High-pressure compressed air line materials question

[Clymber]

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.

 

[CRG]

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.

 

[MiketheEngineer]

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

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

 

[blacksmith37]

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.

 

[Clymber]

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.

 

[israelkk]

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.

 

[moltenmetal]

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?

 

[SJones]

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