Nominal Pipe Size - Wikipedia

Nominal Pipe Size (NPS) is a North American set of standard sizes for pipes used for high or low pressures and temperatures. "Nominal" refers to pipe in ... NominalPipeSize FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch ThisarticleisabouttheU.S.standardforpipesizes,abbreviatedNPS.FortheU.S.standardforthestraightthreadformonpipe(alsoabbreviatedNPS),seeNationalPipeThread. NominalPipeSize(NPS)isaNorthAmericansetofstandardsizesforpipesusedforhighorlowpressuresandtemperatures.[1]"Nominal"referstopipeinnon-specifictermsandidentifiesthediameteroftheholewithanon-dimensionalnumber(forexample–2-inchnominalsteelpipe"consistsofmanyvarietiesofsteelpipewiththeonlycriterionbeinga2.375-inch(60.3 mm)outsidediameter).Specificpipeisidentifiedbypipediameterandanothernon-dimensionalnumberforwallthicknessreferredtoastheSchedule(Sched.orSch.,forexample–"2-inchdiameterpipe,Schedule40").NPSisoftenincorrectlycalledNationalPipeSize,duetoconfusionwiththeAmericanstandardforpipethreads,"nationalpipestraight",whichalsoabbreviatesas"NPS".TheEuropeanandinternationaldesignationequivalenttoNPSisDN(diamètrenominal/nominaldiameter/Nennweite),inwhichsizesaremeasuredinmillimetres,seeISO6708.[2]ThetermNB(nominalbore)isalsofrequentlyusedinterchangeablywithDN. InMarch1927theAmericanStandardsAssociationauthorizedacommitteetostandardizethedimensionsofwroughtsteelandwroughtironpipeandtubing.Atthattimeonlyasmallselectionofwallthicknesseswereinuse:standardweight(STD),extra-strong(XS),anddoubleextra-strong(XXS),basedontheironpipesize(IPS)systemoftheday.Howeverthesethreesizesdidnotfitallapplications.Also,in1939,itwashopedthatthedesignationsofSTD,XS,andXXSwouldbephasedoutbyschedulenumbers,howeverthoseoriginaltermsarestillincommonusetoday(althoughsometimesreferredtoasstandard,extra-heavy(XH),anddoubleextra-heavy(XXH),respectively).Sincetheoriginalscheduleswerecreated,therehavebeenmanyrevisionsandadditionstothetablesofpipesizesbasedonindustryuseandonstandardsfromAPI,ASTM,andothers.[3] Stainlesssteelpipes,whichwerecomingintomorecommonuseinthemid20thcentury,permittedtheuseofthinnerpipewallswithmuchlessriskoffailureduetocorrosion.By1949thinnerschedules5Sand10S,whichwerebasedonthepressurerequirementsmodifiedtothenearestBWGnumber,hadbeencreated,andother"S"sizesfollowedlater.Duetotheirthinwalls,thesmaller"S"sizescannotbethreadedtogetheraccordingtoASMEcode,butmustbefusionwelded.[4] Contents 1Application 2Blockageorballtest 3NPStablesforselectedsizes 3.1NPS1⁄8toNPS3+1⁄2 3.2NPS4toNPS9 3.3NPS10toNPS24 3.4NPS26toNPS36 3.5Additionalsizes(NPS) 4Seealso 5Notes 6References 7Bibliography 8Externallinks Application[edit] BasedontheNPSandscheduleofapipe,[5]thepipeoutsidediameter(OD)andwallthicknesscanbeobtainedfromreferencetablessuchasthosebelow,whicharebasedonASMEstandardsB36.10MandB36.19M.Forexample,NPS14Sch40hasanODof14inches(360 mm)andawallthicknessof0.437inches(11.1 mm).However,theNPSandODvaluesarenotalwaysequal,whichcancreateconfusion. ForNPS1⁄8to12,theNPSandODvaluesaredifferent.Forexample,theODofanNPS12pipeisactually12.75inches(324 mm).TofindtheactualODforeachNPSvalue,refertothetablesbelow.(Notethatfortubing,thesizeindicatesactualdimensions,notnominal.) ForNPS14andup,theNPSandODvaluesareequal.Inotherwords,anNPS14pipeisactually14inches(360 mm)OD. ThereasonforthediscrepancyforNPS1⁄8to12 inchesisthattheseNPSvalueswereoriginallysettogivethesameinsidediameter(ID)basedonwallthicknessesstandardatthetime.However,asthesetofavailablewallthicknessesevolved,theIDchangedandNPSbecameonlyindirectlyrelatedtoIDandOD. ForagivenNPS,theODstaysfixedandthewallthicknessincreaseswithschedule.Foragivenschedule,theODincreaseswithNPSwhilethewallthicknessstaysconstantorincreases.UsingequationsandrulesinASMEB31.3ProcessPiping,itcanbeshownthatpressureratingdecreaseswithincreasingNPSandconstantschedule.[a] Somespecificationsusepipeschedulescalledstandardwall(STD),extrastrong(XS),anddoubleextrastrong(XXS),althoughtheseactuallybelongtoanoldersystemcalledironpipesize(IPS).TheIPSnumberisthesameastheNPSnumber.STDisidenticaltoSCH40S,and40Sisidenticalto40forNPS1⁄8toNPS10,inclusive.XSisidenticaltoSCH80S,and80Sisidenticalto80forNPS1⁄8toNPS8,inclusive.XXSwallisthickerthanschedule160fromNPS1⁄8 intoNPS6 ininclusive,andschedule160isthickerthanXXSwallforNPS8 inandlarger. Blockageorballtest[edit] Whenapipeisweldedorbentthemostcommonmethodtoinspectblockages,misalignment,ovality,andweldbeaddimensionalconformityistopassaroundballthroughthepipecoilorcircuit.Iftheinnerpipedimensionistobemeasuredthentheweldbeadshouldbesubtracted,ifweldingisapplicable.Typically,theclearancetolerancefortheballmustnotexceed1millimetre(0.039 in).Allowableovalityofanypipeismeasuredontheinsidedimensionofthepipe,normally5%to10%ovalitycanbeaccepted.Ifnoothertestisconductedtoverifyovality,orblockages,thistestmustbeseenasastandardrequirement.Aflowtestcannotbeusedinlieuofablockageorballtest.Seepipedimensionaltable,SpecificationASMEB36.10MorB36.19Mforpipedimensionsperschedule. Stainlesssteelpipeismostoftenavailableinstandardweightsizes(notedbytheSdesignation;forexample,NPSSch10S).Howeverstainlesssteelpipecanalsobeavailableinotherschedules. Bothpolyvinylchloridepipe(PVC)andchlorinatedpolyvinylchloridepipe(CPVC)aremadeinNPSsizes. NPStablesforselectedsizes[edit] NPS1⁄8toNPS3+1⁄2[edit] DNdoesnotexactlycorrespondtoasizeinmillimeters,becauseISO6708definesitasbeingadimensionlessspecificationonlyindirectlyrelatedtoadiameter.TheISO6708sizesprovideametricnameforexistinginchsizes,resultingina1:1correlationbetweenNPSandDNsizes.ISO6708doesnotincludevaluesfor"DN6"or"DN8",howeverASMEB36.10Mlistthe"DN6"and"DN8".Also,theEuropeanStandardEN12516-1(Industrialvalves-Shelldesignstrength-Part1:Tabulationmethodforsteelvalveshells)specifiesthedimensions"DN6"and"DN8",respectivelytheirequivalentsNPS1⁄8"andNPS1⁄4". NPS[7] DN (dimensionless) OD[in(mm)] Wallthickness[in(mm)] Sch.5s Sch.10s/20 Sch.30 Sch.40s/40/STD Sch.80s/80/XS Sch.120 Sch.160 XXS 1⁄8 6 0.405(10.29)[8] 0.035(0.889) 0.049(1.245) 0.057(1.448) 0.068(1.727) 0.095(2.413) — — — 1⁄4 8 0.540(13.72) 0.049(1.245) 0.065(1.651) 0.073(1.854) 0.088(2.235) 0.119(3.023) — — — 3⁄8 10 0.675(17.15) 0.049(1.245) 0.065(1.651) 0.073(1.854) 0.091(2.311) 0.126(3.200) — — — 1⁄2 15 0.840(21.34) 0.065(1.651) 0.083(2.108) 0.095(2.413) 0.109(2.769) 0.147(3.734) — 0.188(4.775) 0.294(7.468) 3⁄4 20 1.050(26.67) 0.065(1.651) 0.083(2.108) 0.095(2.413) 0.113(2.870) 0.154(3.912) — 0.219(5.563) 0.308(7.823) 1 25 1.315(33.40) 0.065(1.651) 0.109(2.769) 0.114(2.896) 0.133(3.378) 0.179(4.547) — 0.250(6.350) 0.358(9.093) 1+1⁄4 32 1.660(42.16) 0.065(1.651) 0.109(2.769) 0.117(2.972) 0.140(3.556) 0.191(4.851) — 0.250(6.350) 0.382(9.703) 1+1⁄2 40 1.900(48.26) 0.065(1.651) 0.109(2.769) 0.125(3.175) 0.145(3.683) 0.200(5.080) — 0.281(7.137) 0.400(10.160) 2 50 2.375(60.33) 0.065(1.651) 0.109(2.769) 0.125(3.175) 0.154(3.912) 0.218(5.537) — 0.344(8.738) 0.436(11.074) 2+1⁄2 65 2.875(73.03) 0.083(2.108) 0.120(3.048) 0.188(4.775) 0.203(5.156) 0.276(7.010) 0.300(7.620) 0.375(9.525) 0.552(14.021) 3 80 3.500(88.90) 0.083(2.108) 0.120(3.048) 0.188(4.775) 0.216(5.486) 0.300(7.620) 0.350(8.890) 0.438(11.125) 0.600(15.240) 3+1⁄2 90 4.000(101.60) 0.083(2.108) 0.120(3.048) 0.188(4.775) 0.226(5.740) 0.318(8.077) — — 0.636(16.154) Tolerance:ThetoleranceonpipeODis+1⁄64(0.0156)inch(0.40 mm),−1⁄32(0.0312)inch(0.79 mm).[9] AsperASMEB36.10M-2018Pipewallthicknessareroundedtonearest0.01 mm(0.00039 in),whileconvertingwallthicknessfrominchtomillimetre. NPS4toNPS9[edit] NPS[7] DN[2] OD[in(mm)] Wallthickness[in(mm)] Sch.5s Sch.10s/10 Sch.20 Sch.30 Sch.40s/40/STD Sch.60 Sch.80s/80/XS Sch.100 Sch.120 Sch.140 Sch.160 XXS[7] 4 100 4.500(114.30) 0.083(2.108) 0.120(3.048) — 0.188(4.775) 0.237(6.020) — 0.337(8.560) — 0.437(11.100) — 0.531(13.487) 0.674(17.120) 4+1⁄2 115 5.000(127.00) — — — — 0.247(6.274) — 0.355(9.017) — — — — 0.710(18.034) 5 125 5.563(141.30) 0.109(2.769) 0.134(3.404) — — 0.258(6.553) — 0.375(9.525) — 0.500(12.700) — 0.625(15.875) 0.750(19.050) 6 150 6.625(168.28) 0.109(2.769) 0.134(3.404) — — 0.280(7.112) — 0.432(10.973) — 0.562(14.275) — 0.719(18.263) 0.864(21.946) 7 — 7.625(193.68) — — — — 0.301(7.645) — 0.500(12.700) — — — — 0.875(22.225) 8 200 8.625(219.08) 0.109(2.769) 0.148(3.759) 0.250(6.350) 0.277(7.036) 0.322(8.179) 0.406(10.312) 0.500(12.700) 0.593(15.062) 0.719(18.263) 0.812(20.625) 0.906(23.012) 0.875(22.225) 9 — 9.625(244.48) — — — — 0.342(8.687) — 0.500(12.700) — — — — — NPS10toNPS24[edit] NPS[7] DN[2] OD[in(mm)] Wallthickness[in(mm)] Sch.5s Sch.10 Sch.10s Sch.20 Sch.30 Sch.Std./40S 10 250 10.75(273.05) 0.134(3.404) 0.165(4.191) 0.165(4.191) 0.250(6.350) 0.307(7.798) 0.365(9.271) 12 300 12.75(323.85) 0.156(3.962) 0.180(4.572) 0.180(4.572) 0.250(6.350) 0.330(8.382) 0.375(9.525) 14 350 14.00(355.60) 0.156(3.962) 0.250(6.350) 0.188(4.775) 0.312(7.925) 0.375(9.525) 0.375(9.525) 16 400 16.00(406.40) 0.165(4.191) 0.250(6.350) 0.188(4.775) 0.312(7.925) 0.375(9.525) 0.375(9.525) 18 450 18.00(457.20) 0.165(4.191) 0.250(6.350) 0.188(4.775) 0.312(7.925) 0.437(11.100) 0.375(9.525) 20 500 20.00(508.00) 0.188(4.775) 0.250(6.350) 0.218(5.537) 0.375(9.525) 0.500(12.700) 0.375(9.525) 22 550 22.00(558.80) 0.188(4.775) 0.250(6.350) 0.218(5.537) 0.375(9.525) 0.500(12.700) 0.375(9.525) 24 600 24.00(609.60) 0.218(5.537) 0.250(6.350) 0.250(6.350) 0.375(9.525) 0.562(14.275) 0.375(9.525) NPS[7] DN[2] Wallthickness[in(mm)] Sch.40 Sch.60 Sch.80s/XS Sch.80 Sch.100 Sch.120 Sch.140 Sch.160 10 250 0.365(9.271) 0.500(12.700) 0.500(12.700) 0.594(15.088) 0.718(18.237) 0.843(21.412) 1.000(25.400) 1.125(28.575) 12 300 0.406(10.312) 0.562(14.275) 0.500(12.700) 0.687(17.450) 0.843(21.412) 1.000(25.400) 1.125(28.575) 1.312(33.325) 14 350 0.437(11.100) 0.593(15.062) 0.500(12.700) 0.750(19.050) 0.937(23.800) 1.093(27.762) 1.250(31.750) 1.406(35.712) 16 400 0.500(12.700) 0.656(16.662) 0.500(12.700) 0.843(21.412) 1.031(26.187) 1.218(30.937) 1.437(36.500) 1.594(40.488) 18 450 0.562(14.275) 0.750(19.050) 0.500(12.700) 0.937(23.800) 1.156(29.362) 1.375(34.925) 1.562(39.675) 1.781(45.237) 20 500 0.593(15.062) 0.812(20.625) 0.500(12.700) 1.031(26.187) 1.280(32.512) 1.500(38.100) 1.750(44.450) 1.968(49.987) 22 550 — 0.875(22.225) 0.500(12.700) 1.125(28.575) 1.375(34.925) 1.625(41.275) 1.875(47.625) 2.125(53.975) 24 600 0.687(17.450) 0.968(24.587) 0.500(12.700) 1.218(30.937) 1.531(38.887) 1.812(46.025) 2.062(52.375) 2.343(59.512) NPS26toNPS36[edit] NPS[7] DN[2] OD[in(mm)] Wallthickness[in(mm)] Sch.5s Sch.10s Sch.10 Sch.20/XS Sch.30 Sch.40s/Std. Sch.40 26 650 26.000(660.400) — — 0.312(7.925) 0.500(12.700) — 0.375(9.525) — 28 700 28.000(711.200) — ? 0.312(7.925) 0.500(12.700) 0.625(15.875) 0.375(9.525) — 30 750 30.000(762.000) 0.250(6.350) 0.312(7.925) 0.312(7.925) 0.500(12.700) 0.625(15.875) 0.375(9.525) — 32 800 32.000(812.800) — — 0.312(7.925) 0.500(12.700) 0.625(15.875) 0.375(9.525) 0.688(17.475) 34 850 34.000(863.600) — — 0.312(7.925) 0.500(12.700) 0.625(15.875) 0.375(9.525) 0.688(17.475) 36 900 36.000(914.400) — — 0.312(7.925) 0.500(12.700) 0.625(15.875) 0.375(9.525) 0.75(19.05) Additionalsizes(NPS)[edit] NPS DN[2] OD[in(mm)] Wallthickness[in(mm)] Std.Wt. Sch.XS Sch.XXS 40 1000 40.000(1,016.000) 0.375(9.525) 0.500(12.700) 1.000(25.400) 42 1050 42.000(1,066.800) 0.375(9.525) 0.500(12.700) 1.000(25.400) 44 1100 44.000(1,117.600) 0.375(9.525) 0.500(12.700) 1.000(25.400) 46 1150 46.000(1,168.400) 0.375(9.525) 0.500(12.700) 1.000(25.400) 48 1200 48.000(1,219.200) 0.375(9.525) 0.500(12.700) 1.000(25.400) 52 1300 52.000(1,320.800) 0.375(9.525) 0.500(12.700) 1.000(25.400) 56 1400 56.000(1,422.400) 0.375(9.525) 0.500(12.700) 1.000(25.400) 60 1500 60.000(1,524.000) 0.375(9.525) 0.500(12.700) 1.000(25.400) 64 1600 64.000(1,625.600) 0.375(9.525) 0.500(12.700) 1.000(25.400) 68 1700 68.000(1,727.200) 0.375(9.525) 0.500(12.700) 1.000(25.400) 72 1800 72.000(1,828.800) 0.375(9.525) 0.500(12.700) 1.000(25.400) 76 1900 76.000(1,930.400) 80 2000 80.000(2,032.000) 88 2200 88.000(2,235.200) 92 2300 92.000(2,336.800) 96 2400 96.000(2,438.400) 100 2500 100.000(2,540.000) 104 2600 104.000(2,641.600) 108 2700 108.000(2,743.200) ≥− Seealso[edit] Britishstandardpipethreadsizes Coppertubingsizes Pipethreadsizes Nationalpipethreadsizes Pipe(fluidconveyance) Pipesizes Standarddimensionratio Notes[edit] ^ThisiscontrarytothePipingHandbook,whichsaysthattheschedulenumbercanbeconvertedtopressurebydividingthescheduleby1000andmultiplyingbytheallowablestressofthematerial.[6] References[edit] ^ASMEB36.10,p. 1. ^abcdefNPS-"NominalPipeSize"andDN-"DiamètreNominal",EngineeringToolbox.com ^ASMEB36.10,p. iv. ^ASMEB36.19,p. iv. ^"PipeScheduleChart".HYSPSteelPipe. ^Nayyar2000. ^abcdefTableofPipeSchedulesfromEngineersEdge.com. ^"ACompleteGuidetoPipeSizesandPipeSchedule–FreePocketChart".HardHatEngineer.Retrieved2017-11-07. ^A9992014. Bibliography[edit] ASTMA999/A999M-14StandardSpecificationforGeneralRequirementsforAlloyandStainlessSteelPipe,ASTMInternational,2014,doi:10.1520/A0999_A0999M Nayyar,MohinderL.(2000)."A1".InNayyar,MohinderL.(ed.).PipingHandbook(7th ed.).NewYork:McGraw-Hill.ISBN 0-07-047106-1. B36.10MWeldedandSeamlessWroughtSteelPipe.TheAmericanSocietyofMechanicalEngineers.2015.ISBN 9780791870273.Retrieved2015-10-02. B36.19MStainlessSteelPipe.TheAmericanSocietyofMechanicalEngineers.2004.ISBN 0791829170.Retrieved2015-10-02. Externallinks[edit] NotesonPipe—PVCPipeweightsandmaxPSI QuickcalculatortodeterminestandardpipedimensionsForCarbonSteelandStainlessSteelpipesasperANSI.(RequiresMembership) Retrievedfrom"https://en.wikipedia.org/w/index.php?title=Nominal_Pipe_Size&oldid=1105984746" Categories:PipingMechanicalstandards Navigationmenu Personaltools NotloggedinTalkContributionsCreateaccountLogin Namespaces ArticleTalk English Views ReadEditViewhistory More Search Navigation MainpageContentsCurrenteventsRandomarticleAboutWikipediaContactusDonate Contribute HelpLearntoeditCommunityportalRecentchangesUploadfile Tools WhatlinkshereRelatedchangesUploadfileSpecialpagesPermanentlinkPageinformationCitethispageWikidataitem Print/export DownloadasPDFPrintableversion Languages DeutschEspañolItalianoPortuguêsРусскийSlovenčinaУкраїнська Editlinks