[lbnaz]

I have been a Union Steamfitter for 48 years now 39 of which I worked at the trade. All of the systems mentioned will work in a shop. I personally used 3/4" (7/8" od) type L copper with sweat joints, dirt legs, and valves for blow off on all my drops. My compressor runs at a 125 psi in the system. The use of black iron sch 40 pipe is used industry wide in most commercial applications and is highly recommended. It resists breakage, bumps, tugs, etc. on the system. PVC is subject to burst with any of the same. Just my 2 cents.