Buried air line

fixerupper · Sep 16, 2012

I plan to bury an airline to a building I remodeled into a truck shop for my son. What's the ceapest type of airline I can use that will hold up to direct burial and 175 PSI? I already have a 3/4" copper line buried from the big shop to the woodworking shop and this will continue out from the wood shop maybe 150'. Copper is out of the question unless a pot of gold falls in my lap real soon lOL. How would schedule 80 PVC work? Is black pipe adequate?

He will be using a 1" air wrench so I plan to continue with 3/4" air line. An idea that entered my mind is to have a 60 gallon air supply tank in the truck shop as it will be about 225 feet from the compressor. I've already found out a buried line will condense water underground, from an unpleasant experience in the wood shop, so I have the idea a supply tank in the truck shop will serve as a water trap along with it's main purpose of acting like a surge tank. Can a person get PVC in 20' lengths or would I have to glue together a bunch of 10 footers? Thanks. Jim

rustyfarmall · Sep 16, 2012

(quoted from post at 12:06:15 09/16/12) I plan to bury an airline to a building I remodeled into a truck shop for my son. What's the ceapest type of airline I can use that will hold up to direct burial and 175 PSI? I already have a 3/4" copper line buried from the big shop to the woodworking shop and this will continue out from the wood shop maybe 150'. Copper is out of the question unless a pot of gold falls in my lap real soon lOL. How would schedule 80 PVC work? Is black pipe adequate?

He will be using a 1" air wrench so I plan to continue with 3/4" air line. An idea that entered my mind is to have a 60 gallon air supply tank in the truck shop as it will be about 225 feet from the compressor. I've already found out a buried line will condense water underground, from an unpleasant experience in the wood shop, so I have the idea a supply tank in the truck shop will serve as a water trap along with it's main purpose of acting like a surge tank. Can a person get PVC in 20' lengths or would I have to glue together a bunch of 10 footers? Thanks. Jim

My local plumbing and heating contractor has the pvc pipe in 20 foot lengths. The jury is still out on using pvc for compressed air, but personally I think schedule 80 would be just fine, especially buried underground, because the pvc won't rust. Black pipe is the old standby for use inside the shop, but I don't think I would want to bury it and expect it to not give problems.

Ivan in Mich · Sep 16, 2012

Pex tubing

BDT in Minnesota · Sep 16, 2012

Search pvc airline explosion.... Pvc is not intended nor rated for compressed air... When it fractures; it shatters... I did run 210 feet of 1" pvc line underground out to a shed.. Reason being; I used it in place of a tracer ribbon in a trench than holds an electrical conduit. AND, An air hose or line can be run inside the pvc..The pvc remains open on both ends.... Do a search on air rated nylon tube for something that is safe and affordable. That's my choice.

fixerupper · Sep 16, 2012

The explosion factor does concern me but it will be buried so I assume it won't be shattering underground. I did buy enough Pex to do the job but I'm sceptical of burying it. Another thought I had was 1 1/4" black pipe with the pex slid inside it but that will double the cost. Maybe it's worth it. Jim

David G · Sep 16, 2012

PVC will make shrapnel when it explodes, you should avoid it. You could lay a larger PVC pipe like others suggested an put an air hose it it.

BDT in Minnesota · Sep 16, 2012

Run an extra line while you are at it- TV cable, phone etc..

Gary in da UP · Sep 16, 2012

I'm wondering why? wouln't you just install another compressor ???

fixerupper · Sep 16, 2012

The new shop only has 15 amp 120v power so it will only run maybe a 5 CFM 120v compressor and that won't cut it for truck tires. I'm only budgeting so much money each year for the project and new 240v service is down the road a ways. The first main goal now that the walls are done is cement floor, enough light to get by, a source of heat and enough air capacity to change tires on a truck. The compressor I do have is a high dollar commercial grade two stage 18 CFM and is underused so this the route I chose to go. Jim

Justin SE IOWA · Sep 16, 2012

I work in the water works industry and we use plastic poly water line that is rated for 200psi. I know other people that also use it for the exact same thing your wanting to do. It comes in rolls from 100' to 500'.

Tim in OR · Sep 16, 2012

a buddy of mine used the same plastic air line used on the big rigs to plumb his shop. He used 5/8" because that is what he got his hands on.
I think a tank at each shop would be a great idea.
Tim in OR

Hal/Eastern WA · Sep 16, 2012

Have you considered running some plastic conduit to protect the PEX in the ground? I bet you could run your electrical in the same conduit if you pulled the cable and PEX through together as you connect the sections of conduit. In my very rocky soil, I always put cable in conduit rather than risking direct burial. I haven"t had any buried electrical lines go bad yet and I think using conduit is worth the extra expense. Hard work to dig trenches here, and I don"t want to have to do them over.

I would also be worried about condensation in the buried air line. A fairly large pressure tank at the end of the buried line would be a good way of dealing with the condensation and giving a good way of draining it.

Before I did the installation, I would do some research with the manufacturer of the PEX to see what they think about using it for an air line long term. Almost everything I have ever heard about PEX is that it is a great choice for water lines. But I haven"t read much about using it for air lines. It sure seems easy to work with and isn"t THAT expensive. If you find out something, please let us know what you come up with. Good luck!

paul · Sep 16, 2012

PVC is a bad choice for air, if it ages, gets exposed to oil or sun for a while, or gets hit it can shatter into a lot of high-powered pieces.

In your case, the portions under ground that probably wouldn't be a problem but I'd be concered about any short exposed ends in each building.

I've heard pex works good, and the rapidair tubes work well.

--->Paul

Stephen Newell · Sep 17, 2012

I have worked around schedule 40 pvc used for air for 40 years and have never seen or heard from anyone I worked with about a pipe exploding on its own. Depending on the size pipe you use PVC pipe is rated at 270 psi or more for 1" or smaller pipe. I suspect the shrapnel stories are from people that came too close or exceeded that threshold. If you don't need 175 psi, you could regulate the pressure down to 100 psi and it would be even safer. I have worked for people that didn't know they need to properly secure the ends where you attach the air hose to. These I've seen get broken off but there was no shrapnel. I adapt to galvanized pipe to where I can securely fasten the pipe to the wall with the air coupler on it. As far as running underground I have my compressor 50' from my shop and have the pipe run underground and I also have another line run 200 yards to my house run underground with 3/4" schedule 40.

Hobo,NC · Sep 17, 2012

I have a run underground in copper its extremely rare I see any water in my air... Any water I have seen is from the compressor... I have a auto drain on the one that makes water why it makes water I don't know other than I spec its the nature of the beast... I run that one in the cooler mo. and the one that don't in the warmer mo. The one that does not have a water issue has a filter with a drain between the pump and tank that catches most of the water before it gets in the tank,,, the one that has a water issue has the filter mounted at the tank were the air exits the tank....

Bill in IL · Sep 17, 2012

I buried galvanized pipe for mine about 10 years ago. Put a conduit pipe in beside it so in the future when the air pipe goes bad I can pull a hose or PEX through it. The conduit would give you more flexibility for the future.

M w J · Sep 17, 2012

I buried 175 Ft of regular air hose in 2000 I have a 6 hp 2 stage compressor and use it to paint and sandblast It don't freeze and it don't leak yet If it does leak I will bury another just like it.

paul · Sep 18, 2012

It's one of those deals, if you are the 99 people it won't never affect you and you wonder what the fuss is about. If you are that one person, well then your world just changed a whole lot & it coulda been prevented....

I don't buy lottery tickets, but I like to keep long-term deals a little bit safe - one plays the odds; if you are installing air pipe why not go a little safer route than PVC? Odds are nothing will happen, but if it does... Braided hose will rupture, metal pipe will pinhole or split a seam, hard plastic will blow around in small pieces with 100-175 lbs of force behind it.

When we have these discussions always several that have picked imbedded PVC out of the woodwork, and so forth, why be exposed to that?

Seems like a pretty simple consideration, play the odds for exposed uses.

--->Paul

old popper · Sep 18, 2012

Look in your Northern Hydraulics catalog for "Rapid Air" tubing. They carry it in 3/4" size as well as half. Just an idea. Dale

scotc · Sep 19, 2012

The PVC will burst at a higher pressure underground because it will be surrounded by dirt, which pushes back on it, unlike air.

Adapt steel to PVC at each end to come out of the ground, and run PVC underground only.

If it does break, it won't be going anywhere.

You might want to put a drip in the line ahead of your secondary tank. Just a T in the line with an adapter and a larger piece of pipe screwed into it, with a ball valve at the bottom of that. It will catch a lot of moisture and help save the tank.

Buried air line

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