Like me, you're runnin' a small shop. To keep my compressor portable, I ran a 25' hose to the airline reel mounted on the wall. If I was going to redo it, placing the compressor in the attic would be a great idea to cut the noise and I'd install a self reeling air hose to the ceiling of the shop. That way it would stay out of the way until needed, and still be able to reach the entire shop.

PVC will explode under high pressures. Copper (soft metal) could expand causing inevitable failure. Iron pipe is the norm here and still the best.

 

No kidding you guys, PVC for air? I have this vision of some part of the line by a window exposed to constant UV that would suddenly schrapnalize at 135 p.s.i. Go figure. At least it won't rust.

 

At an electronic manufacturing plant where I worked as a design/draftsman 20 years ago they had a problem with low air pressure at the front workstations because of the long run from the compressor out back.

The boss had this great idea to take six foot long sections of 4" diameter PVC and cap the ends to make a "storage tank" to put under each table. They used standard PVC cement to attach the end caps.

This guy was an actual genius and in theory a remote storage tank is a great idea but his implementation? Not so much.

I can't remember if it was hours or days before one of the end caps blew off of one of the "tanks", but I do remember how relieved the boss was that no one was in the line of fire.

He had it all ripped out and ran new lines. I told you he was a genius.

Bothus

 

I know of some airplane owners/mechanics that recently used Duratec tubing… it is a lot like PEX for airlines, google "Duratec airline".

I dont know about the cost, but do know that the building inspector said that PVC was forbidden because it is extremely hazardous at air pressure.

 

If PVC is the wrong choice then about 80% of the woodworking shops in America are wrong.

 

I've been using PVC at 130 psi for the past 15 years with no problems. All the joints are glued and where pvc and brass meet has a wrap or two of teflon tape. Most auto repair shops around here do the same.

 

Found this a while back, I have been meaning to post it for a while…

Complete Garage Air Kit

which appears to be a HF version of this

RapidAir Master Kit

 

No matter how you figure it steel pipe is the way to go it is easy to work with and last forever, using the rubber air hose is not good as the hose will swell and chaf and then let loose and you got this wicked snake tearing everything apart. Use steel and run it at an angle so the moisture drains back to the tank.

 

I know this is an old thread, but if anyone (like me) comes looking again, this info would be good to have.

First - check this link- it describes the different options you have, what to avoid, and why.

The only other thing I would suggest is that while black pipe may rust quicker than galvanized pipe, the galvanized pipe may flake off inside the pipe and jam tools (like paint guns etc) while the black pipe will not - that's why it's used for natural gas distribution instead of galvanized pipe.

 

That advice is very interesting wish it had something one the Nylon hose in the kit I previously posted….

 

You might check with your insurance company. I own a automotive repair shop and wanted to install pvc, my insurance co. would not insure me if I used it. They say there has been many instances where the pvc will exploded if it is accidentally hit or something dropped on it. They claim it is like a bomb.

 

I haven't met a plumbing fitting yet I couldn't make leak.

 

Well,

Even though this thread is quite old, but I can't stop myself to add my 2 cents worth, although I could see someone using PVC pipe used for air use, I would never use it if the compressor had any oil in it.
The reason is that oils attack the molecular structure of plastics breaking up the bonds in the material weakining it. This is speacially true of the lubricating oils used in compressors.

However if the compressor is of the dry type then this should not be a problem.
In order to minimize the possibility of breaking the connection to the compressor (99% of the time this breaks occur at the threaded side) as this connections are subject to heat and vibration.

The solution, simple, use a piece of flexible hose to interconnect the compressor to the PVC. That should take care of it.

How fun and be safe

 

Make sure you glue the fittings well. i had a compressor burn up over a weekend due to a joint failure and the compressor ran all night.

 

I installed PVC air lines in my shop last week.
I now found out that this is forbidden by law in many states

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

 

Well I am glad I check here before I ran my air lines. I was going to use PVC, but now I think I will run galvanized pipe. Any suggestions on the size of the pipe. 1/2, 3/4 or 1" Then reduce to my air tools. What diameter of hose do most of you use?

Update, just read a little more and looks like black gas pipe is the way to go.

 

Bigger pipe is better. It works like a holding tank and your compressor works less. Cycling on and off is what wears them out. Just as long as you don't go so big that it over heats the compressor. I strongly disagree with the PVC naysayers. The PSI for PVC to rupture is much higher than an air compressor will ever reach. ¾ schedule 40 is rated at 480 PSI. I run a 26,000 sqft auto restoration shop that was originally a GM dealership built in the early '70's. Before the recession we had 45 employees. At least 15 were using an air tools at one time. I'm talking inline sanders and DA's, big air hawgs. We have a 15hp compressor with operating pressure around 175 psi. The compressor runs almost continually. Originally the shop was plumbed with gal. pipe. Galvanized pipe causes a lot more condensation and rusts after long exposure. The metal gets dangerously thin right at the treads. But keep in mind we are talking 35-40 years. I have re-plumbed about half the shop with ¾ schedule 40 PVC and had no problems. I think those who have had an issue with PVC have not installed it properly. I had one employee who made a repair and only glued and skipped the cleaner that softens the plastic prior to gluing. As soon as he aired up the system it blew apart. Also whatever material is used it needs to be strapped down tightly or it will vibrate and break. Water in the form of condensation is our biggest problem. We drain the main tank often. We have inline water separators everywhere and they are drained multiple times a day. Our main line was built into the roof rafters. I think this helps as it is harder for the water to travel vertically out of the compressor. Also each work station has a line that drops straight down from the ceiling. We also have run a short line a few feet straight down below wherever a rubber work hose connects. At the end of this line is a gate valve. This allows water to drop down past the working line and enables us to open the system wide and the blast of air helps suck water out of the horizontal runs. It is also helpful locate the compressor as low as possible and to run the line straight up after coming off the compressor. This helps keep the water in the tank. The most common accident connected with the air compressor is the hose end that connects to the tool breaking off. This happens way too often and it tends to beat you while you are trying to get to a valve to shut the air off.

 

Also I agree with Jerry: the compressor has to be isolated from any hard line by installing a rubber hose. I use a 2" I.D. Hydraulic hose running off of the compressor to the hard line to isolate vibration. This hose blows out about every two years. I assume it is a combination of heat, oil & vibration. This doesn't make much sense as that is exactly the kind of service hydraulic hoses are designed for. I guess I am probally pushing it too hard. Remember I am running a huge commpressor very hard in a hot climate. The compressor motor is as big as a VW bug motor. I run three tanks plumbed together: one is around 250 gallons and two are 80 gallons. As my compressor is a dual piston type it does blow some oil. I wish I could afford a screw type compressor but they run around 15 grand in the size I need. I noticed someone in the thread mentioning oil breaking down PVC. I have not had this problem. I'm not saying failure isn't a possibility. Most of my PVC has seen 15 years of hard service. For all I know it could start poping tommorow. But for a one man shop I can't see how PVC won't last for a very very long time if installed correctly.

 

The standard installation for low cost piping that is suitable for air systems would be black iron pipe. Galvanized pipe would not add any significant benefit because the inside of the pipe is NOT fully coated with the galvanizing process and heerefore the pipe will rust internally.

Heavy wall copper is a good but expensive solution.

PVC and other plastic pipes should not be used for compressed air or other compressed gas systems.

 

I have to agree that PVC could be used, but should is a different story. I had a kickback go flying and hit the wall about 2" inches to the left of my line coming down from the loft where the AC is parked. I have the Rapid Air stuff lined up for a fall project as a result.

 

I am going with the Black pipe in 3/4". Pex would probably work but that would be more expensive than copper. Thanks fof the suggestions.

 

Even though this is an old thread, it's one that seems to resurface in a lot of forums on a regular basis. I'm getting ready to pipe my shop that I moved to last fall, and am debating this issue from the cost, safety and durability perspectives. I know several guys that run PVC and most have had no problems. I know one guy who ran the rapidair system and couldn't get it to stop leaking, though that could very well be an installation issue. I asked him if he used a plastic tubing cutter (frequently called a PEX cutter and cuts the tubing square with no burrs). The blank look on his face was all the answer I needed.
Now - having said all that, and based on 40 yrs of engineering and building (everything from cars to machinery to houses), here's my 2 cents worth:

I've seen copper systems and worked with black pipe systems (just installed 500 lf of it in a machine shop last fall). I've worked with all of these materials extensively. I was using the nylon hose/push connect (industrial version) on manufacturing equipment in the early '80's. It was "new" then, but was a lot more versatile than hard lines, more durable than rubber. I pulled some SCH 80 PVC out of that machine shop, and it is one of the options up for consideration at this time also. And since I am one of the many Americans "underemployed" by the economy, cost is a serious consideration.

The most important consideration on putting in any system other than stock length rubber hose (come on now, who would really do that?) is your skill level. If you are Picasso with a wood chisel but aren't sure what a tubing cutter or crescent wrench is, call in a buddy that is. No matter what type of system you install, a sloppy job will be a continuous headache. And this is not the place to learn self-taught pipefitting or PVC plumbing.
Rigid pipe near the ceiling with a steady (1/8/lf) slope to a water drain is best approach to a trouble free system, period. Some slope it back to the compressor, I find it works best to slope away from the compressor. Turn all your Tees up - come off the top of the pipe and leave the condensation in the main line (to drain down to the water trap at the end). Support the pipe adequately to keep the drainage working. Buy a 25' section of rubber hose (at least 1/2" ID), coil it up on the concrete floor and hook one end to the compressor, the other to a good quality water/oil filter BEFORE it goes into the piping. The coiled up pipe on the concrete acts like a condenser and will allow the filter to remove most of the water and oil from the air.

THE CHOICES
PVC SCH 40 - Pro's: cheapest solution. Cons: Like copper, all PVC is not alike. Just because it's white and in the rack at the box store doesn't mean that it's good quality ore even schedule 40. DVW is also white and in those racks, but it's a lot thinner and lower rated. Some fittings will interchange but again, are not equal. Considerations: Run it up to the ceiling out of harm's way. Anchor it every 4-5' and immediately before a hose connection. If you can solder (or know someone who can) buy copper shower head elbows to anchor your hose connections. They are threaded on 1 end, slip (solder) on the other and have 2 ears to screw to the wall or ceiling. Don't screw them to drywall, it will give when you plug & unplug the hose, leading to an eventual failure of the PVC just above the fitting.

PVC schedule 80. Double everything of SCH 40 except cost - that's triple. I priced out the fittings for my 2 bay shop system (I scavenged the pipe) at a local plumbing supply where I can buy wholesale. $80 (which is why I've not made a decision yet).

Black Piipe. The choice of most industries.Pros: cheapest of the hard pipe, readily available most everywhere.Cons: .Harder to work with, you will need a threading die and a pipe vise. Forget the teflon tape, you need the liquid teflon for this stuff. As this stuff is a low tech, mass produced product, expect some fittings with pin holes. Considerations - Check it carefully when you buy it, if it's not clean inside then it never will be. Buy this at a plumbing supply house, not a box store. Keep the water out of it and it will last forever.

Galvanized Pipe. Double everything of the Black Pipe. Overkill unless you are running it outside or in a very wet environment.

Copper - Pros: Easier than Black Pipe, at least twice the price but you don't need the threading equipment. Use type L, use the soft grades (read the printing on the pipes - I think L is the red print). You may have to get this at the plumbing supply also. Pre-soldered fittings work great if you don't know how to solder, but you will pay dearly for them.

PEX - Pro's - easy to work with, like the nylon, if you use the right tools. Cons - you need special tools to cut and crimp. If you use this, avoid the coils and use the rigid pipe. There are different grades of PEX - type tubing (not just colors). You may want to do some research on these before going this route. I have read that there is a PEX -type tubing that is rated for air use, but haven't seen any. Even though I have all the tools and ti's probably the cheapest, I am still researching it.

Rubber hose - Pros: easiest solution for the average non-pipefitter/welder/plumber. Cons: any air hose over 10 is a problem and if you use cheap (box stores/HF) air hose, it is at best a temporary solution. If you are determined to go this route, go to McMaster Carr and buy bulk hose and fittings.

Pre-made systems: RapidAir (nylon tubing), GaragePak (aluminum tubing). Probably the easiest for the d-i-y guy with a limited knowledge of pipefitting/plumbing. They are pricey ($200-$500) but take all of the unknowns out of the process.

See why it's such a hard decision?

 

I'll add one little bit of information to your extensive coverage, Dave549.
Mice, rats and squirrels all like to chew on rubber and nylon.
For that reason I wouldn't want those materials in hidden spaces like under floors or in attics.

 

I have had the RapidAir system (www.rapidairproducts.com) in my shop for almost 2 years now. It is a great system, easy to put together and I have had zero problems.

 

My son is the plant engineer at a manufacturing plant. They relocated to a new building and there was PVC that had been installed by the contractor. This was a 4" line. The problem with larger pipe is that the fittings are made for waste lines and they are only half the length(glue area) of the fittings made for pressure. My son did some research on the internet and found an article that stated the air compressor oil made the PVC brittle and it would explode like schrapnel. The contractor said he used it all the time and wasn't going to take it out and replace it with welded steel like the plans called for. That was when my son presented him with a contract that said he was responsible for all accidents cause by exploding air lines. The steel was installed. Now on the other side I have a friend that runs a small machine shop and he uses 1" PVC and 180 psi air. 25 years and no problems. I am still hedging myself. I am dragging air hoses around. I have seen people buy air hoses and cut them and use them for air piping. I have had too many failures in air hoses to want to do this. I can buy steel pipe for only a little more. When I saw the air lines sold in Northern Hydraulics I wanted them but they are expensive and come with very few fittings. I have asked about running air in PEX and so far no one seems to know of anyone that has tried it. If you want to continue to use the PVC there are adapters sold at Lowes that enable you to attach PVC to copper. This might be a possibility. Just remember the larger the pipe the lower the pressure must remain to prevent catastrophic consequences. Probably surges like those caused by nailers cause many of the problems. Again, has ANYONE used PEX for air??