过程危害性分析-ProcessHazardAnalysis.ppt

FunctionalsafetyEngineering ProcessHazardAnalysis DefofHazard IEC61508 4ApotentialsourceofharmNOTE Thetermincludesdangertopersonsarisingwithinashorttimescale forexample fireandexplosion andalsothosethathavealong termeffectonaperson shealth forexample releaseofatoxicsubstance Achemicalorphysicalconditionthathasthepotentialforcausingdamagetopeople environmentandproperty Initiatingevent InitiatingeventisthefirsteventinansequenceAstresscorrosionresultinginaleak ruptureoftheconnectingpipeline ruptureoftheconnectingpipelinetotheammoniatank IntermediateEvent IntermediateEventisaneventthatpropagatesormitigatestheinitiatingeventduringaneventsequenceImproperoperationactionfailstostoptheinitialammonialeakandcausespropagationiftheintermediateeventtoanincident Inthiscasetheintermediateeventisatoxicrelease Incident IncidentisalossofcontainmentofmaterialorenergyLeakofammoniafromaconnectingpipelinetotheammoniatank producingatocivaporNotalleventspropagatesintoincidents IncidentOutcome Incidentoutcomeisthephysicalmanifestationoftheincident Fortoxicmaterials theincidentoutcomeisatoxicrelease ForflammablematerialstheincidentcanbeaBoilingLiquidExpandingVaporCloseExplosion flashfire EffectZone Foranincidentthatproducesanincidentoutcomeoftoxic thatareaoverwhichtheairborneconcentrationexceedssomelevelofconcern Consequence Ameasureoftheexpectedeffectofanincidentoutcomeincidentcase Aqualitativedefinitionoftheasingleresultofanincidentoutcome Terms InitiationEvent usuallycreatesanIntermediateEvent whichmaycreateanotherIntermediateEvent whichmaycreateanotherIncident wheretheresultiscalledanIncidentOucome dependingoncircumstancesresultinginConsequences WhatisprocessHazardAnalysis IEC61508 1specifies3functionsTodeterminethehazardsandhazardouseventsoftheEUCandtheEUCcontrolsystem inallmodesofoperation forallreasonablyforeseeablecircumstancesincludingfaultconditionsandmisuse Todeterminetheeventsequencesleadingtothehazardouseventsdetermined TodeterminetheEUCrisksassociatedwiththehazardouseventsdetermined ProcessHazardAnalysis PHA ObjectiveIdentifyprocesshazards estimatetheirrisksanddecideiftheriskistolerableTaskHazardidentificationAnalysisofLikelihoodandConsequenceConsiderationofnon SILLayersofprotection CommonPHAMethods ChecklistWhatif Whatif ChecklistHAZOP HazardandOperabilityStudy FMEA FailureModesandEffectsAnlaysisFaultTreeAnalysisAppropriateEquivalentMethods NotonemethodfitsalloftenuseseveralmethodsHAZOPmostcommoncanuseatanylifecycle TypicalPHARequirements HazardoftheprocessPreviousincidentswithcatastrophicpotentialEngineeringandadministrativecontrolsConsequencesofengineeringandadministrativecontrolfailuresFacilityciting layout access exposure Humanfactors errors ergonomics Qualitativeevaluationofeffectsoffailures Recommendationsforgoodprocess MultidisciplineteamProcessandsystemengineersOperatorsandMaintenancesafetyengineersOftenoneindependentasafacilitatorBringinpeoplewithspecialcompetenceonspecificequipmentDocumentprocessInsurerecommendationsareacteduponRevisitanalysiseveryxxxperiod 5years PHAStep1 Hazards SIFIdentification CharacteristicsHAZOP HazardandOperabilityStudyCharacteristicsoftheHAZOPmethodTeambrainstormingsessionsBasis P IDdrawingsUseofGuidewords ICI WidespreaduseinindustryandEngineeringContractorsResultOverviewofallpossibleunwanteddisturbancesDeterminationofpotentialSafetyFunctioninplaceActionplanningforimprovementsorrequiredclarifications HAZOP prerequisite LinediagramorP IDshavetobecompleteandinfrontofeachteammemberandsplitupintonodes Equipment Vessels ProcessdescriptionhastobeinplaceandcompletePossibleapplicableSafetyFunctionssuchasreliefvalvesandSensors SafetyValvescanbealreadyproposedbytheProcessengineers buthavetobeexaminedandfullyjustified DocumenttheresultsiftheHAZOPandjustifypotentialSafetyFunctions safeguards PHA HAZOPResults ColumnParameter LiquidLevel IdentifyingSIFfromPHAreports WhatinformationdoIneed DescriptionofthesafetyinstrumentedfunctionsfrompreviousstudiesHazardbeingpreventedanditsconsequencesInitiatingEventswhichcausetheconsequenceSafeguards bothSISandnon SIS usedtopreventtheconsequencefromoccurring SIFDescription FindalltheexistingandrecommendedSIF HAZARDandConsequences Thehazardthatisbeingpreventedanditsconsequenceisfoundintheconsequence Initiatingevent InHazop initiatingeventincausescolumnWhatifandChecklistquestionsPotentialformultipleinitiatingeventsperhazard Safeguards Findbothnon SISandSISSafeguards otherthenSISunderstudySafeguardapplytoinitiatingevents multiplesafeguardsperinitiatingeventmayexist IdentifySIFsfromP ID PHAStudiesnotalways100 effectivePastexperienceofLicensorsandDetailedDesignContractorsisincorporatedintothedesignSIFisthedesignpackagearenottypicallydifferentiatedfromothercontrolloopsIdentificationofSIFbasedonP IDrepresentationrequirecontrolengineeringexpertiseHazard consequenceandsafeguardsrelatedtoSIFrequireprocessandriskassessmentexpertise PHAStep2ConsequenceAnalysis WhatisincludedinconsequenceAnalysis ShouldconsiderFatalityandinjuryPropertydamageBusinessinterruptionsEnvironmentaldamageThirdpartyliabilityCorporateimage ConsequenceAnalysisMethods EstimateandCategorizeStatisticalConsequencemodelingMinor impacttolocalareaSerious Couldcauseserousinjuryorfatality orpropertydamage 1Monsite 5Moff siteExtensive 5ormoretimeworsethanSerious StatisticalConsequenceAnalysis Useaccidentstatisticstocalculateaverageconsequence Advantage WelldefinednumberProblems Applicabilityofdata isthenewsituationsimilarenoughIsthereenoughdatatobestatisticalsignificantExIn5yearsperiodtherewere235explosionsinindustrialboiler17peoplewerekilled 84wereinjuredPLL 17 235 0 073perincidentPI 84 235 0 358perincident ConsequenceModeling Consequenceifafunctionofeffectzone occupancyandvulnerabilityOccupancyistheaveragenoofpeople orotherreceptors intheeffectzone randomandnormallyoccupiedbuildingsVulnerabilityistheprobabilityoffatalities orotherharmlevel givenapersonintheeffectZoneConsequence Occupancy Vulnerability PHAStep3 LikelihoodAnalysis Likelihood FrequencyHazardlikelihoodaccordingtoIEC61511part3ReferstoafrequencysuchasthenumberofeventsperyearofermillionhoursLikelihoodAnalysisMethodsEstimateandCategorizeStatisticalLikelihoodModeling LikelihoodCategorization StatisticalanalysisofLikelihood AccidentlikelihoodcanbedeterminedfromthelikelihoodofsimilarpreviouseventsDependonsufficientnumberofsimilareventstoprovideproperbaseGoodforcommongenerichazardssuchasThelikelihoodofdeathfromlightningis1 10 7peryearNotgoodforunusualequipmentandmorespecificprocessaccidentprediction FaultPropagationModeling AnalyzethechainofeventsthatleadstoanaccidentUseeventratedataofindividualcomponentsnotentiresystemsComponentsfailureeventdataiseasiertofindCalculateoveralllikelihoodusingprobabilitylogic EventTreeAnalysis GoodfaultpropagationmodelforprocessriskestimationEventchainsconnectsingleinitiatingeventtomultipleoutcomesthroughintermediatebranchpoints DrawanEventTree EventtreeforfireresultingfromanoverturnedtruckofgasolineAssumetheinitiatingeventisatanktruckaccidentTheprimaryeventbranchesareIsthetruckoverturned Doesthetanktruckleak Doestheliquidpoolfindasourceofignition ResultEventTree OutcomeprobabilityExample DataAccident1 7years 0 143Probabilityofoverturn1 10 0 10Probabilityofleakafterturnover1 3 0 33 otherwise1 6 0 16 Probabilityofignition 20 inallspillcases 0 2 Calculatelikelihoodof OverturnandspillwithoutfireOverturn spillandfire EventTreeCalculation