Compressed air piping

Dee2

Board of Directors, Vice President
Gene
Staff member
Corporate Member
CU, AL, or ??? What is in your shop?

FWIW, I have no experience sweating joints.
 

Phil S

Phil Soper
Staff member
Corporate Member
The problem with PVC is it will shatter/explode when pressurized and the hit with an errant piece of lumber.
The shattering causes very sharp pieces flying about - definitely not what you want.
Yet still my shops have 1" PVC. I solved the shatter hazard by slipping the PVC into 1 1/4" EMT (electrical conduit). The advantages of 1" tubing is it holds a lot of air plus it cools the hot/moist compressed air. My air compressor is at the other end of the house and there is about 100' of PVC/EMT between the compressor and the shop. I installed a drip leg at about 60' and I get dry air in the shop
 

Oka

Casey
Corporate Member
PVC Used for air must be Sch 80 (pricey) not 40, Forget using it unless you need /want PVC.

Pex will work but at the terminations convert to steel or equal (copper. This makes a better more robust system. Remember to secure every change in direction both sides within 8" of the 90° or Tee. This will prevent thrust kick on the pipe when there is a sudden loss or increase in the pressure.
 

tvrgeek

Scott
Corporate Member
Well, I have no problem sweating copper, but right now, my shop air is 5/8 hose reel. One of these days I'll run copper again.
 

FredP

Fred
Corporate Member
Prevost aluminum. It's pricey (got mine free) but it's a very nice system.
 

bobsmodels

Bob
Senior User
Hi

Some of it depends on your layout. For example, distance from your compressor to furthest drop, how many drops, etc. Make a drawing (see attached example) it will help. I had been acquiring parts for an air line but just kept using air hose and portable small tanks. Finally, after about 6 years last February I just decided to do it. Original plan was all black pipe. However, I happened to have a supply of copper type L pipe which was just about enough and about 30% of the fittings. So I just did it with copper. I know you said you have no experience with joints. Hey a new skill to learn, find a plumber acquaintance and ask for some lessons, it is actually not difficult at all with practice. I had not soldered copper pipe in 6 or 7 years. I practiced on some pipe and fittings – made a real mess of the first few joints, but then got my act together. I have 10’ ceilings and at 74 lifting is not my forte any longer. Copper is nice and light.

No matter what you do I suggest that each of your drops have a shutoff, a drain, and a regulator, see my pictures. To make connections easy I used push connectors with airline flex hose (acts as shock absorber also) for the connection to the regulator which then doubles as a union, making removal, lining up, and servicing much easier. I run the line pressure at 135psi and adjust the local regulator for the tool I am using.

Bob

Compressor-Hook-up.jpg
Pre-Soldering-joints.jpg
Garage-Drop.jpg
Mill-Drop.jpg
 

Attachments

  • Shop Air Line Copper Ver 3.pdf
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Charles Lent

Charley
Corporate Member
Mine is all soft copper with flare fittings and Leak Lock, a refrigeration sealant used to make leak free joints. Soft solder will creep and blow apart too easily. Keep an eye on them. Where I worked went with silver solder after several incidents with regular water pipe soft solder.

Charley
 

tvrgeek

Scott
Corporate Member
Mine is all soft copper with flare fittings and Leak Lock, a refrigeration sealant used to make leak free joints. Soft solder will creep and blow apart too easily. Keep an eye on them. Where I worked went with silver solder after several incidents with regular water pipe soft solder.

Charley
You are suggesting failures of properly sweated connections with what kind of pressures? Of course, when you sweat a joint, you likely will anneal the area, so safe working pressures should be below 300 PSI or so.
 

bobsmodels

Bob
Senior User
I worked with Harris technical department on what solder to use to avoid any problems at 175 PSI line pressure. I told them I had stay brite 8 . Asked if their 95/5 would handle those pressures on type L pipe and fittings. He quoted me several tables and advised that either would have no trouble handling an air line at that low of a pressure. By using silver solder on hard pipe the strength is drastically reduced since you anneal the copper, the tables show strength using low temp vs silver solder temp solders. Youdo not anneal the hard copper using the low temp solder.

Thank you for the heads up on creep. I will check in with them and ask about the creep issue, both Harris technical and a friend at company that does lots of high pressure piping. Never thought about creep.

Bob
 

Oka

Casey
Corporate Member
All copper pipe M, L, or K will hold 250 psi @ 1 " dia (I think it is actually 285psi .... higher the smaller the diameter.
Antimony/tin solder joints hold to around 500 psi.. If you use propress 1" is around 200psi higher @ 3/4 or 1/2". Bottom line.... all soldered joints will handle most compressor pressures.
 

Rwe2156

DrBob
Senior User
Unless you have a very high pressure system IMO copper pipe is total overkill, not to mention very expensive, the same with black iron pipe.

I used the Rapid Air system and full disclosure, before that I used [GASP] Sch40 PVC. Yeah, yeah I know. It lasted almost 20 years.

I just became aware the 1/2" RapidAir tubing I used is only good for 5 years.

We'll see.......

So Dee2, if I had to do over, I'd go with RapidAir MAXline in the 3/4" size b/c it is has a longer lifespan.
 

Gofor

Mark
Corporate Member
Unless you have a very high pressure system IMO copper pipe is total overkill, not to mention very expensive, the same with black iron pipe.

I used the Rapid Air system and full disclosure, before that I used [GASP] Sch40 PVC. Yeah, yeah I know. It lasted almost 20 years.

I just became aware the 1/2" RapidAir tubing I used is only good for 5 years.

We'll see.......

So Dee2, if I had to do over, I'd go with RapidAir MAXline in the 3/4" size b/c it is has a longer lifespan.

As you note, PVC does work. The main problems are that over time it becomes brittle, making it susceptible to damage, but the main problem I have seen in shops piped with PVC is the flexibility, which causes significant sagging in the longer runs, especially in the hot summer months. The areas that sag (and this would also apply to PEX), become water traps that can dump water into your system at the most inconvenient times. Rigid piping, slightly sloping to your down pipes that have the drip leg drain valves that bobsmodels illustrated will help keep the water under control.
 

Charles Lent

Charley
Corporate Member
If you cool the air below the environmental temperature at your air compressor location, and avoid drawing the air off the top of your compressor tank, you won't have moisture in your air lines.

I ran the pipe that normally connects between the air compressor outlet to the top of the tank, running it instead through a repurposed automotive AC condenser coil from a small foreign car. The outlet of this coil was then connected to the inlet on the top of the tank. All of the hot compressed air went through this coil to get to the tank. I placed this coil so the fan in the air compressor pulley pulled air through the fins in this coil, removing most of the heat before it reached the tank. The condensed water then fell to the bottom of the tank where I drained it off every night after using the air compressor. The result was no moisture problems in my air lines.

Charley
 

mkepke

Mark
Senior User
RapidAir 3/4" pipe user here. It’s been in for a couple years..only light use so far tho.

I soldered up a run of copper pipe in between the compressor and the RapidAir pex to act as a heat exchanger and to provide a drip leg.

-Mark
 

Hmerkle

Board of Directors, Development Director
Hank
Staff member
Corporate Member
What about using sharkbite with copper?
Anybody with any experience?
I know it would be pricey, but it eliminates the sweating learning curve...
 

Oka

Casey
Corporate Member
I personally not a fan, I have had them leak on plumbing more than once. Biggest problem is usually the connection was not cleaned correctly or the push-click function was not fully engaged or it just failed. On projects I manage these are usualy what comes with a insta-hot faucet heater, a water cooler or water filter in those package kits.
 

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