On Jun 15, 9:16*pm, "Ralph Mowery" wrote:
"fftt" wrote in message

...

On Jun 15, 5:51 am, Hipupchuck Pressure is pressure but air is not
water.......its a stored energy
thing.
That's why pressure vessels are "hydro-tested" *for re-
certification... a pressure vessel that fails when pressurized with
water, fails with a "spurt" not a "boom".
Most, but not all, plastics are not ok for compressed gas
applications ...its a matter of failure mode; ductile vs brittle.

I did not know for sure, but I was thinking that water would sort of squirt
out if the pipe burst,but air would rush out much faster and give a faster
release of enegery. *That would propel the shards much faster.
Where I work we extrude melted plastic under 1500 psi from a hole 3/8 inches
in diameter but it is so thick that is just barley gets out of the pipe.
Water under that same pressure would go across the room. *I sort of think
water vers air at 100 psi would act similar.

Gas under high pressure has WAY more stored energy than water under
the same pressure.

It's a compressibility issue; gases are compressible, water (for
purpose of the this discussion ) is basically incompressible.

cheers
Bob