MSSSP-126-2007SteelIn-LineSpring-AssistedCenterGuidedCheckValvesStandardPracticeDevelopedandApprovedbytheManufacturersStandardizationSocietyoftheValveandFittingsIndustry,Inc.127ParkStreet,NEVienna,Virginia22180Phone:(703)281-6613Fax:(703)281-6671e-mail:info@mss-hq.org`,,```,,,,````-`-`,,`,,`,`,,`---MSSSTANDARDPRACTICESP-126iThisMSSStandardPracticewasdevelopedundertheconsensensusoftheMSSTechnicalCommittee114andtheMSSCoordinatingCommittee.ThecontentofthisStandardPracticeistheresultoftheeffortsofcompetentandconcernedvolunteerstoprovideaneffective,clear,andnon-exclusivespecificationthatwillbenefittheindustryasawhole.ThisMSSStandardPracticeisintendedasabasisforcommonpracticebythemanufacturer,theuser,andthegeneralpublic.TheexistenceofanMSSStandardPracticedoesnotinitselfprecludethemanufacture,sale,oruseofproductsnotconformingtotheStandardPractice.Mandatoryconformanceisestablishedonlybyreferenceinacode,specification,salescontract,orpubliclaw,asapplicable.UnlessotherwisespecificallynotedinthisMSSSP,anystandardreferredtohereinisidentifiedbythedateofissuethatwasapplicabletothereferencedstandard(s)atthedateofissueofthisMSSSP.(SeeAnnexB.)InthisStandardPracticeallnotes,annexes,tables,andfiguresareconstruedtobeessentialtotheunderstandingofthemessageofthestandard,andareconsideredpartofthetextunlessnotedas“supplemental”.Allappendicesappearinginthisdocumentareconstruedas“supplemental”.“Supplemental”informationdoesnotincludemandatoryrequirements.Themetric(SI)unitsandU.S.customaryunitsinthisStandardPracticeareregardedseparatelyasthestandard;eachshouldbeusedindependentlyoftheother.CombiningorconvertingvaluesbetweenthetwosystemsmayresultinnonconformancewiththisStandardPractice.Thisdocumenthasbeensubstantivelyrevisedandrearrangedfromthepreviousedition.Itissuggestedthatiftheuserisinterestedinknowingwhatchangeshavebeenmade,thatadirectpagebypagecomparisonshouldbemadeofthisdocument.AnypartofthisStandardmaybequoted.Creditlinesshouldread“ExtractedfromMSSSP-126,2007,withpermissionofthepublisher,theManufacturersStandardizationSociety.”ReproductionprohibitedundercopyrightconventionunlesswrittenpermissionisgrantedbytheManufacturersStandardizationSocietyoftheValveandFittingsIndustry,Inc.OriginallyApprovedDecember,1999Copyright©2000byManufacturersStandardizationSocietyoftheValveandFittingsIndustry,Inc.PrintedinU.S.A.CopyrightMSSProvidedbyIHSunderlicensewithMSSNotforResaleNoreproductionornetworkingpermittedwithoutlicensefromIHS--`,,```,,,,````-`-`,,`,,`,`,,`---MSSSTANDARDPRACTICESP-126iiFOREWORDWorkonthisstandardbeganabout1990tofulfilltheindustry’sneedforastandardcoveringthisuniqueclassofcheckvalves.Theintentofthestandardistoincludein-line(nobonnet)checkvalveswhoseclosurememberisassistedbyaspringinshuttingbeforetheflowingmediacandevelopsignificantreversevelocity.Becausethiseffectreducesthepossibilityofwaterhammer,thesetypesofvalveshavealsobeentermed“silentcheckvalves”.ThisStandardPracticecallsthevalves“centerguided”meaningthattheclosurememberisguidedintothecenteroftheflowforcingtheflowingmediatopassaroundit.Additionally,theclosurememberremainsperpendiculartotheflowingmediathroughoutitsentiretravel.ThisStandardPracticewasfirstpublishedin2000.CopyrightMSSProvidedbyIHSunderlicensewithMSSNotforResaleNoreproductionornetworkingpermittedwithoutlicensefromIHS--`,,```,,,,````-`-`,,`,,`,`,,`---MSSSTANDARDPRACTICESP-126iiiTABLEOFCONTENTSSECTIONPAGE1SCOPE..…………...…………………………………………………………………………………..……...12STANDARDUNITS………………………………………………………………………………..……......13VALVESTYLESANDCLASSES………………..………………………………………………..……….14ENDCONNECTIONS……................................….......................................................................…………..25MATERIALS………………..……….................................................................................................………26DESIGNREQUIREMENTS...……….................................................................................................………37DIMENSIONSANDTOLERANCES……......................................................................................………...38WELDREPAIR……….……………………………………………………………………………………..79TESTING……….....….………………………………………………………………………………………710MARKING...………….……………………………………………………………………………..……….811PAINTING....………….……………………………………………………………………………………..8TABLE1Face-to-FaceDimensionsforFlangedClass150,300,and600GlobeStyleCheckValves(Inch)…..……………....41MFace-to-FaceDimensionsforFlangedClass150,300,and600GlobeStyleCheckValves(mm)……...…….……....42Face-to-FaceDimensionsforFlangedClass900,1500,and2500GlobeStyleCheckValves(Inch)................….…...52MFace-to-FaceDimensionsforFlangedClass900,1500,and2500GlobeStyleCheckValves(mm)……...…..….…...53Face-to-FaceDimensionsForClass150,300,600,900,and1500WaferStyleCheckValves(Inch)…...…………...63MFace-to-FaceDimensionsForClass150,300,600,900,and1500WaferStyleCheckValves(mm).……...………...64Face-to-FaceDimensionsforClass150,300,and600FlangeInsertStyleChec