Air Distribution

Most shops I have seen use iron pipe for air, but I was just looking at a couple on-line specs sheets on PVC and it looks like if I were to distribute
air at 125 PSI in my shop using 1" Schedule 40 PVC I would have about a 30% safety margin at the worst case scenario. That's based on 120F operating temperature. While yes it does hit 120F here in the desert once in a great while I don't think its ever gotten above 105 in the shop building. Better safe than sorry though.
Wadda ya think?
P.S. I have seen other shops use PVC also, and they said they never had any problems.
The only real issue I see is that "wish this hose was 2 inches longer" factor. I could probably mitigate that by using brass fittings at the ends and securing them properly at the wall, and of course the fact that there would be air all over the shop instead of in one corner would help quite a lot.
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Not regarded as a good idea.
http://www.osha.gov/dts/hib/hib_data/hib19880520.html
http://www.hotrodders.com/forum/pvc-air-lines-108824.html
Gets brittle, fractures, plenty of sharp high-velocity shards.
Dave
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You cannot use regular Sch. 40 PVC pipe for compressed air, as it is known to explode. The cracks in it run faster than the speed of sound in compressed air, therefore the appearance is that your entire pipe exploded at once.
http://www.google.com/search?q=pvc+pipe+compressed+air+explosion
i

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On Tue, 10 Mar 2009 12:03:03 -0500, Ignoramus26567

=======Another problem is that in the case of fire, if the pvc pipe becomes involved, air pressure may convert the pipe into a flame thrower spewing molten burning plastic if it doesn't explode.
The price difference with black or galvanized iron is not *THAT* great and most good hardware stores will cut pipe to length and thread for you. Be sure to include "drip legs" and blow down/drain valves at frequent intervals to avoid water in the lines problems.
Good luck, and let the group know how you make out. Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
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On Tue, 10 Mar 2009 12:56:07 -0600, F. George McDuffee
If you feel you MUST use galvanized pipe...remember, you are GOING to get flakes of Galv in your tools.
Its a given. Its pretty much Verbotten to use galvanized pipe with CNC machiney, along with teflon tape.
Use both at your own risk.
Gunner
"Human nature is bad. Good is a human product A warped piece of wood must be steamed and forced before it is made straight; a metal blade must be put to the whetstone before it becomes sharp. Since the nature of people is bad, to become corrected they must be taught by teachers and to be orderly they must acquire ritual and moral principles." Sun Tzu
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On Tue, 10 Mar 2009 12:34:56 -0700, Gunner Asch
<snip>

<snip> --------- A good point and another reason to use a filter/regulator/oiler immediately before your air tool or other equipment and no teflon tape, etc. on the downstream side.
For an example see: http://www.use-enco.com/CGI/INPDFF?PMPAGE51&PMITEM1-1110 http://www.harborfreightusa.com/usa/itemdisplay/displayItem.do?itemidE009&CategoryName=&SubCategoryNameand many others.
Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
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On Mar 10, 2:28pm, F. George McDuffee <gmcduf...@mcduffee- associates.us> wrote:
et> wrote:

"no teflon tape, etc. on the downstream side. "
There's nothing wrong with properly applied teflon tape. It's when it's applied to the last and next-to-last thread on a fitting that it becomes a problem. Before I began work- in in the service department I applied tape to thousands of fittiings without problem. Others, less attentive to details, had numerous problems. We were all using the same tape and fittings so I've concluded application is the key.
dennis in nca
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A sane practice is that for expensive machines that do not tolerate various particles, to install an air filter right on them. Ergo, that's what my plasma cutter does.
This is also what the Dumore No. 24 automatic drilling head (for sale) does.
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On Mar 10, 2:20pm, Ignoramus26567 <ignoramus26...@NOSPAM. 26567.invalid> wrote:

"A sane practice is that for expensive machines that do not tolerate various particles, to install an air filter right on them. Ergo, that's what my plasma cutter does."
It would be difficult to add a filter after every junction. But careful attention to detail works as well.
dennis in nca
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All this discussion got me curious about the relative strength of copper vs. black steel pipe. As I suspected, the black pipe is stronger. 1/2" black schedule 40 is rated at 10,380 psi bursting pressure, while 1/2" Type L copper (hard) is rated for 4,600 psi bursting pressure.
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Either one works fine. But if you can stand the pain involved when you pry open your wallet, use the Copper. You will hanve much less crap in your air - Steel rusts, galvanizing flakes, and then the rust and zinc flakes and etc. get carried to places you don't want them.
Myself, I silver-braze the lines so some brain dead plumber goes "Waitaminit, maybe that isn't the water line..." But you can use the same pipe hangers and insulators.
--<< Bruce >>--
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On Tue, 10 Mar 2009 12:34:56 -0700, Gunner Asch

Use galvanized to an air filter, with brass or copper from there to the QD. Put air filters on the "important" stuff.
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I was told this is not safe. So, I used copper tubing. Very easy to add a drop, just cut and sweat in a "T". Its worked well for 20 years now.
Karl
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it'll work fine...as long as you run the PVC inside steel pipe.
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I had PVC air pipes for years until the warnings first appeared here. Then I replaced them with iron near the wood stove and copper elsewhere, just before the price skyrocketed. Some of the old PVC pipes fragmented like glass when I tried bending them, others crinkled.
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wrote:

DO NOT use PVC for compressed air. It is fine untill it fails - and then it is EXTREMELY DANGEROUS. There is a reason it is NOT ALLOWED by OSHA etc. It turns into high velocity shrapnel on failure.
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wrote:

Bob..at least once a year, I get called in to replumb a shop that had PVC pipe that decayed due to compressor oil, heat etc etc and finally blew out, often taking entire banks of florescent lights off the ceiling, blowing shit everywhich way etc.
Im not telling you not to do it. Ive seen some up for as long as 10 yrs with no explosions. But each and every piece Ive taken down had the structural composition of a grahm cracker. Drop it from 3 feet and it shatters like glass.
If you put up PVC...every bit has to be firmly secured to something rigid. After a couple years...putting any strain on it, thumping it, tapping it, pulling on it..and its gonna break. With luck, no one gets hurt.
Just my .02USD worth. My own home shop, is salvaged black pipe, mixed with air hose all running into homemade manifolds with taps for QDs all over the place. Only in places that I need a LOT of volume, such as die grinders, DA sanders and so forth, do I use a lot of pipe.
Black pipe is cheap if you buy it at a wholesale plumbing supply place such as Ferguson Express etc. I think Im paying $11 for a 20' joint of black. One of the tricks in doing a shop is to never ever use 90' elbow. Only use Ts and plug off the unused side. Sooner or later, you will need to put in another run or valve or line there.
Last year, I ran 3000+ feet of pipe air lines in (2) shops, one being 35,000 sqft, the other being about 10,000 sqft, but in 4 different units of a "industrial strip mall", and installed 4 screw compressors and a couple piston pumps total.
Its one of the things I do to make a living..and Im quite qood at it. Ive turned down jobs where they wanted PVC. I dont want the liability.
Gunner
"Human nature is bad. Good is a human product A warped piece of wood must be steamed and forced before it is made straight; a metal blade must be put to the whetstone before it becomes sharp. Since the nature of people is bad, to become corrected they must be taught by teachers and to be orderly they must acquire ritual and moral principles." Sun Tzu
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This one gets MY vote!
One of the tricks in doing a shop is to never ever use 90

Pete Stanaitis -----------------------
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I use that idea for air, water, and coolant. When available, we use crossing tee's. Also known as a cross depending on were you live.
Wes
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wrote:

In black steel pipe, absolutely. Plugs are cheap, and a tee is only a few pennies more than an elbow.
Build your natural gas lines the same way, plus go one or two sizes over what you think you need. Because you'll always end up adding something later, and you'll need the extra flow capacity.
In Copper pipe it's not a huge deal to un-sweat an elbow and sweat in a tee, but the more important part is to plan ahead for the eventual expansion. No battle plan survives intact past the first fired shot, and shop layout plans are the same.
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