ANSI-ESD S4.1-2006

ANSI/ESDS4.1-2006ReaffirmationofANSI/ESDS4.1-1997FortheProtectionofElectrostaticDischargeSusceptibleItemsWorksurfaces–ResistanceMeasurementsElectrostaticDischargeAssociation7900TurinRoad,Bldg.3Rome,NY13440AnAmericanNationalStandardApprovedJuly17,2006ANSI/ESDS4.1-2006ESDAssociationStandardfortheProtectionofElectrostaticDischargeSusceptibleItems-Worksurfaces–ResistanceMeasurementsApprovedFebruary26,2006ESDAssociation®ANSI/ESDS4.1-2006ESDAssociationstandardsandpublicationsaredesignedtoservethepublicinterestbyeliminatingmisunderstandingsbetweenmanufacturersandpurchasers,facilitatingtheinterchangeabilityandimprovementofproductsandassistingthepurchaserinselectingandobtainingtheproperproductforhisparticularneeds.Theexistenceofsuchstandardsandpublicationsshallnotinanyrespectprecludeanymemberornon-memberoftheAssociationfrommanufacturingorsellingproductsnotconformingtosuchstandardsandpublications.NorshallthefactthatastandardorpublicationispublishedbytheAssociationprecludeitsvoluntaryusebynon-membersoftheAssociationwhetherthedocumentistobeusedeitherdomesticallyorinternationally.RecommendedstandardsandpublicationsareadoptedbytheESDAssociationinaccordancewiththeANSIPatentpolicy.InterpretationofESDAssociationStandards:Theinterpretationofstandardsin-so-farasitmayrelatetoaspecificproductormanufacturerisapropermatterfortheindividualcompanyconcernedandcannotbeundertakenbyanypersonactingfortheESDAssociation.TheESDAssociationStandardsChairmanmaymakecommentslimitedtoanexplanationorclarificationofthetechnicallanguageorprovisionsinastandard,butnotrelatedtoitsapplicationtospecificproductsandmanufacturers.NootherpersonisauthorizedtocommentonbehalfoftheESDAssociationonanyESDAssociationStandard.ThecontentsofESDA’sstandardsandpublicationsareprovided“as-is,”andESDAmakesnorepresentationsorwarranties,expressorimplied,ofanykindwithrespecttosuchcontents.ESDAdisclaimsallrepresentationsandwarranties,includingwithoutlimitation,warrantiesofmerchantability,fitnessforparticularpurposeoruse,titleandnon-infrigement.DisclaimerofGuaranty:ESDAstandardsandpublicationsareconsideredtechnicallysoundatthetimetheyareapprovedforpublication.Theyarenotasubstituteforaproductseller’soruser’sownjudgmentwithrespecttoanyparticularproductdiscussed,andESDAdoesnotundertaketoguarantytheperformanceofanyindividualmanufacturers’productsbyvirtueofsuchstandardsorpublications.Thus,ESDAexpresslydisclaimsanyresponsibilityfordamagesarisingfromtheuse,applicationorreliancebyothersontheinformationcontainedinthesestandardsorpublications.LimitationonESDA’sLiability:NeitherESDA,noritsmembers,officers,employeesorotherrepresentativeswillbeliablefordamagesarisingoutoforinconnectionwiththeuseormisuseofESDAstandardsorpublications,evenifadvisedofthepossibilitythereof.Thisisacomprehensivelimitationofliabilitythatappliestoalldamagesofanykind,includingwithoutlimitation,lossofdata,incomeorprofit,lossofordamagetopropertyandclaimsofthirdparties.Publishedby:ElectrostaticDischargeAssociation7900TurinRoad,Bldg.3Rome,NY13440Copyright©2006byESDAssociationAllrightsreservedNopartofthispublicationmaybereproducedinanyform,inanelectronicretrievalsystemorotherwise,withoutthepriorwrittenpermissionofthepublisher.PrintedintheUnitedStatesofAmericaISBN:1-58537-103-3CAUTIONNOTICEDISCLAIMEROFWARRANTIESANSI/ESDS4.1-2006i(ThisforewordisnotpartofESDAssociationStandardS4.1-2006)ForewordThepurposeofanESDprotectiveworksurfaceistoaidinthepreventionofdamagetoESD-susceptibleparts.Thereareseveralwaysthesesurfacesmayacttoprovidethisprotectionandtheyareoftenconfusedinpractice.Oneinvolvestheremovalofchargeresidingonthesurfaceofamaterial.Asecondcharge-removaltaskinvolvesthechargeonanobjectsuchasatoteboxthatisplacedonthesurface.Inthiscase,thechargemustflowacrossthezonebetweentheobjectandtheworksurface,whichcaninterposeaconsiderablecontactresistance.Athirdchargeremovaltaskinvolvescurrentflowfromacharged,susceptibledeviceplacedonthesurface.Inthiscase,alowdischargecurrentmaybedesirable.Thedegreeofprotectionaffordedbyaworksurfaceisstronglyrelatedtothetimeneededtodischargeanobject.Inpractice,someformofresistancevalueiscommonlygivenasanindicationoftheeffectivenessoftheworksurface.Strictlyspeaking,thisdescriptionisincompletesincedischargetimedependsonseveralotherfactorssuchastheeffectivecapacitanceoftheworksurface,contactresistanceandtheactualdischargepath.However,thecapacitancedoesnotusuallyvaryasmuchasresistance.Theothereffectsareverydependentontheindividualsituation.Asaresult,resistanceseemsthebestsinglepredictorofperformanceofESD-protectiveworksurfaces.Thisstandardreliesonresistivemeasurements,utilizingstandardinstruments,toprovideameansofevaluationmaterialsorinstalledworksurfaces.Conversely,resistivityismeasuredbyspecificequipmentandisusedtoestablishanintrinsicmaterialproperty.Resistivitymeasurementsarenotwithinthescopeorpurposeofthestandard.Thisstandardsetsforthresistancetestmethodsthatcanbeusedtocharacterizeworksurfacesandtoobtainrelativeestimatesoftheirabilitytoremoveelectricalchargefromnon-insulativeobjectsplacedonthesurface