So i have been tasked with plumbing up an air system in our new building from scratch and wondering what my options are. Ones I can think of are: Copper (too expensive) Galvanized steel pipe (maybe) DOT air line (line isn't bad but fittings are pricey) PEX (?) PVC (i know...it could explode and kill me....) ? This is a very large building (80'x120') so it's important to be cost efficient. What would be my best option? Also this is primarily an equipment shed that will be used some of the time for servicing the equipment, so how should i lay out the the outlets?