Designation:D7418−22StandardPracticeforSet-UpandOperationofFourierTransformInfrared(FT-IR)SpectrometersforIn-ServiceOilConditionMonitoring1ThisstandardisissuedunderthefixeddesignationD7418;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONThispracticedescribestheinstrumentset-upandoperationparametersforusingFT-IRspectrom-etersforin-serviceoilconditionmonitoring.Thefollowingparametersaretypicallymonitoredforpetroleumandhydrocarbonbasedlubricants:water,soot,oxidation,nitration,phosphateantiwearadditives,fueldilution(gasolineordiesel),sulfateby-productsandethyleneglycol.MeasurementanddatainterpretationparametersarestandardizedtoallowoperatorsofdifferentFT-IRspectrometerstoobtaincomparableresultsbyemployingthesametechniques.Twoapproachesmaybeusedtomonitorin-serviceoilsamplesbyFT-IRspectrometry:(1)directtrendanalysisand(2)differential(spectralsubtraction)trendanalysis.Theformerinvolvesmeasurementsmadedirectlyonin-serviceoilsamples,whereasthelatterinvolvesmeasurementsobtainedafterthespectrumofareferenceoilhasbeensubtractedfromthespectrumofthein-serviceoilbeinganalyzed.Bothoftheseapproachesaredescribedinthispractice,anditisuptotheusertodeterminewhichapproachismoreappropriate.1.Scope*1.1Thispracticecoverstheinstrumentset-upandoperationparametersforusingFT-IRspectrometersforin-serviceoilconditionmonitoringforbothdirecttrendanalysisanddiffer-entialtrendanalysisapproaches.1.2ThispracticedescribeshowtoacquiretheFT-IRspec-trumofanin-serviceoilsampleusingastandardtransmissioncellandestablishesmaximumallowablespectralnoiselevels.1.3Measurementandintegratedparametersforindividualin-serviceoilconditionmonitoringcomponentsandparam-etersarenotdescribedinthispracticeandaredescribedintheirrespectivetestmethods.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Nooth...
