Black pipe or galvanized for shop air lines?

[rswyan]

Remember it is compressing the air it sucks in, where it is located. If that air is humid, it will make lots of water. If that air is dry, it won't. Having it located in an air conditioned space, will also reduce the amount of water it produces because the air is drier.

A point that is well worth considering ... given that there are multiple benefits ...

I've had the AC in the shop "on" pretty much continuously (even if in "Energy Saver" mode) for the last month. The compressor has an automatic drain valve on it that cycles every time the compressor runs ... and I'm seeing very little moisture come out of the drain valve.

The tank does get pretty warm every time it runs ... but it also cools off very rapidly ...

 

[ray66v]

The compressor has an automatic drain valve on it that cycles every time the compressor runs ...

An automatic drain is a great option, and will no doubt extend the life of the tank, since most people don't drain theirs religiously.

 

[franklin2]

A point that is well worth considering ... given that there are multiple benefits ...

I've had the AC in the shop "on" pretty much continuously (even if in "Energy Saver" mode) for the last month. The compressor has an automatic drain valve on it that cycles every time the compressor runs ... and I'm seeing very little moisture come out of the drain valve.

The tank does get pretty warm every time it runs ... but it also cools off very rapidly ...

I can verify this also. The one factory I worked at had over 750 cfm worth of compressors in various parts of the faciltiy, all contributing to one common loop in the plant. They all had very large dryers, automated dumping valves, and 3 large tanks. The place was not airconditioned, and we always had major water problems in the humid summer. Lots of equipment failures because of it.

I moved on to work at a medical facility that was climate controlled. It only had about 300cfm worth of compressors, but they did use the climate controlled air, and they did not have near the problem the other facility had.

 

[franklin2]

A point that is well worth considering ... given that there are multiple benefits ...

I've had the AC in the shop "on" pretty much continuously (even if in "Energy Saver" mode) for the last month. The compressor has an automatic drain valve on it that cycles every time the compressor runs ... and I'm seeing very little moisture come out of the drain valve.

The tank does get pretty warm every time it runs ... but it also cools off very rapidly ...

I can verify this also. The one factory I worked at had over 750 cfm worth of compressors in various parts of the facility, all contributing to one common loop in the plant. They all had very large dryers, automated dumping valves, and 3 large tanks. The place was not air conditioned, and we always had major water problems in the humid summer. Lots of equipment failures because of it.

I moved on to work at a medical facility that was climate controlled. It only had about 300cfm worth of compressors, but they did use the climate controlled air, and they did not have near the problem the other facility had.

 

[jwmorris]

I have copper and PVC. If you are just using the air, to air up tires and such, I don't think a little rust will matter.

If you are using air tools, pneumaic cylinders, etc you can destroy a lot of dollars with little chunks of rust. Also why many expensive machines like CNC mills and lathes have dryers, filters and regulators mounted on the machine itself.

 

[mtrmn]

I have not had time to go through this thread, but my air systems are all 1" schedule 40 PVC. I run 150 PSI in my shop. so far=zero problems.

 

[ray66v]

I have not had time to go through this thread, but my air systems are all 1" schedule 40 PVC. I run 150 PSI in my shop. so far=zero problems.

You can have zero problems, 7 times in a row, when playing Russian roulette.

That doesn't mean it's safe. It just means you were lucky.

PVC compressed air piping is against code. It is an OSHA violation. It has injured people. That been proven repeatedly.

 

[KennyG]

I have not had time to go through this thread, but my air systems are all 1" schedule 40 PVC. I run 150 PSI in my shop. so far=zero problems.

Just to remind people the issue is not PVC pressure capability (although it is generally less than metal) it is failure mode. Yes, a PVC pipe can set there at 150 psi for years and nothing will happen. However, if you drop a heavy weight on it, especially at low temperature, it will explode and send sharp plastic fragments great distances. In the same situation, a metal pipe may crack but won't explode. That's why use of PVC is expressly forbidden by building codes and OSHA.

If you are happy with that risk (and I will freely admit I have more than a few things around my place that would make a safety inspector turn pale), OK, but I personally would not work in a shop with PVC air lines.

 

[drizler]

I did my shop in copper and have been very happy with the results. 84' of 3/4" along the top and four drops using 1/2". All my takeoffs rise vertically with a drain at the bottom of each drop.

Same here. Easy to set up and solder. I have had mine (all 3/4" since the late 90's with no problems. I did use regular 50/50 solder because it's a lot easier to use than the new stuff. The only leaks are as you would expect at the quick disconnects.

 

[mikehaugen]

Alright, so I was a kinda taking a middle road here... I could understand people using pvc and figured they were probably alright, but I would use metal of some kind, mostly because I have acces to any tooling I would need for iron or copper. I have since changed my mind.

We have 2" diaphram pumps at work that pump waste water to a holding area in another area of the plant. For those that don't know, a diaphram pump used air pressue on diaphrams to pump liquids... the outlet port of the pump will deliver the liquid at the same pressure as the incoming air supply- we run around 95 psi in our plant. The liquid end of these are piped with 2" pvc pipe (some is sch.40 but most is sch.80). So I went to turn on one of these pumps a couple days ago and heard a large loud "crack" and water started coming from the ceiling. The outlet pipe ran up the wall and up to another pipe along the ceiling, and it broke right at the elbow. Now realize that this was at the top of the run where the pressure would be the lowest and there is no restriction between there and were it dumps into an open tank. I imagine there would be a small surge because the pump had just turned on, but I can't imagine pressure at that point exceeding maybe 50psi. I thought of this thread immediately. I now KNOW what I will run when I do my garage/shop.