Running compressed air underground

[DerekW]

Never run compressed air in PVC. It can explode and act like shrapnel causing injury or worse. Copper or sch 40 steel pipe would be much better. If your going to bury it you will need to apply pipe wrap primer and a 10 or 20 mil pipe wrap with 50%overlap tp prevent corrosion. It is also a cood idea to install a die-electric nipple or union to help with electrolosis. When above ground make sure you slope your line to a drip leg that you can blow down once in awhile to remove moisture. Also a good idea to run your drops off of the top to prevent moisture from reaching your air tools.

hey finally someone I feel has common sense or some kind of bad experience to warn others about so when they do it they can say "yup had to learn the hard way that fellow told me not to do that, wish i listened to wise words". honestly I have been in a few shops with pvc pipe run. plain and simple i think it sucks. the one shop had a line seperate after some time. then another time something managed to hit the PVC in the area exposed 12 above shop floor level and the pvc burst and that incident too put the entire shop out of order and into a shop air repair frenzy. oh not to mention the pvc line that burst underground while I was on vacation and they had to dig it up to repair it to get shop operational again. at that same shop the pvc leaked also constantly. we had 2 compressors one was back up for big compressor but it did us no good when the main supply line failed in a 8 bay 4wd shop.



the other shops also had leaks. I learnt way back my potato gun days pvc cant handle pressure.

 

[Royk]

In the garage, I'll run copper. I'm familiar with it and find it easy to work with.



Here's my new idea for underground: 4" corrugated, nonperforated flex drain pipe. I'll pre-run the electric, phone and a conventional air hose through it as well as an extra cord for pulling though any future stuff. Gentle curves should make any future pulls easy.



Roy

 

[MAshley]

Corrugated pipe, may get crushed, and collapse.

It also may bend it weird shapes when you backfill making it difficult to pull other lines in. Also it isn't rated for power. Personally it would be a bad choice. Spend the $$ and get the right conduit pipe. Power, phone, air, and water could all be run with direct burial, or in conduit. If you like the ideas of expansion then run 1 or 2 extra empty lines.

 

[Briman]

Electrical code does not allow high voltage (AC) and low voltage (phone) in same pipe. You could run the 4" drain pipe and then run seperate conduits thru it for the AC and Phone. Depending on your power needs in the detached building and the distance run, your AC cable will probably be fairly large.

In the garage, I'll run copper. I'm familiar with it and find it easy to work with.



Here's my new idea for underground: 4" corrugated, nonperforated flex drain pipe. I'll pre-run the electric, phone and a conventional air hose through it as well as an extra cord for pulling though any future stuff. Gentle curves should make any future pulls easy.



Roy

 

[LMcCary]

Please listen to SOUTH DAKOTA, do not use PVC. Some of you are just lucky enough to get by for a long time use. But many people have been hurt from PVC explosions. Just a friendly warning!

LMcCary

 

[GHarman]

Please listen to SOUTH DAKOTA, do not use PVC. Some of you are just lucky enough to get by for a long time use. But many people have been hurt from PVC explosions. Just a friendly warning!

LMcCary

See also reply #15. GregH

 

[Royk]

Corrugated pipe, may get crushed, and collapse.

I've heard a couple other people say this, yet I have tons of the stuff on my property and none has ever collapsed, even the shallow dug pipes that I drive over often. I've had triaxle loads of stone go over some with no problem. This particular pipe will see virtually no traffic other than my compact farm tractor.



What type of conduit do you bury in the ground? Black poly? Wouldn't steel rust over time? I used direct burial AC wire (type UF I believe) when I built my horse barn in the past, but I wouldn't want to do that with an air hose or phone line.



As far as codes, one of the perks of living way out in the boonies is that some things may be "overlooked".



Roy

 

[msperos]

I have sold commercial piping for the last 15 years. Do not run compressed air in PVC. There is no maker of PVC that condones it's us for compressed gas. We sell a product called KITEC, it is fantastic for compressed gas it is two layers of polyethylene with an aluminum layer in between. It is a little pricey but worth it to insure my kids safety when around charged air lines.

 

[tgordon]

Brimann, is that a national code, or a state code?



If you are going to go with underground pipe and run everything through it, I would go with a poly, just less likely to conduct electricity in the event of an exposed wire etc. Just my . 02 woth.



Troy

 

[Briman]

National electric code.

 

[tgordon]

I better stick to the shade tree work after the final inspections are done:-laf



Troy

 

[tony597fitter]

What we do in the field is use 3" or 4" pvc and run copper through that. You can pick up soft copper rolls in 50' and 100'. Just snake the line through your straight lengths of pvc and then put the elbows on it. You can get away with 1/2" copper for air lines.

 

[Dieselnut59]

I've heard a couple other people say this, yet I have tons of the stuff on my property and none has ever collapsed, even the shallow dug pipes that I drive over often. I've had triaxle loads of stone go over some with no problem. This particular pipe will see virtually no traffic other than my compact farm tractor.



What type of conduit do you bury in the ground? Black poly? Wouldn't steel rust over time? I used direct burial AC wire (type UF I believe) when I built my horse barn in the past, but I wouldn't want to do that with an air hose or phone line.



As far as codes, one of the perks of living way out in the boonies is that some things may be "overlooked".



Roy

I am also thankful for living in the "boonies"! I buried a 2. 5" conduit from my house to my shop (250'). While the trench was open, I also buried a 50 amp direct bury cable so I can run my well and house (all gas appliances) with my welder/generator (in the shop) if the power goes out. I pulled phone, data, coax (for satellite TV) and several # 12 and # 10 wires just in case I ever need anything 3-phase in the house or want to switch a light from either location. I also pulled a 4 conductor low voltage wire for future security, etc use and a "puller wire" in case I need to feed anything else through in the future. The feds will never know what's in there! I do as much as I can using my common sense and flying "under the radar" of "big brother"!

As for the air, I just might pull a pvc hose through the conduit. It will be nice to have an air supply at the house in case I need it! I like that idea!