OK THE GOOD THE BAD THE UGLY ,, PVC ?..brittle ..YES...degradaition from chemicals maybe.
Cast Iron ...tough but will over time definately rust from the inside out .."seen it happen" and fail.
Galvanized , will definately corrode and and fail in time ....I HATE GALVANIZED ....so I am Bias.
If you are building or redoing your shop air supply .....I an most will agree ...I know this is expensive ...but bye OSHA regs and all that is right in the world ..for safety and long term use ...COPPER is the choice ..for any air supply system ...so make your choice ?..for me i dont worry bought the PVC in my shop but then again i didnt have to spend 10 times more for what copper would cost ...so it is each his own on this subject.
NOUGH SAID
