Designation:D1709−15aStandardTestMethodsforImpactResistanceofPlasticFilmbytheFree-FallingDartMethod1ThisstandardisissuedunderthefixeddesignationD1709;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Thesetestmethodscoverthedeterminationoftheenergythatcausesplasticfilmtofailunderspecifiedconditionsofimpactofafree-fallingdart.Thisenergyisexpressedintermsoftheweight(mass)ofthemissilefallingfromaspecifiedheightwhichwouldresultin50%failureofspeci-menstested.1.2Twotestmethodsaredescribed:1.2.1TestMethodAemploysadartwitha38.1060.13-mm(1.50060.005-in.)diameterhemisphericalheaddroppedfromaheightof0.6660.01m(26.060.4in.).Thistestmethodcanbeusedforfilmswhoseimpactresis-tancesrequiremassesofabout50gorlesstoabout6kgtofracturethem.1.2.2TestMethodBemploysadartwitha50.8060.13-mm(2.00060.005-in.)diameterhemisphericalheaddroppedfromaheightof1.5260.03m(60.0+0.25,−1.70in.).Itsrangeofapplicabilityisfromabout0.3kgtoabout6kg.1.3Twotestingtechniquesaredescribed:1.3.1Thestandardtechniqueisthestaircasemethod.Bythistechnique,themissileweightemployedduringthetestisdecreasedorincreasedbyuniformincrementsafterthetestingofeachspecimen,dependingupontheresult(failornotfail)observedforthespecimen.1.3.2Thealternativetechniqueprovidesfortestingspeci-mensinsuccessivegroupsoften.Onemissileweightisemployedforeachgroupandthemissileweightisvariedinuniformincrementsfromgrouptogroup.1.3.3Thestaircasetechniqueandthealternativetechniquegiveequivalentresultsbothastothevaluesofimpactfailureweightwhichareobtainedandastotheprecisionswithwhichtheyaredetermined.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Thevaluesstatedinparenthesesareforinformationonly.NOTE1—Testsonmaterialsthatdonotbreak,foranyreason,arenotconside...
