Air Lines

[Tom Norton]

So I am going to install air lines in my shop. Will go with copper or black pipe. If copper can I use the less expensive type M?

[jerry nazard]

Tom,

The same question was recently posted over in FWW Knots. The consensus was that types K and L were rated for compressed gases. I did not find anything on a quick Google search.

I used type L in my shop for what it's worth.

Best!

-Jerry

[Jim Becker]

Tom. welcome to SMC!

Stick with the thicker wall copper for this application.

[Josh Mountain]

I'm thinking of running air lines as well. I saw a shop in a wood mag supplement with lines of copper zig zagging down a wall for moisture.

Does anyone have expertise with this? Are you just letting the water flow out (down the ramp) after depressurizing?

Also should the inside of my air tank be rusty? It was like that from day one. Do I need to treat that? Thanks in advance and apologies if I hijacked!

[Billy Dodd]

When the air gets pumped into the compressor and goes by the pistons it gets warm and cools inside the tank which creates condensation in the tank which makes the rusty water in the tank you see when you drain the tank. Which is why you're suppose to do it every day. The zig zag you seen going up the wall works as a condenser which is suppose to cool the air before it gets to the top. There should have been a tee where the compressor hooked to the wall with a drain valve headed out the bottom so you could drain the line there.

[Josh Mountain]

yeah I decompress each time and drain. Just wondering if I need to worry about that rust or throw some we up there or something.

[Billy Dodd]

I have a tank that's been around for 20 plus years with nothing added to it and I probably drained it 30 times in all that time. I used good filters on it and I would drain it before I sprayed anything ( so it might have been a little more than that) but that's about all you do to them. And change out the oil every now and then.

[Don Eddard]

I'm thinking of running air lines as well. I saw a shop in a wood mag supplement with lines of copper zig zagging down a wall for moisture.

Does anyone have expertise with this? Are you just letting the water flow out (down the ramp) after depressurizing?

Also should the inside of my air tank be rusty? It was like that from day one. Do I need to treat that? Thanks in advance and apologies if I hijacked!
If you're just using compressed air to blow sawdust and fill tires, then you can get by with pretty much nothing more than a hose from the compressor. Pneumatic tools prefer dry air though, and spraying really requires dry air. In order to dry the air, it must be cooled. The cheapest way to cool the air is to run it through a length of pipe. I've seen recommendations saying 50' is a good target distance, but sometimes your shop size or wallet can limit that a bit. For dry air, it is important to have vertical drain drops at key locations in the piping. Here is a diagram showing some typical piping methods.

http://www.tptools.com/StaticText/airline-piping-diagram.pdf

The zig zag trick is a way to get a lot of pipe length crammed into a smaller space. All of the zig zag piping arrangements I've seen have drain valves at the bottom of each vertical leg. Three zig zags, three drains. The water accumulates at the bottom of the legs, and should be drained off periodically. They work well. I've seen several examples of these air drying arrangements posted on the web, but they have all been on other forums, so sorry, no links. :rolleyes:

And I respectfully disagree with Billy's opinion that draining once or twice a year is sufficient. That's begging for problems, from rust and scale getting into air tools, to leaks in the tank itself. The tank and compressor manufacturers recommend daily draining for a reason, and it's not just because they like to hear the hissing sound. ;)

[David G Baker]

I haven't installed my stationary air compressor since moving to Michigan but when I do there will be automatic float drain valves at the compressor and on any vertical drops. This costs more but is worth it in the long run depending on what you use your compressed air for.
I also have a supply of filters that will be installed at the compressor on the line leaving the unit and at any critical point where I need moisture and oil free air. All of my air equipment came from a motion picture lab that I once managed so the air had to be oil, dust and moisture free to keep from ruining film I processed.

[Anthony Whitesell]

The link Don provided says no plastic, copper, or galvinized. Black pipe only.

[Billy Dodd]

Don,
If you noticed in my first post I stated you're suppose to drain the tank every day which is what the manufacture says to do. I just stated in the second post that (from being lazy or whatever reason) I didn't drain my old compressor very often. Which by the way still works fine today. I replaced it with a bigger compressor for spraying HVLP. Billy

[Sam Layton]

Hi Tom,

I installed type L copper pipe in my shop. I would never use type M for anything, it is to thin. I ran the pipe into the attic, and then ran a little over 40' before going to any of my drops. I have never had any moisture in the air. The only place I can find water/moisture is in my compressor drain.

[Randal Stevenson]

http://www.copper.org/applications/plumbing/techref/techref_main.html


The copper tube handbook has what you want.

[Dave Lessley]

Tom,

Iron pipe is really the only think you want to use. Iron pipe helps with the condensation process to eliminate water from your air. Copper will do this but is not has robust as iron pipe. It can split and ones it goes you can end up with shrapnel which is why you would never, never, never use PVC.

Most schools of thought reccommend 50 feet of pipe before your water trap for condensation running down hill towards your water trap and gauge. For example I have my compressor at one end of my shop. The pipe goes up to the ceiling with a petcock on a tee at the bottom with about 6 inches of pipe for water to collect. It goes up to the ceiling the length of the shop drops 4-6 inches and runs back to the compressor and down to my water trap. All running down hill 1/8 inch per foot or so. You can run pipe off of that anywhere you want just putting clean outs at any point that is lower than what is able to run back to the water trap.

This is best practice. Everyone will have there version. I worked in the automotive refinishing industry for 14 years. This is what most compressor and water trap manufacturers reccommended. It comes down to what makes you happy, how much money and time you have and how much risk your willing to take. At the end of it all air comes out.

[Jerry Booher]

I have a 25-year old 5hp single-stage compressor in dry Arizona. I still have rusty moisture every day, but I don't drain it as often as every day.

I had a zig-zag manifold with 80' of M copper running down a wall. Still had a lot of moisture. Sandblasting was really a problem with water passing through the filter. I think that it may be too hot here for the copper to function as a condensor. The pipes were always hot.

Jerry

[Reed Wells]

Sorry Guys but, I have had 3/4" pvc in my production shop for about ten years now and I have never had a leak or a blowup. As far as water in the lines, I will say that that could be a prob for me. I never knew that metal would eliminate the moisture content. Now, that said, If I were to redo my shop ( not knowing about metal and moisture ), I would not hesitate to go with sched. 40 PVC again.

[David Freed]

I installed a spring loaded drain valve on my air tank, with a shallow catch pan under it. They come with a 4' pull cord that makes it very conenient to drain it several times a day. Whenever you walk by you can pull on the cord for a few seconds and then go on with what you are doing. I will agree that it would be better to remove the moisture before it gets in the tank.

[Randal Stevenson]

Sorry Guys but, I have had 3/4" pvc in my production shop for about ten years now and I have never had a leak or a blowup. As far as water in the lines, I will say that that could be a prob for me. I never knew that metal would eliminate the moisture content. Now, that said, If I were to redo my shop ( not knowing about metal and moisture ), I would not hesitate to go with sched. 40 PVC again.


Publically acknowledging a OSHA fineable violation?

[Dave Lessley]

Jerry,

The nature of sandblasting and the volume of air required and being in Arizona and possible humidity would be an issue under the best of conditions. Copper transfers and absorbs heat quite easily but if your ambient temperature is already high then there is no place for the heated air to condense. I have heard of people in warm/hot climates with high humidity running a coil of like 1" copper tubing in a refrigerator with a drain at the bottom with the coil starting at the bottom and working it's way to the top allowing them to bleed off the water that runs down as it condensates. Here the transfer works in your favor as the copper readily conducts the cold and the heated air is drawn to it. they also make driers unlike a filter for contaminates it is full of dessicant (sp?) sand that absorbs the moisture as it passes through it. The one I saw in use was about the size of a 16 gal drum.

[Edward Warren]

Sorry Guys but, I have had 3/4" pvc in my production shop for about ten years now and I have never had a leak or a blowup. As far as water in the lines, I will say that that could be a prob for me. I never knew that metal would eliminate the moisture content. Now, that said, If I were to redo my shop ( not knowing about metal and moisture ), I would not hesitate to go with sched. 40 PVC again.

Code aside, I've worked in two auto shops some time ago that had PVC lines. Then, in '99 I put PVC lines in my garage/shop when I moved in. No problems ever so far...knock on wood. I do have them "strain-relieved" at the couplers with good anchoring.

[Edward Warren]

I installed a spring loaded drain valve on my air tank, with a shallow catch pan under it. They come with a 4' pull cord that makes it very conenient to drain it several times a day. Whenever you walk by you can pull on the cord for a few seconds and then go on with what you are doing. I will agree that it would be better to remove the moisture before it gets in the tank.

David - can you provide a link or some more info on this valve?

It sounds perfect for me since my compressor is mounted very high and not easily accessible.