PVC for air according to OSHA

[ccvstmr]

Having worked in industry for a number of years, we had an incident in one of our Lancaster, PA plants where the polycarbonate bowl on a high pressure air filter/regulator exploded (90 psi air line). The plastic shards pierced a perforated metal sound enclosure wall partition. Nobody was injured. It was believed the use of synthetic oil in the air system caused the polycarbonate bowl to fail. Following that episode, guidance documents were amended to require metal bowls or metal shrouded polycarbonate bowls only.

It's amazing how cheap things or doing something cheaply can end up costing so much. Word to the wise...do it right, or don't do it. Is your life, health and well being...or that of your friends and loved ones worth doing it any other way? Think twice. Carl B.

[Jacob's dad]

I am nearing the installation point for the air lines in my shop and I plan on using copper. I found this copper tube handbook (see attached) on-line at a forum where folks can talk about their home shops and garages. I can't remember the web address for I found it a year or two ago and then quit visiting the site because the same few folks would fight, feud and flame each other similar to this site where I lurk but rarely post for being flamed on the danger of stainless steel boilers and the affects from not using distilled water only even though I have experience in personally seeing the effects that steam has on stainless steel used for steam boilers.

Jeff

[Jacob's dad]

It appears that it did not allow me to make the attachment above due to the file size.

Jeff

[Jose Rivera]

Jose -- I had pvc air lines in a former shop and never had a problem, but chose to put copper in my current shop. I see you're planning 3/8", but my advice would be to go bigger. I have 1/2" copper line now with a run of about 30 feet, and the pressure drops if I'm using a air-hungry tool like a grinder or needle-scaler. I wish I'd gone to 3/4".

I installed a long run of 3/4" air piping and now I wish I had gone even larger. The far end is roughly 150' from the compressor and the pressure drop is sometimes a problem.

If the cost of pipe hadn't shot up so high, lately, I would install a loop around the buildings where air is delivered. That would provide a dual path out to the far end.

Orrin

Interesting; I have been doing some thinking so I can use the second compressor with the larger tank and this postings from Berne and Orrin kind of fit on what I am thinking on doing.

The larger line I take that serious and abandoned the thought of using less than 1/2". My run is about 15' only.

As for the second compressor I am thinking to have it connected to the same line. This way I will have more air storage and turn both on only when I need lots of volume of air.

Any input negative on what I am planning is welcome.

Thanks gentleman.

[Steve_in_Mich]

I don't know what size compressors you plan to use in tandem but one possible downside might be the strain they put on your electrical supply if they should both start at exactly the same time.

[jpfalt]

When you use two compressors on line, set one for your highest working pressure and on for about 10 psi lower. That way the operation is cascaded with the higher setting compressor being the one that normally runs. The other one kicks in when the first compressor can't keep up with demand. That limits the electrical issues as well because one compressor is running at rated current when the second one starts.

To even out wear on the compressors, switch the settings every few months or years as appropriate.

In Oregon, the regulations for PVC pipe for compressed air requires a shrapnel barrier around the outside of the PVC pipe.

I have used Parker PolyFlow, (polyethylene air line tube) for years with no problems. It balloons before it bursts, stays in one piece and doesn't throw shrapnel.

[Jose Rivera]

I don't know what size compressors you plan to use in tandem but one possible downside might be the strain they put on your electrical supply if they should both start at exactly the same time.

Part of the plan is to lower the pressure switch on one (the second one) so it will only come on at a lower pressure as a back up when lots of air is being used.

I could get a larger unit but having these two I'll try to make the best of it.

[Jose Rivera]

When you use two compressors on line, set one for your highest working pressure and on for about 10 psi lower.

Woops, you must have posted as I was writing

[Jose Rivera]

I have used Parker PolyFlow, (polyethylene air line tube) for years with no problems. It balloons before it bursts, stays in one piece and doesn't throw shrapnel.

Something to consider, I'll check pricing and cost of fitting against steel pipe.

I will post later on when I get started changing over on what my findings are.

[steamin10]

You might consider copper for a small installation. It used to be WAY cheaper than steel piping. It is more now, but so is steel. (all the steel pipe and fittings are Chinee at he home store now.) But for a small installation it may not be a big enough diference to influence your wallet. It will hone your soldering skill and really is a fast install compared to steel pipe. Wont rust and flake, is easy to cut in and make additions.

I did some furniture refinishing, with two 60 gallon air units on line for media blasting the finish off. They were run with staggered set points so the air use controlled how they ran. A breaker box was set on one machine and controlled the initial startup. After one unit was running for a few seconds, full tilt , the other was started and run up to pressure together. When top pressure was reached the lowside unit shut down and a few minutes later the second unit hit limit. By staging the lowside unit just lower than the highside setpoint it will not come on, unless air use outruns the high unit.

[Jose Rivera]

suggestion well taken steaming10.

I really love soldering copper tube.

[jpfalt]

The only negative about plastic and soldered copper is fire safety.

Plastic is worst with copper second.

In the event of a fire (and once I had one), the plastic gives out somewhere around 160 degrees and you get a line rupture which fans the flames (if any). Soldered copper joints do the same thing at the solder melting temperature.

It becomes important to shut down and bleed down your air system when it isn't being used to avoid having a small fire turn into a large fire.

If you don't plan on having any fires, then the above is not relevant.