The difference between Pipe & Tubes

Introduce the difference between pipe and tube. Contrast from outside diameter, wall thickness, tolerance, price, use, quality, etc.

1. PipeandTube
“I’mPipe”
“I’mTube”
“Wearedifference!!”
1.PipeDiameterandTubeDiameter
Pipediameterreferstoanominaldiameter-notactual.PipeSchedulereferstothepipe’s
wallthickness(youcanfindtheschedulechartandspecification).Theactualphysicaloutside
diameterislargerthanit’snominalOD.
Thediameteroftubingontheotherhandrefertotheactualoutsidediameter.Inother
words,theactualphysicalODofatubeisjustthesameasit’snominalOD.
Forexample:Theactualoutsidediameterof11/4”pipeis1.625″–while11/4”tubehasa
true1.25″outsidediameter.
Pipesaccommodatelargerapplicationswithsizesthatrangefromahalf-inchtoseveral
feet.Tubesaregenerallyusedinapplicationsthatrequiresmallerdiameters.While10-inch
pipesarecommon,it’srarethatyouwillcomeacrossa10-inchtube.
2.WallThicknessDifference
Thewallthicknessofpipesandtubesisanimportantfactortotelldifference.The
thicknessoftubingisoftenspecifiedbyagaugeforthinnerthicknessesandforthickertubingit
isindicatedbyfractionsofaninchormillimeters.Thenormalrangefortubingis20gauge,

2. whichmeasures.035inch,uptoathicknessof2inches.Thewallthicknessofapipeis
referredtoasapipeschedule,whichyoucanfindtherelevantbetweenpipescheduleand
thicknessinmillimeterorinchinspecificationASMEB36.10.Themostcommonschedulesare
SCH20,SCH40andSCH80.Schedule40isthemostcommonand80isextraheavy.Which
isneededtobenoted,thepipescheduleisnotsetforalldiameters;itvaries.
Forexample:
Diameter8inch/219.1pipe,pipescheduleisSCH40=wallthicknessis
0.322inch/8.18mm,
Diameter12inch/323.9pipes,sch40referswallthicknessof0.406inch/10.31mm.
Thereisnoformulabetweenthepipescheduleandwallthickness,theonlyistoreferto
theASMEB36.10orrelevantstandards.
3.PipesTolerance&TubeTolerance
Pipesareusuallyusedfortransportingordistributing,thenthepropertiesofpressureor
straightness,roundnessarestrictlyspecified,thetoleranceforpipesismoreloosethantubes
comparatively.Herethetolerancereferstodiametertolerance,wallthicknesstolerance,
straightnesstolerance,roundnesstoleranceetc.
4.ManufacturingDifferenceofpipesandtubes
Aswementionedabove,tubeswillrequirehigherlevelrequirements,consequently,even
fromthematerialproducingtothepipeortubemanufacturingprocesswillbedifferent.Tubes
willrequiremuchmoreprocess,tests,inspectionthanpipes.Thedeliverytimewillbelonger,
too.Theyieldoftubesarecomparativelymuchlowerthanpipes.Pipemanufacturingiseasier
comparetotubesandit’sinmassproduction
5.Cost&Price
Aspertotheabove,tomanufacturetubeswilltakemuchmorelabor,energy,materialetc,
sotheproductioncostissurelyhigherthanpipes.Andjustbecausethehighlevelrequirement
oftubes,thelowyieldoftubeswillalsoincreasethecostandprice.Whiletheprocessofpipes
iseasier.Andpipesaremanufacturedinlargelotandcutthecost.
6.UseofPipesandTubes
Pipesareusedforfluidsandgases,suchaswater,oil,gasorpropaneorassteampipe,
boilerpipeetc.Justbecauseofthis,theoutside&insidediameteristhekeymeasurement—
itindicateshowmuchcanflowthroughthepipe.Alsothat’sthereasonwhythepressurerating
issoimportant,becausethepressuremustbeunderthetransportordistributepressurerange.
Tubes,however,areoftenputtouseinapplicationsthatrequirepreciseoutsidediameters,
likewithmedicaltubes,weaponpart,industrialparts,coolertubes,heatexchangertubesand
boilertubes.Tubesareusuallyusedinmedicalarea,construction,structureorloadbearing

3. etc.Thisiswhytheoutsidediameterisimportantbecauseitindicateshowmuchitcanholdas
astabilityfactor.
7.MechanicalPropertiesandChemicalProperties
Forpipesthepressurerating,yieldstrength,ductibilitypropertiesaremoreimportant.
However,fortubes,thehardness,tensilestrength,highprecisionisthekeytohighquality.
ThoseelementslikeC,Mn,S,P,Siarethemainchemicalelementsforpipes,andthereisfew
microelementsrequirements.Whilefortubing,themicroelementsareveryimportanttothe
qualityandprocess.
Connectingpipesismorelaborintensiveasitrequireswelding,threadingorflangesand
relevantequipments.Tubescanbejoinedquicklyandeasilywithflaring,brazingorcouplings,
butforthisreason,theydon’tofferthesamestability.Pipeweldingissaferthan“tubejoin”.
9.Ductibility
Pipeisavailableinrigid“joints”,whichcomeinvariouslengthsdependingonthematerial.
Tubing,inparticularcopper,comesinrigidhardtempered“joints”orsofttempered(annealed)
rolls.Sometubingalsocomesinrigid“joints”orflexiblerolls.Thetemperofthecopper,thatis
whetheritisarigid“joint”orflexibleroll,doesnotaffectthesizing.
10.Quantity
Forlongtransportordistributing,pipingisoftenusedinmassquantityandforlong
distanceapplication.So,theorderofpipesareusuallylarge.Whiletubesmaybeusedinsmall
quantity.
11.PipeEndandTubeEnd
Pipeendsareusuallyinplainorbeveledsoastowelding.whiletubesarewithcoupling
endsorspeciallyendfinish,likeirregularends,specialscrewthreadetc.
12.Application
Pipesaccommodatelargerapplicationswithsizesthatrangefromahalf-inchtoseveralfeet.
Tubesaregenerallyusedinapplicationsthatrequiresmallerdiameters.While10-inchpipes
arecommon,it’srarethatyouwillcomeacrossa10-inchtube.