PVC airline explosion aftermath....
- Thread starter ZRX61
- Start date
alwaysFlOoReD
Well-known member
So what causes PVC to deteriorate? Oxygen?
not discounting the dangers of using PVC, but I think this video must have been staged. perhaps intentionally fed high pressure to it to get it to burst. how coincidental he got footage of turning the air on & filming himself when it popped!
readhead
Well-known member
It said “dramatic reinactment”. That could have been filmed a month later.
Walkers
Well-known member
He shows that particular part is staged.
I guess I missed that part
Qualitytools
Well-known member
Interesting that it's schedule 80 (grey) which is supposed to be a lot more durable than schedule 40 (white) which is mainly used for sprinklers.
csp
Well-known member
He's in the UK, so standards may be different than what we're used to in the US.
jmarkwolf
Well-known member
I've read that long term exposure to ultra-violet light also aggravates the problem.
Moral of the story, don't use PVC for compressed air.
Firebrick43
Well-known member
It oxidizes and UV light but mostly its bad for compressed air systems because it work hardens. A compressed air system with a piston compressor, depending on design, can have a lot of pressure pulses. These pulses over time (much less time than say a water system due to the number/density of the pulses) harden the pipe causeing it to become more brittle and then shatter.
Its a well known problem in water systems, large ones not so much as water towers and such keep pressure pulses to a minimum. The underground utilities only like to use PVC when they cant keep sharp rocks out of the trench as polyethylene is much more resilient in almost every regard except from sharp abrasions.
I have seen a real push back on PVC/CPVC systems in commercial/industrial environments for even water as it has been shown to have a low lifespan and therefore higher lifecycle cost.
I saw a case here locally that they installed CPVC in a 7 story apartment building against the advice of several journeyman on the job.
Once they turned on the hot water the main vertical riser expanded so much in length that it sheared off the horizontal trunks on the 6th and 7th floor. They replumbed the main vertical risers in copper like what was originally suggested. They could have plumbed the whole building in copper for what the flooding damage and lost rental income was in the end.
Packard V8
Well-known member
Yes, No, Maybe. I know several friends who've used plastic pipe for air supply successfully for forty years. During the same time period, some of these same friends have had random accidents with controlled substances, alcohol, motorcycles, ORVs, boats, guns and most frequently, expensive divorces. You never see the bullet that kills you.
But no, PVC is not recommended for air supply. It's just cheap, easy to work with and doesn't kill you every time.
jack vines
But no, PVC is not recommended for air supply. It's just cheap, easy to work with and doesn't kill you every time.
jack vines
dutchgray
Well-known member
In the UK, the white PVC pipes are typically only used for waste drains and tank overflows and even then typically only up to 2", we use much heavier grey (for internal or outside applications) or orange (for underground) pvc with slip on couplings with rubber seals, though you can get glue couplings for the internal, for waste, you can get 3" grey which can be used for vents, though 4" is typical and the smallest you can use for your main waste or for toilets and also in 6" in orange for underground, bigger than that would be a twin wall plastic, concrete or clay pipe.
Grey PVC pipe like in the video is used for pressurised water applications and is available in many sizes, not something we commonly use in domestic water supplies, copper, pex and occasionally even galvanised pipe are used.
Mains Water supplies from the meter are now all blue MDPE pipe from a coil, with plastic couplings that screw together and use o ring seals, they are pretty much insisting a barrier pipe is now used for domestic supplies because of possible contamination through the pipe.
We use the same pipe in yellow for gas, the joints are welded for that and in black for pumped non potable water applications, sewage treatment tank outputs, sump pumps etc.
The chance that it might kill you once is good enough reason to not use it....
LynnW
southalabama
Well-known member
I’ve seen it blow. I was out of the blast zone.
Not for me.
Not for me.
Snapped-off
Well-known member
Found this is a stranger's garage today. Atleast it's a short run. 
merkyworks
Well-known member
Thought the same.
beemerphile
Well-known member
Wow. That's dangerous! Maybe the PVC pipe manufacturers; OSHA; most compressor manufacturers; the Plastic Pipe and Fitting Association; and most people with three digit IQ's should warn against its use with compressed gases!
mike93lx
ALLIANCE MEMBER
Wow, that's a wild idea. You think it could happen?
mike93lx
ALLIANCE MEMBER
Pipe bombs usually aren't very longFound this is a stranger's garage today. Atleast it's a short run.
Totally unrelated to using as airline but I've seen what happens to even large heavy pvc pipe when the old school potato gun was "hot loaded"! Lucky nobody got killed over that deal! We weren't using the recommended "hair spray" but a buddy of mine found some other shop supply items that really ramped up the velocity of the potato in order to make mashed potatoes against the side of an old hopper wagon. From 50 feet we were getting hit with chunks of potato bouncing back at us until he was bleeding from pvc shrapnel...then we quit and fortunately walked away. Not sure an airline would have the pressure that had but it could still cause the shrapnel if it exploded.
Joel
Joel
Monza Harry
Well-known member
I was told years ago that it is the oil that causes the degradation, being as most polymers are petrochemical based that made sense, but UV and plastics are known enemies, work hardening would also seem like an issue as plastics can be brittle and soft simultaneously kind of unintuitive. Either way not worth the risk, let's save on the pipe or the glue or the solder*/braze does the savings/risk outweigh the damage. Think of the things in a twenty foot radius of the piping. The rad on your wife's brand new car, the new A/C unit, or best reason NOT TO, your first grandson comes to get grandpa for dinner. NOT WORTH IT!
*Lead/Tin isn't the right stuff either, use 45 Silver! https://mccombssupply.com/98002-luc...e-450-45-silver-solder-5-ounce-brazing-alloy/ Harry
*Lead/Tin isn't the right stuff either, use 45 Silver! https://mccombssupply.com/98002-luc...e-450-45-silver-solder-5-ounce-brazing-alloy/ Harry
Greeny
Well-known member
When we bought this place, the shop had PVC airlines. I cringed when I saw them while getting a tour from the PO. He laughed and said they'd been working fine for 30 years. Fast forward to just after closing and I'm replacing the PVC with PEX. I dropped a 10' section of the 30 year old airline from the ceiling to the shop floor and it shattered into a gazillion pointy pieces. I feel much better now that it's all PEX runs.
beemerphile
Well-known member
Back when I was stupid enough to make a potato gun out of PVC pipe I was smart enough to make a loose cover for the barrel out of 1/4" hardware cloth laced together. It was loose enough to allow the gases to escape but strong enough to hold the fragments. The thing making PVC potato gun barrels even stupider is the fact that most large diameter pipe available in the big box stores is low pressure DWV pipe.
FIFY