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PolarLNGFeedGasPipeline
BasisofDesignPreparedfor:
Revision1September03,2013
MichaelBakerJr.,Inc.1400WestBensonBlvd.,Suite200
Anchorage,Alaska995039072731600
124937MBJDOC001
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PolarLNGFeedGasPipelineProject BasisofDesign
124937MBJDOC001Rev.1February2013 Pageiofiv
RevisionHistory
Rev Date Comments BakerApproval PolarLNGLLCApprovalA 09/14/2011 Draft
B 09/21/2011Updatedpercommentsreceived.Updatedsection5.3.1toASCE710previouslywas705.
C 10/13/2011RemovedreferencetousingexistingVSMandupdatedrouteneartheHalliburtonPad
D 11/21/2012UpdatedprojectpersonnelandincorporatedcommentsfromClientandSPCO
E 01/08/2013 IncorporatedSPCOcommentsdatedDecember21,2012.
0 02/08/2013 IssuedForPublicComment
1 09/03/2013 UpdatedAlignmentatPolarPad
Title Name Signature DateMichaelBakerJr.,Inc.ProjectManager JasonGardner
MichaelBakerJr.,Inc.ProjectEngineer JoshGreenhillMichaelBakerJr.,Inc.CivilEngineer TobyLovelace,PEPolarLNG,LLCProjectDirector DougSmith,PMPWesternIndustrialResourcesCompanyProjectLead
EricFranklin,PMP
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PolarLNGFeedGasPipelineProject BasisofDesign
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TableofContents1.0 INTRODUCTION...............................................................................................................................12.0 PROJECTOVERVIEW.........................................................................................................................3
2.1 PIPELINEROUTE................................................................................................................................32.2 PIPELINECONFIGURATION...................................................................................................................4
2.2.1 EXPANSIONLOOPS.......................................................................................................................42.2.2 SUPPORTS..................................................................................................................................5
2.3 LAUNCHERANDRECEIVERBARRELS.......................................................................................................53.0 DESIGNPARAMETERS.......................................................................................................................6
3.1 PIPELINEDATA..................................................................................................................................63.2 DESIGNLOADS..................................................................................................................................6
3.2.1 INTERNALDESIGNPRESSURE.........................................................................................................73.2.2 HYDROSTATICTESTLOADS............................................................................................................73.2.3 TEMPERATUREDIFFERENTIAL........................................................................................................73.2.4 GRAVITYLOADS..........................................................................................................................83.2.5 SNOWLOAD...............................................................................................................................83.2.6 WINDLOADANDWINDINDUCEDVIBRATION(WIV)........................................................................83.2.7 LOSSOFSUPPORT........................................................................................................................83.2.8 EARTHQUAKELOADS....................................................................................................................93.2.9 LOADCOMBINATIONS..................................................................................................................9
4.0 PIPESTRESS..................................................................................................................................104.1 ALLOWABLESTRESSCRITERIA............................................................................................................104.2 PIPELINESTRESSANALYSIS................................................................................................................11
5.0 PIPELINESUPPORTS........................................................................................................................125.1 SUPPORTDESCRIPTIONS....................................................................................................................125.2 SUPPORTDESIGN.............................................................................................................................135.3 STRUCTURALANALYSISOFPIPELINESUPPORTS.....................................................................................14
5.3.1 SUPPORTLOADING....................................................................................................................146.0 CIVILDESIGN................................................................................................................................16
6.1 ROADCROSSINGS............................................................................................................................16
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ListofTablesTABLE1.1 FEEDGASCOMPOSITION..............................................................................................................1TABLE3.1 PIPELINEPARAMETERS.................................................................................................................6TABLE3.2 DESIGNLOADING.........................................................................................................................7TABLE3.3 LOADCOMBINATIONS..................................................................................................................9TABLE4.1 ALLOWABLESTRESSFORABOVEGROUNDPIPELINES........................................................................11TABLE5.1 ALLOWABLEADFREEZESTRESSESFORVSM...................................................................................14ListofFiguresFIGURE1.1 POLARLNGPIPELINEBETWEENSEAWATERINJECTIONPLANT(SIP)PADANDPOLARLNGFACILITY.........2FIGURE2.1 TERMINATIONATPOLARPAD........................................................................................................4FIGURE2.2 TYPICALZLOOPCONFIGURATION...................................................................................................4FIGURE5.1 TYPICALSLIDINGSUPPORT..........................................................................................................13FIGURE5.2 TYPICALGUIDEDSUPPORT..........................................................................................................13FIGURE5.3 TYPICALANCHORSUPPORT.........................................................................................................13
AppendicesAPPENDIXA CODES,STANDARDSANDSPECIFICATIONS..................................................................................A.1
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List of Abbreviations and Acronyms AISC AmericanInstituteofSteel
ConstructionANSI AmericanNationalStandards
InstituteAPI AmericanPetroleumInstituteASCE AmericanSocietyofCivilEngineersASME AmericanSocietyofMechanical
EngineersBOP BottomofpipeBPXA BPExploration(Alaska),Inc.CFR CodeofFederalRegulationCVN CharpyVNotchDF DesignfactorDOT DepartmentofTransportation(U.S.)DS12 DrillSite12FBE FusionbondedepoxyFNG FairbanksNaturalGas,LLCFS1 FlowStation1g GravityGPB GreaterPrudhoeBayHSM HorizontalsupportmemberIBC InternationalBuildingCodeILI InlineinspectionLNG LiquefiednaturalgasLRFD LoadandResistanceFactorDesignMAOP Maximumallowableoperating
pressureMMscfd MillionstandardcubicfeetperdayPBU PrudhoeBayUnitpcf PoundspercubicfootPPM PartsperMillionpsf PoundspersquarefootSIP SeawaterInjectionPlant
SMYS SpecifiedminimumyieldstrengthTOS TopofSteelTVA TunedvibrationabsorberUHMWPEUltraHighMolecularWeight
PolyethyleneVSM VerticalsupportmemberWIV Windinducedvibration
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1.0 IntroductionThePolarLNG,LLC(PolarLNG)programwillconstructafeedgaspipelineandanaturalgasliquefactionplantinDeadhorse,Alaska,adjacenttothePrudhoeBayOilFieldonAlaskasNorthSlope.Theliquefiednaturalgas(LNG)willbetransportedbytrucktoFairbanks,Alaska,whereitwillbestoredandvaporizedon demand. The LNGwill provide FairbanksNaturalGas (FNG)with a larger supply to increase gasservicewithinitsservicearea.PolarLNGisplanningtoinstallthefeedgaspipelinebythesecondquarterof2014.Thepipelinewilltieinto the Seawater Injection Plant (SIP) 10inch nominal diameter fuel gas line at an existing flangedconnection.Fromthistiein,thepipelinewillpassthroughameteringskid,tobedesignedbyothers.Onthe downstream sideof themetering skid, thepipelinewillproceed crosscountry to the Polar LNGfacilitynearDrillSite12(DS12).ThepipelinewillbeincompliancewithDOT(49CFR192)regulations.Thepipelinewillberoutedwithinanewrightofway.ThenewpipelinewillbeNPS8 (8inchnominaldiameter),API5LX65 carbon steel,andhavea totallengthofapproximately18,600feet.Thepipelinecapacitywillbe32millionstandardcubicfeetperday(MMscfd)offeedstockgas.Table1.1showsthefeedgascomposition.Thepipelinewillbedesignedforamaximum allowableoperatingpressure (MAOP)of1480psig,with anormaloperatingpressureofapproximately650psig.Thepipelinewillbecoatedwith two layers (approximately40mils)of fusionbondedepoxy (FBE) forcorrosionresistance.Thepipelinewillonlybe insulated forshortdistancesateach anchor support. Thepipelinewillbe installedonnew vertical andhorizontal supportmembers(VSM/HSM).AmapoftheprojectareaispresentedinFigure1.1.
Table1.1 FeedGasComposition
Components DesignGas(Mole%) RichGas(Mole%) LeanGas(Mole%)Methane,C1 80.1 80.6 79.4CarbonDioxide,CO2 12.05 12.4 11.8Ethane,C2 5.25 5.6 5.2Propane,C3 1.65 1.9 1.5Nitrogen,N2 0.61 0.64 0.58Butane 0.28 0.35 0.26Pentane 0.04 0.05 0.04Hexane 0.02 1.02 2.02HydrogenSulfide,H2S 12PPM 40PPM 20PPMWater,H2O 3PPM 6PPM 3PPMNote:CompositionsarefromthePolarLNG, FeedGasPipelineDesignBasis,RevB,receivedfromPeakOilfieldServices.
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Figure1.1 PolarLNGPipelinebetweenSeawaterInjectionPlant(SIP)PadandPolarLNGFacility
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2.0 ProjectOverview2.1 PipelineRouteThepipelinewillfollowthealignmentshowninFigure1.1.AnewpipelinerightofwaywillbeobtainedbyPolarLNG.ThepipelinealignmentwillstartneartheoriginoftheSIP10inchnominaldiameterfuelgas line, travel to themetering skid,andhead southalonganew rightofwayuntil turningeastatalocation north of theHalliburton Pad. The pipelinewill turn south toward DS12, remaining east ofHalliburtonPad,until reaching thenorth shoreofMcDermott Lake.Thepipelinewill then follow thenorthernandeasternshoresofthelaketoitsterminusatthePolarLNGPadnearDS12.To support the construction of the new pipeline, an ice road approximately 30 feet wide will berequired.Work and turnaround areas, roughly 120 by 120 feet, will be spaced along the route. Aminimum7 feetofclearancewillbemaintainedbetween the tundrasurfaceand thebottomofpipe,exceptatroadcrossingswherethepipelinewilldescendbeforeenteringasteelcasing.AmeteringskidwillbeinstalledattheSIPPadtodeterminethevolumeofgaspurchasedbyPolarLNG.Theportionofthe linebetweenthetieinandthemeteringskid isoutsidethe jurisdictionoftheU.S.DepartmentofTransportation(USDOT)andtherefore isnotgoverned49CFR192.ThissectionwillbedesignedinaccordancewithASMEB31.8.PolarLNGwillbetheresponsiblepartyfortheoperationandmaintenance,andtheemergencyresponseforthissectionoftheline.The pipeline will terminate at the Polar LNG Facility pad as shown in Figure 2.1. Receiver barrelconnectionswillbeinstalledatthislocation.
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Figure2.1 TerminationatPolarPad
2.2 PipelineConfiguration2.2.1 ExpansionLoopsToaccountfortheeffectsofthermalexpansion,Zstyleexpansionloopswillbeused,showninFigure2.2.Two90degreebendswillbeused in typical sections.Stressesanddisplacements calculatedwillgoverntheallowabledistancebetweenanchors.
Figure2.2 TypicalZLoopConfiguration
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Pipe bends used at expansion loops and piping intersectionswill be prefabricated induction bends.Routingandconfigurationoptimizationwillbeconductedtominimizethenumberof inductionbends.Allpipebendswillhaveaminimum radius requirementof three times thenominalpipelinediameter(3D)toaccommodatetheuseofinlineinspection(ILI)tools.2.2.2 SupportsAminimumspacingof3.5feetwillbemaintainedbetweentheendsoftheexistingHSMbeamsandthenewpipesupportbeamsintheareaneartheSIPpad.Typicalsupportspacingwillbeapproximately55feet.Considerationwillbegiventoaccommodatefieldchangesupto5 feetresulting frommassive iceorotherconditionsencounteredduring installationofthesupports,variationsinsurveyinformation,andavoidanceofanynaturalormanmadestructuresnotpreviouslyaddressed.NorthSlopeBorough regulations requireaminimum clearanceof7 feet frombottomofpipe to thetundrasurface.Thesaddleseachwillprovideadditionalelevationtothebottomofpipeandwillraisethe pipeline to an elevation to allow the midspan sag of the pipeline to exceed the clearancerequirement.Thiseliminatestheneedforcariboucrossingsalongthealignment.
2.3 LauncherandReceiverBarrelsThepipelinewillbedesignedtoaccommodateconnectionoftemporary/portablelauncherandreceiverbarrels to allow deployment of inline inspection (ILI) and maintenance tools. The launcher barrelconnectionswillbe locateddownstreamof themetering skidand receiverbarrel connectionswillbelocatedatthePolarLNGfacilityforusebyoperations.
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3.0 DesignParameters3.1 PipelineDataThePolarLNGpipelinewillbedesignedaccordingtothecodes,standards,andspecificationsasoutlinedinAppendixAof thisreport.Thepipelinewillnotbe insulated for themajorityof thealignment.ThepipelinewillinsteadbecoatedwithtwolayersofFBEcoating,approximately4050milsthick.AsFBEisnotUVresistant,thisthicknesswillallowfortheoutersurfaceofthepipetochalkwhilestillaffordingadequate corrosionprotectionof thepipe steel.Thepipelinewillbe insulated for shortdistances ateachanchorsupport.Thiswillallowatypicalanchorsaddledesignthatclampsaroundtheinsulationtobeused.ThepipelinedesignparametersaresummarizedinTable3.1.
Table3.1 PipelineParameters
Parameter TieintoMeter CrossCountry HalliburtonPadtoPolarLNGPadProduct FeedGas FeedGas FeedGas
GoverningCodes ASMEB31.8 CFR49Part192 CFR49Part192LocationClass 2 1 3
CodeDesignFactor(DF) 0.60 0.72 0.50NominalPipeDiameter 8inch 8inch 8inchMinimumWallThickness 0.226inch 0.199inch 0.259inchDesignWallThickness 0.322inch 0.322inch 0.322inchCorrosionAllowance 0.0625inches 0.0625inches 0.0625inches
MaterialGrade API5LX65 API5LX65 API5LX65SpecifiedMinimumYield 65,000psi 65,000psi 65,000psi
ASMEB16.5Rating Class600 Class600 Class600MaximumAllowable
OperatingPressure(MAOP) 1480psig 1480psig 1480psig
Allbendswillhaveminimumradiiofthreetimesthenominaldiameterto facilitatepassageof ILIandmaintenancetools.
3.2 DesignLoadsDetailed industry requirements regarding allowable internal pressure and other loads, loadingcombinations,orlimitationsoncombinedstatesofstressarepresentedinASMEB31.8,ASCE710,andprojectdesignspecifications.The design operating conditions are defined to include all normal operating conditions andenvironmental loadings.Design loads include internalpressure,temperaturedifferential,deadand liveloads,windload,hydrostatictestloads,andloadsimposedbyearthquakes.PipelinedesignloadingsaresummarizedinTable3.2.
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Table3.2 DesignLoading
OperationalLoadingsforPipelineMAOP 1480psigMaximumOperatingTemperature 100FMinimumTemperature 50FTieInTemperature 25FInsulationThickness NoneSpecificGravityofContents(Air=1.00) 0.72PipeGuideSaddleFrictionCoefficient(UHMWPElinerandFBE) 0.25
1
PipeSlideSaddleFrictionCoefficient(PTFEandStainlessSteel) 0.10
1
DeadLoadsPipeSteelUnitWeight 489pcf
OccasionalLoadsWind 110mphSnowLoad(ground) 50psfEarthquakeAcceleration 0.213g1Actualfrictioncoefficientsreportedbythemanufacturer(s)arelower(0.18forguidesand0.04forslides).Analysiswillberunforeachsetoffrictionvaluestodeterminecontrollingcase.
3.2.1 InternalDesignPressureThe pipelinewill be designed to 1480 psig (based on ASME B16.5 Class 600 flange rating)which isgreater than theMAOPof thePBUFieldFuelGaspipeline (1440psig).Theoperatingpressureof thePBUFieldFuelGaspipelineis575650psig.3.2.2 HydrostaticTestLoadsThepipelinewillbetestedtoatleast1.5timestheMAOP.Onehydrostatictestwillbeperformedfromthe flange connection off the 10inch SIP fuel gas line to themetering skid, and the otherwill beperformed from themeteringskid to thePolarLNGpad.Thesouthernportionof thepipelinewillbeLocation Class 3. Themaximum hoop stress during hydrostatic testingwill be less than 95% of thespecifiedminimum yield strength (SMYS). The pipeline design is expected to accommodate the testconditionsasa contingency load.The load combination formodelinghydrostatic testingon installedpipetypicallyincludesinternalpressure,gravity,thermaldifferential(duringtesting),and1/3windspeed(approximately37mph).3.2.3 TemperatureDifferentialPipestressesfromtemperaturedifferentialwillbecalculatedperminimumdesigntemperatureandthemaximumpipewalltemperature.
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PipestressesfromtemperaturedifferentialswillbecalculatedperASMEB31.8.Theoperationalrangeforthepipeline is50Fto100F,whichhasbeenverifiedwithPolarLNG.TheoperativeparagraphofASMEB31.8states:
The total range in temperature fromminimum design temperature to themaximumdesign temperature shallbe considered,whetherpiping is coldsprungornot.Shouldinstallation,startup,orshutdowntemperaturesbeoutsideofthedesigntemperaturerange,additionalanalysiswillberequired.Inadditiontoexpansionofthelineitself,thelinear and angular movements of the equipment to which it is attached shall beconsidered.
Forcesandmomentsactingonpipelinesupportswillbecalculatedbasedonacoldspringtemperatureof 25F. These forces will be determined using a temperature range specified from 25F to 50F(contraction)and25Fto100F(expansion).3.2.4 GravityLoadsThegravityloadsincludetheweightofthepipe,contents,andexternalcoating.Thehighestfluidweightthatthepipelinewillexperiencewilloccurduringhydrostatictesting.3.2.5 SnowLoadAminimum design ground snow loadof 50psf per Polar LNGdesign criteriawillbe converted to acomparabledesignsnowloadasperASCE710.Itisassumedthatsnowloadingonlyappliestolocationsidentifiedbyfieldoperationswheresignificantsnowdriftisexpected.Typically,snowdriftaccumulatesadjacenttopadsandroads,andanywherethepipeline isnotadequatelyelevatedfromthetundra(atleast5feetapproximately).3.2.6 WindLoadandWindInducedVibration(WIV)Designwindspeedforabovegroundpipelines is110mph.ThedesignwindpressurewillbecalculatedusingASCE705asrequiredbytheInternationalBuildingCode(IBC).Thedesignwindexposure isC,the importancefactor is1.00,andthetopographicfactorKzt isequalto1.00.Theforcecoefficient istakentobe0.8.Thegusteffectfactoristakenas0.85.ThevelocitypressureexposurecoefficientKzisdefinedas0.85.Thepipelinesareanticipatedtobebetween7and15feetabovegradeforthemajorityof thealignment.This results inawindpressureofapproximately18poundsper square footon thepipeline.Thenewpipelinewillbeevaluatedforsusceptibilitytowind inducedvibration.Segments identifiedassusceptiblewillbemitigatedusingtunedvibrationabsorbers(TVA),reducingdistancebetweenVSM,orother suitable techniques. Baker will perform a simplified screening analysis to determine thesusceptibilityof thepipeline toWIV. If susceptibility isconfirmedby thiscalculation,SSD, Inc.willbeconsultedtouserefinedanalysistechniquestodeterminetheproperTVAconfigurationtodampenthepredictedvibrations.3.2.7 LossofSupportThedesignloadanalysiswillincludescenariosinvolvinglossofsupportduetofrostjackingorsettlingofat leastoneVSM.Thiswillensure thepipelinewillnotbuckleor rupture ifone support isno longercontactingthepipeline.
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3.2.8 EarthquakeLoadsTheNorthSlopeisconsideredalowseismicriskzone;therefore,simplifiedstaticearthquakeloadsareusedintheanalysis.Seismiccriteriaforpipelinedesignarebasedonmappedspectralaccelerationvalueswithanestimated2percentprobabilityofexceedanceduringa50yearreturninterval(2500yearreturninterval),andSiteClass B soils. Based on USGS data, the project area has approximate maximum short period and1secondspectralaccelerationsofSS=0.319gandS1=0.109g,respectively.ASCE710,Table11.41,givesthe site coefficient for Site Class B as 1.00 for short period spectral accelerations of less than 0.50.Designspectralaccelerationisspecifiedtobe2/3ofthefactoredspectralacceleration,whichresultsindesignshortperiodand1secondspectralaccelerationsof0.213gand0.073g,respectively.Theshortperiodspectralaccelerationwillbeusedinpipestressanalysesoftheabovegroundpipelines.3.2.9 LoadCombinationsLoadsonthepipelinesandsupportswillbeanalyzedfortheloadcombinationspresentedinTable3.3.
Table3.3 LoadCombinations
LoadType DescriptionPipelineLoadCombinations
Testing Operating Contingency1 2 3 4 55 6 74 8 9
Primary InternalPressure(Hoop) X X X
Primary InternalPressure(Longitudinal) X X X X X
Primary HydrostaticTestPressure X X
Primary GravityLoads X1 X X X X X
Primary OccasionalLoad(Wind,Seismic,Etc.) X2 X X
Secondary TemperatureDifferential(50Fto100F) X3 X X X
Primary LossofSupport X
Secondary TemperatureDifferential(50Fto25F,25Fto100F) X1Gravityloadforhydrostatictestincludestheweightofthehydrostatictestfluid.2Onethirdofthedesignwindspeedisincluded.3Temperaturedifferentialforhydrostatictestisbasedonanassumedhydrostatictesttemperatureof60F.4Combination7isappliedtowardsforces,moments,anddisplacementsonlyanddoesnotapplytowardsinternalpipelinestress.
5Stressresultingfromworstcaseoccasionalloadwillbereported.Reference:ASMEB31.8,GasTransmissionandDistributionPipingSystems
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4.0 PipeStressASME B31.8 addresses detailed industry requirements for gas pipelines. Based on the nature anddurationofthe imposed loads,pipelinestressesarecategorizedasprimaryorsecondarystresses.Theprimaryandsecondarystresscriteriaaresummarizedasfollows: Primary Stresses Primary stresses are stresses developed by imposed loads with sustained
magnitudesthatare independentofthedeformationofthestructure.Thebasiccharacteristicofaprimarystressisthatitisnotselflimiting.Thestressescausedbythefollowingloadsareconsideredasprimary stresses: internalpressure,externalpressure includingoverburden,anddeadand liveloads.
Secondary Stresses Secondary stresses are stresses developed by the selfconstraint of thestructure.Generally,theysatisfyanimposedstrainpatternratherthanbeinginequilibriumwithanexternal load.Thebasic characteristicofa secondary stress is that it is selflimiting.The stressescaused by the following loads are considered as secondary stresses: temperature differential,differentialsettlement,andearthquakemotion.
Combined Stresses The three principal stresses acting in the circumferential, longitudinal, andradialdirectionsdefinethestressstateinanyelementofthepipeline.Limitationsareplacedonthemagnitudeofprimary and secondaryprincipal stresses andon combinationsof these stresses inaccordancewithacceptablestrengththeoriesthatpredictyielding.
4.1 AllowableStressCriteriaCircumferential, longitudinal, shear,andeffective stressesare typically calculated taking intoaccountstresses fromall relevant loadcombinations.Calculationsconsider flexibilityand stressconcentrationfactors of components other than straight pipe. Allowable stresses for aboveground pipeline arepresentedinTable4.1.
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Table4.1 AllowableStressforAbovegroundPipelinesCriterion Value Basis LoadComb.
Testing
HoopStress(hydrostatictestpressure) 0.95SMYS ProjectDefined1 1LongitudinalStress(hydrostatictestpressure,hydrostatictesttemperature,hydrostatictestlive,gravityloadandtheoccasionalload)
0.95SMYS ProjectDefined1 2
Primary
HoopStress(designpressure) (DF)SMYS2 B31.8,805.2.3 3LongitudinalStress(designpressure,gravityload) 0.75SMYS B31.8,833.6 4LongitudinalStress(designpressure,gravityload,andotheroccasionalloads) 0.75SMYS B31.8,833.6 5
Secondary
ExpansionStress(temperaturedifferential) 0.75*TSMYSB31.8,833.6,
841.1.8,841.1.81 6
CombinedEffectiveStress(sustainedloads,i.e.,pressure,gravity,andtemperaturedifferential) 0.90SMYS ProjectDefined 8
EffectiveStress(sustainedloads,i.e.,pressure,gravity,temperaturedifferential,andlossofsupport) 0.90SMYS ProjectDefined 91Sincetestpressure isstipulatedas1.25timesthedesignoperatingpressure,theminimumtestpressureforthemajorityofthelinewouldcorrelateto0.90SMYS(1.250.72);thereforetheprojectdefinedvalueof0.95SMYSwaschosentoaccountforhydrostaticheadeffectsduetoelevationchangesalongthepipelineroute.
2DF=0.50,0.72
4.2 PipelineStressAnalysisAcompletestressanalysiswillbeperformedtoassurethatthedesignwillperforminaccordancewithspecifications,codes,andstandardstocovereachPipelineLoadCombination(Table3.3)andAllowableStressesforAbovegroundPipelines(Table4.1).
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5.0 PipelineSupportsNewpipesupportswillbeevaluated inaccordancewiththeLoadandResistanceFactorDesign(LRFD)methodpresentedinAISCSteelConstructionManual,13thEdition.Thestressesinthesupportswillbeevaluated using the interaction formulae presented in Chapter H of AISC 36005 within the SteelConstructionManual.
5.1 SupportDescriptionsTypically,threevarietiesofpipesupportsareusedinabovegroundarcticpipelines:sliding,guided,andanchorsupports.Sliding supports allow lateral and longitudinalmovement of the pipeline (to relieve stresses due tothermalexpansion(andcontraction).Slidingsupportsaremostoftenusednearbends.Forthisproject,slidingsupportswillbedesignedasasingleVSM (typicallypipe)withaweldedcapplate, towhich isboltedanHSM(typicallyawideflangedbeam).Aslidebearingplate(PTFE,e.g.,Teflon)isweldedviaacarbonsteelmountingplatetothetopsurfaceoftheHSM.Thepipelinesaddle isfixedtothepipelineandfreetoslideonthebearingplate(polishedstainlesssteelstripsweldedtothebottomofthesaddlefurtherreducefrictiononthebearingplate).SeeFigure5.1Guidedpipesupportsallow longitudinalmovementofthepipeline,butrestrict lateralmovement,andareusedinstraightrunsofthealignment.ConstructedofasingleVSMandHSMwithcapplatesimilarto the sliding support, the guided saddle is attached to the beam and the pipeline rests on a liner(UHMWPE,e.g.,Tivar)withinthesaddle.SeeFigure5.2.Anchorsupportshavetheprimaryfunctionofresistingthe longitudinalmovementofthepipeline,butarealsodesigned to resist rotationsand lateralmovement.Due to the fixedboundary condition theanchorsupportprovidesforthepipeline,anchorsrequiremorestrength;assuch,theyaredesignedtobe constructed of two VSM and cap plates connected to a single HSM. Typicalmoment resistancerequired necessitates anHSM able to resist torsion. Sincewideflanged beams do not economicallyresist torsion and rectangular tube shapes are not able to meet low temperature Charpy impactrequirements,abuiltupbeamusuallyconsistingofawideflangedbeamwithplatesteelboxingintheflanges,isusedinstead.SeeFigure5.3.
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Figure5.1 TypicalSlidingSupport Figure5.2 TypicalGuidedSupport
Figure5.3 TypicalAnchorSupport
5.2 SupportDesignVSMwillbe installedvertically inoversized,drilledholesandbackfilledwithdensesandwaterslurry.TheVSMdesignwillincludeevaluationofthethermalregimeandgeotechnicalconditions.The capacity of a VSM to support longterm loads in adfreeze is temperature and soil propertydependent. A lower temperature below freezing corresponds to higher adfreeze strength. A designtemperatureprofiletofullembedmentwillbebasedontypicalactivelayerdepthmeasurements,VSMskinmeltallowance,andinsitusoiltemperature.ThedesignsoilstrengthvaluesappliedtoresistVSMloads, both long term and short term, will be for icerich soils and will be dependent on the soiltemperatureprofile.TheVSMdesign is limitedby the strengthof theVSM steel, the strengthof the steel/sandadfreezebond,andthestrengthoftheinsitusoils.DesignadfreezecapacityforVSMiscalculatedassumingthebond strength profile presented in Table 5.1. Minimum embedment will be 15 feet. No adfreezestrength is allowed for embedment inmassive ice. Embedmentwill be increased 1 foot per foot ofmassiveiceencountered,ificeinexcessof3feetisencountered(thebasedesignprovidesforupto3feetofmassiveice).
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Table5.1 AllowableAdfreezeStressesforVSMDepth (Feet)
Design Adfreeze From To
Land Surface 3 40 psi jacking (upward)
3 9 12.5 psi
9 14 18.75 psi
14 25 25 psi
25 Bottom of VSM 31.25 psi
5.3 StructuralAnalysisofPipelineSupportsThe typical descriptions of new pipeline supports are assumed based on previous experience. Newpipelinesupportswillbecategorizedintogroupsbasedonsimilarstickupheights(fromtundratoTOS),depth of active layer, support type, andmagnitude of pipeline operating forces. Amodel of eachsupportgroupwillbe createdusingRISAStructuralAnalysis software.A structuralanalysisofeachmodelwillverifycompliancewithAISC36005coderequirements.The structuralconnections foreach typeof supportwillbedesigned toadequately resist theappliedloadings,alsoinaccordancewithAISC36005.VSMfoundationdesignistypicallybasedonstrengthaswellasdeflectionrequirements.InadditiontothestrengthrequirementsofAISC36005,theVSMwillbedesignedtoresist lateraldeflectionsduetoenvironmentalforces,and longtermcreepunderoperational loadingassociatedwiththerelaxationofthe soil VSM interface. As detailed geotechnical investigation of each VSM location is not practical,standardassumptionswillbeusedtodeterminethedesigndeflectionduetoeachoftheseeffects;assuch,thedeflectionscalculatedwillnotbefieldverifiable.5.3.1 SupportLoadingPipelinesupportswillbeanalyzedwithconsiderationto loadingperASCE710andthissection.Sevenloadcombinationsarelistedinsection2.3.2ofASCE710,forusewiththeLRFDmethod.Severalloadtypesdonotapplytopipelinesupports,suchasfloodload,lateralearthpressureload,rooflive load,andrain load.Gravity loadsfromthepipelinecontentsaretreatedasdead loads;therefore,live loads also do not apply. Fluid load is considered part of dead load and therefore is includedwhereverdeadloadisincludedperASCE710.Loading fromthermaleffectson thepipeline isnotspecificallyaddressed inASCE710.LoadcaseTreferstoselfstrainingloads,whichareequivalenttothermaleffectsonstructuralmembers,butdonotpertain to external loads applied to the structure. Section 2.3.5 of ASCE 710 elaborates on theapplicationofselfstraining loads,effectively leavingtheapplicationofthermal loadstotheengineersdiscretion.Forthepurposeofpipelinesupports,thermal loadingfromthepipelinewillbeappliedasadead loadwith the corresponding load factors. This assumption is based on the high probability ofthermaleffectsandthesustainednatureofthermalloadingduringpipelineoperation.
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Removing loadsthatdonotapplyandotherassumptions leavesthefollowing loadcombinationsfromASCE710:
1. 1.4D2. 1.2D+0.5S3. 1.2D+1.6S+0.5W4. 1.2D+1.0W+0.5S5. 1.2D+1.0E+0.2S6. 0.9D+1.0W7. 0.9D+1.0E
Loadcombinations6and7willnotbeincludedintheanalysisastheyareintendedtoconsiderwindandearthquakeloadonastructurewithreducedweight.Toaccomplishthisinamoreconservativemanner,load combinations 4 and 5 will bemodified to have a dead load corresponding to that of emptypipelines.HydrostatictestloadingisnotspecificallyaddressedinASCE710;however,sinceitisatransientevent,itisassumedthatequation4isthemostappropriateloadcombination.Inthiscase,deadloadisbasedonwaterwitha specificgravityof1andwillnot include thermal loading from thepipeline.Thermaleffects are considerednegligible since it is assumed thehydrostatic testmediumwillbe at ambienttemperature.Wind loading is reduced since hydrostatic tests are not conducted during high windevents.Itisalsoassumedthehydrostatictestwilloccurduringthesummerseason,andthereforesnowloading,S,doesnotapply.Basedontheseassumptions,theloadcombinationforthehydrostatictestis:
4a. 1.2D+1.0((1/9)W)Operating,thermal,test,earthquake,anddeadloadswillbedeterminedfromtheresultsofthepipelinestressanalysis.SnowloadingwillbedeterminedaspreviouslydescribedinSection3.2.5.Windloadingwillbedeterminedbytheformula
Where: qZ=Velocitypressureevaluatedattheelevationofthepipe(Equation29.3.1ofASCE710)
G=GusteffectfactorCf=ForceCoefficientAf=Projectedareanormaltothewind
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6.0 CivilDesign6.1 RoadCrossingsThecurrentroutehasthreeroadcrossings.Typically,casingsareaminimumoftwostandarddiametersgreaterthanthepipeline.Casingisolatorswillbe installedaroundthe insulatedpipeandwillservetoelectricallyisolatethepipelinefromthecasing.Wallthicknessofcasingswillbebasedoncommerciallyavailablematerialsandfitforpurpose.Spacing between new casings and existing casings will be based on the anticipated compactionequipmentandcompactiontestingmethods.Typically,newcasingsarespaced18 inchesfromoutsideofnewcasingtooutsideofexistingcasing;however,theexactspacingwillbeevaluatedonacasebycasebasis.Invertelevationsfornewcasingswillbe locatedtoachievetheminimumcoverdeterminedbydesign,typically12inches.Ifnecessary,theexistingroadsurfacewillberaisedtoprovidetheminimumcover,usingpitrungravelonsecondaryroadsorcrushedrockfinishingcourseonhightrafficroads.Materialrequirements forgraveland finishingcoursewillbespecifiedonthedrawingsandwillbedeterminedbasedonwhat is available at thepermittedpit source andprior experiencewith thematerials. Theminimumcoverateachroadcrossingwillbeevaluatedspecificallywhengravelfillisrequired,basedonthetypeofroadandtheexpectedtrafficanddesignvehicle.MinimumcoverandwallthicknessrequirementsforcasingsatroadcrossingswillbeevaluatedperAPIRP1102,withloadingfromadesignvehicledeterminedbyinformationprovidedbythePBUOperator.Typically, the design vehicle is themost recent and heaviest drill rig in use at the time of design.Currently,Doyon14andParkerDrilling272Land273Ldrillrigsarethecontrollingdesignvehicles.
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AppendixA Codes,StandardsandSpecificationsPipeline and pipeline support design will be performed in accordance with the codes, standards,specifications,andrecommendedpracticeslistedbelow.
49CFR192,TransportationofNaturalandOtherGasbyPipeline:MinimumSafetyStandards AlaskaGeneralSafetyCode(AGSC),OccupationalSafetyandHealthStandards ASCEStandard7,MinimumDesignLoadsforBuildingandOtherStructures AmericanInstituteofSteelConstruction(AISC),AllowableStressDesign(ASD)/Loadand
ResistanceFactorDesign(LRFD),SteelConstructionManual,13thEdition AmericanPetroleumInstitute(API)5L,SpecificationforLinePipe,44thEdition,2007 API6D,SpecificationsforPipeLineValves API1102,SteelPipelinesCrossingRailroadsandHighways,6thEdition API1104,WeldingPipelineandRelatedFacilities,20thEdition API1163,QualificationSystemsStandards ASMEB16.5,PipeFlangesandFlangedFittingsNPSthroughNPS24 ASME31.8,GasTransmissionandDistributionPipingSystem ASTMA572/A572M07StandardSpecificationforHighStrengthLowAlloyColumbium
VanadiumStructuralSteel ASMEBPVSectionVIIIBoilerandPressureVesselCodeSectionVIIIPressureVessels IBC,InternationalBuildingCode,asadoptedasAlaskaBuildingCode IMC2006,InternationalMechanicalCode,asadoptedasAlaskaBuildingCode NFPA70NationalElectricalCode
ThefollowingtableisapplicableforthedesignandengineeringofthepipelinetiedintoaBPXAsystem.2009PROJECTDIRECTORATEPROJECTSTECHNICALSPECIFICATIONS
DOCUMENTINDEXWITHREVISIONNUMBER/DATEASOFOCTOBER27,2009
Number Title RevisionDateofLatestRevision
GENERALCRTGA00004 NationalCodesandStandardsDesign 1 8/23/2004CRTGA00005 PEStamping 0 1/31/2003SPCGA00003 SpecificationStyleGuide 0 7/16/2002SPCGA00004 BPXAEngineeringDrawingandDocumentRequirements 4 5/00/2007
SPCPRNSS00007001 BPXAAsBuiltDrawingProcedures 0 2/15/2006ARCTIC
CRTAK0402 GeneralSiteConditionsDesign 0 9/14/2007
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2009PROJECTDIRECTORATEPROJECTSTECHNICALSPECIFICATIONSDOCUMENTINDEXWITHREVISIONNUMBER/DATEASOFOCTOBER27,2009
Number Title RevisionDateofLatestRevision
HSECRTAK7602 Health,Safety&EnvironmentalProtectionDesign 0 9/2/2008
CIVIL/STRUCTURALCRTAK0420 CivilEngineering 0 6/2/2008CRTAR00001 ArchitecturalDesign 1 8/23/2004CRTSS00001 StructuralDesign 2 10/5/2006SPCAK04902 MaterialToughnessRequirementsforStructuralSteel 0 6/2/2008SPCCE00001 CivilMaterialandConstruction 0 3/25/2002SPCSS00001 StructuralSteelWelding 1 1/15/2002SPCSS00003 VSMandPileInstallation 1 10/27/2010SPCSS00008 BeamandPileCapFabrication 0 12/20/2001SPCSS00013 StructuralSteelFabrication,DetailingandErection 1 7/23/2002SPCSS00014 StructuralLowTemperatureSteelPlatesSpecificationfor
PipelineSupports1 1/15/2002
SPCSS00015 ModulePileMaterialsandFabrication 1 1/15/2002SPCSS00016 StructuralPipeforSupportPiling 1 1/15/2002
CORROSIONANDCOATINGSPCMA00002 ExternalCoatingsforModeratelyCorrosiveService 0 9/22/2004SPCMA00004 External Pipe Coating Application of Fusion Bonded
Epoxy0 2/20/2003
GP0670 CorrosionMonitoring ETP 8/29/2005MECHANICALEQUIPMENT
CRTAK4335 ValvesforPipelines 0 4/12/2007CRTAK6201 Valves 0 4/12/2007CRTAK6202 ValveSpecificationandProcurement 0 4/12/2007
SPCAK62012API608MetalBallValves(NPS1/4toNPS20uptoClass800)
0 8/10/2007
SPCAK62013 API6DBallValves 0 5/9/2007SPCAK62015 API602Gate,Globe,andCheckValvesuptoNPS2 0 5/9/2007
SPCAK62016Ball, Plug, and Other QuarterTurn Valves CommonMaterial
0 5/9/2007
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2009PROJECTDIRECTORATEPROJECTSTECHNICALSPECIFICATIONSDOCUMENTINDEXWITHREVISIONNUMBER/DATEASOFOCTOBER27,2009
Number Title RevisionDateofLatestRevision
SPCAK62017 RisingStem(GateandGlobe)ValvesCommonMaterial 0 5/9/2007SPCPP00081 ValveDataSheetIndex 6 4/3/2006
MECHANICALPIPINGCRTAK4300 PipelineSystems(OverviewDocument) 0 5/9/2007
CRTAK4301Criteria for Onshore Pipeline Design and ProjectExecution
0 4/12/2007
CRTAK4304 QA&QCforPipelineProjects 0 6/2/2008CRTAK4307 SelectionoftheDesignBasisforPipelines 0 4/12/2007CRTAK4308 SelectionandUseofPipelineCodesandStandards 1 9/28/2007CRTAK4309 HydraulicDesignofPipelineSystems 0 5/9/2007CRTAK4317 PipelineRiskManagement 0 8/10/2007CRTAK4320 OnshorePipelineSystemDesign 2 9/28/2007CRTAK4322 AbovegroundPipelineFacilities 1 9/28/2007CRTAK4328 PipelineCrossings 0 12/5/2007CRTAK4331 LinePipeMaterialSelectionandProcurement 0 12/20/2006CRTAK4332 PipeHandlingandLogisticsforPipelines 0 4/12/2007CRTAK4340 OnshorePipelineConstruction 0 5/9/2007CRTAK4346 CriteriaforPipelineHydrotestandPrecommissioning 0 4/03/2009CRTAK4347 PipelineCommissioningandHandovertoOperations 0 6/2/2008CRTAK4392 WindinducedVibration(WIV)AssessmentandDesign 0 12/17/2007
CRTAK4394Assessment of Pipe Spans Deformed by Extreme SnowLoads
19/27/2007
SPCAK42201 LowyieldCarbonSteelPipe,FlangesandFittings 0 11/18/2007SPCAK42203 GasketProcurement 0 8/10/2007SPCAK42204 StudBoltingProcurement 0 8/10/2007SPCAK43311 Manufacture of Longitudinal or Helical Seam SAW
LinepipeinGradesuptoX801 5/9/2007
SPCAK43312 ManufactureofHFIorERWLinepipeinGradesuptoX70 1 5/9/2007SPCAK43313 SeamlessLinePipeinGradesuptoX80 2 9/14/2007SPCAK43317 Manufacture of Carbon Steel Induction Bends for
PipelinestoISO15590inGradesuptoX800 8/10/2007
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2009PROJECTDIRECTORATEPROJECTSTECHNICALSPECIFICATIONSDOCUMENTINDEXWITHREVISIONNUMBER/DATEASOFOCTOBER27,2009
Number Title RevisionDateofLatestRevision
SPCAK43317A InductionBends(ASMEB16.49) 0 5/9/2007SPCAK43401 AbovegradeArcticPipelineConstruction 0 5/9/2007SPCAK43411 PipelineSupportSaddles 0 9/28/2007SPCAK43412 PipelineSupports 0 9/28/2007SPCAK43413 TeflonSlidePlates 0 9/28/2007SPCAK43414 PipelineSupportAnchors 0 9/28/2007SPCAK43901 PipelineMaterialsandLineClasses 0 9/11/2007SPCAK43927 HighyieldCarbonSteelFlangesandForgedFittings 0 9/28/2007SPCAK43928 HighyieldCarbonSteelFittings 0 9/28/2007SPCAK52102 ShopAppliedInsulation 1 9/27/2007SPCAK52103 PreformedInsulation 0 8/10/2007SPCAK52104 FoaminPlaceInsulation 1 9/18/2007
PROCESSSAFETYCRTAK4802 HazardandOperability(HAZOP)Study 1 4/15/2009GP4801 HSSEReviewofProjects(PHSSER) 1 6/8/2009GP4804 InherentlySaferDesign(ISD) 1 5/5/2009GP4805 HazardIdentification(HAZID)Study 1 2/13/2009CRTAK4354 DepressurizationandRepressurizationofPipeline
Systems0 6/2/2008
WELDINGANDFABRICATIONCRTAK1801 WeldedFabricationandConstruction 0 6/2/2008CRTAK1802 StorageandControlofWeldingConsumables 0 6/2/2008CRTAK4333 WeldingofPipelines 0 9/14/2007SPCAK18012 InServiceWelding 0 6/2/2008SPCAK42103 BranchConnectionWelding 0 5/9/2007SPCAK42104 HotTapping 0 12/5/2007