Designation:D7546−15StandardTestMethodforDeterminationofMoistureinNewandIn-ServiceLubricatingOilsandAdditivesbyRelativeHumiditySensor1ThisstandardisissuedunderthefixeddesignationD7546;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodcoversthequantitativedeterminationofwaterinnewandin-servicelubricatingoilsandadditivesintherangeof10mg/kgto100000mg⁄kg(0.001wt.⁄wt.to10%wt./wt.)usingarelativehumidity(RH)sensor.Methanol,acetonitrile,andothercompoundsareknowntointerferewiththistestmethod.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Warning—Samplestestedinthistestmethodcanbeflammable,explosive,andtoxic.Usecautionwhenhandlingthembeforeandaftertesting.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D4175TerminologyRelatingtoPetroleum,PetroleumProducts,andLubricants3.Terminology3.1Fordefinitionsoftermsusedinthistestmethod,refertoTerminologyD4175.4.SummaryofTestMethod4.1Analiquotofsampleisheatedtoatemperaturebetween25°Cto200°Cwith1°Cresolution.Thesampleismaintainedataconstanttemperatureforthedurationofthetest.Dryinertgasflowsovertheheatedsampleandcarriesthethermallyevolvedmoisturepastarelativehumiditysensor.Thesensorsignalisintegratedovertimetoprovideameasurementoftotalmassofwaterinthesample.4.2Thesampleinjectionmaybedoneeitherbymassorbyvolume.4.3Thistestmethodutilizesanhydrouscompressedgasorambientairpassedthroughadesiccanttopreventcontamina-tionfrommoisturepresentintheatmosphere.4.4Viscoussamplescanbeanalyzedbypreheatingthemtoplacetheminamorefluid...
