PVC is allowed by OSHA if it's encased in some outer conduit, so that if it ruptures the outer conduit absorbs the shards.
If it was me, I'd dig a hole near the compressor and put some kind of conduit or in-ground compartment in, run a line down into that compartment, switch to schedule-40 PVC, run that fairly deep underground in the Earth all of the way to the other end, install a similar compartment there, and switch back. That lets the Earth absorb any PVC rupture along the line, lets the compartment absorb one at either end, and keeps something like a cast iron pipe from being put directly into Earth where it would probably rust.
On another note, I'm using PVC in my workshop, partially because lots of it was already there. I'm not especially worried about any given pipe rupturing. I'm more worried about a PVC to brass joint failing, or a PVC coupling giving out where the glue is. All of the PVC in my shop is rated for 600psi, and since my compressor tops out max at 155 when the overpressure valve would kick in, and since the compressor is currently shutting itself off at 125psi, the chances of a catastrophic blowout are very, very low.
Some day maybe I'll replace it with something stronger, but that'll probably wait for a more powerful compressor to cause a demand for it.
