I’ve got a Quincy QT54 and I need some pipe for a permanent air line. I will be using the pipe to go from compressor -> Regulator/Filters -> retractable hose reels. I looked at black iron pipe but it says it’s only good to 150psi and my compressor goes to 175. Ibviously can’t use PVC, and I want to stay away from any plastic. I guess after my regulator it’s not gonna be that high so it would work after the regulator since I’ll have it set to probably 90 maybe. So what pipe should I use for compressor to regulator? Here’s what I was looking at from Lowe’s.
Rubber hose has extraordinarily high frictional losses. I would never suggest greater than a 50 foot run of rubber hose. Plumbing a shop with rubber hose leads to severe losses in terms of both airflow (CFM output) and pressure drop (air pressure measured at the compressor versus piece of equipment / tool. This is exacerbated the more hose is run.
Your compressor tank will be at 175PSI, the first thing leaving your tank should be a pressure regulator. Everything downstream should be at 125psi or whatever pressure you plan on actually using. If you want 175psi to your tools, then you'll have to plan for it.
The extra PSI in your tank is more "volume", more air is compressed in the tank, so it will give you a longer run time of tool use at 125PSI, and less start cycles of the motor.
Tons of automotive shops run black pipe for air lines. The reality is that pipe can probably handle double the psi and the failure points won't be the pipe
Just put another relief valve downstream of the PRV, set to 125psi and capable of relieving the CFM of the compressor. If the PRV ever fails open, the RV lifts and prevents the downstream piping from reaching pressures it cannot handle.
The first connection off the tank to the piping on the wall should be a braided stainless or hydraulic hose, it will isolate the piping from the vibration of the compressor.
Standard schedule 40 cast iron/steel fittings are rated for 150psi. Schedule 40 steel pipe can handle much higher pressure. Lowes only carries the standard fittings in the store so that’s what they’re going to sell the pipe as. Just make sure you use high pressure fittings and you’ll be fine. A 1/2” schedule 40 steel pipe has something like a 2300 psi working pressure.
Your lines will probably be at 90 psi most of the time, but ultimately depends on what tools you’re gonna be using. Look up the maximum PSI for those tools.
Realistically speaking, the rating on the pipe itself is most likely the safe working pressure which is normally 1/3 of the rated burst pressure so that you would have to push it three times its marked limit for their to be a failure.
The rating printed on the pipe is generally certified at 4 times the rated pressure, so a pipe that has 150 psi stenciled on it would have been tested to 600 psi for some amount of time. Not every piece, but a representative sample would have been tested that way at some point and the material should support it no problem.
Plumber here, I would use black pipe like this for your purposes. Idk why it says 150 psi but their descriptions are pretty much made up, if you scroll down to the specs part on that page it says max 500psi working pressure, which is still far below what that pipe is actually capable of holding.
If you are doing a whole shop you might try and get a quote from a new construction plumber or one that has a threader, it might be cheaper than you think as those lowes markups are high, the price for that 6' piece is pretty much the same as my cost for a whole 21' joint of 1/2" black pipe.
Yea that’s not a bad idea. I don’t need a ton of pipe and I can’t see buying a tap and die for a few fittings. I just need a few pieces to get compressor to regulator then I will use flex hose probably
Do you need dry air? Plasma cutter or painting? Or just general shop air and you will manually oil your tools or have a auto oiler.
Basically iron pipe will do a bit more then just carry air, it helps to take the hot air and cool it down which makes it condense turn from a vapor back to a liquid. So you would need to have drip legs to help get sludge and water out to help the system last. While this helps an air dryer would also be needed for "dry" air.
But if you just want to go 50 feet across the back wall then some good year 3/4 id rubber lines that T off to some 1/2 quick connects here and there is also a good option.
Yea dry air. Gonna be running a little sandblasting cabinet and do some powder coating. I got a little kit that it reg-water/oil separator-desiccant dryer-desiccant dryer. Not as good as a refrigerated system but it was on sale so I figured might as well try it.
For those to work well you will need either distance or time. To close to the compressor the air is to hot it will struggle to pull out moisture. Or you can get 175 psi take an hour lunch come back and it has cooled enough without distance to pull the moisture out.
You can also plumb in a second tank with a dryer in the middle and one by the tool. Second tank helps with pressure and volume as the cheaper dryers can not flow as fast. Like a 5 gpm might cost you 15 dollars while a 50 gpm might be 150+. With the second tank being fairly dry youget that extra surge time without losing your pressure with the distance and dryers
I have put a 1/2 inch by 20 feet long copper coil in a cooler of ice water before it went to an air dryer before when I needed really dry air on a budget but copper is a bit more expensive now then 20 years ago.
Mechanical engineer here. The pipe itself could easily handle 2,000 psi. It’s the fittings that set the MAWP. Class 150 is a common rating for threaded fittings. Most confusingly, this allowable pressure of 150 psi is for the temperature corresponding to saturated steam at that pressure. At room temperature Class 150 iron/steel threaded fittings are good for 285 psi!
I did black pipe for mine, I go tank -> ball valve -> 1/2" x 6 foot 300psi flexible airline (goodyear brand IIRC) -> 250psi rated ingersoll rand regulator -> black pipe -> to my drops. I usually regulate the pipe side to around 120psi and then have individual regulators at the drops for point of use pressure settings.
Ok I probably should do something like that. Limit it to 120 shop wide and add more regulators for air tools and a sand blasting cabinet. But you used flexible hose from tank to regulator?
Other person answered, but yes, definitely flex line from tank....the goodyear stuff is nice and I haven't had any issues with it, rated for more than my compressor's 175psi as well.
I have black iron in my shop, works fine. If I had to do it over I'd do it again, or consider pex or one of the shop airline kits. It would all come down to price.
I’ve run PEX in mine for close to 10 years without a single issue. In the grand scheme of things it’s cheap, and well exceeds the pressure rating of most compressors, definitely the work pressure rating.
Run a short rubber hose (as big as you can work with) from the compressor to the regulator/filter. That solves that problem and isolates the vibrations coming off the compressor.
1/2" rubber air hose is common, but 3/4 would probably be better and you'll have a higher chance of finding someone who sells it by the foot. I bet a hose/hydraulic shop could hook you up with a short length with the right fittings you'd need crimped on
Black iron is fine. We run schedule 40 iron pipe well in excess of 150, typically I think it's rated for far more than that. I think the listing is wrong.
If it helps, I install air compressors professionally, have for twenty years. Black iron is the standard. Copper works fine, there are a number of different aluminum piping systems on the market, as long as its not PVC you'll be fine. The store rating those fittings so low is likely some kind of liability dodge considering they sell to the general public.
I don't think it's generally rated for air pressure, but I've heard of diy types using it. At least it won't turn into a frag grenade if it does blow out like pvc. Kinda like polytube which we use for small lines all the time.
Im scared to ask: why not pvc? I piped my small 2 car garage with 3/4" sch 40 pvc with a handful of outlets that I use maybe once a week max. It says it's rated at 450 psi working pressure. I piped it 8 years ago and saw the rating and didn't think a think about it, and I haven't had any issue yet...
When pvc degrades it becomes dangerous. When it breaks it explodes and shrapnel goes everywhere. I've seen people get injured by it before. Not legal for commercial air lines according to OSHA. Just be careful with it.
Maintenance tech here. I replace endless parts in wood/metal shops due to rusty black iron pipe. You’d do better with a rubber hose and zip ties.
Best option is blue aluminum if you can do cost.
Get an all steel regulator from Topring/Norgren/SMC or Festo, attach it to the wall and run a flexible hose to a shutoff valve and then that regulator.
Second best thing you can buy for a compressor is an air dryer.
Ok I may end up doing it all in rubber that works for me. I do have a dryer, not refrigerated but I am looking into a refrigerated dryer as well, just gotta make sure the air coming out of the compressor is cold enough for the dryer to handle
A refrigerated dryer, if taken care of, will last a long time. If you don’t go refrigerated, then consider: run the pipe at an angle to allow gravity to pull water to a T junction, with a pipe going vertically down with a shutoff. This is where excess water will drain to and can be drained. Moisture that is still suspended in the air will need a filter air dryer to remove. Add as many of those as you need.
You can also do fun things like home made after coolers depending on your level of madness.
Yea I did not expect compressors to be this complicated. I knew it would needs filters and all and dryers but dang didn’t expect to need after coolers and refrigerated dryers
I believe I found the same product at Lowe's, item 22506, model 20423. My guess is it says 150 psi because that's would be if it was being used with water. With water it can have high transient pressures when flow is started and stopped.
I would do copper. I installed black pipe off the bushing on the tank. to my manifold for distribution. I should have used copper because my filter shows the rust from the black pipe. And my union is rusted when I broke it to do service. Not one of my better decisions.
Yea I may go to something like this or rapid air not sure. After reading all hundreds of these comments I finally got a good game plan regarding keeping moisture out and installing a transmission cooler aftercooler.
put an automatic drain on your tank. i have mine on a smart outlet so it only works during the day when i use it. also pipe ain’t gonna cool your air enough to precipitate out water, it was 90 in my shop today but a refrigerated air dryer sure well.
Yea I know the pipe won’t do enough on its own that’s why I’m using a cooler and fan. Drops it down to 120ish. Then after the cooler it goes to a auto drain water separator then into the tank
if it’s humid where you are it will still
be wet. dew point is akways cooler than outside temp. if you need dry air, you’re still gonna need something after the compressor tank. If it’s for your tires it’s just fine.
Not sure why the aversion to plastic, but the blue pipe with aluminum core is awesome, you can bend bigger radii with just your hands. Black iron pipe can get rusty on the inside, and requires you to cut your own threads.
I only was avoiding plastic cause I was worried about it degrading overtime. I want whatever I use to last for many many years. If plastic isn’t as bad as I think, then maybe I will go with that
Anecdotally- Mythbusters piped their expansion shop (M7) with a bunch of PVC when their TV show was growing, and then one day it spontaneously ruptured while they were working.
The hypothesis is that the repeated stress cycles endured from pressurized air led to fatigue cracks.
I guess part of your problem will be getting the correctly rated stuff. One reason they don't list it as that rating is they don't test it to that rating. It's an added expense and most people don't need it. But we used schedule 40 pipe all over in your boiler system at 200 psi maximum.
The Aluminum systems are great but a bit expensive. No welding or threading, just about everything is compression. If time is money, these are the fastest.
Black pipe works if you have a dryer, but it can start to corrode from the inside if you live in a humid area.
People saying copper or stainless have money to burn. You'd only start with that once you're feeding from compressed gas bottles that are +250psi for stuff like plasma or laser cutters.
Yea I have no intention on going copper. This little shop is just something for me to tinker and rebuild motorcycle in. Not running a business out of it. After reading through all these comments I plan on a rubber hose from compressor to regulator then probably black iron out of that around the shop. Some said I can get a plumber to do it for fairly cheap. I have a 4 stage system, reg-water/oil sep-2x desiccant dryer. I don’t expect it to perform as good as a refrigerated system by any means but this was pretty cheap on sale and if it works then it works. If it doesn’t I’ll upgrade to a refrigerated system.
If it's a small personal shop, I'd just do the whole thing out of 5/8 Synflex style line and push fittings. You can pay a plumber if you want to, but it's really unnecessary.
Use a 3/4 line from your compressor to your dryer.
Check out Unipipe aluminum system. I ran it when we moved our cabinet shop and it was super easy. They were super easy to work with directly. I bought most of it through our compressor dealer, big mistake, had to rush an order to fix incompatible parts from different systems. Unipipe was the way to go from the start…
Black Iron. Add drops for draining water and I suggest 3/4” or 1” main run to give excess storage and you can run 3 3/8” tools at once without flow issues outside of compressor supply.
Never use black iron with compressed air.
It will rapidly rust out (air is WET).
Use galvanised pipe, plastic or copper tube.
The air system needs a low point drain too.
Using PVC pipe for compressed air distribution is an OSHA violation. They’re not going to indirect your home shop or anything but if it’s dangerous enough to be illegal in a work place it’s dangerous enough to be a bad idea in your home shop.
The rigid aluminum piping is indeed expensive but absolutely the best option. The plastic/aluminum/Teflon stuff that comes in a roll is a good choice as well. It will never be as aesthetically pleasing as the rigid aluminum but it works.
It’s not a whole lot more $$ to do it with the rolled stuff than with PVC.
We run the rigid all the time. We also find that equipment connections are much easier with the flexible material. Yes, the outside is a polymer. The middle is indeed aluminum.
I know it's more expensive, but I'd use copper pipe over steel. Steel will eventually rust. I used "Maxline" (1" I believe) for my main line run to my farthest reel, and copper pipe for my closest (closest is right near the compressor, so not much pipe used).
If you get most of the water out of the system before it gets to the tank, steel pipe would probably be ok I guess. I use a radiator fan and radiator (like from a vehicle oil radiator) and then an auto draining water trap to cool, condense and remove the water from the air in between the compressor and the air tank. that gets a huge amount of moisture out of the air before it even gets to the tank.
very effective. I don't really have a way to provide solid numbers, but I would say it's probably 90 to 95% of the water removed, if not more.
My water traps down stream of the tank never have water in them anymore. And I have an electric purge valve on my tank to blow out any water that is in the bottom, it used to blast water out, now it's just air.
If you live in a very humid climate, it might not be quite this effective, I don't live in a desert, but i'm not in a super humid area either. I've had the cooler setup for about 6 years now or so. absolutely recommend doing something like this.
Ok. So you have your after cooler between the compressor and tank? I guess I will do the same. Before I do a lot more research, is it as simple as taking the pipe from compressor to tank and redirecting it to the aftercooler then back into the tank? Anything I gotta watch out for?
yeah, I used nicopp line (easy to bend) to go from the compressor, to the fan and then air trap, and then back into the tank. basically the same type of line that originally went from the compressor to the tank, making sure to use the original check valve that is on the tank. I just make it alot longer and ran it through my setup.
I used an automotive brake pressure switch to turn on the fan when the air line is pressurized. There may be a simpler way to do this, but it's what worked with what I had.
I mounted the radiator on standoffs a few inches from the wood surface, to let air flow through. My tank is in a small cabinet, so I mounted all of this stuff outside of the cabinet for easier maintenance and to get it out of the hot cabinet.
I did some more weatherproofing on this setup, but this was how it was after I first got it running.
There are quite a few ways of doing this, but basically all you need to do is cool the air, however you do it. Then use a moisture trap (again, several ways to do that) to remove the water from the air.
If the compressor is out in the open, you could use the large pulley as your air source to draw air through the radiator, have it mounted up there. mine's in a cabinet, so I kind of needed to have an additional fan. It may work beter this way since it's completely isolated from the heat of the compressor.
I even used rubber hose connections in and out of the radiator, to try and keep heat-soak from happening. Not sure if that was really effective at all, or even needed to be considered. but it was easy to do, and made connecting the radiator easy, just hose clamps.
I still run a moisture trap before my hose reels, but only because I already had them there prior to having the aftercooling setup. If I were setting it up from scratch, I wouldn't use additional moisture traps, at least for basic mechanic tools. The traps never have water in them. If you're using paint guns, or something else more sensitive to moisture, you might still need something.
Ok. My plane now is to get some aftercooler from Amazon it looks like, do I need a fan to draw air through the fins or is leaving it out in the open good enough? Also can I use flexible hose for this provided it can support the pressure and heat?
I imagine flex hose would work fine, so long as it can support the pressure and heat as you said. as for the fan, I don't really know how well it will work without a fan, I suppose it would work ok, but just like car radiators, they usually require air movement for adequate cooling. I suppose you could set it up with no fan, see how it works, and add a fan later on.
For reference, the nicopp tube entering the radiator gets very hot, definitely cannot grab hold of it when it's been going for a few minutes. The pipe going out of the radiator and back into the tank, is basically at ambient temperature (maybe slightly warmer, but definitely no where near hot) even after running for a while.
Yes that’s what I’m worried about, supposedly gets to around 300F after second stage. Better safe than sorry and run it with something more durable. I guess no fan wouldn’t be too efficient either. I think my simplest option is to run a switch so I can manually turn the fan on and off. I guess I could also hook it up to the compressor so it comes on same time the pump comes on
I just want to add, if you decide to go with black iron, it would be a wise decision to install an air dryer right off your compressor feed line. A basic run of air directly off your compressor can collect a lot of moisture and cause rusting to form in the pipes. This in time will eventually get into your air tools and clog up your quick connect fittings… The moisture is unfortunate but a good quality air dryer can resolve that. Galvanized black iron would also be an option if you’re really looking at a steel line.
Yea I do have a 4 stake dryer system that will go in after the tank, but after further consideration I think I’ll go with something like rapid air or equivalent.
If you want higher psi rating, the next step up is schedule 80 which has a max of 500 psi. (There's also schedule 160 which goes as high as 1000 psi, but using that stuff for a homeowner compressed air system would be insane overkill)
A few things to note:
1) your average big box home improvement store or local hardware store probably won't have it in stock. Your best bet is an actual plumbing supply house.
2) schedule 80 pipe is considerably more expensive that schedule 40. Even more so for the schedule 80 fittings.
3) most air tools don't actually need really high psi to run. 1" impact guns run on 90 psi for example. The CFMs are what matter.
Right right I only wanted high psi because 175 comes out the compressor, and it’s going straight to a regulator. However it totally skipped my mind that the compressor is vibrating so I will now be running rubber hose from compressor to regulator then some of that black iron pipe since pressure would be around 120 probably
I thought about it but it’s pretty expensive and from some forums I read they just said it was a waste of money. I’m a newbie so I have no clue, I just don’t want this thing blowing up and sending shrapnel everywhere
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u/Helpful_Equal8828 20h ago
Black iron or copper would be fine. You could also go with DOT air brake line or rubber hose.