Which type of copper to use for air compressor?

[Todd.Brock]

I am replacing the copper tubing between the pump and the tank. Its a 2 stage 175 psi pump. It is about 2 feet of copper. Currently, it appears that drawn pipe was used from the factory and bent, unless 15 years of heat cycles have hardened it. I would like to use soft tubing with new fittings. For those that have redone the tubing for an aftercooler, or whatever reason, does it matter which type? My local distributor has K and L available in soft tubing. Looking at lowes.com, I see some variants have a 235 psi pressure rating. Looking at copper.org, just about any version will be 2700psi or greater. I also see a lot of ratings at 100 degrees. I suspect the outlet temp would be closer to 200 ish degrees.

So... What is your recommendation for soft tubing?

 

[djjsr]

Tables 3a, 3b and 3c cover pressures at various temperatures.

http://www.copper.org/applications/plumbing/techref/cth/tables/cthindex_table.html

 

[Outlawmws]

Type L or K typically for common Copper pipes/tubes, Type M is not rated for Compressed Air.

 

[djjsr]

Type M is not rated for Compressed Air.

Reference please.

 

[Todd.Brock]

Well, it seems I have "refrigeration " tubing. I called an HVAC supply and they said go to the plumbing supply. I went to the plumbing supply and took a look and said go to an HVAC supply. I called a HVAC installation guy and he said I have the 3/4" OD line you need but no compression fittings b/c we only solder or braze ..He will only charge 5 bucks for the tubing. THE ONLY PLUS!


So ...I think the type of copper is the least of my dang problems! Even if I could find it, I couldn't assemble the compressor if I wanted to.


Here is a pic of what I am trying to replace. It is so dirty, crusty and hard to bend in and out of place to replace the check valve. The threads are slightly goobered on the male fitting Is there a way to clean up that spot with a file?


Oh wait it keeps coming. I ordered a check valve with no unloader port. 20% restock fee, shipping both ways, makes me thinking I am going to be drilling and tapping the 1/4 line in the new check valve. I hate stupid mistakes...

 

[Provincial]

Reference please.

The link in post #2 shows that there is a great difference in wall thickness between the three main types. For instance, in 1/2 inch size type K has a wall thickness of .049, type L has a wall thickness of .040, and type M has a wall thickness of .028.

Type M would be more vulnerable to bursting, but more importantly, physical damage. It would also be harder to bend without damage.

 

[theoldwizard1]

How about a piece of stainless braided hose. A hydraulic shop can make you one up. Even if they don't have the exact final fitting they will have something you can run an adapter into.

 

[Outlawmws]

Reference please.

Try the link in post #2 and I think it was the first list of "Uses"...

 

[Steevo]

Ok, you are in Cincinatti, and you are ordering these pieces instead of just walking in to one of the dozen or more hose and fitting places in town?
Look under hydraulic hose, or look for Parker store, there are quite a few in your area.
Also, Grainger stocks the tank fittings and sells them as cheaply as anyone.

Here is one source:
http://www.cincinnatihose.com/

 

[djjsr]

Type M would be more vulnerable to bursting, but more importantly, physical damage. It would also be harder to bend without damage.

It was posted that type M is not approved for compressed air. That is not true. Type M is approved for compressed air and table 3c shows 3/4" annealed is rated for 319 psi@ 300 degrees, which are pressure and temperature not likely to be reached by a garage compressor.

No doubt that K and L are stronger but M will work for any compressor or air distribution system in a typical garage.

As far as damage or bending, annealed copper is soft. It's designed to be bendable. I work with copper quite a bit and have never found annealed copper of any type that is hard to bend. You can hit it with a hammer, put a hell of a dent in it and it still works just fine.

 

[gte718p]

How about a piece of stainless braided hose. A hydraulic shop can make you one up. Even if they don't have the exact final fitting they will have something you can run an adapter into.

When mine gives up the ghost that is how I'm going. Its also a perfect time to add an A/C condenser and a small fan to cool the air. Wait all projects do not need to grow into monsters :

 

[djjsr]

Here's another link. Scroll down to compressed air.

http://www.copper.org/applications/plumbing/techref/cth/cth_2select_recom.html

 

[Outlawmws]

Your link:

"Compressed Air
Use copper tube of Types K, L or M determined by the rated internal working pressures as shown in Tables 3a, b, c, d and e. Brazed joints are recommended. "

My Link:

Application
Type M
- Domestic water service and distribution
- Fire protection
- Solar
- Fuel/fuel oil
- HVAC
- Snow melting
- Vacuum

OSHA Specifically requires that any pipe/tube used for compressed Air be certified by the manufactured for that use... Its not on the Applications list...

Tyke K & L:

- Domestic water service and distribution
- Fire protection
- Solar
- Fuel/fuel oil
- HVAC
- Snow melting
- Compressed air
- Natural gas
- Liquified petroleum (LP) gas
- Vacuum

- Domestic water service and distribution
- Fire protection
- Solar
- Fuel/fuel oil
- Natural gas
- Liquified petroleum (LP) gas
- HVAC
- Snow melting
- Compressed air
- Vacuum

 

[djjsr]

Interesting. I assume that means it has to be on the application list to be approved by OSHA? But it's ok if your not subject to OSHA regulations?

 

[Trey T]

Type M:

Working pressure of 3/4" diameter pipe: 332psi @ 250degF

Yeah, it will work just fine.

 

[Todd.Brock]

Steevo, thanks for the suggestion. I don't think about the Parker store. I have bought plenty of things there. My though process was I didn't want a 50 ft roll of tubing from HD/ lowes. I called the plumbing supply next door for soft copper by the foot. I assumed it was 1/2" at quick glance. I then measured and its 3/4"OD. Hence the calling around.

I will give the Parker store a visit and get it done. I was referencing ordering just the check valve for the compressor. I always like to source fittings local.

 

[trbomax]

A class act is the ss braided,but in order to be temp rated for compressor discharge it must be teflon tube. Its not cheap. A couple days ago I had a 45" #10 teflon braided discharge hose made up at the Parker store,it was $90.

 

[Outlawmws]

Interesting. I assume that means it has to be on the application list to be approved by OSHA? But it's ok if your not subject to OSHA regulations?

As I understand it, the manufacturer has to list it as approved for Compressed air. those specs we are looking at are not from a manufacturer,

As far as being "subject to OSHA standards", if something goes wrong and there is an injury, and you aren't meeting "Accepted" standards, your royally screwed in court...

 

[Outlawmws]

Type M:

Working pressure of 3/4" diameter pipe: 332psi @ 250degF

Yeah, it will work just fine.

So will PVC by that logic, but that horse has been beat to death several times over...

 

[Todd.Brock]

Yeah trbomax, thanks for the feedback. While the cats meow, 90 bucks ain't happening! I will give them a visit.

 

[zkling]

Try Ohio Hydraulics over in tricounty, they can make just about anything. I have bought a few lines from them before and they were reasonable. Parker has a great selection, but dang near puts you over a barrel to buy anything in a low quantity.

As for the unloaded issue. If all of the other dims are the same I too would just D&T that piece. Just watch your drill size to make sure it is tight. Probably a NPT fitting (hard to tell size from pics).

As others said, not type M for compressed air. If you do use copper, but real careful to get a smooth kink free bend.

 

[Fixnair]

FYI Your discharge temp could go as high as 450* After a long run. It will be at least 300* after after running 15 minutes.
Do not try to bend it by hand. Use a tubing bender. Maybe you can rent one.

 

[theoldwizard1]

A class act is the ss braided,but in order to be temp rated for compressor discharge it must be teflon tube.

Good tip !

 

[Todd.Brock]

Thanks for all the advice. should i be using a tubing bender for soft copper ? I have a conduit bender that I was just going to use the outside as a guide. I need a 45 degree bend to the right and that is all. Or do you mean a tubing bender for copper pipe?

 

[Trey T]

That "horse" is made of different material; behaved differently under pressure, bend, or external force.

So will PVC by that logic, but that horse has been beat to death several times over...

 

[gagreen]

Thanks for all the advice. should i be using a tubing bender for soft copper ? I have a conduit bender that I was just going to use the outside as a guide. I need a 45 degree bend to the right and that is all. Or do you mean a tubing bender for copper pipe?

Copper can act funny and crush easily. A bending tool like this can make it a whole lot easier. Linked the cheapest i could find so I won't speak for the quality but it is a simple tool that for most would be rarely used, one of those cases when cheap may be the route you would want to take or you can try another direction.

Annealed copper can have a very long service life if you anneal it at proper intervals in service as well.

 

[Outlawmws]

That "horse" is made of different material; behaved differently under pressure, bend, or external force.

And yet is still not approved for compressed air use. I'm inclined to trust the Manufacturer's advice on this since if something DOES happen and to lands you in court, the manufacturer will say "We don't recommend this product for that use and do provide other qualified products " or something to that effect...

 

[Todd.Brock]

I scored a 3 ft section of copper tubing from a HVAC supply for 5 bucks. It's Meuller ACR. Looking on their website it has something to do with Nitrogenized. WTH does that mean?

 

[Trey T]

So what were their bases to not recommending it, or vice verse?

And yet is still not approved for compressed air use. I'm inclined to trust the Manufacturer's advice on this since if something DOES happen and to lands you in court, the manufacturer will say "We don't recommend this product for that use and do provide other qualified products " or something to that effect...