Designation:D1291−06(Reapproved2011)StandardPracticeforEstimationofChlorineDemandofWater1ThisstandardisissuedunderthefixeddesignationD1291;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticeprovidesameansofestimatingthequan-tityofchlorinerequiredtobeaddedtoaunitvolumeofwatertoaccomplishapredeterminedtreatmentobjectiveortocompletelyreactwithallchlorinereactablesubstancesinthewater,orboth.1.2Temperature,pH,andinitialchlorinedosageareallvariablesinestimatingtheoptimumchlorinationpractice.Theeffectsofthesevariablescanbeevaluatedusingthispractice.1.3ChlorineresidualisdeterminedusingTestMethodD1253.1.4Thispracticeisapplicabletoalltypesofwaterinwhichthestatedtreatmentobjectivecanbeevaluatedorresidualchlorinecanbemeasured,orboth.1.5ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.Foraspecifichazardstatement,seeNote1.2.ReferencedDocuments2.1ASTMStandards:2D1129TerminologyRelatingtoWaterD1193SpecificationforReagentWaterD1253TestMethodforResidualChlorineinWaterD1293TestMethodsforpHofWaterD3370PracticesforSamplingWaterfromClosedConduits3.Terminology3.1DefinitionsofTermsSpecifictoThisStandard:3.1.1chlorinedemand—theamountofchlorinethatmustbeaddedtoaunitvolumeofwaterunderspecifiedconditionsofpH,temperature,andcontacttimetocompletelyreactwithallchlorine-reactablesubstancesinthewater.Itisdefinedasthedifferencebetweentheamountofchlorineappliedandtheamountoffreechlorineremainingattheendofthecontactperiod.3.1.2chlorinerequirement—theamountofchlorinethatmustbeaddedtoa...
