why you don't use PVC for air line

[2059]

I can't imagine there isn't a "Pipe and valve" guy on the site that won't weigh in on this (especially you industrial and oil patch guys).

I think your orig. post ND74 brings to light the importance of recommended piping for any pressurized delivery system. There are several "schedule" ratings and a use for each. Your photo looks like SCH 120 pvc sprinkler application. Schedule 40 pvc is used for residential plumbing, most dwv and some pressure delivery. I'm sure you can get away with it for compressed air, but I wouldn't. Schedule 80 is heavy industrial use. PEX line is polyethylene, damn near indestructible however, I wouldn't use it for compressed air because of the fittings and the explosive energy/pressure of compressed air. No residential water system delivers the static pressure plus there's a difference between pneumatic and hydraulic energy at failure. Iron pipe is the safest for rigid piping, rated rubber hose for flex. there are extruded aluminum systems for air delivery on the market with engineered fittings that are top notch but expensive.

To each his own. IMO safety first.

 

[bm02tj]

I use galvanized steel pipe for all my air lines. I figure there are much better uses for PVC pipe than 150 lbs. of air.

that is good for strength but zinc flakes are hard on stuff

 

[Meep-Meep]

Steel pipe or silver brazed copper for me.

 

[Cranky]

Read some negative posts on using PVC for air a couple of years ago on another site and it has me somewhat worried especially since my Sch 40 3/4" system is 30 years old. Even turned the pressure down some. One good thing is it's not used nearly as much as it once was and the PSI is bled down quite a bit when not in use. A couple of good thingx is mine was put together with a minimal amount of glue and isn't thin wall. How many have seen sch 40 systems blow out?

 

[2059]

How many have seen sch 40 systems blow out?

None. You'll probably be ok but if you ever do start seeing failure you might consider iron pipe.

 

[Runner 68]

None. You'll probably be ok but if you ever do start seeing failure you might consider iron pipe.

X2. I have worked around PVC systems for years and have never seen one fail but you do hear the stories. The system in the attached garage is PVC, only pressurized when needed. I think about it more than used to though.

If you decide to re-do your system Cranky, seriously consider PEX. I think a 100' roll of 3/4 is only around $20. I considered doing copper or galvy pipe when I built my shop but I had about 200' of line to run and wasn't too juiced about the cost. If you go with PEX use the ring band crimpers for your connections. No leaks in about 3 years now.

 

[AMX364]

Worked at one garage that used PCV piping for the air lines and when it gets cold in Texas the lines are brittle under high pressure. They always kept line repair parts on hand to make quick repairs. I used copper lines for my shop and have not had any issues and was easy to work with.

 

[ND74ROADRUNNER]

i used the correct primer and the correct glue this the second garage I have done with pvc. It will be the last time I use it for air.I have our race trailer with it in but never used it, but its coming out this winter.

 

[69rtse4spd]

I always use 3/4 black iron pipe and fittings. It's just the right way to do it.

Same here.

 

[mike71ssp]

and remember not to use power tools or sharp objects... pipe bombs are fun....

 

[Cranky]

Setting off air bags under power lines is safer than setting off pipe bombs but gives you the same rush

 

[zyzzyx]

Just wondering, some of you say that you run 150psi in your systems. Air tools are supposed to be operated at around 90psi. What do you use 150psi for?
If you're using the "bigger is better" rule, then I understand, but your compressor has a harder time recovering back to 150psi than to say 100psi. If you're
trying to keep the compressor from turning on so often, then get an air receiver to store more capacity. You'll be surprised at your electric bill after you install
a bigger receiver! If you don't believe me, put an Amprobe on the motor and measure the current draw from 110 to 150psi. The difference will be more on
a single stage compressor, but also has a difference on two stage units also. Another thing to think about is the current inrush when the unit starts. The amount
of current needed to start a compressor is about 30% of what the whole cycle uses, so if the unit starts less it's easier on the parts and the wallet!

 

[Runner 68]

Just wondering, some of you say that you run 150psi in your systems. Air tools are supposed to be operated at around 90psi. What do you use 150psi for?
If you're using the "bigger is better" rule, then I understand, but your compressor has a harder time recovering back to 150psi than to say 100psi. If you're
trying to keep the compressor from turning on so often, then get an air receiver to store more capacity. You'll be surprised at your electric bill after you install
a bigger receiver! If you don't believe me, put an Amprobe on the motor and measure the current draw from 110 to 150psi. The difference will be more on
a single stage compressor, but also has a difference on two stage units also. Another thing to think about is the current inrush when the unit starts. The amount
of current needed to start a compressor is about 30% of what the whole cycle uses, so if the unit starts less it's easier on the parts and the wallet!

I have all my outlets out of the wall, going into a filter then T-ed into a coupler for full pressure then into the regulator with another coupler coming out of the regulator. That way I have full or regulated pressure at all stations. It just depends on what I'm doing. Impact wrenches, airing up tires, or just plain blowing something off at a 150 PSI is wonderful.

 

[ws27]

Just wondering, some of you say that you run 150psi in your systems. Air tools are supposed to be operated at around 90psi. What do you use 150psi for?
If you're using the "bigger is better" rule, then I understand, but your compressor has a harder time recovering back to 150psi than to say 100psi. If you're
trying to keep the compressor from turning on so often, then get an air receiver to store more capacity. You'll be surprised at your electric bill after you install
a bigger receiver! If you don't believe me, put an Amprobe on the motor and measure the current draw from 110 to 150psi. The difference will be more on
a single stage compressor, but also has a difference on two stage units also. Another thing to think about is the current inrush when the unit starts. The amount
of current needed to start a compressor is about 30% of what the whole cycle uses, so if the unit starts less it's easier on the parts and the wallet!

You hit the nail right on the head. One more thing I'd like to add is the volumetric efficiency of the compressor diminishes as pressure goes up. Factor that in and you've got a great case to keep pressure at a minimum to get the job done.

Only problem is impact guns sure do work better at a higher pressure.

I'll post some pictures soon on what I am doing in my shop.

 

[Cranky]

But it takes nearly 150 PSI to blow up a plastic soft drink bottle! Just another way to blow sheeet up without using explosives

 

[BarrsRestoration]

We had aluminum lines installed in my restoration shop. It's a loop system that was professionally installed and it is well worth the money. Besides being safe, the air is cooler and drier than it would be with any other piping.
Long ago I worked in a shop that had PVC lines. After seeing what happens when that junk explodes, I won't stand near a PVC air line in anyone's shop.