Pex-Air Compressor Line?

[Travis Johnson]

I just got done reading a great article about the new PEX tubing used for waterlines inside of homes in Fine Homebuilding this month. I am not a plumber but it seems like that stuff would be great to plumb up the air compressor lines in my new shop.

They had a picture in the article that showed the hose with a blowout as the pressure neared 1000 psi...far less than the 150 psi I would would be running and even then the compression fittings stayed intact. I know PVC plumbing is not a good canidate because it loses strength as the temperature increases, but PEX is used a lot as waterlines for radiant floor heating so heat versus strength should not be a problem. And finaly the article stated that PEX has the connections to be used interchangably with copper, pvc, black iron pipe, so hooking up quick connect couplings and air hoses would not be a problem.

Overall I was thinking this would make installation much simpler and look cleaner inside my shop than copper tubing (2nd choice) or black iron pipe (last choice). Any thoughts on using PEX this way?

[Bob Childress]

Travis,

I don't know for sure if PEX would work for your application, but I do know that it needs to be totally protected from UV light, or it will deteriorate in a little as 60 days. Ideally, it should be buried in the wall or attic or basement. It should not be exposed to direct sunlight, ever.

Maybe some plumber/Creekers can tell you more.:confused:

[tod evans]

travis, i see no reason pex wouldn`t work........BUT, have you read this?
http://www.tptools.com/statictext/airline-piping-diagram.pdf
there`s a reason all the oldtimers recomend black pipe, i listened when i installed my system and my lines are dry. if you`re only using small amounts of air like for nailguns you`ll probably be fine. but if you plan on painting or running pneumatic tools i`d reconsider....02 tod

[Allen Bookout]

Good information tod. I used metal pipe and my first drop is about 40' from the compressor and I am getting no water in my water seperator. At times in the past I have used long lengths of hoses but always got water in the seperator. Therefore I say go with black pipe as suggested in the link information and by tod. Living in Florida I decided to use galvanized pipe. After reading your link it looks like that I made a mistake and should have used black pipe. Guess that I will just leave it and wait for clogs.

[Larry Cooke]

I just got done reading a great article about the new PEX tubing used for waterlines inside of homes in Fine Homebuilding this month. I am not a plumber but it seems like that stuff would be great to plumb up the air compressor lines in my new shop.Travis, here's a link for you:

http://www.plasticpipe.org/applications/productinfo03_5_1.php

It says it used for compressed air and gas applications. Personally, I went with copper - guess I'm more old school than I care to admit but I wouldn't feel comfortable with plastic for my air lines.

Larry

[Charlie Plesums]

I don't know about PEX pipe, but one of the fire-code arguments against PVC air pipe is that, in event of a fire, the pipe melting will fan the flames. Also the pressure variations in air pipe are apparently greater than in water pipe, causing stress failures with flying shrapnel. Both arguments seem a little wild for my taste, since I have seen plastic pipe used for compressed air, but I wasn't around for a failure.

[Larry Cooke]

Both arguments seem a little wild for my taste, since I have seen plastic pipe used for compressed air, but I wasn't around for a failure.Charlie,

Our company (many years ago) opted to use PVC for the airlines in our shop. I was working late one night when I heard this loud shrill and whistling sound that got louder and louder. I thought at first it was a jet engine (our warehouse used to be under the approach for an Air Force base) and that a plane was coming in too low. Well when it exploded I literally hit the deck (read darn near did something in my pants if you know what I mean.)

It was the PVC air line of course that had failed. I was about three feet from it when it happened. I was lucky, none of the pieces hit me. The next day we replaced our lines with copper.

Here's a link from OSHA regarding PVC for airlines:

http://www.osha.gov/dts/hib/hib_data/hib19880520.html

Like I said, I'm not a fan for using plastics for compressed gasses of any kind. Especially when they can be affected by UV's.

Larry

[Travis Johnson]

Larry,

I have never seen PVC pipe explode, but I have heard about it. I was telling a guy at work the same thing when he was hooking up some compressed air lines for his home automobile style shop. He is one of those guys that will do as he wishes anyway and is not going to listen to you no matter how compelling the argument.

PEX however is far different from PVC because PEX does not lose its strength like PVC Pipe does. PVC pipe has plenty of PSI strength at 150 psi or so...but compressed air gets hot and that is what weakens the plastic. Personally I would NEVER use PVC for compressed air lines.

I just though PEX might work out better as you could have long runs without multiple joints in it. After thinking about all this, I just might use copper afterall.

[Larry Cooke]

PVC pipe has plenty of PSI strength at 150 psi or so...but compressed air gets hot and that is what weakens the plastic.Travis,

It's true that compressed air gets hot, however the heat is generated between the head of the compressor and the tank. When the air comes out of the tank the heat has for the most part dissipated.

What really affects PVC is the UV's not so much the heat in this case. PVC has a very low temp rating - at 150 deg. it will loose its ability to hold it's shape so if temperatures were really the issue you would see a lot of PVC air lines ballooning rather than exploding.


I just though PEX might work out better as you could have long runs without multiple joints in it. After thinking about all this, I just might use copper afterall.Actually, PEX might be a good alternative - I don't have any on hand experience with it. One thing I would do (if I were to use it) would be sure that it's shielded from any UV's. Btw, if you have fluorescent lighting then you're adding UV's to the mix. I don't want to try and talk anyone out of using a new material but personally I'm not one to be the guinea pig anymore.

If you do use the PEX, let us know how it all works out.

Larry

[Ken Garlock]

Travis, save some time and effort and go to the borg and pick up a stack of 1/2" rigid type "L" copper tubing. It will outlast you. Some will recommend 3/4" but I haven't seen the need for anything larger than 1/2". After all, the inlet on most, if not all, hand air tools is 1/4" anyway, so the extra air reservoir in 3/4" pipe doesn't mean much.

You didn't say what your compressor was, but I placed my 5hp IR in a separate room, actually a garage, to cut down the noise and I am glad I did. You really don't want to be around my compressor when it is running.

A side benefit of using copper is that you get to tune up your soldering skills.:)

[Travis Johnson]

You didn't say what your compressor was, but I placed my 5hp IR in a separate room, actually a garage, to cut down the noise and I am glad I did. You really don't want to be around my compressor when it is running.

A side benefit of using copper is that you get to tune up your soldering skills.:)

I have not purchased my compressor yet, but I was planning on placing it inside my attached snowmobile shed for the very reason you mentioned...noise. The only thing that concerns me is that my snowmobile shed is not heated. I am not sure how well that will want to start up when the weather dips down to 20 below, but then again its not like I will be using the compressor much then anyway. I'll most likely be riding the snowmobile :)

As for the copper lines, I was thinking I would go with flared fittings. I do not solder much and at work we use a train load of flared copper fittings...literally as I am a Railroad Machinist.

Any additional thoughts on flared fittings and placing my compressor in an unheated portion of my snowmobile shed? I am attaching a picture so you can get a sense of how my snowmobile shed/ workshop is arranged.

http://www.railroadmachinist.com/sitebuilder/images/Shop_Front-217x140.jpg

[Rick Lizek]

I've talked to the PEX folks about using it for airlines and they wouldn't stand behind such an application. Chemaire is rated for air. There is also an aluminum piping sytem rated for air but it's pricey as well.
http://www.garage-pak.com/compressed-air-piping-general-information/compressed-air-piping-system-safety.html
http://www.nibco.com/assets/ChmairOvrw.pdf I'm dealing with commercial and industrial applications so I like to make sure there are no insurance or liability issues. Here's a good piping diagram. The T's for drops should always be pointed up.
http://www.tptools.com/statictext/airline-piping-diagram.pdf

[Ken Garlock]

Travis, if you feel comfortable with flair fittings, go with it. I considered flair for my piping, but decided that, for me, the hassle of getting a good flair was more work than soldering.

Regarding the compressor, take a look at Northern Tools website, in particular the Ingersoll Rand compressors. I have the two stage 5 hp IR, and it serves me well. Northern Tool is just an 'order taking' facility for IR. The compressors are shipped from the Tennessee factory free of freight charges.

[Kyle Kraft]

Right on Tod! At my last employer we embarked on the task of piping our entire plant in "textbook style". The compressor discharged into a 4" copper loop ran underground around the compressor room with a timer condensate drain at the lowest point. After that it went through an IR thermal mass dryer and a 1000 cfm filter...we had the driest air system in SW lower MI

Kyle in K'zoo

[Jesse Messick]

Travis,
I have run quite a bit of pex for radiators, radiant heat, etc. (Several thousand feet last year). Really, the stuff is a pain to work with. We even bought an uncoiler, which makes it easier to unspool, (which is the main problem, as it wants to flop all over the place) but it's still a pain.

Actually, check into Flexeel air hoses, maybe you have seen them. They are polyurethane air hoses, like that you would run to a finish nailer for example..You could buy them in 1/2 diam. I believe, and it would be rated, have no uv problems, etc. Just use barbed fittings to make splices, etc.
I use my 50 footer almost every day, and I think it weighs in at 1 pound!

[tod evans]

travis, if you`re dead set on using anything but iron pipe be aware that unless you install your piping, copper especially, in some type of thermal mass such as kyle spoke of, underground, then your piping system will do very little to aid in moisture removal. if you check on refridgerated driers you`ll find that black pipe may be a very cost effective way to pipe your system. you`ll also likely find that your compressor will have a hard time starting in sub zero weather and whatever condinsate forms in the tank will freeze. so if you mount the compressor in the shed provide some type of heat source to keep it above freezing...02 tod