Designation:D8408/D8408M−21StandardGuideforDevelopmentofLong-TermMonitoringPlansforVaporMitigationSystems1ThisstandardisissuedunderthefixeddesignationD8408/D8408M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1ThisguidepresentsfactorstoconsiderwhendevelopingLong-TermMonitoring(LTM)Plansformonitoringtheper-formanceofbothactiveandpassivevapormitigationsystemsinbuildings.Thisguidewillalsoassistindevelopingappro-priateperformancestandardstomakesurethatvapormitiga-tionsystemsremainprotectiveofhumanhealth.Activeandpassivevapormitigationsystemshavebeenusedforanumberofyearsoncontaminatedpropertieswhereresidualvolatilecontaminantsremainintheground.Thisguidediscussesavarietyofvapormitigationssystems;however,itsfocusisonthedevelopmentoflong-termmonitoringplansforvapormitigationsystemsthataredesignedtoremaininplaceformultipleyears.1.2ALTMPlanprovidesclearperformancegoalsforavapormitigationsystemwhichhelptoreducepotentialconfu-sionandineffectiveprojectmanagement.TheLTMPlanalsodefinesperformancemonitoringtimeframestoefficientlytestthevapormitigationsystems’effectivenesswithoutunneces-saryandcostlyover-testing.Thiswillalsopromoteconsistentmonitoring.Vapormitigationsystemsareofteninstalledwith-outadequateconsiderationofthelong-termmonitoringre-quirementsnecessarytomakesurethattheyremainprotectiveofhumanhealthforaslongasthesystemremainsinplace.ThisguidanceaddressestherequirementsoftheLTMPlantomonitoravapormitigationsystem’scontinuedeffectiveness.InstallationverificationthatthevapormitigationsystemwasinstalledcorrectlyistypicallyaddressedintheRemedialDesignstageofacontaminatedPropertyManagementandisnotcoveredinthisdocument.1.3LTMPlanlimitations,constraintsandpotentialsourcesoferrorarediscussedinthisstandard.Thisguidedoesnotendorseamitigationsystemvendorortesting...
