Underground Air Line?

[renolaw]

Our shop build (visible in rr) is coming along well and we have a dilemma. From the main garage to the shop is 97'. We are in the process of adding a utility trench to carry two #80 lines of conduit-- one for all the juice and another for phone and cable lines. A trusted buddy suggests adding a 3rd line to carry some air hose as well. Here's why.

the main 'garage' has a 30 gal compressor and installed hose reels. Now that we have the new 'shop' going in, its either get a 2ed compressor or, like suggested, run a long air line from the gasrage to the shop and plumb it out that way. seems simple and nothing to lose, but i humbly seek my fellow pirate brothers' advice.

is this doable or silly? seems nice to be able to use the remote compressor and not need ear protection when in the shop. This is a residential appliction, so no commercial woes or whatever.

thanks guys for ur ideas and suggestions. Here's the trench. Yes, it's all rock and the jackhammer does help...

http://i2.photobucket.com/albums/y12/RARECJ8/DSC02406.jpg

http://i2.photobucket.com/albums/y12/RARECJ8/DSC02407.jpg
mb

[rockcrawln]

I don't see why SCH 80 or even SCH 40 wouldn't do the trick. The only think I don't know about is the effect of the freezing conditions on the PVC since the pipe isn't very deep. Just make sure you prime and glue the pipe well.

[nate379]

I wouldn't even waste my time with a 30 gal air compressor to run air lines to another building.

Now if you want to put a 60-80 gal compressor in your garage, and noise in the garage isn't an issue, that'd work out pretty nice.

You could just build an outbuilding on the side of the shop for the compressor, or like in my Dad's shop, the compressor is on the 2nd floor of the shop and you can't hear it other that the ceiling vibrating a little bit.

Is that trench even deep enough?... how deep does frost go? Any cars going to run over the ground? Any foot traffic? Personally I'd go at least 3 feet, but that's perhaps because I grew up in Northern Maine where the frost is pretty deep... water lines are 6-8 feet under.

[Aces'n'8s]

I thought water expands when it freezes and air compresses when it becomes chilly....below freezing point. So why does the depth i.e. frostline matter? I would worry more about priming and glueing the joints correctly than cold air fracturing a line.

BTW, man I'm I glad I didn't have to trench that soil. That soil looks like something an evil USMC drill instructor would use to break in a mouthy recruit.

[Jeepermat]

I wouldnt bother unless you plan on getting a much bigger compressor

[472Scout]

Sounds like a great plan. I hate compressor noise. Maybe run some wires for a remote switch while you're at it.

Why not just use one big PVC pipe for all the lines. EMI?

[PTSchram]

the use of PVC for air lines has been discussed before.

Galvanized iron is probably the best. I suspect that by the time you bought the pipe and assembled it, you'd begin to think a second compressor was a good idea.

[randii]

As much fun as that ditch was to dig, I can't see using anything that might ever fail (PVC, for instance). I'd probably use some galvanized pipe and make damn sure it doesn't have leaks before I bury. Put it in at enough of an angle to ensure that it drains to the low point, and have some mechanism to bleed off condensate, even if that means using an auto-drain valve, such as: http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?ItemId=1611787219 (cheaper ones are available, but this was the results of a quick search).

For sure, run as large a conduit as you can afford just in case you ever change your wiring needs... digging that ditch again would suck hard.

Randii

[Travis Waldher]

I hate to say it, but I would dig deeper.

Depending on how much power you intend to pull through the power conduit, you may cause EMI problems for your data conduit if the two are too close.

I'de also run 1" galvanized for the air. Even if you don't use the compressor in the other building in the future because of it's size. It can be handy having an airline in a remote building when your air compressor is in the new building.

[300sniper]

I thought water expands when it freezes and air compresses when it becomes chilly....below freezing point.

i will almost guarantee that an underground line will get quite a bit of water in it from the air compressing. it is most likely to be the lowest part of the system and no way to drain it.




if you do wish to do this i would suggest running a 1-1/2" - 2" sch40 pvc pipe as a sleeve with your air pipe going through it, especially if there is going to be concrete placed over it. if there ever is a problem with the pipe you will only need to expose the ends to yank the main pipe out of the sleeve and replace it. this will also protect the main pipe during back fill. definatly still bed it with and cover it with at least 6" of sand.

like others have said, i think you're asking too much out of your 30 gallon compressor.

weather you do or don't do the air line, i would recommend adding an additional conduit for future use. you never know what you may want to add later down the line. the ditch is dug now and conduit is cheep.

[renolaw]

thanks for all the replies. the original plan is to add a separate line for air-- sleeved of course. my contractor buddy, doing most of the work, suggested a special copper then lay the line inside that. (their business is designing and constructing gas stations, fuel tanks, etc.) The plan was to sell the 30 gal and put in a big mutha in the garage to supply the shop as well. After much thought, i'm nixing the air line idea. will likely get another compressor and build a 'dog house' for it outside nest to the shop. the trench is in solid rock and meets local codes. two lines will go in-- one for power from main panel to sub panel (97' distance) The other line will carry cable (for the dish network receiver) and a phone line to hard wire the shop. We will also add a 3rd pipe w/ just a pull strap, t hen fill it in properly-- sand, DG, etc. then concrete over-- or maybe use pavers as is favored by the missus. here's a pic of the epoxy flooring just finished this week.

http://i2.photobucket.com/albums/y12/RARECJ8/DSC02411.jpg



and the 'solar-star' sun powered attic fan.

http://i2.photobucket.com/albums/y12/RARECJ8/DSC02414.jpg

[Red90YJ]

It's a great idea use it as a conduit. Once in place pull a rubber hose through it for air. And a wire back to kill the switch. That way you don't need to worry about sealing the pipe.

[tsm1mt]

FWIW, I would run the air line. As others said, something "big" (I ran 3/4" throughout my shop).

At one end, leave an open pit with a trap door, so you can pull the cover, get a bucket under the pipe, and open a drain valve because the water WILL condense in the pipe (which, if you have a way to get it out, would be a very good thing).

I'd put a 60/80gal unit in the old garage, away from my ears.

I'd then put the 30gal unit in the new shop (or just a 30gal tank) to serve two purposes.

1) you want an air receiver to store air in the shop, in case you draw air faster than the 1" (or 2" or whatever) line wants to supply it.

2) you could then stagger the pressure switches so that you usually run the 60/80 unit in the garage, but if your demands exceed what it can put out, the 30gal in the shop kicks in to help out.

[renolaw]

It's a great idea use it as a conduit. Once in place pull a rubber hose through it for air. And a wire back to kill the switch. That way you don't need to worry about sealing the pipe.

i still may be convinced to do this after all-- idea is to lay three #80 PVC pipes and simply pull the 3/4 or 5/8 air hose thru one and adapt it to the main compressor (after junking the 30 unit) and to the shop's hose reels. what is there to lose? if it fails, then i an pull it thru and replace it w/ another or scrap the idea all together. hummmm.....


i'm mmre worried about Electromagnetis interference by running power next to phone/cable. side by side or one on top of the other, i don;t remember. plumbers coming in two days, so i'll post up pix either way.

mb

[tonka22]

burry a 2" pvc and run a soft line through it. if the line degrads just pull a new one through.

[KRMNALMIND]

Run the air in type L copper and just wrap it in 10mil tape. Some sort of drain at your lowest point would be fine. I have run hospital med-gas oxygen, air and medical vacuum. If You can buy a dryer for your supply line it will keep your tools in better shape and keep all condensation out. Also you will never out run a 3/4" line. Just take a look at what coming from the motor to the tank. however the added size means added volume to your system. Also run a ball valve somewhere before your line comes outside and goes underground keeping that line empty as much as possible would also help keep moisture out. I seriously doubt that you would get enough condensation to worry about especially up in our little high desert. the only time would be winter real low temp with that hot air being pumped out some people have built a secondary tank to deal with this to cool the air before it goes down the line that way all the moisture is trapped and drained at the secondary tank. her isa dryer for $300. i was a union plumber for 13 years after i got out of the Marines. I have run miles of pipe on and above ground. you could run this cheaper but this way is solid tried and true. hope that helps.

Semper/Fi

Craig http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=40211

[renolaw]

tnx for the ideas and ur service to uncle sam. where are you located?

mb

[KRMNALMIND]

I'm out in Ferntucky. we are in Reno just about every week and my wife works at Renown medical so sheis there every day. I just started piping out my garage. Now its time to make my son crawl under the house so i can have air quick connectors at each corner. I hate having to drag 200' of hose for every little project. another thing i was going to add above. at each of your points of use add a 6" drop leg with a drain fitting on it. that will make servicing it very simple if necessary. Also you are welcome but never need to thank me. the Marines Saved me as far as i am concerned. I was reborn into someone who knew what honor meant. While my time in the Gulf taught me how to prioritize the important things in life. sorry to ramble

Semper/Fi

Craig

[renolaw]

i have friends that are active over in sandland and another retired master g. sgt. oh, the stories he tells of sneek-n-peek missions in countries we cannot even pronounce will raise the hair on ur neck. Pm for directions and we'd be happy to give u a showing of what we're doing on the shop. we live in panther valley just north of mc carran..

mb

[Hackfabricaton]

Go back to the plan where you were gonna build the attached compressor room. Pour the slab thick and isolated from the shop slab. Mount the unit on 'isolators', insulate the room, use an outside air intake, and have some ventilation for the unit...These things (I've got a 7.5hp IR) put out a lot of heat. I can heat up my 2.5 car garage using mine in the dead of winter.