January 29, 2008
When you say repair shop, is this a commercial business? Before going the cheap route and installing PVC, some warnings direct from the McMaster Carr catalog/website:
"Warning! Never use PVC fittings and pipe with compressed air *or* gas."
"Plastic pipe fittings are not rated for pressure, however, the pressure rating for pipe is often used as a reference. Keep in mind there are several factors that will reduce the pressure rating. For example, threads on a fitting will lower the pressure rating by approximately 50%. A reducing fitting will also lower the overall pressure of a system. And, as temperature rises, the amount of pressure a system can withstand decreases."
This is why PVC can and will break while under pressure and exposed to the inherent heat generated during air compression. Yes, I understand many people do and have used it with no problems. Good luck with that, please keep your safety glasses on. If this is a commercial business, you need to eliminate this liability and do it right. At my place of work, we are on the third set of plastic pipe in ten years. The PVC, well it had broken in about six different locations before they decided they needed to spend money on a completely different (air approved) plastic. (against my advice) It started failing after two years. Not ones to learn from their mistakes, they replaced it with yet another type of plastic, and yes, it has experienced failure as well. Myself, I''m a pretty good learner from other peoples mistakes. (even more so from my own) So when it came time to install the air system in my shop at home, it was done in black steel, and I have none of those breaking/shattering put-your-eye-out issues. More importantly, I have a pipe that is approved for the air I put through it. I wish anyone the best of luck with a PVC install, but when the manufacturer/supplier advises against using it, you are assuming some liability, especially if you have employees.
A couple different versions of compressor piping are online at Sharpe, one is here:
The other is here:
I wouldn''t recommend the first version, as the pipe layout and drain system is useless. All the water will drain down to your outlets, exactly where you don''t want it. In the second version, all the outlet go up first (from the main supply), then to the outlet. The main supply is sloped to promote drainage of any water that condenses, and by having the outlets go up first, the water should stay in the main supply line until it reaches the drain.