Compressed Air Line Question

[Sawyer Rob]

I've seen a couple compressor tanks start leaking, but I've never seen one blow up and fire missiles of plastic shards all over the shop.

You may not care about the folks in your shop, but from time to time, kids and neighbors walk into my shop and I don't need one of them loosing an eye or much worse!

SR

 

[ray66v]

You want to have drains on your low points, for condensate, in air lines.

If you use anything flexible, it creates the likely possibility, that there will be bellies you can't drain.

Rigid pipe allows you to easily maintain slopes to your drains.

Do not use PVC. The pressure rating is for water, not air. Yes, there is a big difference.

Some people have not had an issue using PVC for air. That does not disprove the fact, that it is proven unsafe.

When it comes to air, and air compressors, bigger is always better. Don't run a lot of skinny pipe.

The rigid aluminum, steel, or copper lines are the best choices.

Steel can be bought in most lengths at the big box stores.

But, if you still need some pieces threaded, and don't have a pipe threader, the big box stores usually do that. As well as any hardware store.

Having a drier at the compressor is ideal. However, there are lots of tricks to help keep the condensed water out of your tools, if you don't.

Running the main lines high, with the drops, coming off the top of them, before coming down the wall. As well as, having the drop continue down past the hose attachment, to a drain, are good practices.

Water traps only work on water that has condensed. And, are unnecessary if you set up the lines properly. Water vapor goes right through water traps. Which is why you still get water, even with a $100 trap.

A drier, is the only way to completely eliminate moisture issues.

 

[ultrarunner]

At work everything is copper with brazed joints... 95% is copper K pipe wall and 5% is copper L

I work at a hospital and did some of the install in 1995 and zero issues.

The lines all have a nice slope and drop legs...

Some equipment is moisture sensitive so I did install a dryer a few months in because we were on the boarder for moisture... since the dryer went in along with an automatic tank drain valve no detectable moisture when sampled.

 

[KennyG]

You actually make me wonder how much of the idea that PVCs gonna blow up and kill you stuff is just hype from mfgrs of alternatives.

It's a violation of OSHA requirements because there are numerous cases of explosive failures and injuries. I've seen them written up in various bulletins from state and local code agencies.

 

[moriboy]

I ran 3/4 Rapid air throughout my shop. Really nice stuff, a little spendy though. It's really easy to install and add onto later if needed.

 

[Deere Dude]

It's a violation of OSHA requirements because there are numerous cases of explosive failures and injuries. I've seen them written up in various bulletins from state and local code agencies.

I was tearing out some sch. 40 PVC used on deionized water lines. I would just toss them on the ground from 15' up and that would just shatter the fittings and sometimes the pipe. I know you aren't in a factory setting and more than likely metal won't bang into a pressurized line hard enough to shatter anything, but you never know.

About 20 years ago my brother put a PVC air line in his basement and ran it outside to his garage. After a year he had to change it because it ruptured for some reason.

 

[TemporaryKubotaOwnerMark]

Try to get bell end pipe . 3/4 in pvc Schedule 40 is rated for 440 psi .

Tha'ts why I said I will use Schedule 80, not 40. 3/4" is rated at 690 PSI.

That's a 5.5 times safety margin over my system pressure (125 PSI). I think that's probably good enough for an underground run.

When I blow out irrigation systems we are using a 125 cfm compressor at 100 psi , blowing into thin wall pvc . In 30 years we have never blown a pipe apart , Maybe a couple fittings blew out , but never the pipe itself .

Intermittent pressure is a whale of a different animal than constant pressure, and you are only introducing 100 psi into an open pipe, not closing the system and holding 100 psi in the pipe, and your air is cold when it's blowing through that pipe.

 

[TemporaryKubotaOwnerMark]

I was tearing out some sch. 40 PVC used on deionized water lines. I would just toss them on the ground from 15' up and that would just shatter the fittings and sometimes the pipe.

Hmmm. I'm wondering if the deionized water may have leached out some of the plasticizers in the PVC, making it brittle. That stuff eats common stainless steel. Industrial fittings that handle it have to be Type 316.

About 20 years ago my brother put a PVC air line in his basement and ran it outside to his garage. After a year he had to change it because it ruptured for some reason.

Yep. No way would I run it in a shop or other occupied area.

 

[EddieWalker]

Hi,
I'm moving soon and will want to run some air lines in my garage and basement. Thinking of putting the compressor in the garage and would like a couple of ports and a hose reel. Then run a line to the basement for some light duty work... airbrush, blowing saw dust etc.

Sounds like you are getting a lot of advice based on what some guys have gotten away with and what's proven to them to be good enough. PVC isn't allowed for the simple fact it's been proven to be dangerous. It might never explode on you, but you really don't know that. It's a gamble that in my opinion isn't worth it.

Since your uses are so limited, if it was me, I would just go with a high quality air hose line. I have two hundred foot hoses that where bought in the 80's that are still working fine. One of them is coiled up on a hose rack outside in the Texas sun every day for well over a decade. I guess hoses go bad, but I've never had one fail on me or wear out so far. Lets say you get 20 years out of a hose, how big of a deal would it be to replace it every two decades?

If you where building a shop and using air tools all the time, I could see the advantages of going with iron pipes or copper, but for just this, I wouldn't spend the money or time to install it.

 

[FTG-05]

Tha'ts why I said I will use Schedule 80, not 40. 3/4" is rated at 690 PSI.

That's a 5.5 times safety margin over my system pressure (125 PSI). I think that's probably good enough for an underground run.


Intermittent pressure is a whale of a different animal than constant pressure, and you are only introducing 100 psi into an open pipe, not closing the system and holding 100 psi in the pipe, and your air is cold when it's blowing through that pipe.

You keep focusing on the wrong thing, which is pressure. PVC may be pressure-rated but it's not materials-rated for compressed air usage. The compressor oils will start to break down the PVC and it will eventually crack and then break (usually explosively).

Do what you want, it's your life, property and loss. But to get on a public forum and *attempt* to try to rationalize the use of PVC for compressed air systems is a fools errand.