I was told by a plumber that PEX deteriorated relatively quickly (1
year?) in sunlight, and that that was why it was always installed
underground or in concealed places, and also that that's why plumbing
suppliers (in general) are not eager to accept returns on it if you've
had it for any length of time - no telling how/where it has been
stored. This is second hand info to me and I don't know if the amount
of light in your shop would be significant, but you may want to do
some research.

mickey

On 20 Dec 2003 22:19:23 -0800, (Leigh Knudson)
wrote:

I have just finished the hydronic heat piping for the new house and
had a couple hundred feet of 1/2" PEX left over from the 3000 feet
purchased. The building inspector was giving me conflicting test
requirements. The installation manual says 60 psi air test and the
inspector wanted a 100 psi hydrostatic test so I got on the phone to
the manufacturer. They sent out an intallation engineer who told me
the PEX could handle a 300 psi hydrostatic test. I suggested it might
be good for shop air in that case and he said it would be just fine.
Remember this PEX is a Polyethylene compound and pretty flexible so it
won't shatter if ruptured. Its not cheap at $.52/ft in 1000 ft rolls
but what can you do with the remnants when the heating system is in.
BTW I never did perform the hydrostatic test as I hadn't quite
finished purging the air from the six water circuits when the
inspector arrived. The system had held steady on 100psi air pressure
for 10 days though so he & I were pretty confident there were no
leaks. The system has seven ball valves, seven unions, a silver
soldered copper manifold and about 20 other joints in it. Anybody got
a shop air system of this complexity that DOESN'T leak. All joints are
above the slab so repair was doable but not necessary.
Leigh@MarMachine