Good advice Bob on not using PVC for air! I have seen that done in an

industrial setting many times and when I questioned it the
maintenance dept.
they would point to the pressure rating on the pipe and claim it to
be OK.

I can't imagine standing next to 1/2" PVC or larger at 120 PSI when it
let go.

I had a 1/8" ID plastic tube let go about 2 feet from my head when
testing a valve years ago. My left ear was ringing for 2 days because
of the sound of the break.