On 22 Sep 2003 02:31:48 GMT, Del Rawlins
wrote:

On 21 Sep 2003 04:31 PM, butch burton posted the following:
(Craig) wrote in message news:3ca216ab.
more tankage. What ever you do, DO NOT...I repeat DO NOT use PVC or
CPVC for pressure piping on your system. Many people use it, but do
not understand that it is not rated for or intended for use with
pressurized air. When it fails, and it will, it will almost always
fail explosively and send shrapnel all over the place. If you don't
belive me, I will show you the pressure rating for PVC with all the
derating factors applied....it's very scary. More questions? ask
away.... Craig C.

Always wondered why people use PVC/CPVC when copper is marginally more
expensive. Some places have large diameter plastic pipes to increase
their air storage "capacity". Kind of like sleeping with a rattle
snake-sooner or later.....

My two cents in; I have used pvc (white plastic) for TEMPORARY
compressed air lines @ 120 psi + and 90 cfm and also Victaulic
grooved in the 2" size. As has been alluded to, but not nailed down,
it is mostly the temperature and time constraints that make pvc an
iffy solution. I do agree that a permanent solution involves STEEL
pipe or IRON pipe (not copper) or properly welded SDR 17 or better
HDPE pipe (use the proper mechanical couplers!) because of the
thermodynamics thing -- rapid expansion results in extreme cooling, or
solid connections near the source will experience extreme heat. This
is what kills pvc -- temperature extreme. This is an engineered
approach for 120 psi (8.3 bar) with sch 40 pvc as a TEMPORARY solution
far from source (thousands of feet/meters) with Victaulic couplers or
equivalent based on a FOS (Factor of Safety) of near 1. Kids, don't
try this at home.