New barn build – compressed air question

[AnotherBueller]

How about steel black pipe?

We're talking about compressed air in an iron pipe, right? There is a reason they don't use air to pressure test metal piping. Yes the pressure will be way below the burst point of the NEW iron pipe, but how about after moisture has corroded the pipe? Metal container + compressed air = bomb.

 

[Williy]

IMHO I believe you will have pressure problems because of the distance

willy

 

[SPYDERLK]

polyethylene pipe is approved for air service, it will also survive freezing as most of the underground sprinkler lines are polyethylene.
Essentially, I am looking for any insight from someone has done this before and ran into some problems that I could not foresee.

I have a 200' 3/4" ID black poly pipe running 150PSI underground from house to barn. Virtually no pressure drop at 20CFM. No problems, 24yrs.

 

[ultrarunner]

30 years ago ran 1” poly from one building to another.

Only issue was when some critter gnawed a hole but it was a simple fix with a shovel and some clamps.

 

[chim]

Poly pipe wouldn't scare me. PVC would. Many years ago our company did a project with an air testing spec. For anyone unfamiliar with Department of General Services projects, these inspectors are often self-appointed gods and most have no working experience in what they inspect. Common sense plays no part and the spec (or their interpretation) is an unbending law. I had one of them request steel certs on copper wire. Following an incident involving high velocity plastic shrapnel we refused to do any more air testing on PVC - regardless of the spec. IIRC it was a 3" or 4" line.

 

[Overtaxed]

I'd use PEX-AL-PEX. 1" would be fine, especially if you have surge tank. No exposed metal, no joints underground (get a long enough roll) and designed to handle compressed air.

 

[turbo36]

I have a 200' 3/4" ID black poly pipe running 150PSI underground from house to barn. Virtually no pressure drop at 20CFM. No problems, 24yrs.

Thank you. Just the experience I was looking for.

 

[turbo36]

I'd use PEX-AL-PEX. 1" would be fine, especially if you have surge tank. No exposed metal, no joints underground (get a long enough roll) and designed to handle compressed air.

Interesting, I will have to look into this.

 

[turbo36]

Poly pipe wouldn't scare me. PVC would. Many years ago our company did a project with an air testing spec. For anyone unfamiliar with Department of General Services projects, these inspectors are often self-appointed gods and most have no working experience in what they inspect. Common sense plays no part and the spec (or their interpretation) is an unbending law. I had one of them request steel certs on copper wire. Following an incident involving high velocity plastic shrapnel we refused to do any more air testing on PVC - regardless of the spec. IIRC it was a 3" or 4" line.

40 years ago when I started my business, I used PVC pipe because it was fast and easy, little did I know that eventually it would fail in a catastrophic way.

 

[turbo36]

I'd consider running it inside a larger pipe as a casing so, when it needs replacing, you don't have to dig again.

I may consider this, I have to run water, gas, and electric to the new shop and was thinking of running the gas and electric and conduit anyway. The water needs to be 4 foot down due to frost in my area.