[chapman1]

I share everyone's rightful concern for safety, and I certainly lack credentials on PVC and air pressure vs. water pressure. At the same time, I have to question whether PVC knows what's inside it (water or air). Pressure, it seems, is pressure.

The documented examples I have seen of PVC failure have occurred at low temperatures, where I will agree, PVC gets brittle and dangerous. If inside a warm building at 1/2 rated pressure, I would tend toward not worrying excessively.