PVC breaks, black pipe as well as galvanized pipe rusts from the inside. Our shop is piped with 1" rigid copper with compression fittings. I run everything through a 50 CFM refrigerated air dryer. I use 1" hydraulic hoses for the dryer. I had a pretty neat installation until the dryer I had for about 20 years quit. I bought a different brand that had the outlets placed differently.

https://plus.google.com/10819770718...7945047986&oid=108197707187186692269

This piping is in an unheated shed and we do get temperatures in the teens, single digits and occasionally down to 0°. We need air, and can't afford freeze ups.