Opinion on plumbed air

Brad Gyde · May 2, 2010

Hey guys,

I've seen plumbed air in shops.. most time using galvanized piping but have saw a couple that used pvc pipe.. so on a fact finding mission I when to Lowe's and had a look around.

To do as I want, using black pipe/galvanized it'd cost me about 400 bucks..
pvc closer to 100 bucks.

I see the pvc is rated for 370 psi (or at least what I looked at)

I don't have a super huge shop, and I don't have a super huge compressor (it puts out about 130 psi) about a 60 gal tank, if I remember right.

What does/would everyone use, and what do you recommend? (the shops I know of with pvc have been using it a while and they say no problems.. dad says no way it'd ever work)

Opinions?

Brad

C.R. · May 2, 2010

I think P V C would work for a while but eventualy the oils in the compressed air will make the p v c weaker over time and it will rupture I would use metal pipes

big jt · May 2, 2010

this has been discussed at great length here but
bears doing again.

The way I remember it there is a PVC that is
approved for air. The Stuff you are looking at in
the big box lumberyard isn't it.

The 370 number you see on the pipe you looked at
is the burst pressure, not the working pressure.
Over time with fluctuations in pressure will
weaken it and it will burst.

You are not talking much money so go with the
black iron. I have heard that Galvinized can
cause issues with air tool motors as it ages and
the galvinizing starts to come off.

Also make sure you put in water traps at every
major bend in the pipe.

jt

730d se · May 2, 2010

The good and bad of PVC

PVC piping is relatively inexpensive, easy to install, lightweight, and corrosion resistant. However, PVC has one MAJOR drawback. It is brittle. An inadvertent impact could cause the piping to shatter, endangering surrounding personnel. Most PVC pipe manufacturers warn against using PVC for compressed air service due to potential liability from such failures.

New thermoplastic piping systems -- using high-density polyethylene (HDPE), for example -- overcome the brittleness problems associated with PVC. They efficiently and reliably deliver compressed air with lower material and installation costs and longer service life than with metal systems. They offer a margin of safety missing from PVC.

These new thermoplastics are safe because they expand at the point of failure, tearing open rather than fragmenting dangerously. They do not accumulate scale on their ID, nor does pitting or corrosion occur, and they are unaffected by synthetic and mineral oils used in compressors.

toolz · May 2, 2010

PVC will certainly work. I've even seen car dealerships plumbed with it, but it still doesn't seem good to me. The stuff I want to get is the blue aluminum piping that came out several years ago just for shop air lines. It's real east to install, and relatively cheap. Look up "Garage Pak" on the net. There may be others that sell it also.

Brad Gyde · May 2, 2010

I'll look into the hdpe.. sounds better.

The reason I didn't really want to use steel is because 1) the cost and 2) every time I have to cut it for a tee, elbow, etc, it would be back to the hardware store for threading..

I'd really like to use something like truck air line, but can't seem to find anything than 1/2 OD.. which is not enough volume, in my opinion.

What about using a large rubber hose (like a 3/4 air hose) and just putting steel drops where I want them? The rubber would be easier to work with IMO.

And sorry, I didn't mean to start a battle.. what actually started it is I think it was a Summit Racing Catalog showed a "plumbed air in a box" for a standard garage, decided eh, not enough volume.. to which someone suggested pvc.. Which I too am a touch leery about.. And I got to do something, cause I am tired of tripping over air hoses.. and it takes about 50 feet to go from compressor to work bench.. thought it'd be nice to have a drop by both benches with a coil hose, and a port going outside, and one in about the center of the shop for the upcoming paint project.

gene bender · May 2, 2010

PVC works fine just run a complete circle around the shop at ceiling then go up a little then down for your drops and have a shutoff at the bottom of the drop to drain foreign material. have a tee for your outlet 6in above the shutoff that will help collect foreign material. Having a complete circle makes sure you have plenty of supply at all stations. I wouls use at least a 1in line at the ceiling drops could be 1/2in.

JMOR · May 2, 2010

(quoted from post at 12:37:33 05/02/10) PVC works fine just run a complete circle around the shop at ceiling then go up a little then down for your drops and have a shutoff at the bottom of the drop to drain foreign material. have a tee for your outlet 6in above the shutoff that will help collect foreign material. Having a complete circle makes sure you have plenty of supply at all stations. I wouls use at least a 1in line at the ceiling drops could be 1/2in.

ABS (Acrylonitrate-Butadiene-Styrene) and others are approved for compressed air whereas PVC is not & does not meet OSHA or local regs in most locations, however, you can find PVC all over the shops of the world, working fine for decades, but for liability reasons, you won't find anyone recommending it for such use.

Chad in Mn. · May 2, 2010

We just did our shop on the farm and used 3/4 inch pex water line. Works real good we run about 130 psi but one line is at 170 psi.

Gun guru · May 2, 2010

PVC is not to be used for compressed air lines, the temp changes hot/cold will make PVC worse over time. PVC shatters when it breaks with compressed air behind it. It is actually against OSHA code to install it.

PEX or the ABS plastic pipe is way better for compressed air lines.

circus · May 2, 2010

if you plan painting you wouldn't want a big hose. The droops would collect and spit out water while painting. It wouldn't cool the air causing water vapor to condense under the lower pressure of a nozzel. Pipe cools the air which condenses the water vapor that then gets trapped prior to your spray gun.

Cas · May 2, 2010

One of the posts caught my eye. I have not put
my air lines in my shop yet. I plan to use
some of the air for painting. The idea of using
steel before a water separator seems to make
sense. As the steel pipe would act as a condenser
to remove water from the air. Would pex or
or other plastic do this?

El Toro · May 2, 2010

I would used use Pex. Hal

Anonymous-0 · May 2, 2010

I plumbed my shop for air using 3/4" galv. pipe... designed it to use full lengths of pipe and off-the-shelf ni pples... only had to have 2 or 3 pieces cut to length & threaded, which were measured and cut with one trip to the hardware store. To do this, I hung all the full lengths of pipe where possible, then measured where I needed to fill in. Really wasn't that big of a deal to do and IMO the peace of mind (knowing the system will not fail) was worth the price of admission ...D

JBMac · May 2, 2010

We plumbed the shop 15 years ago with pvc, up and out of the way of any impacts. Its never bursted, but leaks in several places, we put in a valve at the the tank. I guess you arent supposed to use it, but other than some minor leaks, it's held up.

Cub n M in OR · May 2, 2010

My vote is for PEX too. Easy to install once you have the crimper. It is a bit spendy, but I think it is worth it.
I was hooking up a water line from a well into a new house on a cold day. Had to chip some of the frozen mud away from the exterior PVC line so I could cut it and glue new fittings on. I accidentily hit the PVC with my pick, and it EXPLODED! I didn't realize the excavation contractor had put 50# of air in the line to leak-test it. It sounded like a shotgun blast, and sent dirt and spear shaped PVC shrapnel flying. No idea why I didn't catch one in the eye. Just lucky that day, I guess. Would hate to have the same thing happen in a shop, with 130psi in the lines.

Ben

paul · May 2, 2010

PVC will age & get brittle.

Some insurance won't cover it.

If it gets bumped hard, it's gonna break.

The problem with PVC, when it breaks it shatters into little shards.

125+ psi will move those shards around with great force & speed. Highly dangerous.

So, a lot of folk have gotten by with using it.

That doesn't mean it's a good idea!

I wouldn't.

Galvanized isn't good either. Flakes will plug things up. Black iron is what you should use.

If you got money, copper works. If it ruptures, it won't explode into shrapnel.

If you are cheap, there are plastic tube based on PEX that can work well, are cheaper priced, and won't fly apart when/if it breaks.

Don't use PVC. imho

--->Paul

Mike M · May 2, 2010

Doesn't anyone use truck air brake line ??

Good for air,fuel and water.

Brad Gyde · May 2, 2010

Mike,

Truck air line would be GREAT if I could get it big enough.

I'll look into the PEX.. We have the crimper, as my house is a mfg'd home, and the house is plumbed with it.

Brad

El Toro · May 2, 2010

They used Pex to replumb my wife's older sister's home in Florida. Her homeowner's association paid for it and it cost around $7000.00. All of those homes in there had the plumbing replaced at no cost to the owners. For some reason her's never leaked until later dripping from the ceiling. No basements in there. Hal
PS: She said they earned their money as it was hot as blazes when they did it.

RodinNS · May 2, 2010

Depends on the flow requirements I guess... but for a lot of things I think 5/8" Synflex (truck air line) would work fine. It would work at least as well as anywhere you'd think about using 1/2" copper...

Rod

sotxbill · May 2, 2010

used pvc over 20 years ago.. it will eventually break if you use it out-side.. I have a few of the lines break where the sun hits it where it goes into the barns around the slabs and the lawn mower and weed eater hits it... but.. 3 bucks worth of repairs and its back up for 20 mores years. the inside pvc has never broken, the buried pvc between barns will pick up condensation and store it in the low spots but any other pipe will do the same. go at least 3/4 inch for good flow for impact tools.. i limit my 175lb compressor to 130lbs on the pvc. at this level, I am able to keep all the lines putting out 100lbs with a 3/4 inch impact wrench running. the schedule 40 pvc is tested at 400 lbs and works very well and is very cheap. I have air in 4 different buildings from one compressor. It does not throw shrapnel, but will crack if you hit it with a riding lawn mower too hard.If painting with a high volume gun, I can put a storage tank (off old compressor) at the far barn and it acts as a buffer to keep the overall fluctuations at a minimum. But it turn out I didnt really need it.

MarkB_MI · May 3, 2010

PEX is certainly a better choice than PVC, but it is not approved for compressed air. There are other plastic pipe systems that are approved, I suggest you look into one of those. I think most are HDPE (high density polyethylene). Pex-al-pex, which is an aluminum pipe sheathed inside and out with PEX, is also approved. Here's one HDPE product:
HDPE pipe for compressed air

kito169 · May 3, 2010

I would (did in my shop) use black iron pipe. then you will not have to worry about it again. Harbor Freight has a pipe threader for $40, a cutter for $20, and a pipe vise for $20. Then you will have this stuff for other uses. I've had these HF tools for over 10 years with good luck. I also use them in the maintenance of four rent houses. Just my .02 Rick

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