Pipe sized tubing 1

[nuche1973]

Got into a discussion about piping and fatigue. The terms that were thrown around were "Piping", "Tubing" and "Pipe Sized Tubing".

We have a blow pipe (I use pipe because I am not sure what is installed) that snapped due to fatigue. The pipe spans 9 ft, with blow holes every 9". Compressed air is pulsed into the pipe and which is distributed into the holes. (It is a reverse air pulse jet bag house). The movement of the air is causing the pipe to oscillate, then crack at the center hole, eventually it snaps.

Ok, here is where it gets complicated: The shop forman says he used 1 in "piping". Another shop guy says it is 1 in "tubing". The Project manager pulled out a book and said that it is 1 in "pipe sized tubing" and added that it is superior to piping.

I know that pipe is not the same as tube. I've never heard of "pipe size tubing", but that doesn't mean it does not exists. My question is: Is there such a thing a "Pipe sized tubing"? and where can I find data on it?

The solution to the problem was to add a series of brackets a the midpoint to restrict the pipe.

"I drank what?!" Socrates?

 

[moltenmetal]

The only "Pipe sized tubing" I know of is round hollow structural steel (HSS) with dimensions matching those of a nominal pipe size. The wall thickness can match a pipe schedule, or not.

It is manufactured to different standards and tolerances and in different materials than piping is. We use it for applications such as handrail. We do NOT use it for any pressure boundary service, period.

 

[nuche1973]

Per AISC 13th edition, the smallest Round HSS size is 1.66 diameter. I don't believe that this is what is installed.

The "bible" that was quoted to me was yellow and black. Perhaps an older Ryerson catalog? I tried to get more information from this gentleman but was ignored.

I believe HSS is grade 42 (Fy = 42 ksi). I agree with not using HSS for pressure, any other thoughts on what was referenced?

"I drank what?!" Socrates?

 

[blacksmith37]

"Pipe " by definition meets certain diameter/ wall sizes. "Tubing" is any size a buyer and manufacturer agree upon and I am unaware that "pipe" sizes are forbidden.
( I always thought it strange that ASTM had/has two different comittees, with mostly the same members).
API defintions are a little different.