# Underground Air Line



## Gregn (Mar 26, 2010)

I finally got my 60 gal. Air Compressor out of storage and moved into the 10×12 shed that it will be housed in. I will be running a 220 line from the shop to the shed for power and plan to bury the Air Line with the conduit for the power. I have some 1" galvanized pipe I thought might be a good candidate for underground Air Line and for the parts that will be exposed to the elements going into both buildings. Once in the walls I thought I would use reducers to go with smaller pipe for Air Line. While I feel confidant this will work and is only a 30' run. I was wondering what you would do in this situation. Since both buildings sit on blocks and have settled into place I don't for see much more settling happening to cause a problem with the Air Line. But I have been wrong before with my calculations, so your opinion matters as someone else may have a better idea.


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## patron (Apr 2, 2009)

for underground pipe
i would use the blue vinyl covered black iron
they require for gas lines
and if you are in a freeze zone
the air will condense into water
inside the pipe and could freeze
water separators work
but not for the first 50' 
insulate well underground
some of those rubber sleeves
and maybe a box made from sheet Styrofoam
the sides can be silicon-ed to the bottom
and the top left with just dirt on it
in case you need to dig it up sometime
a union in the line helps all repair work

i have to bury my water line 5' to keep it from freezing
and my air compressor under the house 
will freeze on extreme cold nights
as does the air hose coming up into the shop

this summer just one skirt to go
(house is up on stilts)
and i can be done with freezing under there


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## Bertha (Jan 10, 2011)

Do you have to use rigid pipe? I think there are specific lines designed for underground. I'm an air guy but mine's blasting my ears out IN my shop.


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## patron (Apr 2, 2009)

not really *al*
but plastic cracks if it freezes

they got some new water lines that expand if frozen 
and don't break and used with some of those push on 
fittings is a great way to go if you don't mind the cost

galvanized rot's over a period of time

why so many old homes need new supply lines to the house


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## Gregn (Mar 26, 2010)

Thanks David I didn't take freeze line into account. I will have to check into the blue vinyl covered pipe.
No Al, I don't have to use rigid pipe. I just happen to have the 1" on hand and had thought it might be a good candidate for a project finally.Noise is one of the reasons for putting it in the shed besides the space requirements in the shop.


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## patron (Apr 2, 2009)

greg

they have tape that goes with the gas line pipe
it could wrap around your 1" line
(might cost a little for a 30' wrap) 
but the insulation is always a good idea
even without the tape
it will probably last your lifetime anyway

i might put a tee in the middle underground
and an access to drain the line if it gets
to be a problem
just make it the lowest in the line
so it runs to it


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## gene (Oct 8, 2007)

Gregn,
The black pipe will cause rust to form in the line because of the moisture content in the air. This can bleed through to tools and spray equipment. Your first idea is the best. As for the settling part. In both buildings, Stub the lines up close to the inside wall with a slight gap. You can find a place that sells hydraulic hoses for large trucks and construction equipment and they will make one up with 1" male threads on each end to give you the flexibility you might require. That's how I connected my compressor, to reduce vibration. I hope this information from an ole plumber is of some help. As for the freeze factor, to be safe, you should bury below your area frost line. 
God bless


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## patron (Apr 2, 2009)

thanks *gene*
i didn't know that about black pipe
but it makes sense


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## Gene01 (Jan 5, 2009)

I've NEVER disagreed with David before. However, I must here.
Remember that natural gas and/or propane is under far less pressure than your compressor can put out. I was advised to use rigid copper or cpvc. Copper is way too expensive, so I used cpvc and left the ditch open for a month to check my joints for leakage. It's been underground for 12 years now, with no problems. I only went 20' and I'm in AZ. It does freeze here, but so far, no busted air pipes. Have had some plastic water pipes to the irrigation system break, though.


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## Maggiepic (Aug 26, 2010)

I would go along Bently's line of thought. Run 1 1/4" plastic electrical conduit and then pull a 3/8" polyurethane air line through it. No worries of flex problems and if you ever have leaks in the the future, just pull a new air line through it. 
Do the same with your power feed, put it in conduit


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## patron (Apr 2, 2009)

all great information

so much to learn
just with the proven things

with the new products and advances

there seems to be no way to learn it all

why LJ's sharing is so good


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## KentS (May 27, 2009)

David, my dad had black pipe for airline in his shop for years. Trust me, rust coming out at 100 PSI as you blow dust off you clothes is painful. (For the safety concious among us, yeah I know, don't use compressed air for that. But we have dark purple carpet in our bedroom and bath. Would you rather deal with high pressure air--or *HER* ! I use galvanized now, but it is not in the ground.

I think I like bentlyj's idea-that is worth thinking about.

All that said, I prefer airlines and dust collection pipe to run overhead. Not as pretty, but it sure is easier to change when you need to-and I find I need to frequently.


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## Gregn (Mar 26, 2010)

Actually Bentlyj your idea isn't as weird as you may think. You and GaryL just continue to confirm what some locals have suggested to me as well. In fact by doing it that way it would keep cost down as I already have the air hose as well to use. So now talking about the frost line and keeping the air line from freezing has me thinking I may need a small heater in the shed to help keep water from freezing in the tank on those cold winter days and nights.


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