Designation:D1998−21StandardSpecificationforPolyethyleneUprightStorageTanks1ThisstandardisissuedunderthefixeddesignationD1998;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thisspecificationcoversflat-bottom,upright,cylindri-caltanksmoldedinone-pieceseamlessconstructionbyrota-tionalmolding.Thetanksaremoldedfrompolyethyleneforaboveground,verticalinstallationandarecapableofcontain-ingaggressivechemicalsatatmosphericpressure.Includedarerequirementsformaterials,properties,design,construction,dimensions,tolerances,workmanshipandappearance.Tankcapacitiesarefrom1900L(500gal)up.1.2Thisspecificationcoversthedesignofstationeryvesselsforuseatatmosphericpressureintendedforusewithliquidsheatedbelowtheirflashpointsandcontinuousservicetem-peraturesbelow66°C(150°F)forTypeItanksandbelow60°C(140°F)forTypeIItanks.1.2.1NFPAStandards30andNFPA31shallbeconsultedforinstallationsthataresubjecttotherequirementsofthesestandards.1.3Forservicerequirementsbeyondthescopeofthisspecification(1.2),suchasexternallyimposedmechanicalforces,internalpressureorvacuum,highertemperatureservice,etc.,otherrelevantsourcesofstandards,forexample,localandstatebuildingcodes,NFPA,ASME,ARM,etc.,shallbeconsulted.1.4ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.NOTE1—ISO13341:2005+A1:2011andISO13575:2012aresimilar,butnotequivalenttothisstandard.1.5Thefollowingprecautionarycaveatpertainsonlytothetestmethodsportion,Section11,ofthisspecification:Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafety,health,andenvironmentalpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.1.6Thisinternationalstandardwasdevelopedinaccor-...
