Designation:D7568−17StandardSpecificationforPolyethylene-BasedStructural-GradePlasticLumberforOutdoorApplications1ThisstandardisissuedunderthefixeddesignationD7568;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thisspecificationcoversatypeofplasticlumberproduct,definedaspolyethylene-basedstructural-gradeplasticlumber(SGPL),foruseasmainframingmembers,includingjoists,stringers,beams,columns;andsecondaryframingmembers,includingplanking,postsandbracing;inoutdoorstructuressuchasdecks,boardwalks,docks,andplatforms.1.2Thisspecificationisapplicabletosolid,rectangularSGPLproductswherepolyethyleneresin(noncross-linked)isthecontinuousphaseandisatleast50%oftheproduct(byweight).1.3Thisspecificationisnotapplicabletoplasticlumberproductscontainingcellulosicmaterialsasadditives,fillersorfiberreinforcements.1.4SGPLproductscoveredbythisspecificationshallnotbeusedastensilemembers.1.5SGPLproductsareproducedusingseveraldifferentmanufacturingprocesses.Theseprocessesutilizeanumberofpolyethyleneresinmaterialsystemsthatincludevaryingpro-portionsoffillers,fiberreinforcements,andotherchemicaladditives.1.6Duetothermodynamiceffectsthatresultinouter-surfacedensificationduringmanufacture,SGPLproductsaretypicallynon-homogeneousinthecross-section.Thisstandarddoesnotaddressmaterialsthathavebeenmodifiedfromtheiroriginalcross-section.1.6.1Thecross-sectionnon-homogeneityisaddressedinthematerialpropertyassessmentsinthisdocumentonlyforapplicationsinwhichtheproductcross-sectionisnotmodifiedbycutting,notching,ordrilling.Forproductsmodifiedinthismanner,additionalengineeringconsiderationsarerequiredandtheyarebeyondthescopeofthisdocument.1.7Forpurposesofthisstandard,anSGPLproductisaspecificcombinationofpolyethyleneresin,togetherwithfillers,reinforcements,andadditives.Eachformulationistobe...
