Designation:F2280−14StandardSpecificationfor“TwistOff”TypeTensionControlStructuralBolt/Nut/WasherAssemblies,Steel,HeatTreated,150ksiMinimumTensileStrength1ThisstandardisissuedunderthefixeddesignationF2280;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thisspecificationcoverstwotypesofheattreated,steel,tensioncontrolbolt-nut-washerassemblies,alsoreferredtoas“sets,”havingatensilestrengthof150to173ksi.Theseassembliesarecapableofdevelopingaminimumpredeter-minedtensionwheninstalledbyapplyingtorquetothenut,whileatthesametimeapplyingacountertorquetoseparatethesplineendfromthebodyoftheboltusinganappropriatesplinedriveinstallationtool.1.2Anassemblyconsistsofatensioncontrolboltwithsplineend(coveredbythisspecification)andasuitablenutandwashercoveredbyreferencetoapplicableASTMspecifica-tions.1.3Thefastenerassembliesareintendedforuseinstruc-turalconnections.Theseconnections,installationprocedures,andtheuseofalternatedesignstructuralboltsarecoveredundertherequirementsofthe“SpecificationforStructuralJointsUsingASTMorA490Bolts”,approvedbytheResearchCouncilonStructuralConnections.1.4Theassembliesareavailablewitheitherround(buttonordome)heads,heavyhexstructuralheads,oralternatedesignheadsdescribedinSection11,insizes1⁄2to11⁄8in.inclusive,intwotypesspecifiedinSection4.1.5TensioncontrolboltsmanufacturedandmarkedinaccordancewiththerequirementsofSpecificationA490,andconformingtothedimensionalandotherrequirementsofthisspecification,willbeconsideredanacceptablealternateunderthisspecificationfortwoyearsfollowinginitialpublication.1.6Thefollowingprecautionarystatementpertainsonlytothetestmethodportions,Sections15and16,ofthisSpecifi-cation:Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstanda...
