using galvanized pipe for air lines

[BTL-A4]

I would like to run an air line from my small compressor to a connector closer to where I use the air hose. The run would be about 15 feet. Can I use galvanized pipe for this? I can use copper, but it's pricey and I've never worked with it. I've heard PVC is a no no. That leaves galvanized. The pressure would be about 150 or so. The compressor is shut off between uses. I might even put a bleed valve on the line so there's no pressure in it except when it's used. I'm thinking a small diameter, like 1/2" would work. Do they even make a smaller diameter? This is used for blowing air off/out of tools, projects, etc., so I don't need massive airflow. Thoughts and comments from those who know would be much appreciated. Thanks!

 

[LXCam]

You don't want to use Galv as it'll end up contaminating your tools. You want to us black iron like they do for gas lines. Also its cheaper so there's that.

But if you want ****, there’s always stainless

 

[The Cobbler]

galvanized will work but not the best choice as it can flake off ,use black. black was industry std for years & probably still is.
there is 3/8, 1/4 and 1/8 but 1/2 is probably easier to get , as well as fittings too.
typical system would be slope the pipe downhill, take the air off the top of the pipe & put a drain end of line

 

[mreisner]

Been using galvanized for close to 30 years in my shop and never had a problem with it. The main part of my shop isn't heated and occasionally I would get a little condensation on it but I've never had a problem. I have a filter at the end of every run and other than a tiny bit of oil never found anything other than them with the exception of moisture either.

 

[Stuart in MN]

Black iron is a traditional choice and should be readily available locally. You didn't mention it but another option is aluminum, from places like RapidAir. Northern Tools is one place where you can buy airline kits, it's relatively inexpensive and easy to install - the piping can be bent by hand to go around corners. https://www.northerntool.com/categories/compressed-air-piping-kits

 

[isb cornbinder]

You don't want to use Galv as it'll end up contaminating your tools. You want to us black iron like they do for gas lines. Also its cheaper so there's that.

But if you want ****, there’s always stainless

I plumbed in 12 drops in my shop. I used black iron pipe. This was in 1990. Now, in 2023, I am dealing with rust corrupted air. I must use an air filter/dryer at every connection. Black pipe is a bad idea.
If I had to do it over, I would buy one of those expandable aluminum kits.
My brother had/has a wood fabrication shop. He installed a rotary compressor ahead of larger airlines. The airlines act as storage and eliminate the need for a tank.

 

[Damon L.]

For those in Menards areas, you can order the rapidair online and get the 11% rebate. The prices are competetive with everywhere else as well.

That's how I ordered my kit. Just got it installed a month ago. 100' 3/4" kit, 3 drops. Had it done in about 8 hours total. I would do it again.

 

[Hohn]

I'm thinking about Rapidair too. Local Rural king has the kit for like $190, pretty reasonable for what you get considering the superior convenience vs running copper or black iron.

 

[nadogail]

In my little workshop I am using an air hose threaded through the ceiling joists.

 

[tarmy]

You don't want to use Galv as it'll end up contaminating your tools. You want to us black iron like they do for gas lines. Also its cheaper so there's that.

But if you want ****, there’s always stainless

Go brass…that should be cheaper

What, nobody is telling OP to use plastic yet?

Black Iron or copper. Mine are all copper only because it was easier just to cut as needed and I didn’t have to guess what all the sizes I would need for the set up.

 

[Rusted Nut]

I have installed plastic pipe for compressed air in a couple of construction projects. It’s definitely not standard ABS/PVC, but there is some available and rated for compressed air supply; which is what I would use if I were doing it.

 

[TurnipTruck]

I used 1” galvanized pipe and 3000psi American pipe fittings from one end of my building to the other, laid on the truss bottom chords and under a couple feet of blow-in Fiberglas. I have occasional traps and two auto blowdowns that come on when the compressor is enabled.
Until retirement, I dealt with relatively high pressures of lethal gasses, sometimes above auto-ignition temperatures, so we were highly motivated to not have leaks.

I guess it kinda carried over to the home shop, as it has held pressure for 3 or 4 months without running the compressor.

 

[Roothawg]

I have been running 1/2" galvanized for close to 25 years. No issues. I am getting ready to build another big shop and I am wondering if the Rapidair stuff is basically jus repackaged Pex/AL rebranded? Anyone know?

Usually people don't tool up to make a speciality product. It usually comes from another industry standard.

 

[engineer2]

Black iron pipe will let rust particles loose in your air. I've disassembled old systems and was amazed how much rust there was. You need a filter at each point of use.
Easy home solution is 1/2" type M copper water pipe with sweat fittings.

 

[The Cobbler]

I used type L copper in my garage with silver soldered connections. yea, it was overkill but it's there for my lifetime & the next persons too.

 

[Steve W.]

You said it’s a 15-foot run? A couple sticks of copper and a handful of fittings isn’t going to cost that much more than other types of pipe.

Plus, you will have the luxury of placing corners EXACTLY where you want them, not relying on the increments found in threaded pipe.

Have you actually run the numbers to compare? You might be surprised on how affordable copper really is.

.

 

[Firebrick43]

If you have drip 6” plus drip legs most all flaked off galvanizing (or rust from black iron) will be trapped.

 

[BTL-A4]

Thanks all! Much appreciated. Further research showed that I might be able to use PEX or PEX-AL-PEX. It's flexible, which seems odd.

In my little workshop I am using an air hose threaded through the ceiling joists.

I thought about doing this, but running the hose along the wall behind the workbench.

ABS is also rated for air, but it looks like it is not used in California because it's tainted with regrind, so it's not as strong. I could only find the larger diameters anyway.

Also looks like prices are pretty similar for the various metal options, but I'd need to learn to work with copper and solder.

The Primefit Kit looks promising ($85) It looks like a cheaper version of the Rapidair one. I got thrown off by the flexible pipe; it just seems like it would be too weak, but it holds 150 psi. I would need to connect it at the compressor at one end and the air hose at the other end. This kit appears to have an extra connector, so I could run the rest of the pipe along the wall and have air farther along.

 

[rharman]

For probably 20 or more years, I've just used one of the Goodyear rubber hoses that HF used to sell to get from my compressor to a ceiling mounted hose reel. Never had a problem, but I do only power up the compressor when needed.

If I were to hard-pipe it, I'd use black pipe but RapidAir would be my absolute first choice for a complex setup.

Simple extension... Just a hose. I see @nadogail went the same route.

 

[4 FN 27]

I used type L copper in my garage with silver soldered connections. yea, it was overkill but it's there for my lifetime & the next persons too.

Our entire Shop is plumbed with 2 inch mains, 1 inch subs and 1/2 drops in Type L Copper. I wouldn't do it any other way.

My home shop is all 1 inch looped around each room with 1/2 inch drops and drip legs. In the next couple of weeks I'll be running another 140 feet of 1 inch.

My ol'Man's shop was done in Black Iron Pipe. Had a 100 HP Screw Compressor and I bet 75 HP was used to fill the leaks.

 

[c39er]

1" galvanized pipe in my shop for for 32 years. 175 lbs maxbair pressure.
Never any flaking or rust issues. System is constantly used.

 

[racecougar]

I have been running 1/2" galvanized for close to 25 years. No issues. I am getting ready to build another big shop and I am wondering if the Rapidair stuff is basically jus repackaged Pex/AL rebranded? Anyone know?

Usually people don't tool up to make a speciality product. It usually comes from another industry standard.

The PEX-AL-PEX lines are sold under a bunch of different brand names, likely from a handful (or less) of actual manufacturers. I have noticed quality differences of the fittings between some brands though. That would be my "watch out".

The stuff is very easy to work with, looks nice once installed, inexpensive, and should last forever without any rust/contamination concerns. I like to run a ball valve at each drop, so that only the air hose in use is live. Having an air hose fail when you're on the other end of the shop is no bueno, especially if there is a nice car within air hose whipping distance.

I also place a little water trap beneath each outlet. That said, compressing conditioned air, draining the compressor tank daily, and using a good filter/dryer arrangement upstream, I have yet to ever get a hint of moisture at the drops.

 

[HoosierBuddy]

Our entire Shop is plumbed with 2 inch mains, 1 inch subs and 1/2 drops in Type L Copper. I wouldn't do it any other way.

My home shop is all 1 inch looped around each room with 1/2 inch drops and drip legs. In the next couple of weeks I'll be running another 140 feet of 1 inch.

My ol'Man's shop was done in Black Iron Pipe. Had a 100 HP Screw Compressor and I bet 75 HP was used to fill the leaks.

2" type L copper is more than $15 per foot around here.

Not saying it's not better...just saying.

I plumbed mine in black iron in 2010. No issues to this point with the iron. I have had to replace the rubber lines on my hose reels.

 

[55bigblockcid]

The only thing galvanized pipe is good for is fence posts.

 

[nadogail]

The only thing galvanized pipe is good for is fence posts.

I like EMT for fence posts.

 

[Monza Harry]

Black pipe is the industry standard. However those systems are pretty much always under pressure [especially if used with a screw-compressor]. For home use depressurization will allow water to fall out of suspension, this will cause rust [black or galvanized], just something to consider. Galvanized is a no go for the reasons mentioned above, now that may or may not rear its ugly head but with the mostly imported pipe the positive results above aren't as likely with the now mostly imported pipe, that 20 year old pipe was all Canadian/American made pipe. Not worth it to me and my toys! Copper is what I am planning on, started collecting parts, now down to the pipe, about $70/10' still so on hold for now. Type "L" (or K) is actually regulated for use I am told, as it is supposed to be better with the pressure pulses/pressure it is thicker & (softer/annealed ?)] and shouldn't crack from that. Solder is supposed to be 45% silver solder, (same as natural gas work) this is to prevent rupture during a fire [800° + melt point]. But no-one uplugs their hoses, so not sure how much help it will actually be. Could I cut corners on those requirements and not have a problem sure, but if something else causes a problem I want no further issues. For a 15 ft. run, grab some air brake tubing (and required fittings) from a truck garage, and plan carefully if updates start the dreaded "project creep". Go to Ingersoll Rand's or one of the other big air compressor mfg's sites for legit info, like taking the air from the top of the line, that would be your 1st or 2nd water filter. Allow proper air cooling [long enough run of pipe/hose] before going into the primary filter/system. Just some things to consider/research. Your stuff and your life, knowledge is your friend. There are many here that will argue that lead/tin solder is good enough but than will argue that it should never be used for electrical connections as it is too brittle, but it's ok for a stored energy device(s) [?]. Take care and keep us posted PLZ. Harry

 

[fourjeepin]

Thanks all! Much appreciated. Further research showed that I might be able to use PEX or PEX-AL-PEX. It's flexible, which seems odd.

I installed pex in my shop a couple of years ago and it works great. Safe, easy, and inexpensive. UV exposure is the only potential issue that I am aware of.

 

[kyrbz]

I currently have black pipe in my shop and get a lot of rust and crud in the lines. Because of that, I have a filter at every outlet. I think I'm going to use a pex system in my next shop.

 

[RAYJAY]

here is my install from 2015 and no rust or problems ....

compressor piping

I am replacing my old sch 40 compressor piping with copper. I will be soldering the joints. Then I got thinking, can I use pex with those push fittings? I will be running 3/4" line, about 60' worth. I have seen the aluminum stuff but would like to source locally. I can not find if anyone has...

www.garagejournal.com

and followed this for the install... http://www.tptools.com/tech-metal-piping.dlp

 

[PoorUB]

You don't need 45% silver to braze copper fir air. As for gas we used 15% silver to braze copper for gas.
Regular plumber's solder if fine as is M copper. M copper will handle typical air line pressures just fine.

 

[PCustoms]

You know you can wipe that excess thread sealant off, right?



For 15' low usage I'd probably use a flex hose. If that didn't work I'd price black pipe (from plumbing supply store, not box store) vs. Copper and go from there. Copper is faster, but black pipe is used in millions of systems.

 

[Chris_Hamilton]

Contrary to what the conventional wisdom says, galvanized works fine. When I was in my 20's I went into business for myself for the first time. I renovated an old building and set it up to do the work I do (paint and body). I got a great deal on a huge lot of 1' 1/4" galvanized pipe, nearly free so I set up all the air lines with it. Ran nearly 200 feet of line. Well I ended up having to close the business 4 years later, another guy took over the building and continued doing paint and bodywork. It has been a continuous body shop since I went into business in 1999. I ended up working for the current owner for almost 8 years. We never had the first issue with the lines or it clogging anything (that's what filters are for BTW). Black Iron (actually just steel now) rusts over time and causes many more problems than galvanized ever will. Ideally copper is the best but the cost can be prohibitive.

 

[4 FN 27]

2" type L copper is more than $15 per foot around here.

Not saying it's not better...just saying.

I plumbed mine in black iron in 2010. No issues to this point with the iron. I have had to replace the rubber lines on my hose reels.

Yep Copper has gone way up since we ran this. Based on the Plant Layout there is 2420.183 feet of 2 inch main +/-. Done in 3 phases as we expanded the operation, 1999, 2004 and 2007.

Adding to the system is easy with Ball Valves strategically placed where can shut areas down, add a T and a another Ball Valve fire up that area again and add to the new T run. Down time is kept to a minimum.

Our Lasers required clean air and Copper is sleep insurance for the process.

 

[racecougar]

You know you can wipe that excess thread sealant off, right?

Come on over and take care of that.

 

[customh]

You said it’s a 15-foot run? A couple sticks of copper and a handful of fittings isn’t going to cost that much more than other types of pipe.

Plus, you will have the luxury of placing corners EXACTLY where you want them, not relying on the increments found in threaded pipe.

Have you actually run the numbers to compare? You might be surprised on how affordable copper really is.

.

This is the most relevant reply here. Assembly of a copper piping system is so much less headache than dealing with threaded connections everywhere.

The Primefit Kit looks promising ($85) It looks like a cheaper version of the Rapidair one. I got thrown off by the flexible pipe; it just seems like it would be too weak, but it holds 150 psi. I would need to connect it at the compressor at one end and the air hose at the other end. This kit appears to have an extra connector, so I could run the rest of the pipe along the wall and have air farther along.

If you're OK with spaghetti on your wall then go for it. I'd venture a guess that there's more miles of Nylon and Polyurethane tubing under pressure in compressed air service than any other material on the planet right now.

Our entire Shop is plumbed with 2 inch mains, 1 inch subs and 1/2 drops in Type L Copper. I wouldn't do it any other way.

My home shop is all 1 inch looped around each room with 1/2 inch drops and drip legs. In the next couple of weeks I'll be running another 140 feet of 1 inch.

My ol'Man's shop was done in Black Iron Pipe. Had a 100 HP Screw Compressor and I bet 75 HP was used to fill the leaks.

Running the "drops" off the top of the mains (as they are) with drip legs off the bottom makes a wonderful system to work with.

 

[Metal-Marc]

I like EMT for fence posts.

I use PVC for fence posts.

 

[Monza Harry]

⁷I looked up some info to be generally disregarded: https://copper.org/applications/plumbing/cth/select-tube/cth_2select_recom.php

Copper Tube Handbook: Table 14.3a

Calculated Rated Internal Working Pressures for Copper Tube: Type K*

copper.org

Brazing is a soldered joint with a melting point above °800 F [from the Harris site if my recollection holds]
50/50 solder melts at °421 F, 60/40 is even lower at °361 F, compressed air is typically at °250 F, so above (or way over) half way, a small problem or over duty cycle and you are getting close to full melt temps weakening starts way before that temp. I pointed out what I did for a reason. Galvanized isn't coated at the joints as threading removes the coating at the end of pipe, internal chamfer, and the threads, therefore they are raw malleable iron, again dry air constantly in use [think commercial/industrial use, not home shop 2-3 nights a week] isn't much of a risk to removing the coating, periodically use will allow rust to start working its way under and start lifting the zinc, to liberate it from its hot dipped prison! I spent many hours finding this information as I, like many here I wanted more than some "guys" word [internet word at that]. Again your lives and stuff, do as you wish, I've shared the fruits of my search with you. Harry
P.S. remember to check the annealed strength of your type "M" tubing and water copper @ 3/4" is usually referred to as 7/8" and 1/2" is 5/8" tubing in the charts approximate OD

Google Search

www.google.com

Google Search

www.google.com

SILVALOY 450

lucasmilhaupt.com

 

[Steve_P]

I used galvanized for ~10 years with no issues. I didn't use black iron because I saw all of the rust and **** in filters at my first job where they used black iron. My present air system is copper. It wasn't cheap, but that was 20 years ago, and it was money worth spent.

 

[BTL-A4]

With this short of a run, cost may not be a major issue. I may go with copper and make sure I use the high-melt-point solder. It looks like I'll need to figure out how to place moisture filters and traps, too. Maybe I'll draw up a plan and share it and you all can tell me how I can make it right.

The other option is to use the Primefit kit. When I discovered it, I got to thinking I could run the lines in a different way, since it comes with 100 feet of hose. I can place the lines up high in the corner where the ceiling meets the wall, and run down drops to connectors so I have air in several places.

 

[Steve_P]

Normal plumbing solder is fine. Unless something has recently changed. I have 3/4" copper tube, 155 PSI, lead free plumbing solder, and it's been trouble free for 20 years.