Black pipe or galvanized for shop air lines?

[franklin2]

Duplicate post.

 

[franklin2]

Alright, so I was a kinda taking a middle road here... I could understand people using pvc and figured they were probably alright, but I would use metal of some kind, mostly because I have acces to any tooling I would need for iron or copper. I have since changed my mind.

We have 2" diaphram pumps at work that pump waste water to a holding area in another area of the plant. For those that don't know, a diaphram pump used air pressue on diaphrams to pump liquids... the outlet port of the pump will deliver the liquid at the same pressure as the incoming air supply- we run around 95 psi in our plant. The liquid end of these are piped with 2" pvc pipe (some is sch.40 but most is sch.80). So I went to turn on one of these pumps a couple days ago and heard a large loud "crack" and water started coming from the ceiling. The outlet pipe ran up the wall and up to another pipe along the ceiling, and it broke right at the elbow. Now realize that this was at the top of the run where the pressure would be the lowest and there is no restriction between there and were it dumps into an open tank. I imagine there would be a small surge because the pump had just turned on, but I can't imagine pressure at that point exceeding maybe 50psi. I thought of this thread immediately. I now KNOW what I will run when I do my garage/shop.

Yes, but it sounds like you are missing the point. The PVC broke for whatever reason, yes it needs to be supported well, blah blah blah. But it's perfectly fine for water or any other liquid that is compatible with the PVC. COMPRESSED AIR is the problem and what we keep harping on in this thread. Compressed air is like a big coiled up spring inside the pipe. When your pipe broke, you heard a loud crack and then got a leak. If the same pipe would have broken with air in it, there would have been more than just one loud crack there would have been several as pieces of the pipe hit parts of the building, and there would have been a huge hole in the pipe.

 

[JRP]

Well yesterday the AC contractor stepped on a copper pipe in my attic that connected to PVC pipe and then the screwed into a galvanized 90 in my well water tank. I did not put the tank there. It came with the house. Anyway it dumped the 70 gallon tank contents into the attic, then the pump turned on an added more water. Which piece of pipe do you think broke? The PVC.

If you have missed the posts about PEX you are missing a lot. It is easier than copper, iron, and PVC, safer, wont freeze and burst, can be cut with a Stanley knife, and sharkbite couplings just push on and can be reused.

It also costs much less than copper or steel, but that is a minor advantage. The only disadvantage is low resistance to UV, so don't use it outside. Faster safer easier cheaper .

Find one person who used PEX for air lines and is unhappy with it.

 

[Blade Breaker]

Well yesterday the AC contractor stepped on a copper pipe in my attic that connected to PVC pipe and then the screwed into a galvanized 90 in my well water tank. I did not put the tank there. It came with the house. Anyway it dumped the 70 gallon tank contents into the attic, then the pump turned on an added more water. Which piece of pipe do you think broke? The PVC.

If you have missed the posts about PEX you are missing a lot. It is easier than copper, iron, and PVC, safer, wont freeze and burst, can be cut with a Stanley knife, and sharkbite couplings just push on and can be reused.

It also costs much less than copper or steel, but that is a minor advantage. The only disadvantage is low resistance to UV, so don't use it outside. Faster safer easier cheaper .

Find one person who used PEX for air lines and is unhappy with it.

Everything about pex sounds good except that I use my black air pipe to hang lots of stuff on all around my shop. Pex would not work for that.

 

[like2wheel]

The only disadvantage is low resistance to UV, so don't use it outside.

I disagree.
The biggest disadvantage of plastic is the poor job it does in removing heat from the air. You need the air to cool so the water vapor becomes droplets that a water trap can remove.

The cost & time savings for plastic is offset by the price & maintenance of more comprehensive methods to keep the air reasonably dry. Or the effect it has in your equipment if you don't.

 

[mikehaugen]

Yes, but it sounds like you are missing the point.

Didn't miss the point, just pointing out that the pvc broke with very little pressure in it. I understand the difference with the liquid/gas thing but there have been people quoting what the max psi is for pvc, obviously that is not trustworthy, especially in something that will see cycling loads.

 

[Scooter78]

Has anybody looked at these set ups?


View attachment 391195

 

[Scooter78]

Sorry first photo didn't load.

 

[Deere Dude]

I worked in a factory and in the process of removing some PVC that was used for water or whatever else I would just drop it to the ground. Sometimes from low heights up to 15-20' up. More likely than not the PVC would shatter into smithereens. I can't imagine what an air line would do if something would drop on a pvc airline with 150 PSI. I think we need a test if somebody is up to the challenge.

 

[BukitCase]

"I think we need a test if somebody is up to the challenge."

My buddy did that, sorry but no pix - building his new house a few years go, he had to run about 800 feet of 1-1/2" PVC along an easement to get the water to his house.

Before burial, he wanted to pressure test - I made him an adapter from garden hose to air QD, with a gauge and valves - warned him about keeping EVERYONE away from the ditch during the test, and why -

He did that, but when walking along the ditch he inadvertently kicked a small rock into the ditch...

No damage to him, but only because the walls of the ditch focused the shrapnel and dirt straight up.

He was more careful testing AFTER replacing that section of pipe ...Steve