PEX for air lines?

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711mhw

Feeling the Heat
Dec 7, 2010
482
Western ME
Any one out there tried it? Did some searching on the web and get mixed results, mostly ok. I used copper in my last shop but now in the new shop I will need something flexible to slide in to the framing 16" o.c. I like to hide it in the wall for a nice finish therefore making repairs a big deal. I'm thinking of running the pex and transition to copper at the point where it will exit through the wall for a coupler/use. I used it for some of my domestic water dist. but just don't have that warm fuzzy feeling for it yet! (especially at 100 or better psi) It seems that the PAP ma be rated for air but not the PEX, but that may just be the lawyers talking. If it werent for lawyers, WE WOULDN'T NEED LAWYERS!!
 
I'd stay away from the Pex if it is not proven for 150psi. I have used pex for plumbing and love it, but you want to do it right the first time. How nice will your drywall finish look when you are ripping it apart to fix the pex? Go with solid copper, 1"pvc, or an industrial gauge compressor hose that is made to last and not crack over time. Good luck!
 
I had used PEX for airlines in my shop. I run my comp at 165 psi no problem. My lines are (were) exposed on the wall, I took the pex down only because it drooped over time (heated shop) and I did not like the look of it. I am currently using black iron pipe (painted). I am also doing some renovations in my shop and considering going to sched 40 plastic water line. I know one person that did that and it looked real nice.
 
Hey Bert. what kind of fittings/connections did you use? I have the copper band type "squeezer" that I used for my dom. water and used comp. type fittings for my hydronic, and only recently tried the sharkbite type on a hot and cold water supply for the far side of the shop (they come right apart with a $2 tool to be able to drain them down if necessary) I would try to keep the number of fittings to a min. As for using a ridgid pipe, I can't sneek it in to the 16" framing, without a bunch of couplings. I would love to be able to use copper and be done with it.
 
Last spring, I plumbed a storage barn, at work, with 3/4" pex, running at 125psi. So far, about 6 or 7 months, no problems. I used the Wirsbo type of expansion fittings - but cheated using the battery operated expansion tool; a heck of a lot quicker than the hand!

If I was going to do copper, I would use "soft" copper, sold in rolls, to get between the studs. Same O.D. as ridged, but has a thinner wall, so a larger I.D., but you can use "off the shelf"/your stock fittings as needed. I THINK it's rated to 300 WOG, but not 100% sure. But, as for the price, it more than ridged for the same linear footage.
 
How about running the lines in the attic, you could have a few copper drop downs in the walls with couplers coming out. Likewise you could put your compressor in the attic and drop down the regulator to the shop along with a switched outlet to turn it on and off. Having the comp. in the attic would reduce noise (if it is not huge and your don't already have it in a closet.) Reading the few posts it sounds like the pex might be strong enough to do the job. Maybe you could contact the manufacturer and see what they suggest and what the max pressure is. Good Luck.
 
711mhw said:
Hey Bert. what kind of fittings/connections did you use? I have the copper band type "squeezer" that I used for my dom. water and used comp. type fittings for my hydronic, and only recently tried the sharkbite type on a hot and cold water supply for the far side of the shop (they come right apart with a $2 tool to be able to drain them down if necessary) I would try to keep the number of fittings to a min. As for using a ridgid pipe, I can't sneek it in to the 16" framing, without a bunch of couplings. I would love to be able to use copper and be done with it.

I used the squeeze crimp type of fittings. Typically copper or yellow / gold brass ones. Like the yellow ones better. I would not put a compressor in the attic as I like to have access to the shut off at the tank in case a hose bursts. I have seen it happen. Right at the tank I always put a ball valve and keep a clear path to it at all times.
 
’bert said:
711mhw said:
Hey Bert. what kind of fittings/connections did you use? I have the copper band type "squeezer" that I used for my dom. water and used comp. type fittings for my hydronic, and only recently tried the sharkbite type on a hot and cold water supply for the far side of the shop (they come right apart with a $2 tool to be able to drain them down if necessary) I would try to keep the number of fittings to a min. As for using a ridgid pipe, I can't sneek it in to the 16" framing, without a bunch of couplings. I would love to be able to use copper and be done with it.

I used the squeeze crimp type of fittings. Typically copper or yellow / gold brass ones. Like the yellow ones better. I would not put a compressor in the attic as I like to have access to the shut off at the tank in case a hose bursts. I have seen it happen. Right at the tank I always put a ball valve and keep a clear path to it at all times.

That a good point Bert about putting it in the attic. I have mine on the floor of the shop and it is loud when it runs, so I have thought about moving it to the attic. It's only a pancake compressor for my nail guns, so it would be easy to do, but I never thought about an emergency shut off.
 
Might look into commercial truck airlines? Should be able buy it off a roll and have the shop crimp fittings on it. Not sure of the cost. Rubber hose type and also there is a type that looks similiar to pex.
 
I just want you to be safe and I dont need alot of blah blah from anyone. Pex and air is a no,no. There is no rating for it and have known someone to loose there eye due to it. Trace oils, light exposure along with an impact was the breakdown cause. It is for water distribution. Even doing an air test on a project if a hydrostatic one cannot be done due to freezing etc the manufacture only recommends a short test of 2 hrs @ a max of 100psi with air. Pex is also not to be exposed to natural light for an excessive period.
Try a gander here if this is the stuff. It should support my experiance with it.
http://www.bow-group.com/documents/InstallGuide/Plumbing/PEXINST-0110R.pdf

Play it safe.
Cheers
 
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