Designation:D1253−14StandardTestMethodforResidualChlorineinWater1ThisstandardisissuedunderthefixeddesignationD1253;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodcoversthedeterminationofresidualchlorineinwaterbydirectamperometrictitration.1.2WithintheconstraintsspecifiedinSection6,thistestmethodisnotsubjecttocommonlyencounteredinterferencesandisapplicabletomostwaters.Somewaters,however,canexertaniodinedemand,usuallybecauseoforganicmaterial,makinglessiodineavailableformeasurementbythistestmethod.Thus,itispossibletoobtainfalselylowchlorinereadings,eventhoughthetestmethodisworkingproperly,withouttheuser’sknowledge.1.3Precisiondataforthistestmethodwereobtainedonestuary,inlandmainstemriver,freshlake,openocean,andfreshcoolingtowerblowdownwater.Biasdatacouldnotbedeterminedbecauseoftheinstabilityofsolutionsofchlorineinwater.Itistheuser’sresponsibilitytoensurethevalidityofthetestmethodforuntestedtypesofwater.1.4Inthetestingbywhichthisstandardwasvalidated,thedirectandbackstarch-iodidetitrationsandtheamperometricbacktitration,formerlypartofthisstandard,werefoundtobeunworkableandwerediscontinuedin1986.Historicalinfor-mationispresentedinAppendixX1.NOTE1—Orthotolidinetestmethodshavebeenomittedbecauseofpoorprecisionandaccuracy.1.5ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D1129TerminologyRelatingtoWaterD1193SpecificationforReagentWaterD2777PracticeforDeterminationofPrecisionandBiasofApplicableTestMethodsofCommi...
