Why is round material available in pipe and inch/mm sizing ?

[theoldwizard1]

Steel (not "water pipe"), aluminum and stainless are all available is these two different sizing standards. Same alloys. WHY ?

(I know the difference in the sizing and what Schedule 10, 40 and 80 means so bother explaining it.)

 

[Old Man Roger]

Total guess here, but maybe it's because the rest of the world is metric?

 

[dogdog]

Total guess here, but maybe it's because the rest of the world is metric?

LOL put it the other way for us...

The rest of the world is not imperial yet.

 

[larry_g]

"Standards are so important that everyone must have their own."

So just what two standards are you referring to?

lg
no neat sig line

 

[MattT]

Total guess here, but maybe it's because the rest of the world is metric?

Not for pipe they ain't. "Metric" pipe threads are British inch threads.

Regards the OPs question pipe is for applications requiring pipe. Material sized by I.D. & O.D. is tube and hollow barstock.

 

[matt_i]

If you want to connect it to NPT systems then you need the ID and OD to match up...

Anything else can be engineered. With thicker or thinner walls....ERW =electric resistance welded or DOM = drawn over mandrel.

 

[Bogie1632]

I believe this is a ASTM International requirement. I know they have multiple standards on marking different materials, along with a whole host of other manufacturing requirements. Most of their standards are available as .PDF for a fee.

Perhaps someone else on GJ has better GTS skills that can verify.

V/R
Bogie

 

[theoldwizard1]

Total guess here, but maybe it's because the rest of the world is metric?

Pipe sizing and inch sizing are both American ?

Why, in the US, is aluminum, steel and stainless round available in both pipe sizing (where the OD stays constant for a given Schedule and the ID decreases for "heavier" pipe) and inch sizing ?

 

[dontlifttoshift]

Pipe is measured on the ID.

Tube is measured on the OD.

Are you asking why both of those exist?

 

[Old Man Roger]

Pipe sizing and inch sizing are both American ?

Why, in the US, is aluminum, steel and stainless round available in both pipe sizing (where the OD stays constant for a given Schedule and the ID decreases for "heavier" pipe) and inch sizing ?

I guess I don't understand the question or the answer..lol

 

[dkmc]

Now lets go find a solution in search of a problem

 

[dr_clyde]

True pipe is it’s own system separate from all other tubes. All pipe is tubing but not all tubing is pipe.

Piping systems rely on a standardized system of sizing stemming from threaded connections. That way they can increase wall size thickness and schedule without the need for new dies and fittings.

For standard schedule 40 pipe, the size is APPROXIMATELY the nominal ID. But in pipe the dimension that matters is the OD, due to the need for interchangeable fittings.

Tubing is simply measured by the OD, ID and/ or wall thickness. 2 are specified when ordering.

If we were to start from scratch today, we probably wouldn’t have pipe as we know it now. Everything would be true tubing due to ease of manufacturing and modern tech. But the pipe system we have is a holdover from back in ye olde days and the sizes have slowly morphed into what they are today. Kind of like how a 2 x 4 isn’t 2 anythings by 4 anythings.

 

[gmwelder86]

Pipe is measured on the ID.

Tube is measured on the OD.

Are you asking why both of those exist?

Pipe over 14” in diameter is measured in OD.

 

[Old Man Roger]

Pipe over 14” in diameter is measured in OD.

OH GREAT! Just one more thing to confuse it all