TheChallengesInvolvedinDesigningaCodeCompliantOverpressure

Protec9on(OPP)SystemRezaRasooli

SolarisManagementConsultants

RezaRasooli–  19yearsexperience–  ProcessSafetyExpertwithSolarisManagementConsultantsInc.

–  BSc.inElectricalEngineering– MSc.inMechatronicsEngineering–  RegisteredProfessionalEngineerinB.C.andAlberta–  CerDfiedAutomaDonProfessional–  ISA84/IEC61511ProcessSafetySISExpert–  ExidaFireandGasPracDDoner–  ISA84standardcommiMeemember– MemberoftheStandardsCouncilofCanada(SCC)andrepresenDngSCCinIEC61511standardcommiMee

ObjecDves&Overview

•  WhyisOPPimportant?•  OPPchallenges•  Whichcodeisthegoverningcode?•  Reviewofavailablestandards•  ReviewofindustrypracDceforwellsites•  HIPSdesign•  HowtosavecostbyusingHIPS

WhyisOPPimportant?•  OverpressureprotecDonisconsideredthelastlineofdefenseagainstpossiblecatastrophicfailureofpressureequipment.ThefuncDonofoverpressureprotecDonisto:– Protectpeople,– PreventunsafeoperaDonofpressureequipment,– Protectequipmentfromfailureduetooverpressure,

– PreventlossofproducDon.

OPPChallenges

•  SinceaPSVistheprimarymethodofprovidingOPPforpressureequipment,almostallpressureprotecDonguidelineshavefocusedonprovidingdetailsonhowtoimplementPSVsanddonothelpmuchwhenaPSVcannotbeused.

– Whichcodeisthegoverningcode?– WhyOverpressureRiskAssessment(ORA)isrequired?– WhatisroleofinstrumentaDoninoverpressureprotecDon?

– WhenshouldweuseHIPSinsteadofPSV?

Whichcodeisthegoverningcode?•  ThebiggestchallengeinevaluaDngordesigninganoverpressureprotecDon(OPP)systemisfindingtherightguidelinewithinthevarietyofapplicablestandardsandhowtodealwithdifferentinterpretaDonsofavailableresources,including:– ASME(BPVCSecDonI,VIII,B31.1,B31.3,B31.4,B31.8)– APIStd521–  CAN/CSA-Z662– ABSAAB-525–  IEC61508,IEC61511orANSI/ISA-61511

ASMEBPVC.VIII.1UG-140OPPbysystemdesign•  UG-140(a):Apressurevesseldoesnotrequireapressurereliefdeviceifthepressureisself-limiDng(e.g.,themaximumdischargepressureofapumporcompressor),andthispressureislessthanorequaltotheMAWPofthevesselatthecoincidenttemperature…

•  UG-140(b):Ifthepressureisnotself-limiDng,apressurevesselmaybeprotectedfromoverpressurebysystemdesignorbyacombinaDonofoverpressurebysystemdesignandpressurereliefdevices…

ASMEBPVC.VIII.1UG-140(b),3•  Theusershallconductadetailedanalysistoiden9fyandexamineallscenariosthatcouldresultinanoverpressurecondi9onandmagnitudeoftheoverpressure.The“CausesofOverpressure”asdescribedinANSI/APIStandard521,Pressure-RelievingandDe-pressuringSystems,shallbeconsidered.OtherstandardsorrecommendedpracDcesthataremoreappropriatetothespecificapplicaDonmayalsobeconsidered.AmulDdisciplinaryteamexperiencedinmethodssuchasHAZOP,FMECA,what-ifanalysis,orotherequivalentmethodologyshallconducttheanalysis.

ASMEB31.3K322.6.3OPPforhighpress.pipingsystems•  SystemprotecDonmustincludeonereliefdevicesetatorbelowthedesignpressureattheoperaDngtemperaturefortherelievingcondiDon,withnodevicesettooperateatapressuregreaterthan105%ofthedesignpressure…

•  ASMEB31.3doesnotprovideanyalternaDveforaPSV.

CAN/CSA-Z662Oilandgaspipelinesystems•  Pressure-controlsystemsshallbeinstalledwheresupplyfromanysourcemakesitpossibletopressurizethepipingaboveitsmaximumoperaDngpressure…

•  Wherefailureofthepressure-controlsystem,orothercauses,canresultinthemaximumoperaDngpressureofthepipingbeingexceeded,overpressureprotecDonshallbeinstalled…

CAN/CSA-Z662,4.18PCandOPPofpiping•  OverpressureprotecDonreferstoasecondlevelofprotecDon(i.e.,beyondthatprovidedbypressurecontrol)thatisrequiredinordertoprotectthepipelinefrombeingoverpressured.

•  OverpressureprotecDonisrequiredtobeconDnuousandautomaDcbecauseitisasafety-typesystem,withoutanyrelianceonmanualintervenDon.OverpressureprotecDoncanbeaccomplishedbypressure-limiDngsystemsorpressure-relievingsystems.

CAN/CSA-Z662,4.18.4AddiDonaloverpressure-protecDonrequirements•  4.18.4.1:ForposiDvedisplacementgascompressors,apressure-relievingsystemshallbeinstalledbetweenthegascompressorandthefirstblockvalveonthedischargesideofthecompressor.Therelievingcapacityofthepressure-relievingsystemshallbeequaltoorgreaterthanthecapacityofthecompressor.

•  4.18.4.2:Forcentrifugalgascompressors,apressure-limi9ngorpressure-relievingsystemshallbeinstalledbetweenthecompressorandthefirstblockvalve,orbetweenthefirstandsecondblockvalvesonthedischargesideofthecompressor.

AERReferenceToolforInterpreDngPipelinePCandOPP•  ThistoolclarifiestherequirementsofCanadianStandardsAssociaDon(CSA)Z662-03:OilandGasPipelineSystems,Clause4.14.1,…

AERReferenceToolforInterpreDngPipelinePCandOPP•  UserNotes–  Thesuitablecasesshowninthediagrams…arenotuniversallyacceptable.

– Allsourcesfromwhichoverpressuremayoccurmustbetakenintoaccount.Forthepurposeofthesediagrams,itisassumedthatothersuitableupstreampressurecontrolequipmentisinplace.

–  Thesuitableexamplesreflecttypicalsystemsandaretobeusedonlyasaguideline.CertainexcepDonsorrestricDonsmaybewarrantedbasedonthecircumstancesandfacilitylayout.Everysystemshouldbeevaluatedcarefully,consideringallpossiblemodesofoperaDon.

DirecDve077:Pipelines—RequirementsandReferenceTools –  Toprotectthewellsitesandtheassociatedgathering

pipelinesystems,thecommonindustrypracDceistouseaback-pressurecontrolvalve(BPCV)locatedonapressurevesselinthebaMeryaspressurecontrolforthepipeline,andtouseapressureswitchlocatedatthewellheadasoverpressureprotecDonthatshutsdownthearDficiallinequipmentatthewell.However,thepipelinesarenotalwaysprovidedwithadedicatedpressurecontrolandoverpressureprotecDonsystem,asrequiredbyCSAZ662-07.

–  TheERCBdoesnotconsiderthisdesigntobemeeDngCSArequirements…

ImportantNote

InaccordancewithClause4.18ofCSAZ662,anoverpressureprotecDondevice(e.g.,emergencyshutdownvalve)incombinaDonwithapressurecontroldevice(e.g.,anautomaDcchoke)maybeusedtoprovideprotecDonforCSAZ662pipelinepiping.ThereisnoregulatoryorCSAZ662coderequirementforapressurerelievingsystemnorfortheuseofHIPSratedcontrols/components.WhereASMEcodeequipmentexistsatapointdownstream,ASMECoderequirementsshallprevail.

ThePressureEquipmentSafetyRegulaDon(PESR)•  38(1):AnownerofpressureequipmentmustensureithasoverpressureprotecDonthatis:

(a)  apressurereliefvalvethatmeetstherequirementsoftheASMEcode,or,

(b)  othermeansofoverpressureprotecDonacceptabletotheAdministrator.

AB-525OverpressureProtecDonRequirementsforPressureVesselsandPressurePiping•  AccordingtothePESR,apressurereliefvalvethatmeetstherequirementsoftheASMEcodeisrequiredforprotecDonofallpressureequipmentunlessthepressureequipmentisprotectedbysomeothermeansacceptabletotheAdministrator.

•  TheAdministratormayacceptanalternaDvemeansofoverpressureprotecDonthatisnotaPRVinaccordancewithSecDon38(1)(b)ofthePESRandSecDon5.5ofAB-525.

AB-525

•  WhenpressurevesselsandpressurepipingareprotectedbyPRVsinaccordancewithSecDon38(1)(a)ofthePESR,thePRVsmust:– provideoverpressureprotecDonforalloverpressureevents(scenarios)validatedwithanORA,and,

– meetalltherequirementsspecifiedinthePESR,thisdocument,AB-524document,andtheapplicableCSAandASMEcode.

AB-525ORA•  ORAmeansOverpressureRiskAssessment.ThisisariskassessmenttodeterminethesourcesofoverpressureandtheMaximumUpsetPressure….TheORAmustuseanorganized,systemaDcanddocumentedapproachconductedbyqualifiedpersonnelthroughamulD-disciplinaryteam.TheprocessusedforORAmustbebasedonrecognizedstandardsandgoodengineeringpracDces(WRC-498,ANSI/API521,ANSI/API-520,etc.).TheORAshallincludealistofSafetyCriDcalElementsuDlizedinthedeterminaDonoftheMaximumUpsetPressure.

AB-525,5.5OtherMeansofOverpressureProtecDon•  ThefollowingaresomeexamplesofothermeansofoverpressureprotecDonthatrequireindividualcase-by-caseconsideraDon:– HighIntegrityProtecDonSystem(HIPS)providingoverpressureprotecDonofsystems(FurtherinformaDononHIPScanbefoundinAnnexEofANSI/API521),

– …,– OtheroverpressureprotecDoncasesthatarenotincludedinSecDons5.1,5.2,5.3or5.4ofthisdocument,

– …,

APISTANDARD5214.2.6RoleofInstrumentaDoninOPP•  Fail-safedevices,automaDcstart-upequipment,andotherconven9onalinstrumenta9onshouldnotbeasubs9tuteforproperlysizedPRDsasprotecDonagainstsinglejeopardyoverpressurescenarios.Therecanbecircumstances,however,wheretheuseofPRDsisimpracDcalandrelianceoninstrumentedsafeguardsisneeded.Wherethisisthecase,ifpermiMedbylocalregulaDons,aPRDmightnotberequired.

ImpracDcalPRDs•  ExtraordinaryreliefloadthatresultsinunrealisDc

knockoutdrumandflaresystem•  Sand,waxorothermaterialsthatcanblockthePSV•  PSVsthatcancausenewhazards•  Atmosphericvent:areaclassificaDonandfacilitysiDng

issues•  Hotprocessortwo-phaseflow•  Environmentaldamage•  WheremulDple,full-sizePSVsarerequiredtofuncDon

simultaneously•  PSVreliefratecancausetemperatureslowerthan

systemMDMT(MinimumDesignMetalTemperature)

APISTANDARD5214.2.6RoleofInstrumentaDoninOPP•  ThedesignshallcomplywiththelocalregulaDonsandtheowner’srisktolerancecriteria,whicheverismorerestricDve.IftheserisktolerancecriteriaarenotavailabletoperformanalysespertheguidanceinAnnexE,thenasaminimum,theoverallsystemperformanceincludinginstrumentedsafeguardsshouldprovidesafetyintegritylevel3(SIL-3)performanceinaccordancewithISAS84.01.

APISTANDARD521AnnexE(HIPS)•  High-integrityProtecDonSystems(HIPS)– AdifferentapproachtooverpressureprotecDonistheuseofaninstrumentedsystem.HIPStypicallyinvolveanarrangementofinstruments,finalcontrolelements(e.g.,valves,switches,etc.),andlogicsolversconfiguredinamannerdesignedtoavoidoverpressureincidentsbyremovingthesourceofoverpressureorbyreducingtheprobabilityofanoverpressureconDngencytosuchalowlevelthatitisnolongerconsideredtobeacrediblecase.

APISTANDARD521AnnexE(HIPS)•  TherearefiveprincipalusesofaHIPS:–  toeliminateaparDcularoverpressurescenariofromthedesignbasis

–  toeliminatetheneedforaparDcularreliefdevice–  toprovidesystemoverpressureprotecDonwhereareliefdeviceisineffecDve

–  toreducetheprobabilitythatseveralreliefdeviceswillhavetooperatesimultaneously,therebyallowingforareducDoninthesizeofthedisposalsystem

–  toreducethedemandrateonareliefdeviceconsequentlyreducingtherisk

TypicalWellsiteforpressures≤5000psig

TypicalWellsiteforpressures≥15000psig

Costofflaresystem$700,000to$4000,000dependingonflowrates

PSVchallenges– Two-phaseflowwithlargeamountofliquids– Six,full-flowPSVsarerequiredtofuncDonsimultaneously

–  largeamountofsandisflowingfromthewell– HighH2Scontent– ExtraordinarybigFKODrequired– Extraordinarytallflarestackrequired– Highcostofflaresystem(makingprojecteconomicallynotfeasible)

– Costofflaresystem$700,000to$4,000,000dependingonflowrates

HIPSDesignpressures≥15000psig

CostofHIPS$300,000regardlessofflowrates

HybridDesignHIPS+PSVs

QuesDons