Isn't that PVC pipe rated at 300 psi? Come on guys, how are you going to exceed that with a compressor that only produces half of that and a regulator that only puts @90 psi in the lines?
I don't doubt that if you exceed the 300 psi in the PVC it will explode but I'd be willing to bet that even if the pipe deteriorated over time it would probably just split and leak, not explode like a grenade.
While we're on the subject, doesn't iron pipe rust?
