On 3 Oct 2005 07:00:33 -0700, "
wrote:

A couple of thoughts, but not an answer to your question.

One is that plastic strength depends a lot on temperature. The part
that is buried is less likely to burst that the bits that are exposed.
So you might want to use stronger pipe where it would be exposed.

Also I think that plastic pipe tends to age and become more brittle
with age. I am not sure that being pressurized accelerates the aging,
but it might. So if you don't need an air line between your house and
shop all the time, I would put in a ball valve so the pipe is
pressurized only when needed.

If you have a lot of it, you might bury two runs so if one bursts, you
already have another run buried. And if that happens, consider adding
a regulator to keep the pressure lower the second time. Also think
about what else you might want to run at the same time. Telephone
line?

Dan
I just finished replacing the gray plastic supply tubes on the main
bathroom sink after about 20 years. I originally installed them
because of their flexibility (~2" radius) allowed for the builder's
latitude in cabinetry. The cold line developed three lateral cracks,
and being in a concealed location, the leak wasn't noticed for a
couple days, so I have quite a mess downstairs, hopefully the carpet
will dry. My point being, I don't trust bent plastic any longer.
Gerry :-)}
London, Canada