PEX for air line

surplusjohn · Nov 11, 2009

I am planning a shop layout and there are going to some pretty long air line runs and would like to use PEX because it is cheap and easy. I have used nylon with good results and don't see any reason to think PEX would not work. Has anyone had negative experiences with it? . Thanks

spope14 · Nov 11, 2009

What is the presure difference between normal city or well water pressure and air in the line? As I also recall, doesn't pex in a home require a pressure regulator on the incoming water line to keep it at about 60 PSI or less? I ask because the fittings may become the issue.

I am not sure about any of this, just remembering some information from a seven years back when I considered redoing the plumbing in my old house (decided to sell it instead, not due to plumbing but health issues in the family).

Interested to hear more.

Areomyst · Nov 11, 2009

The shop I used to work at used PVC with results that could have been fatal. The line coming from the compressor was all PVC at a sharp 90 degree going into the building. One day we heard a big deep boom sound, followed by a WOOSH! of air.

When we went out back, the 90 degree bend pipe had broken due to the vibrations from the compressor and the high air pressure. The original part that went into the compressor was some 40 feet away, and the way it was broken, it was pretty sharp!

They decided to ignore warnings to use a rubber hose going from the tank to the PVC lines and instead repaired it the same way it was before. It took a month, but it happened again. Good thing nobody was on the loading dock...

Company is out of business now.

I fear that PEX is probably not up to par. I'm told that high pressure copper is a suitable substitute for the iron pipes. I'm just using an air hose reel hooked to the ceiling for now. Then again, I honestly know nothing about PEX. I thought it was basically a lot of "click joint" connections and such? Doesn't sound like good stuff for high pressure, but I could be wrong. Keep us posted, and correct me if need be.

~Josh

mark thomas · Nov 11, 2009

I was thinking about PEX for air, but tentatively settled on this instead:

http://us.kaeser.com/Products_and_Solutions/piping/pipe.asp

More expensive, but has some advantages...

surplusjohn · Nov 11, 2009

not considering using PVC, I know that degrades. PEX is rated at 200 PSI, plan on using black for better uv protection, and it won't even be exposed to UV.

joe m · Nov 11, 2009

I like the Kaeser piping. We have it installed at work 5 years ago and no problems with any leaking. Nice part of the system was if you need a coupler or drop from the main line drill out a hole and clamp around fitting. No need to dissemble joints. Good system.

Limy Sami · Nov 11, 2009

Any help? ............. FYI the pressures are in bars (metric) ..... 1 bar = <> 14.7lbs sq"

http://www.plasticpipe.com.cn/pipe_pexpipe.htm

L Vanice · Nov 11, 2009

I plumbed my shop air with copper tubing except for the fittings at the outlets, which were brass quick disconnects and steel pipe thread adapters. I would not use plastic.

Larry

Ray Behner · Nov 11, 2009

John,

You might want to check with your insurance co. and state fire marshall. Here in Ohio it's not allowed because a fire would melt the pipe and the air would fan the flames. Same goes for soldered copper pipe. Must be mechanical joints.

Ray

surplusjohn · Nov 11, 2009

there is about 130 ft of 3/4 inch line needed, that will probably have to be moved a few times in the next year or so. copper would be fine, but 3/4 inch copper is pricey.

Clive603 · Nov 11, 2009

This stuff sounds more like what you need http://www.durapipe.co.uk/Product/Detail.asp?BID=11. Allegedly its very easy to install. Presumably something similar can be got state-side.
Plastics can do unexpected things under pressure and I'd be very chary about using something not specifically designed and tested for air applications.

Clive

cecilstrange · Nov 11, 2009

I plumbed a 4,000 square foot shop for air with schedule 80 PVC. The fire marshall came twice a year and never complained. I used it for twenty years. I had to make five or six repairs due to occassional leaks that would develop and because of a couple of accidental collisions. I sold the shop twenty years ago and the new owner is still using the same pipe.

I was advised to use PVC by a Snap-On tool dealer who was in and out of a lot of shops every week. He said it was a lot better than metal for moisture control. I also had pet-cocks for draining every vertical drop from the main line.

behindpropellers · Nov 11, 2009

JL Sargent · Nov 11, 2009

#1: They actually make a PEX just for air! It has an aluminum liner or similar. Look for that.
http://www.plasticpipe.com.cn/pipe_pex-al-pex.htm

#2 PVC for air is a big time NO NO. Literally explodes in the right conditions. OSHA has all kinds of write ups about it and some of those references have been posted right here on PM before. Snap On dealers need to stick to selling tools off their trucks because they don't know jack about using PVC for air supply.
http://www.osha.gov/dts/hib/hib_data/hib19880520.html

Now, what else ya wanna know? :smoking:

SND · Nov 11, 2009

I don't think there would be any problems with a good PEX. To leak test the plumbing on my new house we left 100PSI in there for a few weeks. When we did the infloor heating I put only 30PSI, 7 guys were walking all over it squishing it on the rebar and all, real rough bunch. Never had a leak, but was told I could/should have put more pressure so its less squishy. But of course if something sharp touches it with enough force it will start to leak.

Ghost · Nov 11, 2009

The water jets at work have what looks like pex for the on machine air plumbing, came like that from the factory. No leaks at 120psi even though guys use the fittings like quick connects.

Limy Sami · Nov 11, 2009

Do you guys have MDPE over there?. like this?

http://www.pipestock.com/mdpe-pipes-fittings-valves/mdpe-pipe-black/

I know it says water, but I've used it many times for air lines with no problems that I know of.

surplusjohn · Nov 11, 2009

just to say it again, I know about PVC, I would not use it for air!.

RE air line PEX with foil liner, what is that for? hmm?

Pete F · Nov 11, 2009

This thread is fortunate timing for me as I just got back from pricing some pipe for my air install. Here in Australia it seems copper is actually cheaper than galv pipe which surprised me a bit, then again nobody uses steel pipe for plumbing here so I really shouldn't have been surprised.

It will be either 3/4 or 1" copper pipe for me then, probably the former as it's more of a plumbing standard therefore the tube benders etc are easier to get for it. I've seen photos of shops with copper installations but all of the "how to" articles I've read have been with steel pipe. Does anyone know of any online resources describing copper installations? The soldering etc is fine, that's just the same as standard water plumbing, but I'm not sure what's used in terms of terminating the lines with the quick connect fittings etc.

Pete

smootz · Nov 11, 2009

I never understood why everyone tries to find an alternative to a tried and proven. Is there that much difference in cost (long run - that is)?

I have had two personal shops and have leased and worked in several others. I have seen the best and the worst.

Black pipe - at least 8 foot vertical directly from compressor - lines run around the edge of ceiling with slight drop to drip leg - upward turned tee's with two 90's to drop legs with additional drains. You will never have water problems and your air system will require zero maintenance for many, many years.

I can't imagine cutting and threading common pipe being too intimating for a machinist or fabricator.

SCOTTIE

PEX for air line

Diamond

Stainless

Aluminum

Titanium

Diamond

Aluminum

Diamond

Diamond

Diamond

Diamond

Titanium

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Stainless

Diamond

Diamond

Cast Iron

Diamond

Diamond

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