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PEX for compressed air?

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marfaguy:
Anybody run PEX for a compressed air line? Since I'm running underground conduit
for a 100 amp line from the main electrical panel out to the shop now's the time to also
run a compressed air line from the shop to the car port (across the breeze way from where
the main panel is). From what I've been able to tell plain old standard 3/4" PEX available from
Loews/HomeDepot is rated at 150 psi for what they call out as potable water lines. I can't see
needing more than 100-120 psi air in the car-port. Air up the tires, blow leaves and crud out of
whatever, and such like.

I know there's a PEX-AL-PEX product made for compressed air but that seems like way over kill for
what I need.

I'd run the run the line inside of a gray PVC electrical conduit probably twice
the diameter of the PEX just in case I need to replace it at some point. 

 I like the PEX idea since I should be able to get it at length so I don't have an underground joint,
not to mention the price difference between it and a k type copper pipe. I've heard bad things
about using PVC for compressed air and given my soil type (heavy black clay with chunks of
limestone that tends to move a lot) I think PVC would be a bad choice. The run's about 150 feet.

What do ya'll (my West Texas origins peeking out) think?

-Charles

Gazz292:
i used nylon pipe for my airlines around the garage, the stuff trucks use for their brake lines, rated for something like 300psi or more, pretty cheap too, buy it off the reel from any truck parts supplier, or aggricultural type place that sells spares (i got mine from a hydraulics pipe supply shop)

one thing to be carefull with tho, you will get water from the compressor migrating to the lowest point of the pipe, which will be underground, so you may want to see about an air drier/water trap before the pipe goes underground.

picclock:
And when the water collects it freezes and no air. So then your out in the snow dribbling anti freeze down the pipe and all over your hands wishing you lived in a temperate climate .. .

Don't ask

picclock

PTsideshow:
Nylon semi rigid tubing, PEX is for liquid only! They clearly state on any site that sells it that it not rated for gas pressure use air or other.  I have two of the horrible fright  whole garage air systems seems they are getting rid of them. has a 100/ft 1/2" nylon semi rigid tube, a number of fittings for a basic set up. everything but the mounting clamps, and the air fittings. So far everybody that has put them in is satisfied with them. Since it is still cold out and I have to finish cleaning the shop. I will be waiting till I get the new compressor in and running.
The fitting for PEX are also not rated for air. and have a tendency to pop off.
I plan on running at 130psig,then regulate at the taps.
brand of speed fittings
For the extra ones that I need.
The semi rigid nylon is about $71.00/100 feet With the 20% coupons the kits were around $35.00 each I wish they had another one, they were a real deal. Some of the end blocks are sort of dorky but I can live with that.

PTsideshow:
I forgot to add that, PEX tubing cannot be used in applications exposed to sunlight, as it degrades fairly rapidly. Prior to installation it must be stored away from light, and needs to be shielded from daylight after installation. Leaving it exposed to direct sunlight for as little as 30 days may result in premature failure of the tubing due to embrittlement. this also means reflected UV radiation/light, will cause material deterioration. As with the people that use PVC hard pipe for air lines. Every maker and seller clearly states that it should not be used. And since like that If you use it and have a catastrophic failure, with injury's you probably only make a lawyer rich trying to collect from the company.
I had a PVC air line set up in the basement overhead, It had a catastrophic failure mid pipe length and plastic  shrapnel was embedded into the wall board. Sorry no  photo's it was BDC (before digital cameras)  :bugeye:
what ever you choose to do, be aware of what can happen.
 :thumbup:

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