Designation:D7315−17StandardTestMethodforDeterminationofTurbidityAbove1TurbidityUnit(TU)inStaticMode1ThisstandardisissuedunderthefixeddesignationD7315;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thistestmethodcoversthestaticdeterminationofturbidityinwater.Staticreferstoasamplethatisremovedfromitssourceandtestedinanisolatedinstrument.(SeeSection4.)1.2Thistestmethodisapplicabletothemeasurementofturbiditiesgreaterthan1.0turbidityunit(TU).Theupperendofthemeasurementrangewasleftundefinedbecausedifferenttechnologiesdescribedinthistestmethodcancoververydifferentranges.Theroundrobinstudycoveredtherangeof0–4000turbidityunitsbecauseinstrumentverificationinthisrangecantypicallybecoveredbystandardsthatcanbeconsistentlyreproduced.1.3ManyoftheturbidityunitsandinstrumentdesignscoveredinthistestmethodarenumericallyequivalentincalibrationwhenacommoncalibrationstandardisappliedacrossthosedesignslistedinTable1.Measurementofacommoncalibrationstandardofadefinedvaluewillalsoproduceequivalentresultsacrossthesetechnologies.1.3.1InthistestmethodcalibrationstandardsareoftendefinedinNTUvalues,buttheotherassignedturbidityunits,suchasthoseinTable1areequivalent.Forexample,a1NTUformazinstandardisalsoa1FNU,a1FAU,a1BU,andsoforth.1.4Thistestmethoddoesnotpurporttocoverallavailabletechnologiesforhigh-levelturbiditymeasurement.1.5Thistestmethodwastestedondifferentnaturalwatersandwastewater,andwithstandardsthatwillserveassurro-gatestosamples.Itistheuser’sresponsibilitytoensurethevalidityofthistestmethodforwatersofuntestedmatrices.1.6Dependingontheconstituentswithinahigh-levelsample,theproposedsamplepreparationandmeasurementmethodsmayormaynotbeapplicable.Thosesampleswiththehighestparticledensitiestypicallyprovetobethemostdifficulttomeasure.Inthesecases,andalternativemeasurementm...
