by Tony
(Fayetteville, NC)
How does galvanized pipe rank for compressed air plumbing?
I am currently using PVC (I know I know, not recommended) and I want to upgrade, however I do not want the cost of copper nor do I have the skills needed anyway, and black pipe rusts like crazy.
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Hi Tony, nice hearing from you.
First off, PVC isn’t just “not recommended”, it could be catastrophic. PVC’s burst threshold lowers the hotter it gets, and I believe that Fayetteville NC might get the odd warmish day?
When PVC lets go, it often shatters, and anyone and anything around could get shredded.
If I had lots of money, my first choice for a compressed air supply line would be copper. But you’re right, it has become very expensive, and even though there are other alternatives to ‘sweating’ the copper, that would be my first choice for putting copper lines and fittings together.
You know, I don’t know of anyone that’s using galvanized pipe as a compressed air line. Don’t know why. As long as the pipe has the pressure rating (and it should), then the galvanized coating would stop rust inside the lines, making it, in my opinion, a good choice.
By the way, I’d much rather ‘sweat’ copper than thread pipe.
Anyone else have any ideas for Tony and the use of galvanized pipe for an air supply.
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Galvanized pipe for plumbing compressed air.
Tony, I’m new to this whole compressor world, but in doing some reading I came across this quote on the TP Tools website. “We do not recommend galvanized metal pipe, as galvanization can come off the inside of the pipe, clogging separators and regulators.”
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Matt…thanks very much for your input! I guess the “toss up” is do you get better quality air from galvanized, with the risk of galvanization coming off inside the pipe, or from black pipe knowing that rust will develop for sure, and that rust will flow down the line to your application.
Regardless of your choice of pipe, you really need to have a filter / separator before each application that uses compressed air. These take out the free water, and will remove the “bricks and mortar” that flows down the air lines before it gets to your application.
Again, thank you very much for “chiming in”. I have never professed to know it all…maybe it just sounds that way sometimes. 😉 I appreciate any input from folks that have done more reading or have more experience than me.
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by Paul Pearce
I judge galvanized piping as a totally wrong application that is doomed to failure.
I can’t imagine how and why anyone would apply this type of weak and inherently flawed piping. It is weak because it is totally susceptible to corrosion, flaking, and pin-hole defects – depending on the skill with which it is dipped.
And once a pin-hole (or even smaller holes) has been established, the corrosion starts immediately.
There is no way on this earth that anyone can guarantee that there is no defect or flaw in a given galvanization – hot-dipped or not hot-dipped.
And then there is the real hard issue of how does one inspect the surface that is really supposed to be doing the “protecting”: the internal pipe surface!
To date I’ve never heard or read of anyone daring to state that the internal surface of a galvanized pipe can be safely guaranteed not to have defects or flaws – because it can’t be inspected.
and that’s not all.
Most, if not all galvanized pipe is threaded. The moment it is threaded, the galvanization has been compromised and breeched. There is
no longer any “protection”, since the galvanization has been stripped and removed at the weakest point – the threads! This methodology or system of ensuring corrosion protection for a pipe has all the ingredients for its own demise.
Paul Pearce
1-705-789-3313 ext 292
ppearce@algonquinauto.com
Algonquin Automotive
1 Crescent Road
Huntsville Ontario
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David says:
You’re right the bottom line is in air quality. If you just using the the air to blow off and clean machinery the galvanized is a perfectly good solution not to mention cost effective.
Look at it this way, galvanized pipe was used in home plumbing for years, downside was rust in the lines. but leaks came way later down the road 10 maybe 15, 20 years. if your just moving air and quality does not matter then by all means use galvanized. If its installed properly then you should get many years of use out of it before there is a problem.
Also keep in mind the environment it is installed in. Outside or inside. If your coming from outside to inside then maybe use copper until you enter the inside. Copper has the same corrosion problems that galvanized has when exposed to moisture it oxidizes and pinholes develop.
I know places completely piped in galvanized pipe with no problems because it is used for just cleaning off equipment. If your using air for pneumatic cylinders and other related applications then yes copper is the best alternative.
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By anonymous
I have my metal fab shop piped with nothing but galvanized. It has been in place for close to 20 years, without any issues at all. We use many different machines, and a vast array of hand tools. My compressor is located in an unheated environment, and the main line then enters the heated workspace. This would certainly seem to increase moisture issues, but to date,it has not been a problem. When I do find minor excess moisture in the system, it’s usually my failure to drain the dryer. Having said that, I would most likely use copper next time, it’s just easier. Save the plastic for moving poo, hopefully downhill.
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Galvanized pipe not as good as it once was?
Galvanized pipes are not that bad. The thing is that galvanized pipes are not as good as they were in the past…
In my backyard I have lots of galvanized pipes produced in 1970’s and 1980’s
And guess what ? there is almost no rust (keep in mind they’re exposed to rain)
I do have some newer pipes too but I don’t keep them outside… because they rust almost instantly when exposed to moisture, rain etc., stuff just isn’t as good as it was in the past…
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Anonymous:
No to galvanized pipe.
galvanized pipe flakes off on the inside that is why they dont use it.
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An aluminum option to using galvanized pipe in air systems:
Try Transair – Aluminum Compressed air pipe system. The alloy will not corrode, plus guaranteed leak free. This system was specifically designed for the distribution of compressed air, inert gases and vacuum.
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And one more saying galvanized is bad:
I have worked as an industrial millwright/mechanic for the past 15 years – 6 of them as a fluid power specialist. I would not recommend using galvanized pipe for any compressed air applications! Regardless of the use of dryers and/or lubricators, there are small flakes of the coating that will flake off of the inside of the pipe. This will cause failures in valving, actuators & air tools.
