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High-pressure compressed air line materials question

High-pressure compressed air line materials question

High-pressure compressed air line materials question

(OP)
I have a client who wants to run a 5000 PSI compressed air line around the perimeter of a shop.  Airflow of 50 CFM max are expected. Can anyone direct me as to what materials may be suitable?  I'm looking at a 1" Sched. 80 welded steel pipe, but I wanted to check other options.  Are hydraulic-type tubing systems allowed or would the potential for failure at a joint be too high?

Thanks in advance for the assistance.
 

RE: High-pressure compressed air line materials question

Clymber,

You may want to rethink Sch 80.  What piping code are you designing your system to meet?  Is this a B31.3 or is there some CGA guideline that you are using?  

From my experience most pressure piping at some point ends up with a threaded connection for something.  Once you have calculated the necessary wall thickness for your welded pipe, calculate how much thicker a threaded pipe connected to the system will be.  

RE: High-pressure compressed air line materials question

I am a dumb structural - but who uses 5,000 psi air???

That can cut off a finger or a limb or your head!!

RE: High-pressure compressed air line materials question

I also, am wondering if someone thought through 5,000 air ? Wave compensaters on offshore drill rigs must use 5 and 10K air systems and they can be a problem : like detonation of compressor oil on the pipe surface- destroying  4",sch 120 A 106.
If necessary, see what Autoclave Eng and Swageloc have to offer.

RE: High-pressure compressed air line materials question

(OP)
Thanks, guys.  This is a military application where they fill a truck tank to 3000 PSI which runs operations on that vehicle.  I think the 5000 PSI requirement includes a safety factor.  The only guideline I've found lists stainless or copper-nickel pipe.  I'm really curious if I can get by with a seamless carbon steel pipe, possibly Sch. 80 or 160.   

RE: High-pressure compressed air line materials question

For some military/Aerospace use of air pressure systems (pressure vessels for example) they have to be internally painted against corrosion if they are made of low alloy or carbon steels. Therefore, I assume the same applies for pipes. But you should follow the appropriate MIL-SPEC. If it allows only stainless or copper-nickel then you can not use low alloy or carbon steels.

RE: High-pressure compressed air line materials question

Presuming you need a relatively large linesize, Swagelok or Parker medium pressure compression fittings and stainless OD tubing would be an option worth considering.  Why mess with welded pipe?

RE: High-pressure compressed air line materials question

You could consider a tubing system arrangement and the Institute Of Petroleum Guidelines For Design, Installation & Maintenance Of Small Bore Tubing Systems will give you further advice and points of consideration.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04
 

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