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pipe or tube

pipe or tube

pipe or tube

(OP)
what is the difference between "pipe" and "tube" ? and what about "piping"
Thanks

RE: pipe or tube

Google "pipe or tube", plenty of info' to explain the differences.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

RE: pipe or tube

(OP)
thanks. Clear

RE: pipe or tube

A "pipe" is used for fluid power or transport systems, whether it be in a plant, pipeline, residential plumbing, etc.. It is referred to by it's nominal diameter, which does not necessarily coincide with it's actual outside or inside diameter, and a schedule which determines it's wall thickness. Engineers are generally interested in the ID of the pipe. They are also generally more rigid than tubing and come in a much larger size range.

A "tube" can also be used for fluid power systems, however, it can also be used in structural applications as well. This can cause the shape of the tube to be round, square, or rectangular. Tubes are referred to by their outside diameter and wall thickness (or gauge), and are generally less rigid than piping. Tubing is often more expensive than piping due to higher manufacturing tolerances.

"Thinking is the hardest work there is, which is probably the reason why so few engage in it."

-Henry Ford

RE: pipe or tube

Are pipes mostly tubular in shape, but not all tubes are also pipes?

Tube is mostly a shape. Pipes generally have stuff going through them.

RE: pipe or tube

You can order things from vendors that are called pipes. In North America, pipes are based on a standard that specifies outside diameters and wall thicknesses. Beyond that, I would say that if someone insists on calling it a pipe, it is a pipe.

--
JHG

RE: pipe or tube

Actually, in North America, at least what's known as common or iron pipe, is NOT sold based on its outside diameter or wall thickness, but rather is specified as described by DGrayPPD above. Tubing, on the other hand, irrespective of the shape of the cross-sectional profile, is sold by the outside dimension(s) and the wall thickness.

The item below should help explain these differences:

https://www.sharpeproducts.com/pipe-or-tube-unders...

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: pipe or tube

My interpretation is "pipe" will be the the schedule sizes that @JohnRBaker's link references. I'll also take the steel grade to be A53. When I see "tube" I usually think (and correct the reference) to an RHSS size. Yield strength, diameter, and wall thickness will be different compared to a pipe. I think verbally pipe and tube are used interchangeably, but in written form I won't call something that needs to be an HSS a "pipe".

RE: pipe or tube

JohnRBaker,

I did not claim that the nominal size equals the actual OD. smile

--
JHG

RE: pipe or tube

pipe is generally rigid and not intended to bend.

most tubing is flexible enough to bend. there are tools for forming an elbow into copper tubing or stainless steel tubing once during initial installation. heat exchanger tubing is an exception to this terminology though.

=====================================
(2B)+(2B)' ?

RE: pipe or tube

I disagree about bending as a distinction. Schedule 40 and schedule 80 rigid conduit differ from “pipe” in that interior is smoother. Conduit certainly gets bent.

RE: pipe or tube

Now conduit introduces a whole new animal to the discussion. And while it's true that pipe can be bent, it usually entails a lot of heat being applied before attempting to actually bend it. Tubing, at least copper, and some of the other mild steel varieties, can generally be bent without the need for heating it first.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: pipe or tube

Besides the smooth interior, how does GRC (referred to as pipe to distinguish it from EMT, where T=Tubing) differ from similar size “pipe”? Plumbers don’t bend pipe because they can use small radius fittings, electricians bend both pipe and tubing because their universe doesn’t include small radius fittings.

You could probably hand the same 10 foot piece of stock to each trade and one would tell you it can’t be bent and the other would ask where you want it to fit.

RE: pipe or tube

Quote:

Besides the smooth interior, how does GRC (referred to as pipe to distinguish it from EMT, where T=Tubing) differ from similar size “pipe”?
They differ at least in function. The potential consequences of residual stresses in a bent pipe (imagine a high energy fluid system) are certainly different than those in a bent conduit. Of course there is a hydro test, and the is possibility of problems even with welding, but maybe the balance of factors plays out against bending. I’m not a mechanical guy, just offering how I’ve heard the terminology used and what I’ve seen.


=====================================
(2B)+(2B)' ?

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