Designation:D2321−20StandardPracticeforUndergroundInstallationofThermoplasticPipeforSewersandOtherGravity-FlowApplications1ThisstandardisissuedunderthefixeddesignationD2321;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Thispracticeprovidesrecommendationsfortheinstal-lationofburiedthermoplasticpipeusedinsewersandothergravity-flowapplications.Theserecommendationsarein-tendedtoensureastableundergroundenvironmentforther-moplasticpipeunderawiderangeofserviceconditions.However,becauseofthenumerousflexibleplasticpipeprod-uctsavailableandtheinherentvariabilityofnaturalgroundconditions,achievingsatisfactoryperformanceofanyoneproductmayrequiremodificationtoprovisionscontainedhereintomeetspecificprojectrequirements.1.2Thescopeofthispracticenecessarilyexcludesproductperformancecriteriasuchasminimumpipestiffness,maxi-mumservicedeflection,orlongtermstrength.Thus,itisincumbentupontheproductmanufacturer,specifier,orprojectengineertoverifyandassurethatthepipespecifiedforanintendedapplication,wheninstalledaccordingtoproceduresoutlinedinthispractice,willprovidealongterm,satisfactoryperformanceaccordingtocriteriaestablishedforthatapplica-tion.AcommentaryonfactorsimportantinachievingasatisfactoryinstallationisincludedinAppendixX1.NOTE1—Specificparagraphsintheappendixarereferencedinthebodyofthispracticeforinformationalpurposes.NOTE2—ThefollowingASTMstandardsmaybefoundusefulinconnectionwiththispractice:PracticeD420,TestMethodD1556,MethodD2216,SpecificationD2235,TestMethodD2412,SpecificationD2564,PracticeD2657,PracticeD2855,TestMethodsD2922,TestMethodD3017,PracticeF402,SpecificationF477,SpecificationF545,andSpecificationF913.NOTE3—MostPlumbingCodesandsomeBuildingCodeshaveprovisionsfortheinstall...
