I've read about using PVC, and does not sound like a long lasting and safe idea to me, although I gather it does work. I won't try it.
Black iron and or copper seem to be the most reliable and pretty expensive. Although there are specialty air line products out there too that are quite expensive.
It's a hard decision and hard to understand and compare the options, risk, and benefits. I don't yet know what I'll do.
Grigg
