Quote Originally Posted by 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.
I don't know where you live but where I am copper is definitely not inexpensive. My plumbing contractor suggested black pipe. He said he has used it for many customers like gas stations and the like. Just remember to add drains at both ends of the run. I do agree to avoid PVC.