Tubes or Pipes?

There is no agreed technical or topological distinction...it's down to common usage in any particular application.

If anyone disagrees I'll arm wrestle 'em!

Del, as you can read from the replys, there seems no definitive answer. I suppose it also raises the question, how short does a tube need to be to be called a washer and, is it true that some Scotish people do perverse things with pipes?

Thanks for all your efforts people but, sadly, I'm no wiser this time!

In the aviation industry, TUBE is what you'll find on an aircraft - you won't find PIPE. Tube is measured by OD and wall thickness; I can't say about pipe but I am sure it comes in different stock sizes and materials than what you'll see with aircraft tubing. Pipe itself is often threaded while tubing is not - it's usually too thin for that. Different means are used to secure tubing (flaring the ends, swaging on fittings, etc.). Pipe thread (has a slight taper to it) is also not used on aircraft.

So while yes, to the average person the terms can be used interchangeably, this is one application where there is a difference. There may be others.

Just being pedantic...

As you only use tube...you can hardly say there is or isn't a difference in your application!

Can't have a difference between just one thing....just teasing don't shoot!

Now were in the realms of Cheshire Cat! (Off with it's head.... but if it doesn't have a body............)

Seriously, as seriously as it gets that is:

As engineers don't we refer to tubes? Pipes are plumbing items or things you can fill at the tobacconist, n'est-ce pas?

Off shore enigneers might want to pump gas down a pipe.

But I agree, I've never smoked a tube.

Ok, so it's a tube if it's something used primarily for supporting a load of some sort, and a pipe if it's primary function is to transport a material without it going everywhere (gas/liquid/powder)?

So the London underground should be 'The Pipe' ? (the load being people [90% odd liquid])

.. Nah, just doesn't have the ring to it!

Not necessarily, it's otherwise known as Infra_Structure!

Especially useful for keeping the sewers apart while still providing free movement for rats. Go Del!

Wouldn't the transporting of a material constitute a load?

US Steel used to make pipe in its National Tube Works, if that's any help.

Tom

hello

i have two question about schedule formula that you wrote it in your reply :-

1- is this formula applicable to general purpose design even high pressure service?

2- shall i add corrosion allownce after i calculate the SHC?

Best regard

For tube the wall thickness is given in gauge or decimal equiv.

Not correct as a general rule, because you can find a tube with a diameter larger than 60 inch (yes and still called a tube because its size and thickness are not belong to standard) and its thickness is specified by a significant mms or inches, not by gauges (BWG). See my definition at post #75.

I have NO basis for verifying or refuting it, but I always thought that tubing was seamless, while pipe has a seam of one kind or another.

Dick

Yep, no basis for that one as far as I know???

What about a Hose?(ie Air hose, water hose,) or how about your car's brake hydraulic line?

So throw Hose and Line into the mix.

Mon repose? 'Ose

Wiktionary can't help on this one...

pipe (plural pipes)

1. A hollow tube that transports water, steam, or other liquid; usually made of metal, ceramic, wood, or plastic.

I hope this quote below could help!

What's the difference between a pipe and a tube? More often than not, people guess it has something to do with the quality of the materials, but that's got nothing to do with it. The difference between a pipe and a tube is how they are measured, and ultimately what they are used for. A pipe is a vessel - a tube is structural. A pipe is measured ID - a tube is measured OD. How they are measured... Pipes are measured ID or inside diameter because they are vessels. Tubes are measured OD or outside diameter because they are structural. Pipes have a consistent ID regardless of wall thickness. In other words, a 1/2" high pressure pipe may need a 2" thick wall, but the ID will still only be 1/2" even tho the OD is 4.5". Generally speaking, a tube will have a consistent OD and it's ID will change. Engineers see tubes and pipes with different eyes. A tube is structural. By having a consistent OD they can vary wall thickness, changing the ID, to increase strength. Because they are consistent OD, they have predictable characteristics.

Again, the difference is simple, it's how they are measured and what their intended uses are.

source: [http://bicyclesports.us/id198.htm]

Another example of terms varying by application. On aircraft, tubes are NOT just structural - they convey hydraulics, fuel, oil, etc. Interesting to see how the bicycle industry uses the terms.

And yep, I knew piping was measured with some funky term - schedules was it.

As far as hose vs. line - I use line as a generic overall term that could mean hose OR tube. One single run of 'line' could vary between hose and tube, so it makes more sense to refer to it as the 'pump pressure line' in an overall functional sense.

Im sorry, but the inside of a 1/2" pipe does change, and the outside stays the same. other wise i would need a diffenent set of pipe thread dies for each wall thickness. Also pipe threads are tapered, so the tighter you turn it the tighter the seal. Pipe also has a seam as does tubing.

The difference is in the mesurments and material.

No seam on seamless pipe- ASTM A106 for example. Seamless crbonsteel pipe for high temperature service

no seam on seamless tubing ASTM A179 for example. Cold drawn Heat exchanger tubes

milo

I have been in the steel business in one way or the other for almost 40 years, believe me that seamless tubing has a seam, the weld is just cut or ground off before drawing it over a mandral (cold drawn). if you dont beleave me buy some, cut it and check it out, or go watch them make it, I have.

the difference is materal and mesurements

craig

Agree to disagree.

I was lab supervisor at USS Pipe Mill Laboratory in Lorain Ohio. All chemical, mechanical, and metallurigical testing. All seamless and pipe mills plus bar mill and semifinsh and product tests. Including cutting out test specimens for tensile testing from Pipe. 5 years. More end of month shipping rush tonnage than most small countries could use.

No seam on seamless. Thats why its called seamless.

Process path: Blast furnace- BOF- Cast ingots- Roll ingots to Round billets- Reheat and peirce billets to make pipe, Finish ends of pipe. Test. Ship.

Seams existed on welded pipe from ERW mill; not on seamless.

Process path for erw: Buy skelp (flat roll steel) from Gary mill, charge onto ERW mill, form and weld skelp, remove flash, cut to length, Finish ends of pipe. test. ship.

May have been NDT on the weld, don't remember.

milo

very few tubes are made this way, HRS (hot rolled seamless) not many sizes are available

most seamless tubes are welded, CDS AND DOM and do have a welded seam

seamless means the seam has been finished (by grinding or with a cutting tool to remove excess weld)

Disagree, Seamless is Not welded;

Welded is not seamless. The weld seam is a seam.

ASTM A450General requirements for CArbon, ferriticalloy, and austenitic steel tubes very carefully differentiates between seamless and welded tubing in its testing schema as follows: " 17) Flattening test A section of tube not less than 2 1/2" in length for seamless and not less than 4 in length for welded shall be flattened cold between parallel plates in two steps . " It gorees on to give different criteria for cracks depending on whether the specimen in welded or seamless.

Metals handbook desk edition: Seam welding: making a a longitudinal weld in sheet metal or tubing.

milo "the engineering is easy, its the doggone communication that drives us nuts!"

This sort of like motors vs engines....

If it runs on electricity its a motor if it runs on fuel it a motor (supposedly). Why do boats have outboard motors?

It's the manufacturing process. Tubes start out as a flat roll of metal and are formed through a series of dies and when the end get really close it is welded. Then it goes through some additional dies to insure that it is round and it is cut to length, stacked and shipped. The roll width determines the diameter.

Pipes are seamless and are formed through extrusion.

I had a bike with "seamless" tubing.

Pipe can also be formed from plate and welded. We use it for shell material in shell & tube heat exchangers per ASME.

Actually ASTM A135 is one example of electrical resist welded pipe made by welding skelp (Flat roll of metal strip.)

At metallurgical training back in the day at USS, we had to learn a bunch of definitions, heres the one they gave us for pipe:

"Pipe is a term used to designate any long hollow body used for conducting gases or liquids.Restricted to the steel industry, pipe is applied to all tubular products intended for the conducting water, fuel, gas steam air, oil etc. The term wrought distinguishes forged iron and steel pipe products from those produced by casting."

Pipe was one of a subset of "Steel tubular products"; All items captioned pipe in the catalog were for conducting some material from point A to B; EVerything else was tubular- Tubular poles, tubular pilings, Mechanical tubes etc. But it was not a clear cut taxonomy, There was structural Pipe for railinigs, fence posts and scaffolds, As well as oil well tubing, Pressure tubes for boiler, superheater, locomotive and heat exchanger applications which seemed on their face to be more a sense of pipe as the application seemed more about containment then mechanics.

Stainless steel Pipe and tubes were divided between Ornamental, Mechanical, and pressure applications.

Its a difficult taxonomy.

milo

Plastic tubing is extruded!

The definition of a word is derived from its usage.

According to Webster's Unabridged Dictionary, these definitions are given:

pipe1,n., v., piped, pip·ing.
–n.
1. a hollow cylinder of metal, wood, or other material, used for the conveyance of water, gas, steam, petroleum, etc.
2. a tube of wood, clay, hard rubber, or other material, with a small bowl at one end, used for smoking tobacco, opium, etc.
3. a quantity, as of tobacco, that fills the bowl of such a smoking utensil.
4. Music.
a. a tube used as, or to form an essential part of, a musical wind instrument.
b. a musical wind instrument consisting of a single tube of straw, reed, wood, or other material, as a flute, clarinet, or oboe.
c. one of the wooden or metal tubes from which the tones of an organ are produced.
d. a small end-blown flute played with one hand while the other beats a small drum.
5. Naut.
a. See boatswain's pipe.
b. the sound of a boatswain's pipe.
6. the call or utterance of a bird, frog, etc.
7. pipes, Informal. the human vocal cords or the voice, esp. as used in singing.
8. Usually, pipes.
a. Music. bagpipe.
b. a set of flutes, as a panpipe.
c. Informal. a tubular organ or passage of a human or animal body, esp. a respiratory passage: to complain of congested pipes.
9. any of various tubular or cylindrical objects, parts, or formations, as an eruptive passage of a volcano or geyser.
10. Mining.
a. a cylindrical vein or body of ore.
b. (in South Africa) a vertical, cylindrical matrix, of intrusive igneous origin, in which diamonds are found.
11. Metall. a depression occurring at the center of the head of an ingot as a result of the tendency of solidification to begin at the bottom and sides of the ingot mold.
12. Bot. the stem of a plant.
–v.i.
13. to play on a pipe.
14. Naut. to signal, as with a boatswain's pipe.
15. to speak in a high-pitched or piercing tone.
16. to make or utter a shrill sound like that of a pipe: songbirds piping at dawn.
–v.t.
17. to convey by or as by pipes: to pipe water from the lake.
18. to supply with pipes.
19. to play (music) on a pipe or pipes.
20. to summon, order, etc., by sounding the boatswain's pipe or whistle: all hands were piped on deck.
21. to bring, lead, etc., by or as by playing on a pipe: to pipe dancers.
22. to utter in a shrill tone: to pipe a command.
23. to trim or finish with piping, as an article of clothing.
24. Cookery. to force (dough, frosting, etc.) through a pastry tube onto a baking sheet, cake or pie, etc.
25. Informal. to convey by an electrical wire or cable: to pipe a signal from the antenna.
26. Slang. to look at; notice: Pipe the cat in the hat.
27. pipe down, Slang. to stop talking; be quiet: He shouted at us to pipe down.
28. pipe up,
a. to begin to play (a musical instrument) or to sing.
b. to make oneself heard; speak up, esp. as to assert oneself.
c. to increase in velocity, as the wind.
[bef. 1000; (n.) ME, OE, musical pipe, tube (c. D pijp, LG p#pe, G Pfeife, ON p#pa) < VL *p#pa, deriv. of L p#p!re to chirp, play a pipe; (v.) ME pipen; in part continuing OE p#pian to play a pipe < L p#p!re; in part < OF piper to make a shrill sound < L p#p!re (cf. PEEP2)]
—pipeÆless, adj.
—pipelike, adj.
—Syn.16. cheep, chitter, whistle, chirp, peep, trill, twitter, tweet.

pipe2, n.
1. a large cask, of varying capacity, esp. for wine or oil.
2. such a cask as a measure of liquid capacity, equal to 4 barrels, 2 hogsheads, or half a tun, and containing 126 wine gallons.
3. such a cask with its contents.
[1350–1400; ME < MF, ult. same as PIPE1]

tube (tÁb, tyÁb), n., v., tubed, tub·ing.
–n.
1. a hollow, usually cylindrical body of metal, glass, rubber, or other material, used esp. for conveying or containing liquids or gases.
2. a small, collapsible, cylinder of metal or plastic sealed at one end and having a capped opening at the other from which paint, toothpaste, or some other semifluid substance may be squeezed.
3. Anat., Zool. any hollow, cylindrical vessel or organ: the bronchial tubes.
4. Bot.
a. any hollow, elongated body or part.
b. the united lower portion of a gamopetalous corolla or a gamosepalous calyx.
5. See inner tube.
6. Electronics. See electron tube.
7. Informal.
a. television.
b. a television set.
8. See mailing tube.
9. the tubular tunnel in which an underground railroad runs.
10. the railroad itself.
11. Surfing Slang. the curled hollow formed on the underside of a cresting wave.
12. Brit. subway (def. 1).
13. Australian Slang. a can of beer.
14. Older Slang. a telescope.
15. down the tube or tubes, Informal. into a ruined, wasted, or abandoned state or condition.
–v.t.
16. to furnish with a tube or tubes.
17. to convey or enclose in a tube.
18. to form into the shape of a tube; make tubular.
[1590–1600; < L tubus pipe]

That is the longest Post I have ever seen....it seemed to cover everything!!!

I am quite jealous!!!

All pipes are are tubes.

Has anyone noticed that after 38 posts we are still at the same conclusion as Dels original answer.

A pipe is a specific tube with a few specific standardized diameter/wall combinations. It can be used structurally or for fluid transport. In the latter case, it is usually, but not always for low/medium applications.

For example, hydraulic components are usually available with either pipe or tube ports, and the circuit, while usually tube, can be pipe instead. Pneumatic circuits, being low pressure and less likely to have a messy leak, are more commonly pipe.

Shell-and-tube heat exchangers are filled with tubing, not piping. So is it something to do with which curved surface matters? If it's tube, the OD requires close attention and if it's pipe, it's the ID that matters? Come on. Someone put this one to bed, please.

That'll be the exception that proves the rule??

Bah, (retreats ignominiously)

Try telling your client that you are going to spec/supply 30" .750"WT, Tube. The answer will be clarified shortly thereafter.

You smoke a pipe, you inflate a tube.

another possibility, a tube is round, a pipe is circular.

Wangito

.....Fallopian Tubes.....where do they fit in? seamless or welded?

Now that depends on the model.

Age is also a factor there.

As was shown in the definition, pipe is a type of tubing. Tubing would be the general catagory. Now take a look where the term pipe is used. It is generally used within the construction/industrial industry, but very rarely within the manufacturing/aerospace industry which should give you a clue. Most everthing said so far has been based on individuals' own experiences, not on where that experience is derived.

Some say it based on ID or OD. These were defined by industries as standards for ease of use, not because they define the difference between the two. Let us for one second drop our pre-conceived notions and look again at the Webster definitions. Pipe is referred to more than once as a "tubing". Tubing I believe was never referred to as a pipe. That should say something to all of us.

You recap nicely what I and several others have said:

Pipe was one of a subset of "Steel tubular products";

All pipes are tubes, not all tubes are pipes.

etc. etc.

Your observation that its one's context that colors our usage is correct.

First mill I worked in we called a portable hand powered hoist a "come along"; next mill I went to, it was called a "chain fall"; Next mill, It was a "block and tackle"; last mill, they just called it a "hand winch." When we'd hire somebody new at the firs tmill, we 'd send them out for a sky hook to see what they'd come back with. It was usually a chain fall, though once they brought a hookers hook (for rigging without letting you r hands touch the cables.

It 's the language, not the engineering that is at issue here.

milo

I choose to retract my last response since after rereading the definitions I see the following at the very end: [1590–1600; < L tubus pipe]. I give up!

The date of adoption blew your cover friend.

Milo"my first emoticon"

I think your finger slipped. Standard tubing is specified OD not ID although I have bought tubing for hydraulic cylinder applications by specifying ID, wall thickness, and surface finish.

Oops, I stand corrected, thanks for catching that point; tube is measured by ID. There might have been a few to many OD's And ID's in my post.

pipewelder

Arh, Pipewelder. THIS is my major issue. I have been fitting up hydraulic systems using compression fittings of one form or another for getting on for 30 years. I also always use tube as it has a controlled OD (I thought) thus compatible with the compression fitting. Although the ID is obviously important to the systems capabilitys, at the end of the day, I have to get the suckers to fit together. Having spent most of my life in the UK where these components are in good supply, I am now in trouble doing the same tasks in Tasmania! It's definately all upside down here!

Thanks everyone for the enormous efforts on these posts. I wish there was a definitive answer but I don't think there is now! Del, you've got a lot of arm wrestling to do!

I feel your pain, I get into the same thing on mostly hydraulic fittings from the UK around the paper mill sometimes. The threads will look the same as the USA standard but they won't fit. I think this is on older stuff mostly though the newer stuff seems to be more compatible. I believe the threads are called imperial threads? I finally found some hydraulic adapters and some crimp type fittings and keep them in stock now. I bet it is fun and a chalange fitting tubing in Tasmania. I would dream one day of a system that would be standard anywhere you go, haha not in my lifetime.

pipewelder

"Standard tubing is specified OD not ID" [admittedly truncated and out of context].

And all this time no one has even mentioned that third major category of long hollow (usually) round (typically) metal objects made to contain, support, or convey something: I give you CONDUIT! One common form is also called EMT, or ElectroMechanical Tubing, pretty clearly establishing that it belongs in the "tube" category. At the local building supply place, it will be sold by nominal ID, and will always be oversize. Ordinary assembly methods include slip-on fittings with set screws or other external clamping / gripping devices, or by welding / brazing, etc. Next to it may be rigid conduit, which is typically assembled by cutting pipe threads on the ends. I suspect that the TLAR* system is used to figure out what pipe die to use with a given size conduit. [*TLAR: That Looks About Right]

Cause trouble? Who, me? It never crossed my mind . . .

Pipe is rated differently .. 1 1/2 inch pipe is roughly 1 5/8 inch "id" and never exact. Allow up to +3/32 for id usually. The "OD" for sch40 is about + 3/8 of an inch for pipe 1/4 to 2 inch 1/2 inch for 2 to 8. "schedule" indicates thickness though im not sure how. Sch40 1 inch is thiner then sch40 6 inch. Higher the sch# the thicker the pipe. Standards are 40 80 and 120, least those are common. It might have more to do with pressure ratings then anything else. To order you would give the sch# and "id" measurements .

Incredible!

The More trivial and stupid the question is, the more posts we have.

What's your conclusion sir?

Wangito.

Obviously, the question was neither trivial nor stupid.

I think the problem lies in the fact that all of these terms are overlapping. It seems that what is 'stupid' is the English language. With all of it's various dialects it's very easy to get confused; and that's if your a native speaker, and reasonably educated.

It as been my experience that, whenever we have this much disention, that we are, most likely, dealing with an etymological phenomenon. We all intrinsically know what a 'pipe' is, or a tube, or a conduit, or a duct is. It's seems to be difficult to arrive at a single, scientific definition. This would also point to a lack of standardization. Who do we appeal to for that?

Orpheuse

I think that there is neither a problem nor overlapping, the definition is very simple as derived at my post #75, and this definition is included in the most common piping handbooks.

Sir,

Please advice M.S Piping Pressure temperature rating calculations,

u have any tables please send me srpipingengineer@gmail.com

With appologize,I dont have.The documents are on the internal network of my office and it is not saveable to send.

A tube does not have to be round. Square hollow steel members are also refered to as tube. Square steel tube is available as pressure tested.

Good point. I cannot ever recall specifying, much less coming across square piping...

This will throw a chink in the string. Ever hear of box tubing? Not used for conveying fluids but is used for structural construction.

Pipe and electrical conduit rated sizes are nominal, meaning within the pipe wall thickness; neither ID nor OD.

I think that the pipe/tube dilemma will never be settled due to the fact that so many people use the two words indifferently! ie. Tube of toothpaste, smoking pipe, tube train, pipe wrench, tube spanner, you can buy a tube of beer in Spain, play a pipe organ, surf a tube, you can pipe music, there are tubular bells, the list goes on! so do you measure the surfed tube from the ID or the OD! Using what sounds right is my philosophy and don't get too bogged down with the technicalities of it all!

shell & TUBE heat exchanger ----> OK

shell & PIPE heat exchanger -----> BAD!!

Pipe is manufactured to standard dimensions, sizes, and standard thicknesses designated as Schedules. Whereas,

Tube (not including furnace or heat exchanger) is similar to pipe, but is manufactured in many sizes of OD's and Wall Thicknesses.

But your statement can't be exactly right as schedules are based on pressure rating so...... if the 'pipe' is plastic sched 40, it would be proportionately thicker!

Anyway, the original question, I think, has best been answered by CowAnon over on the other new thread. It's not really a matter of mechanics but more, a definition of terms in english!

I have to say that, looking at the problem from just the mechanical view point, you are probably not far off the mark!

Dear friend

If asme B31.1 is in your available , refere to section 100.2 definition , will find a fairly exact definition.

Yes moheshams, you are right

Since most of us are working in accordance with ASME code, so we have to look for ASME B31.1 (Para. 100.2) for pipe and tube definition:

Quote pipe and tube: the fundamental difference between pipe and tube is the dimensional standard to which each is manufactured. A pipe is a tube with a round cross section conforming to the dimensional requirements for nominal pipe size as tabulated in ANSI B36.10, Tables 2 and 4, and ANSI B36.19, Table 1. For special pipe having a diameter not listed in these Tables, and also for round tube, the nominal diameter corresponds with the outside diameter.

A tube is a hollow product of round or any other cross section having a continuous periphery. Round tube size may be specified with respect to any two, but not all three, of the following: outside diameter, inside diameter, wall thickness; types K, L, and M copper tube may also be specified by nominal size and type only. Dimensions and permissible variations (tolerances) are specified in the appropriate ASTM or ASME standard specifications. Unquote

And this definition is matching with my previous post #75. Thank you moheshams, and I voted for you.

Dear Mr.Beej50,

Tube is referred in Terms of O.D, and Wall Thickness.

Pipe is referred as Nominal Dia, and Class or Duty.

DHAYANANDHAN.S

Thanks for that dhayanandhan but you are a bit late to the party. When I posted this originally, I was a young man.

Also I believe your answer is incorrect as PIPE measurement is refered to in NOMINAL BORE not diameter. It may seem symantics but that's what this was all about.