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Re: Thinking of using PVC pipe for air?

Posted: Sat Apr 08, 2017 10:13 pm
by SteveHGraham
Yes, I know what table salt is. There are other salts of chlorine. I said "salts" because I didn't know what the chlorine turned into after reacting with pee, mucus, sweat, dead skin, excrement, and so on. I figured maybe the machine was able to salvage some of the chlorine by breaking up some of the compounds it formed. I read about it today, and it's impossible to get a straight answer, because 99% of the sites that mention electrolysis chlorination are trying to sell the machines. One site says the chlorine rejoins the sodium on the way back to the filter.

The Genie-Chlor people used to bring salt in, in bags the size of pillows. Today I read that the pool my family had would have required 1,000 pounds of salt in order to get the chlorination process up and running.

The prep school I went to before high school shocked its pool one day and promptly put us in it. The pool was outdoors, and you could smell the chlorine fifty feet away! In classes later that day, the kids could barely see.

Re: Thinking of using PVC pipe for air?

Posted: Sun Apr 09, 2017 9:36 pm
by John Hasler
The chlorine ends up forming various complicated compounds with the organics. The sodium forms sodium hydroxide.

> One site says the chlorine rejoins the sodium on the way back to the filter.

Don't buy anything from them. They know less than nothing about their product.

Re: Thinking of using PVC pipe for air?

Posted: Wed Aug 01, 2018 4:19 pm
by liveaboard
I used PEX tubing; runs through 3 shops and a short spell underground.
I have no idea if it's good in the long run, but it works great now.

Re: Thinking of using PVC pipe for air?

Posted: Sat Aug 11, 2018 12:26 pm
by b4autodark
John Hasler wrote:
Wed Apr 05, 2017 8:07 am
SteveHGraham wrote:They bypassed the safety switches! And they weren't just using PVC for air...they were using it for an explosive gas! That's Darwin territory.

In fairness, I would imagine hydrogen would also blow iron pipe into smithereens.

Not surprised that it happened at a university. Common sense and the kind of sense that helps people get good grades are not always found together.
[You wouldn't want to use iron pipe around chlorine.]
What do you base this on? I worked as a plumber at a major city water works and we had liquid chlorine delivered by railroad tanker to the filter plant. All the piping was schedule 80 socket welded carbon steel pipe from the railcar platform to the diffusers, the entire system. Even the railroad tanker was carbon steel!

We had to disassemble certain portions of piping annually for inspection, I never remember and corrosion. We chlorinated steel water mains whenever we got done working on them. They carry chlorinated water their whole service life.

Re: Thinking of using PVC pipe for air?

Posted: Tue Sep 25, 2018 3:02 pm
by Mr Ron
I have heard good and bad things about using PVC for compressed air. When it shatters it can be lethal is one. I have used it for years in my shop and have not had any problems with it. My thoughts on PVC for air is: to run PVC in places where it will not be exposed to people, so if it does explode, it won't harm anyone. Use it only for low pressure <100 psig.

Re: Thinking of using PVC pipe for air?

Posted: Wed Sep 26, 2018 6:30 am
by tornitore45
I understand it like this:
You can compress air
The energy from compressing it is being held by the pipe
You cannot compress liquid
Compressor technicians fill air tanks with water when they pressure test.
The energy of compressing air is stored 99.99999999% in the air and the balance is stored in the pipe.
Pipes, like water are uncompressible (to a certain extent) that is why water, like steel, stores only a infinitesimal energy when compressed during pressure testing.

On the other hand metal bending may store large energy like a spring.

Re: Thinking of using PVC pipe for air?

Posted: Wed Sep 26, 2018 7:38 pm
by steamin10
DO NOT USE PVC WHERE THERE IS OIL, OR SUN. Better to use a rubber line and wind it around the shop. When the pvc degrades it will blow at the least cause, and the shattered pieces are missiles that are unpleasant. Spend a dollar and avoid the rush.

Re: Thinking of using PVC pipe for air?

Posted: Sat Feb 09, 2019 10:29 am
by 4gsr
I worked at a place in the early 2000 that had 2" SCH 40 PVC pipe plumbed throughtout the shop. It was up in the ceiling where in the summer it got up over 160 dgress F. They had a insulated suspended ceiling in the 15,000 sq/ft facility. I worked in engineering group and my office was next to the shop. We heard an explosion in the shop, went to investigate. Walked out in the shop, there was a cloud of dust toward the back of the shop. Insulation flying around in the air, and a loud air sound. After every thing settled down and they got the compressor shut down, we were able to get a better look, the air line blew out at the elbow coming from the compressor into the shop. Took out about 20 foot of PVC pipe in all sort of pieces along with the suspended ceiling in that area. The ceiling tiles probably contained the pieces of PVC pipe from killing anyone. They replaced the section of pipe, gave it time to cure, back on line they went. I left there shortly after that, have no idea if that PVC ever got replaced or not. I know the plant is still there.

My own workshop, I recently purchased a Rapid-Air system for the garage/shop. It uses PEX piping with manifolds placed at the locations you want to hook up a airline to. I modified the manifold blocks for multi-purpose use for me. So far it has worked flawlessly for me but with one problem, some of the NPT threaded fittings are still leaking air. Most of that is my fault on how I threaded them. :roll:

Re: Thinking of using PVC pipe for air?

Posted: Sat Feb 23, 2019 9:32 am
by liveaboard
As stated earlier, I used PEX tube; no one seemed to know of any objection to it.

But I now found out that PEX gets very soft when heated; so, if someone was stupid enough to cut steel next to the air tube, and for instance the sparks were spraying over the PEX, and it had pressure in it at that time, then I guess it would probably burst.
And if that hypothetical person lived out in the country somewhere, and didn't have any PEX couplings left, then that person [not that this actually happened of course] would find that their compressed air installation wasn't going to work until a shopping trip to town could be made.

I'm sure no one clever enough to be using this forum would be thick enough to do something like that.
Just saying.

Re: Thinking of using PVC pipe for air?

Posted: Sat Feb 23, 2019 9:58 am
by 4gsr
Look up "Rapid-Air" industrial installations. You will be amazed how much PEX is used today for air lines. Definitely agree, it's not an good idea to use in an area where welding is being done or any high heat being used, industrial ovens and such. For my home shop application, this stuff is nice! Easy to run, easy to change out if you want to do something different. One thing I would be careful with is the fittings, I would suggest using the Rapid-Air or the other brand of fittings for air. I would leave the "Shark-Bit" fittings for water use, that way you don't get into an conflict later in life over any incident that could come up with. Just my two bits worth. Ken S.

Re: Thinking of using PVC pipe for air?

Posted: Sat Feb 23, 2019 1:24 pm
by liveaboard
out here in rural Portugal, I'm lucky if I can get regular water fittings!
Some have o-rings that fit inside the pipe; but actually, I've had no trouble with leaks in the PEX fittings.

Re: Thinking of using PVC pipe for air?

Posted: Sat Feb 23, 2019 2:04 pm
by warmstrong1955
My shop is plumbed in with hydraulic hose. It's overkill, but the stuff was leftovers from jobs here and jobs there, including the crimp-on fittings.
The JIC fittings are plated, so no problems with corrosion.
Works great if it's 'free', but would be spendy thing to design & install it that way.

Bill