Underground air line?

[Bennie]

I did a search and couldn't find anything on exactly what I'm looking for.

I'm in the process of building a shed 12' away from my attached garage/shop. I would like to get an air line run out there from my garage mounted compressor (ingersoll 3hp 60gal). Right now it will be an air supply to the shed. Long term I will move the compressor out there and it will then be feeding the shop. It will be run under class 5 gravel.

Any recommendations on what pipe to use? It will be about a 25" run. Should I be worried about condensation? I have a drier right off the compressor.

 

[gorilla]

I ran an air line from the compressor in my garage to my machine shop building underground about a year ago. I used 3/4" galvanized gas pipe. I chose the gas pipe because it's covered with a plastic coating to protect it from corrosion and was cheaper than copper. I knew that some water would collect in the pipe so I felt the galvanized pipe would be better in that aspect also. I haven't seen any water in the shop but all I use the air for is blowing off chips and an occasional air tool. I do have a water trap at the compressor.

 

[akdiesel]

As mentioned I would use the gal pipe. If you bury it to the standard depth like electrical wire you could still damage copper or lite gauge material if you drive something heavy over it. But I would also install a second collection tank out there for water to knock out.
Is your shed going to have heat? If not I would install a shut off valve in the garage to keep the line empty when not in use since you are in a northern climate and blow down your shed system when done to clear the lines of any moisture.
This may be a little over kill but better to be prepared then have to do it over again.

 

[Bennie]

The shed will never be heated on a regular basis and probably won't even be setup for heat for a couple years.

 

[Frank The Plumber]

K or L copper tube, no worries no rust.

 

[larry_g]

If you can run the pipe at a bit of an angle you can put a T on the low end and a riser to the shop. Continue the pipe on straight past the T and then 90 up to a blow off. The straight run past the T will be a water trap that is the lowest part of the pipe there fore the blow off at the end of the pipe. Plan for the water and you will have no problems.

lg
no neat sig line

 

[78Bird]

i was gonna mirror larrys advice, put a trap with a T on it to a drain valve that comes above ground at 1 end or the other, slope the line a little towards it, and the pressure can blow out any trapped water down there.

Copper won't corrode, ever. Galv is 2nd choice.

 

[Frank The Plumber]

Galvanized is more expensive than M copper and may be more than K. It rusts pretty bad in the ground depending on soil conditions.

 

[darkk]

We have 3" sch 40 grey pipe for underground wiring from our main garage to our smaller 22x24 storage garage. The distance is about 20 between, we're going to snake a regular air hose through the pipe with the electric. Should be OK.

 

[Frank The Plumber]

You could fish tape a rope through it and pull a fresh roll of copper into there and never worry about it again.

 

[Sureshot]

I would run the plastic conduit between the two buildings and then push truck air line thru it or pull regular rubber airline and if you ever have a problem you can run a new one. While you are at it I would run extra conduit or black plastic water pipe so in the future you can run water lines, tele, ethernet, speakers, cable etc and you will have all the options avaiable without redigging the yard.