Black pipe or galvanized for shop air lines?

[n3gxq]

It is my "intent" (key word) to plumb my pole barn for air on my next trip home. I've read a number of posts here, and know that PVC is not the way to go, so metal pipe is definitely what I'll be using. My question is, should I be using black pipe or galvanized for the lines? I won't be running an oil system, as I'll be occasionally painting, and I won't be using tools enough that manually oiling them would be a problem.

I'll be installing a water filter and drops with ball valves throughout the barn. Is the small amount of water in the lines enough of an issue that it even matters as far as potential rust is concerned? I know a lot of this is opinion based, but I've gotten a lot of good information from this site, and am definitely willing to listen to what anyone has to say.

Black pipe will work fine, as will several of the newer products, such as PVC-coated aluminum tubing (no threads - compression fittings) and SOME plastics. Many plastics (and fittings) are just not designed for the pressures that can occur in a shop environment air system.
Regardless what type, always follow these rules: 1. Slope the pipe back to the air source, with a tee & drain valve below the inlet tee for condensate. 2. ALL taps must come off of the top of the air line, then turn to whatever direction you need them. This prevents moisture transfer. 3. All drops should have a drip leg & drain valve on them. All of these are to help prevent moisture transfer. If you plan on using a lot of air and/ or delicate air-operated equipment, consider a refrigerated air dryer.
I ran hundreds of feet of black pipe (mostly 2") in a tool & die shop, using 2-20 hp and 1-10 hp compressors, running 2 shifts per day, back in the early 80's. Still very much in use today! The newer tubing-type products are easier to install, but black pipe still reigns as king of structural integrity. Hope this all helps!
John

 

[Mark 42]

Show me anywhere that says PVC is rated for air. There are far more dangerous blowouts with PVC than the proper methods like Cu or iron.

Is copper rated for air?

Sched 80 is pretty strong:
PVC Pipes - Pressure Ratings

For me, PVC is fine. It's pretty low risk.
I seriously doubt the failures shown were below 150 PSI.

PEX looks interesting though.

 

[Scooby074]

Black iron in my shop.

I had a chat with a pneumatic rep the other day talking about piping. The Pex-Al-Pex pipe has a tendency to go all wavey if there are not enough clamps used.

He was pushing rigid coated aluminum from a european company. Man it was NICE. Cost was less than having black pipe installed due to ease of installation (well, thats what he said ). I should have compared to copper. I bet with the high price of copper it would be cheaper or at least no more expensive. Particularly nice were the drops. They had a pre-bent upward loop to help keep crap from going down to your tools. Nice smooth interior too.

If I was building a ground up system and wanted something real nice and rust free, Id think strongly about going with rigid aluminum over copper.

The stuff he was selling was called SicoMat. SICOMAT - aluminum tubes pipes nylon fittings couplings collars brackets compressed air distribution

 

[turdkicker]

use type L copper solder it with 95-5 solder take your DROPS OFF THE TOP condensate drains off bottom this pipe will handle most shop compressors if not all if you need to add a drop its easy to do I ve been an industrial plumber ,pipe fitter for 15plus years don't forget to grade your pipe and if you want to impress your friends may I recommend STAINLESS TUBING it polishes up nice and you also can silver solder it together, it ll last well beyond a lifetime

 

[BethelHntr]

Copper might work for some but if installing in a large building could get mighty pricey at $3 bucks a foot.

 

[blackdog2086]

Like most TBN members, I'm looking to get the most bang for my buck. I want to do this once, and only once, so if it costs me a little more initially, I still consider it a savings in the long run to have a safe reliable system. Even though some of the plastics available would probably work, I'm still leaning toward metal piping.

Until reading some of the posts, I hadn't considered copper, which I've worked with extensively while building my house. It's been quite awhile since I priced it, and a bit of internet research has me pretty much ruling it out. The pipe itself isn't cheap, but the fittings are what really raises the price of a complete system. I do like the idea of soldering rather than taping and pipe doping threaded connections. The cutting to needed lengths is a breeze with copper also.

I'm thinking that n3gxq is right in that as long as I can keep it clean and dry, I'll be OK with black pipe. I'll have to plan plenty of drops, as well as a good filter system, but I think if I do my part and drain regularly, I'll be OK.

With that being said, it'll probably be six months before I get home to install my system. Keep posting your thoughts and experiences, as I'll probably change my mind a dozen times between now and then as new ideas come in.

 

[turdkicker]

I know copper is a bit pricy but lasts try and find used most of the stuff I ve installed over the years was type L find an old warehouse or commercial building you can also use black pipe we ve installed miles of the stuff FOR OUR NATURAL GAS LINES here in Canada (Saskatchewan) inside and outside for years if your worried about rust paint it with tremclad again look around can find it used but you have to thread it or properly weld it

 

[69chevy]

I used truck air brake lines in my pole barn. Can withstand temp extremes and super easy to work with. Plus I used push to connect fittings so I can change and put drops wherever I want. Drops all over the shop make it nice. And was plumbed in a short time.

I did too. I think it's nylon tubing, 3/4" diameter. I have a two stage compressor that maxes out at 180psi. Not a single problem in over 20 years.

 

[sockmonkey]

My compressor specs recommended black iron pipe. I mounted the compressor on Anti-Vibration pads that I bought from the compressor dealer. I also used a flex line to go from the compressor to my black iron pipe. (that flex line was danged expensive!). I came off the tank with a 1' nipple, a 1" tee, and full port ball valve in order to drain the line without draining the tank in case of problems later. That came in real handy when a contractor broke the line during a roof replace! The mfr. (Ingersoll Rand) recommended running a 1" main line with 1/2" for the drops. I came off the main line with 1" to 1/2" tees Pointed the tees up, and with a 4" nipple & 1/2' elbow ran the 1/2' line to the desired locations & regulators. I used a few union fittings on the main line for places of possible expansions. I also used full-port ball valves in front of each regulator. (really helpful for when the reg. goes bad) I put a tee fitting vertically at each regulator to feed the regulator with the horizontal part, while the other vertical port continues with a 6" nipple for a particulate trap. (This is required for natural gas installations, and is really beneficial for compressed air too) A ball valve at the end allows quick, easy cleanouts.

 

[rototiller2]

Some of my friends have used pvc with no problems and I have 3/4" and 1/2" copper at 175 psi. Both work fine for air lines and are far cheaper and easier to work with. But if you want to use steel it will work too. Just make sure that you add some traps for the rust and water.

In industrial applications, black pipe is always used for the compressed air.