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MSSSP-44-2006MSSSteelPipelineFlangesStandardPracticeDevelopedandApprovedbytheManufacturersStandardizationSocietyoftheValveandFittingsIndustry,Inc.127ParkStreet,NEVienna,Virginia22180(703)281-6613Email:info@mss-hq.org(s)atthedateofissueofthisMSSSP.(SeeAnnexD.)InthisStandardPracticeallnotes,annexes,tables,andfiguresareconstruedtobeessentialtotheunderstandingofthemessageofthestandard,andareconsideredpartofthetextunlessnotedassupplemental.Allappendicesappearinginthisdocumentareconstruedassupplemental.Supplementalinformationdoesnotincludemandatoryrequirements.Thisdocumenthasbeensubstantiallyrevisedfromtheprevious1996edition.Itissuggestedthatiftheuserisinterestedinknowingwhatchangeshavebeenmade,thatdirectpagebypagecomparisonshouldbemadeofthisdocument.Non-toleranceddimensionsinthisStandardPracticearenominal,andunlessotherwisespecified,shallbeconsidered“forreferenceonly”.TheMetric(SI)unitsandU.S.CustomaryunitsinthisSPareregardedseparatelyasthestandard;eachshouldbeusedindependentlyoftheother.CombiningorconvertingvaluesbetweenthetwosystemsmayresultinnonconformancewiththisStandardPractice.Anypartofthisstandardmaybequoted.Creditlinesshouldread‘ExtractedfromMSSSP-44,2006,withpermissionofthepublisher,theManufacturersStandardizationSociety.’ReproductionprohibitedundercopyrightconventionunlesswrittenpermissionisgrantedbytheManufacturersStandardizationSocietyoftheValveandFittingsIndustry,Inc.OriginallyApprovedJuly,1952Copyright©,1985byManufacturersStandardizationSocietyoftheValveandFittingsIndustry,Inc.PrintedinU.S.A.MSSSTANDARDPRACTICESP-44iiFOREWORDTheManufacturersStandardizationSocietyoriginallydevelopedthisStandardPracticeinresponsetothecontinuedrequestsforsteelpipeflangesforpipelineuse,particularlyinsizeslargerthanthosecoveredbyANSIStandardB16.5onSteelPipeFlangesandFlangedFittings.Thelinepipeisuniquelycharacterizedbyhigh-strength,coldworked,thin-wallofthecarbonsteelgrade,whichnecessitatesspecialconsiderationsfortheweldingendoftheflanges.ThesizeandpressureclassrangewasoriginallyNPS26throughNPS36inpressureclassescustomarilydesignatedinANSIStandardB16.5as300,400,600,and900lb.The1970editiondeletedtheslip-onflangesforlackofdemand,andaddeda150lb.classandcoverageforsizesNPS12throughNPS24.Additionalcoveragewasalsonecessitatedbytheadventoftheuseoflinepipeofgradeshavingminimumspecifiedyieldstrengthhigherthanthe52,000psimaximumcontemplatedatthetimeofinitialdevelopment,andthereforestillthinnerwalls.Insomeinstances,thisadventwidenedthedifferentialbetweenthetensilepropertiesoftheflangesteelversusthatofthematingpipesteel.This,inturnnecessitatedgreaterflexibilityintheselectionofhubdimensions,sothatvariouscombinationsofmaterial-strengthandflange-dimensionscouldbeutilizedtosupplytheflanges.Section5onFlangeDesignwasintroducedatthispoint,andisoneofthekeyfeaturesofthisstandard.The1972editionincludedthecoverageofblindflangesinallpressureclassesandclarificationoftextrequirementsforbetterunderstandingandusageunderthemorediverseconditions.The1975editionexpandedthesizerangeabovesizeNPS36.ThedrillingtemplatesfortheClass150flangesoftheNPS38andlargersizescontinuedthepreviousphilosophyofadoptingthedrillingtemplateoftheClass125ofANSIStandardB16.1.However,thedrillingtemplatesoftheClass300flangesoftheNPS38andlargersizesdidnotcontinuetheadoptionoftheClass250ofANSIStandardB16.1drillingtemplates,nordidtheNPS38andlargersizesofClasses400,600,and900continuetheextrapolationofANSIB16.5drillingtemplates;instead,thesedrillingtemplateswerenecessarilydesignedmorecompactlybecauseoftheincreasedloads.WhiletheseflangesaredesignatedbythecustomaryANSIStandardClass150,300,400,600,and900,theiruseisalmostentirelyconfinedtocrosscountrytransmissionpipelinesatatmospherictemperatures.TheflangeshavebeendesignedprimarilyforuseattheircoldratingswhichconformtotheANSIStandardB16.5ratingsof1000F,andareintendedprimarilyforattachmenttorelativelythin-wall,high-strengthcoldworkedpipe,and,high-strengthbutt-weldingfittingsinpipelineserviceattemperaturesof4500Fandlower.However,flangesforgedofothermaterialsarecapableofpressuretemperatureratingsasspecifiedinSection2.1.The1980editionwascreatedtobringthedocumentintoclosereditorialalignmentwithANSIB16.5.However,outofrecognitionofthesuccessfulexperie