Designation:D1498−14StandardTestMethodforOxidation-ReductionPotentialofWater1ThisstandardisissuedunderthefixeddesignationD1498;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoverstheapparatusandprocedurefortheelectrometricmeasurementofoxidation-reductionpotential(ORP)inwater.Itdoesnotdealwiththemannerinwhichthesolutionsareprepared,thetheoreticalinterpretationoftheoxidation-reductionpotential,ortheestablishmentofastan-dardoxidation-reductionpotentialforanygivensystem.Thetestmethoddescribedhasbeendesignedfortheroutineandprocessmeasurementofoxidation-reductionpotential.1.2ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D1129TerminologyRelatingtoWaterD1193SpecificationforReagentWaterD2777PracticeforDeterminationofPrecisionandBiasofApplicableTestMethodsofCommitteeD19onWaterD3370PracticesforSamplingWaterfromClosedConduits3.Terminology3.1Definitions—Fordefinitionsoftermsusedinthistestmethod,refertoTerminologyD1129.3.2DefinitionsofTermsSpecifictoThisStandard:3.2.1oxidation-reductionpotential,n—theelectromotiveforce,Em,developedbetweenanoblemetalelectrodeandastandardreferenceelectrode.3.2.1.1Discussion—Thisoxidation-reductionpotential(ORP)isrelatedtothesolutioncompositionby:Em5Eo12.3RTnFlog@Aox/Ared#where:Em=ORP,Eo=constantthatdependsonthechoiceofrefer-enceelectrodes,F=Faradayconstant,R=gasconstant,T=absolutetemperature,°C+273.15,n=numberofelectronsinvolvedinprocessreaction,andAoxandAred=activitiesofthereacta...
