Is there any consensus for or against PVC or CPVC for air lines. My compressor produces 150 psi. I already have copper for my present distribution system but I need to add a branch and the price of copper is profanity inducing.
Max
This is one of those recurring threads. Never use PVC for air lines because of the (perhaps small) danger of explosive shattering.
Nobody seems to agree with me, and I don't know why it is such a strange idea, but I use 1/2" air hose. It is cheap, safe, specifically made to handle air, and easy to install. It has worked fine in my shop for the last ten years, and still looks like new.
Vaughn
There is no rating for either PVC or CPVC to be used as air lines. It is for incompressible fluid use only. When you run the calculations per ASTM B31.3 for compressible gas lines, you will find that you are only allowed to pressurize it to about 4 psig max, before you exceede the stress limitations of the plastic. Virtually all have a ultimate stress of 7000 psi or less.
In other words, don't use it because if it gets any damage, it goes off like a bomb and will spray shrapnel in virtually every direction.
If you already are using copper and can't afford to continue, get a union that is rated to connect copper and steel and run the leg with black iron instead.
It's a hotly contested item, but if you read the documentation on the ratings stamped on the PVC and CPVC, it will open your eyes..Run a google search on the subject too.......Besides, do you really want to install a potential bomb in your shop?
Craig
Black pipe is a good idea, and actually pretty convenient, in many ways. You can have the plumbing house cut 20' lengths in a variety of sizes (5' and 3' are typically useful), and thread them. Get an assortment of nipples, incl. 6", 12", and 1/2x1/4x1/2 T's, and it's pretty non-critical plumbing, where you can pitch the pipe back for drainage, angle the T's so water stays out of the connecting hose, etc. Unions can make the installation easier, as well. And overall it's easy to take apart, modify, etc. Altho the hose idea is good, the black pipe is probably not that much more expensive, per foot, and the T's/fittings are likely cheaper. I did my shop in a mixture of black pipe, copper, hose, whatever made the most sense in a particular locale.
"Proctologically Violated©®" wrote in message news:Y45dh.413$ snipped-for-privacy@newsfe10.lga...
No problem. I have a set of pipe threaders (1/2 thru 1 1/2") and I can put a bi-metal union between the copper & the black pipe. The plastic would have been easier though. :-( Thanks much to all.
Max
I have PVC airlines throughout my shop and into my house, but my air is very dry of oil, and the lines, for the most part, are cast in concrete. I do not recommend PVC for airlines, no more than anyone else. When it fails, it does so catastrophically. None of my lines that are not encased in concrete are exposed, so should I have a failure, I don't risk hurting anyone. All ends that are exposed make a transition to black iron pipe before leaving the concrete.
If you're hell bent on plastic air lines, there is just such material available, expressly for compressed gasses. It's colored green, and is made of ABS. Your local plumbing supply house can probably fill you in on the necessary information. Be advised, if you think copper is expensive, hold on to something when they price the plastic for you.
Harold
Draping hose around creates traps for condensate, which is poison for performance and tool lifetime. Assuming you don't have a refrigerated dryer ahead of it (not just a filter).
On Tue, 05 Dec 2006 01:55:07 GMT, with neither quill nor qualm, "Max" quickly quoth:
Against, by a 3:1 margin. While I'd used systems in PVC for years, I wouldn't do it again.
No kidding. Use PEX, galv pipe, or black pipe instead. If you can find lengths of 2" pipe cheap, use that. It also doubles as an air storage chamber...if you can lift it. ;)
Another inexpensive route is to use regular air hose for the wall line. It'll have to be replaced sooner, but it works just fine. The HF PVC hose @ $10 for 100', it sure beats soft copper tube on price.
- Better Living Through Denial ------------
Bad. If you are in a colder climate, even worse. It has been a while since I last bought copper tubing to make an antenna but the ease of installation compared to threaded pipe seems worthwhile.
Wes_S
The shop where i work has PVC behind the sheetrock. First thing i did when i came back to work after 3 years somewhere else, was to repair a dozen or so leaking 10 year-old exposed joints. Then, I could walk around with a stethoscope and figure on where to dig into the walls. Every now and then a joint blows somewhere and i have to stop work and fix it. PVC is good for temporary rigs, but if you are planning on living with it, black iron is the best, and it cools the air and condenses water. Even just using iron for the first 15 feet makes a difference. The TIP / Skat sandblasting catalog has a lot of good info on system design.
...or you can simply terminate your air line with a moisture trap. Actually, we tie-wrapped our hose tightly to a water pipe that happened to be heading in the proper direction, and routed the hose to avoid drip loops. We have been using this setup for a decade now with no perceived ill effects. Air hose can be just as good/bad as properly/improperly installed pipe.
Vaughn
Vaughn Simon wrote in article ...
Unless you've tie-wrapped the hose to the pipe every half-inch or so, there are STILL going to be areas between the tie-wraps where the hose sags ever-so-slightly, and is not tight up against the pipe.......shallow areas in which condensate can collect.
You would be amazed a how much moisture can actually collect over the length of the hose in these low points.
Good ol' fashioned black iron pipe IS the correct answer here......
yeah... but unless those sags are really profound, air motion will carry the water past them.
LLoyd
Perhaps, but after ten years of daily use of our shop's system, I am still waiting to be amazed by slugs of moisture. We have had zero issues, and we don't even have water traps at our outlets.
I don't disagree that black pipe makes a wonderful installation. That said, my experience is that properly installed hose can be a perfectly safe and workable alternative.
Vaughn
LOL..true enough. The other day though..I was in a shop that had used some 1" rubber hose to extend air service into the next portion of the building. A machine tool tech from another company was working on a machine and had a 1/4" air line off, and pissing air as he puttered around with something or another. As I was working on my machine..I looked up and saw a droop in the air line high on the wall..so took a chunk of stock, and pushed upwards on the drooping loop for a few seconds..then quickly went back to doing what I was supposed to be doing. About 4 minutes later.. I hear this shriek and see a small but energetic fountain of water rising up over the other machine..which ended pretty quickly as the slug of water ran out. The now sodden tech squelches by me on the way to his truck for a dry shirt..muttering and shaking his head.
After he passed..all I could do was put my head down..and laugh my ass off. Last time..it was me squelching for the truck...one of the Viets did it to me....
That droopy bit of hose has provided some real entertaiment over the years...
Gunner
Rule #35 "That which does not kill you, has made a huge tactical error"
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