Best Pipe for Compressed Air

[Henro]

Hi,

Now that I finally got an air compressor, I want to pipe the air around to different points inside my shed.

I have seen people use copper tubing (same stuff as used for water) for this purpose, and I think some have used PVC.

Perhaps Black iron pipe would be the best?

What have you used? What would you recommend?

Seems like the copper tubing would be the easiest and cheapest way. But would it be the safest way? Somehow I think not...

Thanks for any advice!

 

[RobS]

I used black pipe at our old house to run a line from the garage to the basement. Worked fine. I've heard people using PVC. Here at work it's mostly copper /forums/images/graemlins/smile.gif

 

[BillyP]

I think I'd use PVC. It sure is easy to work with and cheap.

 

[shvl73]

Why not use flexible air hose stapled w/ romex staples?
I bought 2 - 50' air hoses at Sam's & I think I paid $30. No elbows needed for corners, 300 psi rated, cheap, easy to splice or T using barbed connectors & it won't rust from condensation. One downside I can think of would be on really long runs at high pressure & high volume there will be some restriction with the smaller fittings on the hose ends.

 

[_RaT_]

Bill check out this link, especially down towards the botom of the page, Rat. Compressed Air

 

[Bird]

Bill, I used PVC, which is specifically NOT recommended by the compressor manufacturers and other experts, presumably because if it ever broke it would shatter and possibly injure someone with flying debris. I never had any break. I think black pipe is the recommended material, although I see nothing wrong with copper. Copper is not likely to break, but even if it does, it would probably just split and not blow any pieces anywhere. I think there might be a bit more of a condensation problem with copper than with black pipe, but whatever you use, you need to include a drip leg with drain (petcock) at the lowest point of your pipe run anyway.

 

[BAC]

I need to do the same thing to my shop (pipe for air) and was wondering about the copper pipe. Do you just solder it together like for water or do you use compression fittings or what? Do you use the same schedule as water?

I have read that PVC is not good as it can explode under pressure, little bits of plastic shrapnel flying around. /forums/images/graemlins/shocked.gif

 

[_RaT_]

Here is the portion of the link that relates to piping material in my previous post.

"Common piping materials used in a compressed air system include copper, aluminum, stainless steel and carbon steel. Compressed air piping systems that are 2" or smaller utilize copper, aluminum or stainless steel. Pipe and fitting connections are typically threaded. Piping systems that are 4" or larger utilize carbon or stainless steel with flanged pipe and fittings.

Note: Plastic piping may be used on compressed air systems, however caution must used since many plastic materials are not compatible with all compressor lubricants. Ultraviolet light (sun light) may also reduce the useful service life of some plastic materials. Installation must follow the manufacturer's instructions.

It is always better to oversize the compressed air piping system you choose to install. This reduces pressure drop, which will pay for itself, and it allows for expansion of the system.

Corrosion-resistant piping should be used with any compressed air piping system using oil-free compressors. A non-lubricated system will experience corrosion from the moisture in the warm air, contaminating products and control systems, if this type of piping is not used. "

 

[DocHeb]

The best would be stainless steel pipe since there would be no rusting. However, the price of stainless outweighs this advantage over black pipe, and with appropriate moisture traps at the compressor, the amount of water in the lines can be decreased. Appropriate drip legs and inclines in the pipe would also help. The advantages of threaded pipe is that it won't fail. The disadvantage is that it is difficult to cut & thread, requires special tools to work with it, and is very difficult to modify after the fact (e.g., inserting another tap in the middle of a run).

There are two thicknesses of copper - type M and type L. Type L has a thicker wall and will be stronger. The advantage of copper is that you can sweat it just as you do for water piping, and it is easy to install without special equipment. The disadvantage over pipe is that there may be a higher chance for failure, but at homeowner's pressures (<135 psi) this is really a non-issue.

A third would be PVC. Although many people use it, it can fail catastrophically. I don't speak from experience, but I'll refer you to:
PVC Pipe in Compressed Air Systems
The Use of Polyvinyl Chloride Pipe in Above Ground Installations.
I suppose that a lot of people use PVC, but then again, a lot of people drill their ROPS. /forums/images/graemlins/smirk.gif

With the ease of installation of copper, the ability to modify it after installation, and the safety advantages over PVC, I installed Type L copper pipe for my compressor.

 

[Egon]

Think I'd go for the heavier copper pipe but if in doubt use welded schedule 80 stainless steel pipe with the appropriate fittings or use the stainless steel with welded on ring flanges.

Egon