shop air line question

[davidlee]

For the past few years I have been using 3/4 PVC pipe for my shop air lines. I am now in the process of sheetrocking in the shop. My question; should I change out the pipe to something else before I close it up inside the walls or is it ok to continue the way I am? I don't want to close them up and have a failure later and have to take down the rock.
If I do need to change it out, what are your recomdations?

 

[Steevo]

If this is a real question and not just someone trying to start a PVC air line battle thread, then the correct answer is no, do not leave the PVC piping in place.
Replace every inch of PVC piping with either copper or iron pipe, or with a structured air system, whether you leave it exposed or enclose it.
Also, enclosing air lines may lead to demolition later if something develops a leak.

 

[bigredmf]

What people need to understand is that PVC is rated for pressure based on it being used with a non compressible fluid.

Because air is compressible the working pressure drops dramatically.

Medium pressure NFPA hydraulic cylinders share designs with NFPA air cylinders yet their nominal working pressures are 1000 psi and 250 psi respectively.

Sure your PVC may work but make sure you do not nick it or damage it. The results could be damaging to your family, friends or your personal health, ride or your shop.

RED

 

[davidlee]

Yes, this was a real question and I appreicate the comments. I will start looking for a structured system and replace all the PVC pipe that I can. Some is already behind a wall. I guess that will have to stay in place until or if it gives me trouble.
I do have a master valve that I always shut off when I am not using air in the shop so the system is not under pressure most of the time.
Thanks for not beating me up for using PVC. It seemed a good idea at the time and I had the pipe at the shop. MY BAD.

 

[LEVE]

A few years ago, I ran 3/4" pvc air lines externally for four drops along the ceiling. Three drops are tied to the garage door rails; the fourth drop is tied to shelving.

They don't get a whole lot of vibration and, like you, I have a dump valve. I rarely use the valve and as yet have had zero problems.

Me, I'd just finish up with PVC since you're almost done. Test it out, and put nail plates on the studs in front of the PVC pipe. But, it is a risk. You can read the answers I got to my install (most were negative) here:

Why NOT to use PVC as a compressed air supply line.

I think there was some valuable information exchanged in the thread.

 

[KB1LTG]

I would say leave it but put a few "Isolation" valves in-line with the system so you can simply leave the bad section in the wall should it blow-up on you.

I would also venture to say that the likelihood of it breaking or leaking would be diminished by the added protection of drywall, IMHO most breaks occur by hitting a pressurized line with something, especially when its cold...Dont ask me how I know this.......

 

[Spareparts]

Do you really think people get on here and strongly recommend not using any type of PVC pipe for compressed air, give links for studys from Gov and Private agencies against using it just so they can type something on their keyboard. They do it for your health and welfare...... The cost saving between PVC and the most structured air system wouldn't put a dent in the ER bill should something happen, or it ruptured and the compressor ran and got hot burning the shop/house down. Practices like this is why we have so many regulations restricting what we do on our own property. To many DO GOODER Type People trying to change the world. Sorry for the rant but sometimes we get to hard headed for our own good. Jim

 

[rharman]

Yes, this was a real question and I appreicate the comments. I will start looking for a structured system and replace all the PVC pipe that I can. Some is already behind a wall. I guess that will have to stay in place until or if it gives me trouble.
I do have a master valve that I always shut off when I am not using air in the shop so the system is not under pressure most of the time.
Thanks for not beating me up for using PVC. It seemed a good idea at the time and I had the pipe at the shop. MY BAD.

It's not *IF* it gives you trouble, it's *WHEN*. It will get brittle and when it fails it will likely shatter.

Replace it now while you're in a sheetrocking mood. One less thing to worry about.

 

[cj7365]

I would say leave it but put a few "Isolation" valves in-line with the system so you can simply leave the bad section in the wall should it blow-up on you.

I would also venture to say that the likelihood of it breaking or leaking would be diminished by the added protection of drywall, IMHO most breaks occur by hitting a pressurized line with something, especially when its cold...Dont ask me how I know this.......

He wont need isolation valves when it blows, there will be holes in the drywall from the plastic shrapnel in which he will be able to repair the PVC

 

[bowtie1972]

So far Mine has hold up for a long time now!!, I have 3/4 pvc pipr inside my walls, it's rated at 450psi ?, but t routed the pipe through the studs, and frame work?. Ialso put in a few drops for water drains that come through the walls, And I ran the air line inside the wall with a vertical manifolr system, becouse water has a hard time running up?.
I have 4, 8.5' vertical with a 4" cross over.