Designation:E1270−88(Reapproved2014)StandardTestMethodforEqualArmBalances1ThisstandardisissuedunderthefixeddesignationE1270;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONThistestmethodisdesignedtotestbalanceswhoselever-armratioissubstantiallyequaltounity.Althoughlargelysupersededbynewtechnologies,equal-armbalancesretainaspecialnicheforveryhighprecisionweighingoflargersamples(usuallygreaterthan1kg)aswellasobjectswithlargebuoyancy(suchasgasbottles).Balancesofthistypecanrangefromsimpleinstrumentsofmoderateprecision(1:10000)toextremelyhighprecisiondeviceswithprecisionof1:10000000orbetter.Anumberofaccessorydevicesmaybeincludedforassistingintheweighingprocess.Thesedevicesmaycontributetoerrorsaswellascanthebasiclevermechanism.Thismethodisdesignedtotesttheentireinstrumentincludingtheaccessories.1.Scope1.1Thistestmethodcanbeusedfortestingequal-armbalancesofanycapacityandsensitivity.Thetestingprocedureshouldenabletheusertocharacterizehisinstrumentsuffi-cientlytodeterminewhetherornotitissuitableforthepurposeforwhichitistobeused.1.2Thecharacteristicstobeexaminedinclude:1.2.1Sensitivityatallloads,1.2.2Leverarmratio,1.2.3Dampingratio(forinstrumentswithoutaccessorydampers),1.2.4Periodofoscillation,1.2.5Precision,and1.2.6Linearityandcalibrationofaccessorydevicesthatprovideon-scaleindicationofweight.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcernsassociatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2E617SpecificationforLaboratoryWeightsandPrecisionMassStandards3.Terminology3.1DefinitionsofTermsSpecifictoThisStandard:3.1.1capacity—maximumloadrecommendedbythemanu-facturer.Usually,thecapacityref...
