PVC for Compressed Air Line

[Greg Caputo]

Hi, everyone. I want to install some piping for compressed air in the workshop. I have a fairly typical weekend warrior shop in the basement. No one else ever uses the shop. The line will have three drops, one of the drops for spraying. I've read a lot over the years about the need to use black pipe or copper tubing. But a recent woodworking magazine featured a piece on using some sort of flexible rubber or plastic hose. And I've seen photos of shops with PVC for the air. I'm leaning towards PVC due to ease of installation and removal, if we ever move. I can't do black pipe...no experience and no tools. I'd rather not do copper if I don't have to. Any experiences or thoughts from folks who are using or have used PVC? As always, thanks for your advice and guidance.

Greg

[Chris Padilla]

PVC and copper (maybe the thicker-walled ones can?) aren't typically designed to handle the PSI load that an air compressor supplies so I don't think they are good materials to use.

The flex rubber stuff you saw might have been air compressor rated or something known as Flexsteel. What magazine did you see this in...what issue?

[Jim Becker]

"Just say no to PVC" for this application. It's not rated for compressed air. Yes, some people have used it successfully, but it's not the right product for the job. Copper is easy and inexpensive.

As to the flexible hose, I use the Flexeel hose that Chris mentions and have a review of it on my web site.

[Ed Labadie]

I think the only PVC pipe that has a high enough pressure rating for air line use is schedule 80. You will probably have a hard time finding it. It's not available at the Borg. Not all plumbing supply houses carry it.

Ed

[Chris Haney]

There was an article in September issue of American Woodworker (p. 57) about using rubber air hose with copper fittings for plumbing a shop with compressed air. At the end of the article, they reference MSC Industrial Supply as a materials source (www.mscdirect.com). It looks like a pretty good alternative to using copper or iron pipes. The MSC part number referenced for the 1/2" rubber hose is 48563720 and can be found on this page of the MSc site: http://www1.mscdirect.com/CGI/NNSRIT...PMPXNO=1903625. It (currently) costs $.78/foot and is cut to length. They also sell other air handling hoses with increased PSI ratings.

[Kyle Kraft]

PVC pipe can rupture suddenly under pressure and is not to be used for compressed air piping. Check the OSHA website. Type K copper is perfectly ok. I actually used type M in my shop, but I regulate my air to 100lbs or less. Copper is nice because you don't get the rust and scale flaking off when moisture is present, however, if you have a properly designed compressed air system you can reduce the amount condensate in it.

[George Leicht]

I would seriously look at black iron. I agree with Jim Becker that copper is easy, but it hasn't been inexpensive for a while. Black iron is not as easy as copper, but it's not that difficult.
George

[Kyle Kraft]

Thats true George, copper has gone out of sight recently. I figure the value of my house and shop has gone up several thousand dollars just 'cuz of all the precious metals in them!

Go rent a pipe threader and a tri-stand and go to her!

[Jeffrey Makiel]

Regardless of pipe material and rating, all pipe has the potential of failure (manufacturer defect, improper installation, being struck by an object, etc). The issue is that PVC will shatter should it rupture thus sending air propelled shards of hard plastic all over the place. This is not the case with copper.

My recommendation: avoid the PVC, CPVC and ABS pipe for compressed air use.

cheers, Jeff

[Brad Townsend]

Although not designed for high pressure air, copper seems to work fine. I suppose theoretically, both it and PVC could burst, but I've never heard of such with copper. The difference as I see it, if copper bursts, it will just split and not send shrapnel flying everywhere. I'm not so sure that would be true of PVC.

[Jeffrey Makiel]

Threaded black pipe can be difficult to get leak tight at air pressures of 125 to 175 psi. This may not be important, but can be a nuisance because it will bleed down the air compressor's tank between uses unless it's valved off near the tank. Black pipe is best suited for low pressure applications like natural gas and low pressure steam (less than 15 psi).

cheers, Jeff

[Keith Weber]

PVC + High Pressure = Shrapnel (IMHO!)

Yes, PVC has the pressure rating, in theory, to handle the pressures you are talking about. But, there are a number of things to consider. The pressure rating of PVC drops considerably in warmer temperatures. In colder temperatures, it becomes brittle. If a pressurized PVC pipe is exposed in your shop, you could accidentally bump it with a long piece of wood as you turn it around. If the bump causes it to shatter, the one who bumped it is going to be in the immediated vicinity during the resultant shrapnel attack. PVC will weaken with exposure to UV light. Try whacking that old sun-bleached PVC pipe in your back yard against a tree and see what happens!

I plan on using type L copper when I get around to doing mine. It handles moisture better than the steel varieties, is easy to work with, and will give me a piece of mind that I'm not working around a potential land mine. Type L is a little more expensive than Type M, but its pressure rating is a little higher.

If you need an alternative, that rubber air hose idea someone mentioned sounds safer than PVC. I don't think that the air would flow as well, though, because the fittings would act as bottlenecks in your system.

Keith

[Robert Mickley]

Nylon tubing, easy to cut, goes together with compression fittings, you can go back later and cut it to add in a drop.

No soldering, no gluing, no special tools.

Rated in a range of about 450 to 550 PSI.
Easy to disassemble and take with you, comes in sizes from 1/8 inch to 3/4

Check out Semi truck parts houses and it can be bought online in price range of .25 to 1.00 a foot For the most part I bet thats cheaper than steel or copper.

[Greg Caputo]

These are great responses and ideas! So much for my hope to use PVC.

Chris has the citation for the magazine article I mentioned. But this method still requires sweating copper for the drops. The nylon tubing idea from Robert is something I've not seen before. It sounds like it could meet all the requirements I have, especially if it can be accomplished with compression fittings. I'll look at the Grainger catalog, but any other ideas for sources?

Thanks to everyone from your help.

Greg

[Rick Lizek]

PVC is banned by OSHA with good reason. Type L or K copper is fine for the shop. Faster to use but pricey is abs air line...
http://www.indelco.com/c-345-compres...ir-piping.aspx
Drops should go up then down, see diagram...
http://www.tptools.com/statictext/ai...ng-diagram.pdf
Info based on fixing improperly insatalled air line sytems.