AmericanNationalStandardANSI/ISA-S12.0.01-1998(IEC79-0Mod)ApprovedOctober15,1998ElectricalApparatusforUseinClassI,Zones0&1Hazardous(Classified)LocationsGeneralRequirementsANSI/ISA-S12.0.01(IEC79-0Mod)—ElectricalApparatusforUseinClassI,Zones0&1Hazardous(Classified)Locations—GeneralRequirementsISBN:1-55617-652XCopyright�1998bytheInstrumentSocietyofAmerica.Allrightsreserved.PrintedintheUnitedStatesofAmerica.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,ortransmitted,inanyformorbyanymeans(electronic,mechanical,photocopying,recording,orotherwise),withoutthepriorwrittenpermissionofthePublisher.ISA67AlexanderDriveP.O.Box12277ResearchTrianglePark,NorthCarolina27709CertainprovisionsofthisdocumentdifferfromanalogousprovisionsofANSI/UL2279.ISAandULareactivelyworkingtoharmonizetheseprovisionsandanticipatejointlypublishingasinglesetofAmericanNationalStandardswhenthesedifferencesareresolved.ANSI/ISA-S12.0.01-1998(IEC79-0Mod)3PrefaceThisISAstandardisbasedonIECPublication79-0.ItistheintentionoftheISASP12CommitteetodevelopanANSIStandardthatisharmonizedwithIEC79-0tothefullestextentpossible.Thispreface,aswellasallfootnotesandannexes,isincludedforinformationalpurposesandisnotpartofANSI/ISA-S12.0.01(IEC79-0Mod).Thesuffix"Mod"indicatesthedocumentisamodificationoftheIECdocumentandincludesU.S.deviationsencompassingbothadditionsanddeletionsofinformation.ThisstandardhasbeenpreparedaspartoftheserviceoftheISA,theinternationalsocietyformeasurementandcontrol,towardagoalofuniformityinthefieldofinstrumentation.Tobeofrealvalue,thisdocumentshouldnotbestatic,butshouldbesubjecttoperiodicreview.Towardthisend,theSocietywelcomesallcommentsandcriticisms,andasksthattheybeaddressedtotheSecretary,StandardsandPracticesBoard;ISA;67AlexanderDrive;P.O.Box12277;ResearchTrianglePark,NC27709;Telephone(919)549-8411;Fax(919)549-8288;E-mail:standards@isa.org.TheISAStandardsandPracticesDepartmentisawareofthegrowingneedforattentiontothemetricsystemofunitsingeneral,andtheInternationalSystemofUnits...
