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Plumbing for shop air?

wvracer821

wvracer821

Well-known member
Joined
May 27, 2020
Member Number
1546
Messages
698
Loc
Morgantown, WV
I finally got my compressor all fixed up and running good. its time for air line plumbing in the shop now and ive been doing some research on the most economical way to do it. I snagged some pex-al-pex (MaxLine from RapidAir) from work out of the dumpster and i wanted to use that but after pricing out the special fittings im not sure i want to use it since ill have a small fortune in the fittings. ive considered black iron pipe but it seems like lots of people have rust issues over time. i briefly looked into using regular pex but the internet had a lot of negative feedback on that. however, I have not found anyone that actually used it and it failed miserbaly. Has anyone here used regular pex for air on here?
 
Third generation plumber here. I use it.

Biggest dangers is hot slag from welding or angle grinder debris can melt a hole in it, and sunlight will attack it. I run it above head, and run rubber hose down the wall.

Whatever you do, don't use pvc. If it bursts, it shatters and throws shrapnel everywhere. Copper would be faster than threading iron, but more expensive.
 
Had PVC in the old shop, was put in in the 90s. My Dad's shop as well.

The shop one was fine until the counter lady who never usually went in the shop area decided to turn the air on and yanked the ball valve WOT in .5 seconds. Shit exploded in several places!
We always turned it on slowly, like a sane person would.

These days with cordless tools, most shops don't need elaborate air systems.
About all I use air for is blowing stuff off, tires and plasma cutter. I just have a 100ft hose on the compressor.
 
Thanks guys. I’m not doing anything super complex. I just want a halo all the way around the ceiling and 6 drops around the shop. Maybe even a hose reel by the door so I can get tires outside quickly. I’m going to start buying some pex bits to start getting it done
 
I did black iron pipe, as long as your air system is decently dry and you have drop legs with valves you can drain, it's perfectly fine. The cheap threaders work fine if you go slow and break the chips often and lube it right up good.

Keep in mind pex pressure ratings are temperature dependent and air systems are way higher pressure than water systems. Typical water is maybe 50-60psi, typical air is 120-175psi.
 
I'm in the process of doing pex. Using 3/4" to get around the shop.

Pex is stronger at cooler temps than warmer. I'm regulating it down where I tie into the pex, for maybe 100-120#.
 
I used the Primefit kit from Amazon. Very easy to install and works great. Also lots of add on parts available.
Blue line at the top.
 

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i used 1" polyethene natural gas line for mine. by doing one inch Halo around half the shop i also increased the volume of air storage for sure. and you get the big burst of air if needed also because its 1 inch supply.
 
I have ran PEX in my shops since 2018 without problem. I run it high along top of wall and drops down to each hose reel. I also do a tee to hose reel and extend below that 12" or so to a valve so it can help catch some water and drain when needed. Luckily last 2 shops have been in the desert so moisture in air isn't an issue.
 
My only regret is not throwing ball valves in front of the quick connects and the hose real. That shit gets leaky with time and it would make it easier to ignore and deal with when needed.
 
Yeah I also have a ball valve off the tank so I can shut off all pex lines to fix any leaks without having to bleed off the entire tank. I also have a 120 gal air tank in opposite corner of my shop that more than doubled air volume so compressor doesn't have to run for very long or often.,
 
MAGADamit! said:
I've had PVC in my shop for 25yrs.

I wonder about it sometimes... :shaking:
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In recent years I find myself saying "it'll be fine up until the point it isn't" pretty regularly from things I see being done around me. The shop I work at is definitely one of those "safety third" types of places. If/When PVC does fail, that it is hard and brittle and the chance of shrapnel is the main issue. You're going to need ungodly pressure to get shrapnel from black pipe, copper is more likely to rip or split, and PEX or HPDE (RapidAir) is soft enough it won't be throwing shrapnel.

chaplinfj60 said:
i used 1" polyethene natural gas line for mine.
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What is the pressure rating on that? Household gas pressure is typically no more than 30 to 60 psi.

TTMotorsports said:
Luckily last 2 shops have been in the desert so moisture in air isn't an issue.
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Humidity is definitely an issue around here and I see people using just rubber air hoses or the plastic pipes having a lot more issues with water in the lines. I run an air dryer, but a combination of black pipe and copper seems to help with condensing any other moisture out of the air.
 
I’m using PEX. My only complaint is I found it difficult for a very clean, looking install. My installation looks pretty heck.
 
I used 1/2 pvc for mine after some consideration of risk. Conclusion I came to is that PVC air lines is a bit like 2 piece rims - perception of risk has considerably outpaced reality, and while it's not 100% safe, it's a pretty minimal risk.

Much of the concern stems from various controllable problems - poor quality joints failing, concern about high temperature strength, degrading due to sunlight, impact damage, etc. Moderate competence does a pretty good job of controlling this.

The only real danger to me is explosion risk and shrapnel, but that's also not that significant if you use small piping. Can also make sure pipe is located in such a way that shrapnel is unlikely to hit you as well.

Wouldn't use anything bigger than 1/2 - highest safety factor and also smallest amount of energy if it ruptures. Larger sizes have enough energy to be genuinely dangerous, but small diameter means low energy and small fragments. Doing some rough math, the energy in 1" of 1/2" air line is enough to accelerate 1 gram to roughly 100 mph. In the real world only some energy goes into fragments, and there's likely multiple ones each taking some amount of energy. Bottom line, outside of a fragment hitting pointy end first in an eye it's unlikely to get an injury worse than a minor bruise or cut.
 
Today there's really no reason not to just use PEX.

I got chastised for using PVC for a DIY Franzinator at the old place. My grandpa's old machine shop has been plumed in PVC for 40+ years and nothing's blown up yet. Ceiling drops, with springy hose coils at most machine stations, plus a few quick connects on various walls. A lot of it is protected behind spray foam, though it was there was a good 15-20 years before it got spray foamed.

Just depends on what level of risk you're acceptable with.
 
I did mine in Pex too. I watched several videos of people doing destructive testing on it. Seems like it fails at around 700 psi and when it fails it just splits nonviolently.
 
Even the RapidAir kits are PEX. They are PEX-A or something but even that isn't rated for over 100 psi at above like 80 degree's
 
To get a clean install on the pex I have simply zip tied them to existing conduit OR i put a drywall screw every ft alternating to go ontop and below the pex at correct spacing for pex to fit between them. Than I install official holders between those, if drywall some spackle in the holes or DGAF becuase it's a shop and basically hidden by the pex anyways.
 
arse_sidewards said:
My only regret is not throwing ball valves in front of the quick connects and the hose real. That shit gets leaky with time and it would make it easier to ignore and deal with when needed.
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I have ball valves everywhere, they're frickin cheap and being able to route or turn on/off sections as needed is awesome. I also have a back feed hook up, so I can plug in a different compressor to the system, isolate my main compressor, and feed it with something else if I ever needed, I usually also use this as a dump for the system after I shut off the main compressor outlet so I don't leave the entire system pressurized.
 
I use the cheap rapidair basic kits. After doing one years ago by hand with copper (when it was cheap) the quickness I can throw this up and make changes wins.

Added another drop for the blast cab - 45 minutes. Ran to the carport with 3 drops - 3/4 of a day, including trenching and drilling through the concrete on both ends
 
SomeGuy said:
I have ball valves everywhere, they're frickin cheap and being able to route or turn on/off sections as needed is awesome. I also have a back feed hook up, so I can plug in a different compressor to the system, isolate my main compressor, and feed it with something else if I ever needed, I usually also use this as a dump for the system after I shut off the main compressor outlet so I don't leave the entire system pressurized.
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Same here. Its nice to turn on and off legs that aren't in use.

My system here is copper line around the plasma torch and welding area, then transitions into aluminum tubing (had a pile of it surplus from an auction) and I am using cheap JIC flared fittings on everything. I have drops with clear legs every so often to catch moisture and drain on occasion. It all has grade to it for proper back drain; but also has a bunch of nice dryers in the system too. I had the materials and they were all easy to work with and very permanent. I have an ICF building too so I was able to recess the hard lines into the walls in a lot of places.
 
The rapid air kits are the way to go over buying the parts individually. I ran the 3/4 with the brass and aluminum blocks at the outlets. After maintaining a factory with 1 inch black pipe I could not do it again even if you were paying me.
 
I also use cheap PVC ball valves without problems. They don't get used very often so no leaks from them and they're somewhat protected to keep from blowing up if hit.
 
TTMotorsports said:
Yeah I also have a ball valve off the tank so I can shut off all pex lines to fix any leaks without having to bleed off the entire tank. I also have a 120 gal air tank in opposite corner of my shop that more than doubled air volume so compressor doesn't have to run for very long or often.,
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Sorry, I couldn't leave this alone.

You meant to say runs less often, but for twice as long (which is still definitely an improvement).

Carry on!
 
PAToyota said:
What is the pressure rating on that? Household gas pressure is typically no more than 30 to 60 psi.
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i have looked up ratings in the past and they very. we use the yellow for normal installations and it is rated at 60psi for the life of the pipe, but that is not what we test the pipe and fitting at. we test at 1.5 times the rated pressure or 90-110 psi. and i even read other places on line it has a rating of 125 psi. so i said fuck it and been using it for over 5 years now.
 
sdmuleman said:
Much of the concern stems from various controllable problems - poor quality joints failing, concern about high temperature strength, degrading due to sunlight, impact damage, etc. Moderate competence does a pretty good job of controlling this.
Click to expand...
Most things people circle jerk about the safety of fall into that category because the people who circle jerk about safety are the kind of people never do shit so they don't understand what is and isn't controllable or to what degree.
 
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