ABB Risk_Assessment_and_Safety_Function_SIL_Determination.pdfVIP专享VIP免费原创优质

—FSMTECHNICALAUTHORITYSafetyInstrumentedSystemsRiskAssessment&SafetyFunctionSILDeterminationSafetyInstrumentedSystemsarefoundonthevastmajorityofprocessindustrymanufacturingfacilitiestoprotectagainsthazardstopersonnel,theenvironmentandplantequipment.OneofthekeyprocesssafetymanagementrequirementsistodeterminethecriticalityofallSafetyInstrumentedSystems(SIS)ontheplantbyidentifyingsafetyfunctionsneededforeachspecifichazardousevent,allocatingsafetyfunctionstoprotectionlayersanddeterminingtherequiredSafetyIntegrityLevel(SIL)ofanySafetyInstrumentedFunctions(SIF).Itisthenimportanttoassesstheriskreductionprovidedbynon-SISprotectionandmitigationfunctionse.g.BasicProcessControlSystem(BPCS)controlandalarmfunctions,mechanicalprotectionorFire&Gasmitigationlayersand,basedonthetargettolerablerisk,determinetherequiredreliabilityofeachSIFidentified.FromtheIEC61508/61511standards,theproperlydeterminedSafetyIntegrityLevelisfundamentalforSISdesignandoperation/maintenance.Itensuresasafetyrelatedsystemsatisfactorilyperformstherequiredsafetyfunctionsunderallstatedconditionswithinadefinedtimeperiod.SILdeterminationistheprocessofevaluatingtherequiredreliabilityforaSIF,takingaccountoftheseverityofthehazardouseventandotherindependentlayersofprotectionthatarecontributingtotheoverallriskreduction.ProperlydefinedSILlevelsallowforsignificantcostimprovementstobeachievedinbothGreenfieldandBrownfieldoperatingenvironments.Assetoperationalsafetyintegritylevelsaremaintainedwhilethecostofownershipfromongoingtestingandmaintenanceisoptimized.InappropriateSILdeterminationcanaffectthesafetyintegrityoftheassetprotectionenvelopeandmayinsomecasesplacetheassetintegrityunderthreat.Inadditiontothis,thepotentiallackofappropriatemethodsbeingusedforSILDeterminationcanleadtoanoverlyconservativeapproachwhichcanresultinbothunnecessarycapitaloutlayandlongtermoperationalspending.BackgroundtotheABBApproachABB’sSILdeterminationpackageenablesassetownerstobecomeconversantwiththerelevanceofSILdeterminationinthecontextoffunctionalsafety,andtothenconfidentlydeterminetheSILlevelandconfigurationrequiredtoachievethesetargets.—Wereservetherighttomaketechnicalchangesormodifythecontentsofthisdocumentwithoutpriornotice.Withregardtopurchaseorders,theagreedparticularsshallprevail.ABBAGdoesnotacceptanyresponsibilitywhatsoeverforpotentialerrorsorpossiblelackofinformationinthisdocument.Wereserveallrightsinthisdocumentandinthesubjectmatterandillustrationscontainedtherein.Anyreproduction,disclosuretothirdpartiesorutilizationofitscontents–inwholeorinparts–isforbiddenwithoutpriorwrittenconsentofABBAG.Copyright©2017ABBAllrightsreservedabb.com/oilandgasSafetyInstrumentedSystems-RiskAssessment&SafetyFunctionSILDetermination/November2017TheApproachEffectiveSILdeterminationrequiresinputandoperationalexperiencecontributionfrommanydisciplines.UtilisingacompetentstudyleaderandanappropriatenumberofrelevantdisciplinessuchastheresponsibleInstrumentationEngineer,ProcessEngineer,OperationalandProjectManagement/Supervisoryrepresentation,includingtheProcessOperatorsthemselves,wecanprovideeffectiveguidancetoobtainmaximumbenefitforthestudyoutcome.Selectionandcalibrationofanappropriatemethode.g.RiskGraph,LayerofProtectionAnalysis(LOPA)orFaultTreeAnalysiswillbeutilisedtoanalysetheeventsidentifiedfromtheearlierHazardStudyphase.Theriskassessmentwilldetaileachpote...