesfromequipmentbetakenfromthegasspacedirectlyabovetheliquidlevel,andnotfromremoteexpansioncompartments,suchastankbracingbands.2.3Theproceduredescribedshouldbecarefullyfollowedtoensurethatthesampleisnotdilutedbyairornitrogen,orcontaminatedbyresidualmaterialsinthesamplingbottle.3.Apparatus3.1GasSamplingBottle—stainlesssteel,Monelmetal,orglass,ofatleast250-cm3capacity,withavalveandahoseconnectoroneachend.3.1.1Thegassamplingbottlemustbefreeofdirt,moisture,oil,orothercontaminants.Itshouldbecleanedbywashingwithanhydrousisopropylalcohol,orothersuitablecleaningagentthatisfreefromresidueuponevaporation.Thebottleshouldthenbedrie...
