Designation:D1981−11(Reapproved2015)StandardTestMethodforMeasuringColorAfterHeatingofTallOilFattyAcids1ThisstandardisissuedunderthefixeddesignationD1981;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1ThistestmethodcoversthemeasurementoftheGardnercoloroftalloilfattyacidsafterheatinginanatmosphereofnitrogenat205°Cforoneortwohours,dependingonwhetheritsiodinevalueisoverorunder15,respectively.Thespecimenmaybeheatedusingeitheranaluminumheatingblockoranoilbath.Thismethodisapplicabletoalltalloilfattyacids.Applicabilityofthismethodtoothertypesoffattyacidshasnotbeendetermined.1.2ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D1544TestMethodforColorofTransparentLiquids(Gard-nerColorScale)D6166TestMethodforColorofPineChemicalsandRe-latedProducts(InstrumentalDeterminationofGardnerColor)E1SpecificationforASTMLiquid-in-GlassThermometers3.SignificanceandUse3.1Thecolorofatalloilfattyacidisreadilyaffectedbyheatandoxidization.Variationsindegreeofheat,timeofheat,andexposuretoatmosphereduringheatinghaveamarkedeffectonthecolorobtained;therefore,conformitytotheequipmentandprocedureoutlinedinthistestmethodisessentialtoaccuracyandprecision.4.HeatingApparatus—MethodA,AluminumBlock4.1ForcedDraftOven,maintainedat20562°C.4.2AluminumHeatingBlock(seeFig.1).Wraptheoutersurfacewithanappropriateinsulatingmaterial.5.HeatingApparatus—MethodB,OilBath5.1OilBath—A5-Lsteelbeakerequippedwithamechani-calstirrerandcontaininganylight-coloredalkali-refined...
