Off topic: Shop Compressed Air Plumbing dangers

Very good point and advice. The shop I am in was also plumbed up with pvc for air, the lines are still there but not connected to air. I had seen pvc lines blow apart before and it is just not worth the risk of injury or worse.
Mike

PVC like most plastics get brittle when old or cold, add compressed air (stored energy) then sooner or later something impacts the pipe and you have a gernade. Steel or copper is first choice, then install with grade to a low point drain when possible.

I was in a shop that had hundreds of feet of 4 and 6 inch schedule 80 pvc installed for a chilled water system, the contractor tested it with compressed air, a 6 inch 90 let loose (poor glue joint) no one with serious injuries but ringing ears and wet pants.

The installation instructions provided by the manufactured warned aginst using it for compressed air.

I was a plumber for a few years and having worked with PVC I could never understand why people use it for air lines. As was said allready copper or steel pipe is the best choice, also having a shut off valve for each air chuck is a good idea.

This is a link to one company that makes air piping systems for do-it-yourself-ers.
http://rapidairproducts.com/

Worth pricing it. I've heard it goes up fast. There are also special plastic glue together pipes and fittings that are approved for air service. The brand we have is green colored and uses special glue, not PVC glue. Have had some leaks in glue joints, so I don't think it is necessarily the easiest stuff to work with. We have some in our shop along with some regular galvanized pipe. I don't think there is any prohibition against galvanized in air systems (and I've heard that it is listed for natural gas and propane these days even though it didn't used to be because of the tendency for the gas to remove the interior galvanizing coating and plug filters and valves. Not sure what has changed in gas piping, but other than black pipe being cheaper than galvanized (I guess), I would use galvanized to stop a lot of the corrosion in the air piping system.

I brought the PVC air lines up in our weekly safety meeting at work today. My plumbing contractor mentioned that in the past 5 years they have seen a number of projects with 200 PSI PEX pipe specified for the air distribution systems up to 1" and steel or copper for the bigger lines. They claim PEX will stay pliable long term. Only time will tell. He says they never use PVC any more.