New barn build – compressed air question

[turbo36]

I am building a new 44’ x 48’ workshop that will be next to my existing 40’ x 60, barn. Instead of buying a new compressor for the new workshop, I am thinking about running a 200 psi rated black polyethylene pipe from from the existing barn to the new barn. Any opinions?

 

[dodge man]

How far away is it?

 

[oldnslo]

Is polyethylene approved for air service. I remember reading a few years ago not to use plastic for air service but that may have been PVC.

Will this be overhead or under ground between the buildings?

 

[newbury]

Black poly in Michigan?
Will it take freezing?

 

[Skeletor]

How about steel black pipe?

 

[repete]

I would suggest an analysis of what you need for CFM of your tools. If all you need is to fill a tire than you do not need a lot of CFM flow. If you want to run air tolls then you need the CFM at a certain pressure.
One option would be to put a storage tank in the second building and have a smaller line fill it. The tank providing the initial burst and then recharge via the smaller line from building 1.
You need to look at what you want to do before deciding a path to follow.
As some said above, plastic is not your ideal option.

 

[turbo36]

It would be buried underground, I plan on having a 100 gallon surge tank in the new barn. seeing that it is rated at 200 psi I don’t see a problem as my system pressure would be 150 psi max.

 

[etpm]

If you are gonna run pipe use the largest diameter you can afford, up to a point. The longer the run the larger the pipe. People make the mistake of using higher pressure to make up for pressure drop over long distances. This is truly a big mistake. This scheme results in much more water in the air delivered. And also in energy wasted. This wasted energy shows itself in higher power bills and less air delivered. And water in the air. So, decide yourself if the piping you want to use is up to then task but then make sure to use large diameter pipe. Over 20 years ago I went through all the calculations required when I installed new air piping in a machine shop I worked in. Being a machinist and not a pneumatic engineer I ended up learning a lot. But the biggest item that could ruin the whole thing was piping that was too small and pressure that was too high for the job. You really want the pressure delivered from the compressor to be not much higher than the system pressure and you want the piping to be large enough to avoid pressure drop that is below what the tools being powered require. It is a BAD thing to have your air powered tools or air guns lose power. This at the very least causes water to drop out of the compressed air which then flows along the bottom of the plumbing until it comes out of your air tool or air gun. The compressor should be up to the task and then some. Probably twice for a home shop.
Eric

 

[turbo36]

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.

 

[BigGG]

It would be buried underground, I plan on having a 100 gallon surge tank in the new barn. seeing that it is rated at 200 psi I don’t see a problem as my system pressure would be 150 psi max.

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

 

[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.