Warning. PVC air line failure

[racecar14]

I built a new shop about three years ago and plumbed my air system with SCH 40 PVC pipe with a 300 psi rating. I had never heard of a problem with doing that utill much later I read a post about safety concerns. But again I assumed those failures must have been with thin cheap PVC. I was in my shop working on my 62 Corvette and all of the sudden I heard and FELT a large boom. About the same as the largest thunder clap I'd ever heard. Then I heard a long and loud spew. I had installed my large compressor in the room behind but still attached to my shop where we store the 4 wheelers. What I found was the first six feet of PVC leading off the compressor was gone and was blown into small inch long razor sharp pieces and were embedded in the walls as far as 20 feet. I can't imagine what it would do if a person was near it. Needless to say I have reply replumbed it with steel pipe. I hope this post helps others avoid my big goof up! Jerry

 

[ElectroLight]

For real?

 

[RECox286]

We don't hear of explosions all that often, but often enough to warrant

continuing to warn against the use of PVC of any thickness. However,

the moral of the story seems to still elude the many who continue to

ignore the warning, and look at price over safety. Glad to hear you

were not in the blast zone, and have re-plumbed the system.

Uncle Bob

 

[mmack66]

http://garagejournal.com/forum/showthread.php?p=3374547

 

[Stuart in MN]

For real?

He's not the only person here who has seen it happen in person - I have, as have several others. It's a real thing.

To racecar14, thanks for reporting; it's good to have actual experiences with PVC recorded here for future reference.

 

[mrpizza]

That is word for word the same thing someone posted the other day.

Just use steel or copper everyone!!!

 

[NHBandit]

NEWS FLASH.. THIS JUST IN... Elvis is dead !

 

[FarmerPete]

Any pictures?

 

[rburke65]

Now be nice NHBandit!

 

[NHBandit]

Now be nice NHBandit!

Sorry it's not my nature.. LoL but it was a joke.

 

[Glenn M.]

What I found was the first six feet of PVC leading off the compressor was gone

You didn't come straight off the compressor with it, did you? You had some kind of a vibration damper in there, like a piece of rubber air line or something, right?

I'd say using PVC for air lines is a bad deal, but I'd like to know if this was vibration related...

 

[NHBandit]

I'm not going to repost all the links I just posted on the other almost identical thread but if OSHA, Eastwood Company, and the link that said people have been killed using air to test PVC plumbing for leaks say it's dangerous that's good enough for me. I got stuff to do but if you're bored just Google PVC air line injuries. I have seen it explode first hand at a shop I used to work at as well. Nobody was near it at the time but it would have been a ****** mess if they were. Nuff said. You wanna play Russian roulette go for it. I'm not your mom..

 

[Spareparts]

Probally not vibration but he did say that it was coming off the compressor, it was probally heat related. All the heat cycles probally made the PVC brittle. I relocated the compressor on my service truck and used 1" DOT plastic air line from the compressor to the air tank mounted under the bed, lasted about 3 days before it blew the line, Replaced it with 1" K copper and other than being a PITA to install it's still there.

 

[SMKS]

I'd like to see the shrapnel embedded in a wall.

Has the OP been actively ignoring the epic arguments over this topic?

 

[tonycastec]

It is important to be specific about both the pipe and the envirnment it is used in.
All plastic does not=pvc.
Sch 40 pvc does not =Sch 80 pvc
PEX & cross linked PEX does not = pvc.
Nylon does not=pvc.
PVC exposed to u.v. or sunlight becomes brittle unless it is rated uvr.
I used to work for a company that made huge quantities of all types of plastic pipes.Exploding pipes(under water) was part of the standard testing procedure.

 

[welder4956]

Any pictures?

 

[Stuart in MN]

Has the OP been actively ignoring the epic arguments over this topic?

Note that he only has three posts here, so he probably hasn't seen all the arguements. Give him credit for providing first hand experience.

 

[The Frisco Kid]

holy ****!

 

[The Frisco Kid]

glad you're ok!

 

[55bigblockcid]

 

[Kevin54]

I built a new shop about three years ago and plumbed my air system with SCH 40 PVC pipe with a 300 psi rating. I had never heard of a problem with doing that utill much later I read a post about safety concerns. But again I assumed those failures must have been with thin cheap PVC. I was in my shop working on my 62 Corvette and all of the sudden I heard and FELT a large boom. About the same as the largest thunder clap I'd ever heard. Then I heard a long and loud spew. I had installed my large compressor in the room behind but still attached to my shop where we store the 4 wheelers. What I found was the first six feet of PVC leading off the compressor was gone and was blown into small inch long razor sharp pieces and were embedded in the walls as far as 20 feet. I can't imagine what it would do if a person was near it. Needless to say I have reply replumbed it with steel pipe. I hope this post helps others avoid my big goof up! Jerry

For real?

'55BBcid......It's not beating a dead horse when it happens like that. It's a warning to others that have ran PVC over and over again. PVC is for water, people, not compressed air.

Above all.....I'm really glad the OP is unscathed from this ordeal.

 

[doan]

So if PVC is rated to 300 PSI, why can't it be used for 125 PSI air? Seems like some people run a hard line to the compressor which probably causes the problem. If it was properly hooked up with a flex line to isolate the compressor would it be ok?

Lots of new houses are plumbed with PVC that manages 50-75 PSI of water pressure for years.

 

[ChevyEFI]

PVC is for water, people, not compressed air.

If the system were never drained, would the PVC
-fill up and be safer?
-act as a bong type filter, negating the need for another type?

 

[Vegaman_Dan]

PVC can handle the pressure, but only when it always has that constant pressure applied from the inside steadily. Your water supply pressure is always applied 24/7 and the pipe is rated for that. But when you start using air, you're flexing the plastic much higher than the water would, but then you don't leave it pressurized steadily all that time either. You run the pressure up and down, fatiguing the plastic. Plastic will expand, but it doesn't contract much after expansion. Ever bend a piece of plastic and see how the bend discolors? You've just changed the density of that plastic, weakening it. Now imagine the entire line doing that when you air up and down the system. Eventually, yes, it will blow. Maybe not today or next week or next year, but it will happen.

And yes, I did it too in one garage until I learned of the problem as well in person. Then I went online and learned that it wasn't uncommon. It's a shame, because the flexibility and adaptability of the materials and fittings was really quite nice. Steel and copper are also adaptable, but take more work accordingly, as well as being more expensive. But with that expense comes reliability and safety.

PEX seems to be coming along with a semi-flexible line that can take the pressure without issue, but the cost of the fittings and specialized tools to make the connections can quickly make iron or copper more affordable.

 

[KCarGuy]

PVC gets Brittle over time.
I would Never, Never, Never (did I say Never?), Never use it for an Air Line!
Nuff Said!

 

[larry_g]

The fundamental difference between water and air under pressure is that air has a bunch of stored energy and water does not. When the PVC line ruptures the air releases a huge amount of energy that fractures the PVC and propels shards like rockets. Water is not compressed and stores essentially no energy and will not propel the fractured PVC shards.

lg
no neat sig line

 

[bwane]

Was it 125 psi or 175 psi?

 

[Higgins]

Just a bit of humor from back in the 70's! I spent a lot of time over in the middle-east during the mid 70's! ALL of the little corner repair keyos (??) were plumed with a type of PVC piping. (*) One place found old scrap PVC and made a HUGE serpentine manifold and was loosely attached to the wall. One day it exploded, and took out the left sides of two cars that was parked in the building. The good news is, no one was injured, however, it wasn't uncommon to loose a repair monkey or two every month. If it wasn't the PVC, it was the storing of hazardous chemicals blowing up while someone was smoking!!!

(*) the reason the shops were not plumbed with copper was, some one would steel it overnight, as for galvanized or black pipe, it wasn't readily available!

AL

 

[Rodhotz]

I still call bs on this, 30 years and no problems. i have pulled cars out and caught an air hose on the bumper and ripped the pvc off the wall and it just broke, no massive explosion, no shrapnel nothing. Drain the line every night and re-energize them in the morning, so the expanding and contracting thing is not happening. As far as the stored energy thing i have had sprinkler pipes bust and guess what it shot up like crazy then leveled out.I am pretty sure if this is happening somebody is not setting it up right and the joints are not glued right either. I had some pics of my old system with a date of 1991 on them and they were still going strong but lost a hd with a lot of my pics. Now i had a friend that did his shop in copper and he blew that apart more times than i can remember, ruptured it right in the middle of the pipes and also separated at the joints from cold solder job he did. That is my $.02 and take it as you will. flame away!

 

[Nick Danger]

I still call bs on this, 30 years and no problems. i have pulled cars out and caught an air hose on the bumper and ripped the pvc off the wall and it just broke, no massive explosion, no shrapnel nothing. Drain the line every night and re-energize them in the morning, so the expanding and contracting thing is not happening. As far as the stored energy thing i have had sprinkler pipes bust and guess what it shot up like crazy then leveled out.I am pretty sure if this is happening somebody is not setting it up right and the joints are not glued right either. I had some pics of my old system with a date of 1991 on them and they were still going strong but lost a hd with a lot of my pics. Now i had a friend that did his shop in copper and he blew that apart more times than i can remember, ruptured it right in the middle of the pipes and also separated at the joints from cold solder job he did. That is my $.02 and take it as you will. flame away!

How much shrapnel did your friend get when his copper pipe ruptured?

 

[Stuart in MN]

So if PVC is rated to 300 PSI, why can't it be used for 125 PSI air? Seems like some people run a hard line to the compressor which probably causes the problem. If it was properly hooked up with a flex line to isolate the compressor would it be ok?

Lots of new houses are plumbed with PVC that manages 50-75 PSI of water pressure for years.

It's because of the difference between a liquid and a gas, and the ductility of PVC. Air is compressible while water is not (well, strictly speaking water is slightly compressible but for practical purposes it's considered non-compressible.) If a piece of pipe containing compressed air breaks, the air inside rapidly expands to many times its original volume. If a pipe containing water breaks, the water volume doesn't change.

Combine this with the ductility of PVC - when it breaks, it shatters instead of simply bending like a piece of copper or steel - you end up with broken shards of PVC being blown all over the place by the rapidly expanding air.

 

[chris142]

Every shop I have worked at had pvc pipe for air lines. Including the shop I'm at now. These lines have been in use since 1977 and with 150 psi. Nothing bad has happened... yet. Passes inspection every year.

I just ran rubber hose at home instead of pipe.

 

[alpinewhite]

It's because of the difference between a liquid and a gas, and the ductility of PVC. Air is compressible while water is not (well, strictly speaking water is slightly compressible but for practical purposes it's considered non-compressible.) If a piece of pipe containing compressed air breaks, the air inside rapidly expands to many times its original volume. If a pipe containing water breaks, the water volume doesn't change.

I agree. To prove this point, popping a balloon filled with air has a totally different effect than popping a balloon filled with water.

 

[914wilhelm]

The air coming out of the compressor is hot. PVC can handle the pressure at room temperature. The strength of PVC rapidly degrades with a rise in temperature and most failures thusly occur close to the compressor.

See the following reference: Note PVC derates to 20% of it's strength at 140F compared to 73F.

http://www.engineeringtoolbox.com/thermoplastic-pipes-temperature-strength-d_794.html

 

[OccupantRJ]

I had my previous shop piped with PVC and was happy..... Until the day I was checking the garage door opener on a step ladder and the vertical PVC air line located less than 18" from my face decided to explode. The only thing that saved me was the 2 x 4 support for the end of the door track that was precisely positioned between my face and the pipe shrapnel. There were 6 inch and smaller shards all over the place. Never again. I have steel pipe in my new shop.

 

[trloh]

Blow buy of rings can also allow oil into the lines. I know polycarbonate water trap vials can be contaminated with this oil and degrade until brittle enough to break.

Amsoil compressor oil for example:

Note: Not recommended for "breathing air" or refrigeration compressors. Not recommended for use with polycarbonate plastic that is not metal covered, PVC plastic and butyl, ethylene-propylene or SBR rubber. PC Series Oil is not compatible with polyalkylene glycol or silicone oils.

 

[tehach]

This thread has potential.

 

[Winmon]

63falcon



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Default PVC air lines are deadly!!



Many years ago I ran my shop airlines utilizing Schedule 40 1" PVC. Seemed like a good idea. Pressure rating marked on pipes was 400 p.s.i. Worked just fine for 8 years or so...but then...I knocked over my 3 "D" cell MagLite and it bumped the line terminated at the end of the run. Holy ****!! The line violently exploded with 125 p.s.i. blowing PVC projectiles all over the place, embedding in anything their path including my forearm. After attempts by my wife and myself to "excavate" the shrapnel from my arm failed, a trip to the medical center was required and proved quite educational. A few things I learned was (1) PVC slivers can be very sharp. (2) When launched at substantial velocity they can penetrate flesh surprisingly deep. (3) PVC does not show well on x-rays and conscequently has to be dug out by feel in a very painful process. I'm sharing this information so others won't have to go through this same nightmare. Of course now everything I read and most of the people I speak with tell me PVC shouldn't be used. Believe me...it's true. Don't take the risk. Sooner or later it will fail, with the possibility of terrible results. I was lucky that my head was not directly in the line of fire or I may have lost an eye or worse. During cleanup from the aftermath, I literally found pieces so firmly embedded in the wood that it took pliers to pull them out, some were as much as 20 feet from the "blast site". I'm running everything temporarily off the tank outlet until I buy and install the Eastwood air line kit. Anyone use the kit? Any feedback?

http://forum.eastwood.com/showthread.php?5861-PVC-air-lines-are-deadly!!

 

[j p smith]

So glad you were not hurt! I have A friend here in Phoenix and his previous machine shop was all done with PVC and the stories he and some of the guys I worked with there could tell. Fortunately no one was injured. The new shop was all done with "L" Copper. Jeff

 

[Ign]

I agree. To prove this point, popping a balloon filled with air has a totally different effect than popping a balloon filled with water.

Not only that, but there's a name for it in industry: it's called, not surprisingly, a hydrotest. When we'd test HDPE pipe liners we'd pump full of water 'til they'd blow. If doing so with air, I may not be here right now.