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Just received a Griot's catalog and noticed they offer a 12mm rigid nylon tubing for compressed air lines. They say it's rated in excess of 350psi. I've been waiting to find a decent quality non-metal air line to keep corrosion to a minimum. I have a 7.5 hp IR T30 compressor with an 80 gallon vertical tank.

My question is does anyone use this system or a similar non-metal rigid air line system? What are the pro's & con's?
 

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Just one of the guys
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We use nylon tubing at work for our airlines. Have had them installed for approx 10-12 years now @100lb pressure 24/7 with no failure. Other than one blew out of the fitting one day. Very hard to catch a snake fighting back. LOL!!. I haven't seen Griots yet as I just received their catalog. Our line isn't very large in diameter so I imagine there is some loss in pressure. But with the fittings you just pull back a sleeve, slip in the line, and pull the sleeve back over. It crimps the line to an airtight seal.

Kevin
 

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Sounds like you guys are talking about PEX (cross-linked polyethylene) tubing and fittings. That's what they use for water in new houses now. I don't remember for sure but I'm guessing it's rated at a high enough pressure (probably more than PVC).

You can get it at your local big box store (home depot, lowes, menards). It takes a special crimping tool for the fittings but they're not too expensive. You could sell it when you're done probably.

I'm sure it's way cheaper at those stores than ordering from Griot's.

Hhmmmm... My buddy has all of the crimping tools, too bad I just put in all new 3/4 inch copper a few months ago. Oh well. I'll remember it for next time.


Later.....
Wally
 

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Standard PVC water pipe is a time bomb. One good whack - like a heavy toool falling on it, and it will shatter sending sharp shards of plastic at high velocity all over your shop. Works fine for water because water does not compress.

I think I'll check out the Pex stuff.
 

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Discussion Starter #6
Thanks for those replies. I remember reading somewhere that PVC can shatter under a pressurized air line (too ridgid I guess). I'll check out the PEX also.
 

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I would definitely stay away from PVC at all costs and PEX is not a great choice either (it can degrade from UV exposure). I don't know why you'd need a hose capable of 350psi unless its for regulated output of nitrogen tanks on pit carts.

There are some neat new products like Trans-Air (Garage Pak) and ALR (Prevost)...both are aluminum tubing but the best bang for the buck is relatively cheap type L copper. SD
 

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If you were building a distribution system to standard commercial specs, the burst pressure would need to be 5 times the working pressure. For a 2 stage compressor, that means an ultimate strength of about 900 PSI. OSHA isn't likely to ever inspect my garage but I do want something with a reasonable margin of safety. I think L copper is used in refergeration applications with working pressures of over 200 PSI but the fittings are all hard soldered in that application.
 

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julmer said:
If you were building a distribution system to standard commercial specs, the burst pressure would need to be 5 times the working pressure. For a 2 stage compressor, that means an ultimate strength of about 900 PSI. OSHA isn't likely to ever inspect my garage but I do want something with a reasonable margin of safety. I think L copper is used in refergeration applications with working pressures of over 200 PSI but the fittings are all hard soldered in that application.
I've never seen any lines in dealerships (or home garages) rated for this kind of pressure (900psi). The cost of plumbing a shop all in stainless steel braided hose (or hard tubing) would be more than the cost of the compressor. And consider the weight of the storage tank with considerably greater wall thickness to hold this kind of pressure. The regulators like the one pictured here can also get expensive since they are manufactured for industrial & medical applications and must be tested to hold high pressures for extended periods.



Most dealerships use hard soldered copper. As a general rule, you should keep the line and system pressures as low as required. For general air tools, this is 90-105psi, for tire changers, pressures of 140psi are often required. The higher the pressure in the system, the more likely you are to develop leaks. Natural gas feeds to homes are generally less than 1/2psi.
 

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Yea, 900psi is a bit extreme, considering my compressor tank is ASTM certified to only 200psi. I agree, the cost of a 900psi rated air delivery system would be astronomical. Your relief valve on the compressor would be popping long before you even got close to that kind of pressure.

Vince
 

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There are apples and oranges here: working pressure and burst pressure. If you have an ASTM tank rated at 200 psi working pressure, it is actually designed to a burst - or failure - pressure of about 1000 psi. I don't know the standards for compressed gas but a 2250 psi oxygen bottle will actually hold a lot more than that but is limited for safety. A threaded pipe system or hard soldered copper may easily withstand a 900 burst standard. I have shop air lines that say 800 psi burst right on the rubber jacket.
Stuff like PEX can have a lower safety factor because it is somewhat resiliant and can absorb surges without cracking.
I think PVC is about 400 psi burst since it is designed for use on a water system that typically would be 50 to 75 psi.
 
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