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OSHA and using PVC for compressed air

5K views 31 replies 22 participants last post by  FTG-05 
#1 ·
I heard once that you were not suppose to use PVC for compressed air, because if something happened it could potentially explode and shoot shrapnel everywhere. I have however seen a few shops that use PVC for this purpose. I really don't see what the big deal would be especially schedule 40 that is rated for well more then what most compressed air systems run at. Let me know what you know, thanks
 
#8 ·
We only use black pipe and copper , all brass termination fittings . PVC is not rated for oxygen , compressed air or inert gas . ( against code around here ) the problem is when pvc degrades enough or gets struck , it blows out (fragments) and usually someone gets hurt . We had a project at St. Elizabeths hospital last year where they pressure tested schedule 80 12" pvc lines in utility tunnels to 120 psi , sent 6 guys to the hospital ( St E's is a mental institution) when the pipe blew . Osha said the pvc should ONLY be tested with water , never compressed air .
 
#10 ·
Its been stated above, in different terms, but its not always the air inside the pvc that dictates it not be used for pneumatic systems. Its the atmosphere of its intended usage that may decide that. In a shop where people are burning and welding? That should be obvious. Not to mention it would be weakened from the UV light a weld gives off. Pressurize it and hit it with something: BAM!!!! Plastic splinters fly everywhere!

Dont do it!!! Even if you put an enclosure around it, I would say its unsafe.

Black pipe.
 
#11 ·
The aluminum piping systems are more expensive than black pipe, but installation is so much quicker that it is comparable on medium to large installations. Plus it is easier to modify later. PVC, as TylerD pointed out has a few hazards, additionally, drop pipes can be vulnerable to being hit by lift trucks, thrown tools ect. Compressors also all pass through minute quantities of their lubricants, particularly rotary screw style, and if you aren't fully aware of the chemical make up of some of the synthetics and mineral mixes you are using, then you may degrade the PVC. With black pipe, if you don't have an excellent drier that drops your dew points down to very low temperatures then you will rust your pipes and have migrating rust particles going to your tools and machines.
 
#12 ·
In my old shop we would blow the hard pipe out once a month and put a rag at the end of the line to see what was in there. We would blow a pint of oil through the line afterwards. We had an air dryer in the system too and there was not a spec of rust. Unmaintained you would have a wet rust system.
 
#13 ·
Always tee off of the top on all drops and pipe a blow down off of the end of vertical runs .
 
#14 ·
we are finishing off an addition on our garage and we are gonna use pex tubing. however its going to be regulated at 125 psi or so cuz we dont need anymore than that
 
#15 ·
We use PVC for our air system and we haven't had but maybe one or two leaks in 2 years. My dads a cheap bastard so realy I can't expect much more than that though.
 
#18 ·
my old shop had all pvc in it, one summer it broke 3 times it all got pulled out and I put pex that is air rated in. The stuff looks just like DOT air line for the big trucks and all the fittings were pushlock. I put this in since I have a buddy that puts in industrial gas systems. They are using this in alot of industrial and commercial applications and medical.

If I was not using that black pipe it would have been
 
#19 ·
Are you guys using some sort of special pex? I thought it degraded from UV exposure. For those who have had issues with PVC blowing to smithereens was it schedule 40, or some thiner stuff? As previously stated schedule 40 is rated at 450 psi if I recall right, since you are using it at 1/3 of its rated capacity I dont see why there would be issues, unless it gets impacted HARD by something. Ive used a good amount of PVC on irrigation projects and Sch 40 is freaking tough, the thin stuff though does suck wpa 120 or whatever it is.
 
#20 ·
Ive run miles of pvc sch40 too in pools and on pumps for WATER. That doesnt mean that Id build an air system with it. Its not designed for that and if something strikes it from the outside its gonna go like a bomb w/fragmented shrapnel.

If you weld or burn in your shop you'd have to be a fool to use it. We've had piesces lying around in the shop for 5 years and if you pick em up and whack em against the floor they shatter. Put 120psi behind that and you've got problems. Anybody who is dumb enought to do this probably doenst wear safety glasses either.

Whats next? Homemade hydraulic cylinders with pvc being the build stock? Some only see 300-350psi. It'd be safe right? Eff that.
 
#21 ·
So it sounds like PVC isnt a good idea, how does OSHA feel about it?
 
#24 ·
Dont use PVC. My former employer learned the hard way. Even schedule 40 busts all to hell.

I should see if I still have the pic of the chuck of schedule 40 pipe I pulled out of his ribcage:doh:
 
#25 ·
I watched a former co-worker sit in a chair in a doctors office as they ground(yes they really use a grinder) slag out of his eyes after a pvc air manifold they rigged up burst and slung all the weld slag and grinding wheel dust into his eyes. Plastic shards in his face. It was cute. They wondered why I always unhooked the compressor and used a hose instead of their "system". Some people dont listen/learn.
 
#26 ·
A friend of mines dad has PVC in the shop where they repair the equipment they use for their gravelpit. They have PVC that goes from the compressor up and over the shop and drops in a place or 2 for hoses. I know for a fact OSHA drops by now and again and guess its ok with them? Its been this way for as long as I can remember, perhaps stroker2 will chime in here at some point

At any rate, you guys have me convinced PVC is not a good choice for an air system
 
#27 ·
I was set on using PVC in my shop until I read some more about it after talking to Tom. ssI was sold on the WP of schedule 40.

At any rate, would it be ok to use some simple 5/8" or 3/4" Air Hose as my feed to my hose reels since I'm only running about 50' from the compressor to my 2 3/8" hose reels.
 
#29 ·
I used 1/2" CPVC in my shop for years with no issues of bursting. When the demand for air got to be too much, I installed a trunk line in a loop around the entire shop made of 1" galvanized steel pipe.

I still use 1/2" CPVC for the drops to the machines....BUT I have seen it become very brittle after long periods of time. I think after reading this thread, I'll replace all of the PVC with steel.
 
#30 ·
Happy with my copper set up.
 
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