running air lines long distances

[bdog]

my breaker box for my house is in my garage. it is a 400 amp unit. my garage is just for parking cars kids bikes wifes junk and i have a seperate detached shop for all my tools, working on things, etc.

i will be buying a 240 v air compressor but my shop only has 120 volt service and is about 80 feet from the garage. instead of running 240 to the shop i was thinking of putting the compressor in the garage and running pipe to the shop. due to high copper prices i was thinking black iron.

questions

1) what size pipe needed to avoid losses? i am looking at a 15-20 cfm compressor at 175. basic home use such as impact, ratchets, ocassional sander maybe paint.

2) any issues running the pipe outside? i have a wooden fence that runs from the garage to shop. was thinking of running the pipe above ground and secured to fence.

 

[CRAZYASTRO]

Can't give u any advise on the size of the lines, but my company (printery) is using three huge compressors and 3,5 inch lines are the "tank". So u could use big enough lines as an extra tank... I dunno about running the lines under the fence, maybe the weather giveu some trouble about water in the lines, but with a good water seperator u shouldbe good...

 

[KenS]

I ran underground service to a 100 amp subpanel in my detached garage-- the garage is about 75 feet from the house-- and have never looked back. The compressor (80 gallon 21 CFM) noise is isolated from the house, plus I have two additional 220 volt outlets for welders-- one in the front of the garage and one in the back. I had heavy-duty 20-amp outlets located 36-inches off the floor installed every few feet around the garage. With the subpanel my lights never flicker even when I'm pulling amps with power tools.

I know there's an ongoing discussion here about pros and cons of copper versus black iron pipe, but I can tell you this for certain: Last night I disassembled a relatively new Milton regular and water separator that had been plumbed with black iron. I could not believe the amount of rust that had accumulated. I have never seen that in copper even years after it has been installed. Yesterday I priced 3/4-inch M copper pipe at $1.59 per foot and I expect the price will be dropping in the weeks to come.

I would estimate your cost to run a copper line from the house to the garage to run in $300 to $600 range, the former for above ground and the latter for underground installation.

The upgraded electrical service is going to cost about $1,500 to $2,500. In either case I would bury the lines. Even if you decide not to go with an upgraded 220-volt subpanel in the garage, do yourself and a favor and when the ditch is being dug for the air line, go ahead an install a run of large underground-rated electrical conduit -- large enough to allow three or four No. 2 cables to be pulled through it, and two extra 3/4-inch to 1 1/2-inch conduits for future needs, i.e., cable tv, internet, telephone, remote garage light switches, intercom, etc. The conduit cost will be $100 at most and will be ready for future upgrades.

 

[bdog]

Thanks for the replies. The problem I have with underground is everything here is underground. In the general area between my house and shop I have a sprinkler system, buried phone line, buried cable line, buried gas line, and buried main electrical feed to house. I have no idea where any of this stuff is and thus am scared to dig a trench for any new lines for fear of digging in to something else. If this wasn't the case I would definitely just trench in an electric line for the shop and put 220 there. I do a lot of welding but my business shop is only a couple miles down the road and I have welders there so I have never really needed 220 for welders in my shop at home.

The reason I go to thinking about putting the compressor in the garage and running the air lines to the shop is that I think it would be safe and not violating any codes to have them above ground. Unless I went with a really large pipe I could secure it to the fence that runs between the garage and shop and it would not be noticable.

The benefits I see are not hearing the compressor when I am working in the shop, having the compressor in the garage in case I need to air up a flat tire on the cars or kids bikes, etc, and ultimately a cheaper install. I just do not know if there is anything I need to worry about by having the lines above ground outside and what size I need to run. I know bigger is better, but I am trying to more or less hide the lines on the fence.

 

[Lyaec350]

Black iron outside is a bad idea. It will rust and look terrible. Just go with copper, that would be fine outside plus 80' of 3/4" copper with a water filter where it enters your shop would be an amazing water separator, that much copper exposed to outside air will really cool the air in the pipes, dropping most of the water out.

Around here 3/4" copper is ~$17 for a 10' stick, so even at $20, you'd only have $160 into the copper pipe, not unreasonable at all. Screw it to the fence (maybe near the bottom under a board or something with those copper clamps and you'd be good to go. Make sure you turned the air compressor off after using it though as that much exposed line would be easy to damage without noticing it letting your compressor run for days until you figured it out.

 

[d110pickup]

I connected my air supply from the detached garage to my basement workshop using PEX pipe. Here's my shop build:
http://www.garagejournal.com/forum/showthread.php?t=10218

Mike

 

[engnerdan]

If you do go the copper route, I would paint it to match the fence, so it is less noticable to anybody. Don't want yoru copper pipe stolen.

-Dan

 

[Major Ramifications]

It would be a hell of a lot easier to run wire than to run pipe. Not to mention you would then have all the electricity you could ever need in your shop.
Wow, you must have one heck of a house to have a 400 amp panel.

 

[bdog]

It would be a hell of a lot easier to run wire than to run pipe. Not to mention you would then have all the electricity you could ever need in your shop.
Wow, you must have one heck of a house to have a 400 amp panel.

Not trying to argue but how? Wire would have to be underground, I would need to locate all the other lines, dig a trench, etc. With pipe it would just be four 20' sticks on a straight run and then some connections on each end to complete it.

My house is nothing special. It is 3000 sq feet but the previous owner was the builder and really beefed up a lot of things which makes me wonder why the shop only has 110 v but that is a nother story.

 

[txz28]

I would be careful with copper pipe or black iron and the newer ACQ pressure treated wood it can rust it quickly from the outside. You may want to add plastic spacers to keep it from touching the wood.

I would probably also do copper for the pipe rusting problem.

One other consideration, where do you live. Will water freeze in the pipe there? If that is the case, put low point drains on the pipe and keep them dry in the winter. You could still freeze water to the inside walls in the winter and eventually plug it up with that long of a pipe, especially if the outside is covered with snow/ice. You probably want to make sure your air is as dry as possible before sending though the pipe if this is a problem. We have no such problem here in Texas.

As for the pressure drop, do not regulate the pressure down at the compressor, the higher the pressure, the more flow you can fit into the pipe. Regulate the pressure down in the garage. I calculated a couple of quick numbers with 175 psi from the compressor, and regulated down to 90 psi delivering 20 cfm @ 90psi. A 2" pipe is fine. The pipe pressure drop is <1.0 psi/100 ft. of pipe.

 

[kvom]

Pex can't be used outside, as it degrades in sunlight.

 

[wilbilt]

Not trying to argue but how? Wire would have to be underground, I would need to locate all the other lines, dig a trench, etc. With pipe it would just be four 20' sticks on a straight run and then some connections on each end to complete it.

My house is nothing special. It is 3000 sq feet but the previous owner was the builder and really beefed up a lot of things which makes me wonder why the shop only has 110 v but that is a nother story.

You could run the electrical in PVC conduit along the same fence as the iron pipe, no?

 

[bdog]

You could run the electrical in PVC conduit along the same fence as the iron pipe, no?

Practically yes, but I don't think so. My area codes, etc state all electrical must be underground. They have no rules for air lines.

 

[speed bump]

Its easier to have 220 in the garage becuase one day you might want a welder as well.

 

[Vicegrip]

a straight 80 foot run of copper better have expansion and contraction abatement or it might crack at the couplings. PEX in a 3/4 PVC pipe or strung through a garden hose might work.

Better yet you mention that you want to use impact guns and other intermittent use air tools. How about a good 120V compressor and just plug it in? The one you mention is big time overkill for what you listed.

 

[Pedro-snapon]

or how about a phase converter.... I'm not sure if they will work but i do remembrance my dad a few years ago getting one to run a drill press that required 240 and he only had 120....

 

[speed bump]

I thought those were to run 3-phase tools starting from single-phase 240V. You mean a step up transformer?

Personally I would bite the bullet and run electrical service. A good surveyor with proper equipment should be able to locate buried water/gas lines for you.

If you run the air lines the distance I would do as OldCarGuy did and remove the water with a refrigerated drier before sending it outside.

Hell, your local utility will come out and mark everything for you for free if your call a couple of days in advance.

 

[bdog]

Hell, your local utility will come out and mark everything for you for free if your call a couple of days in advance.

Even if it is my own lines? By that I mean after the meter. The meter is in the alley. It goes underground from there to my house.

I do have a 120V compressor now and it does not really keep up. It is an oiless craftsman and is loud.

I may look at running the 220, but as I said above no need for a welder as I have mig, stick, torches, chop saws, basically a complete metal shop for my business that is a couple miles down the road. Any welding I go there.

 

[dwilliams35]

Practically yes, but I don't think so. My area codes, etc state all electrical must be underground. They have no rules for air lines.

you sure that isn't just a pvc issue? Put it in steel conduit and there really shouldn't be a problem.

 

[rickairmedic]

You can call BUDS ( buried utilities department ) in your area and they will come out and mark everything in your yard for free . We have to do it all the time when digging for sewers and water lines and yes they will mark your yard even on your side of the meters . The utlity companies have maps of everything burried in your yard that wasnt put in by a homeowner .


Rick

 

[bdog]

Actually I think it is a deed restriction not so much an electrical code.

We do not have an HOA but there are a buttload of rules in my neighboorhood. The airlines on the fence probably would hack them off but I doubt they could stop me. Besides I was going to run them inside the fence about 6" above ground. Would not really be noticable.