PVC airline explosion - pictures

[broncorick]

That is what people don't get: liquid is incompressible and is why it is used for lifting. Air copmresses and stores like a spring. Just say no to PVC. RApid air is fast and eay

compressed air has stored energy. liquid doesn't compress so no stored energy

fill a balloon with air & poke it, what happens?
fill a balloon with water & poke it, what happens?

 

[bczygan]

 

[Shadowdog500]

It's not a dead horse until people stop using it all together.


Chris

 

[Caman]

That is what people don't get: liquid is incompressible and is why it is used for lifting. Air copmresses and stores like a spring. Just say no to PVC. RApid air is fast and eay

I will repeat, it doesn't matter what is in the pipe, 9 bar is 9 bar, air or liquid. Yes, air is compressed and has more energy behind it when released, but the pressure on the walls of the pipe is THE SAME when contained within the pipe.

 

[coldh2o]

10bar of LIQUID, not gas.

Wrong. As noted by others, pressure is pressure, regardless of the medium.

I will repeat, it doesn't matter what is in the pipe, 9 bar is 9 bar, air or liquid. Yes, air is compressed and has more energy behind it when released, but the pressure on the walls of the pipe is THE SAME when contained within the pipe.

This

 

[joe_padavano]

What about compressor oil that does get in the line and degrades it over time.
What about the fact that PVC gets brittle over time.
What if you accidently hit it with a ladder(or something else) and it explodes mid line(which has nothing to do with installation error)
What about the fact that the manufacturers specifically state that it is not to be used for compressed air above ground.

People have been killed from PVC air lines exploding, why even play the time bomb game.


Chris

Other than the oil (good call), I'll ask again, how are any of those different for liquid or air? Hitting the pipe with a ladder will produce a different result if water (at the same pressure) is in the line instead of air? I think not.

One more time: I don't use or advocate PVC for air lines, but at the same pressure, why does it matter if the internal fluid is water or air?

 

[Strouty]

Sorry guys, I still think it sounds like you are defending PVC for air lines. Maybe if you add that in the posts. I understand your point, but I know there are people that do not understand.


You two should get a room. Regardless of the science you are making it sound like it is safe to use PVC because it is rated at a certain pressure for liquid not gas.

I will repeat, it doesn't matter what is in the pipe, 9 bar is 9 bar, air or liquid. Yes, air is compressed and has more energy behind it when released, but the pressure on the walls of the pipe is THE SAME when contained within the pipe.

Wrong. As noted by others, pressure is pressure, regardless of the medium.



This

When a gas builds pressure it compresses, therefore you have a larger volume of gas trying to escape then a non compressible fluid. In other words if a liquid breaks the PVC you would get wet, if a gas breaks the PVC you would get injured or killed by shrapnel.

 

[hpw]

OSHA Hazard Information Bulletins
The Use of Polyvinyl Chloride (PVC) Pipe in Above ground Installations

The Dallas Regional Office has brought to our attention a potential serious hazard existing with the use of polyvinyl chloride (PVC) plastic pipes for transporting compressed gases in above ground installations. An employee in a Texas plant was injured recently by a rupture in a PVC compressed air line. Plastic projectiles from the point of rupture caused lacerations of the employee's hand. This is noteworthy because the Plastic Pipe Institute, in its Recommendation B dated January 19, 1972, recommends against the use of thermoplastic pipe to transport compressed air or other compressed gases in exposed plant piping.

https://www.osha.gov/dts/hib/hib_data/hib19880520.html

 

[Strouty]

PVC is like a grenade that you have no control over when the pin will be pulled. It may lay dormant for years and never have an issue or it could blow up when you are standing next to it. Can PVC take air pressure, yes, but for how long? Should you put air pressure in it, no.

 

[Caman]

You two should get a room. Regardless of the science you are making it sound like it is safe to use PVC because it is rated at a certain pressure for liquid not gas.

When a gas builds pressure it compresses, therefore you have a larger volume of gas trying to escape then a non compressible fluid. In other words if a liquid breaks the PVC you would get wet, if a gas breaks the PVC you would get injured or killed by shrapnel.

I never ONCE said it was safe to use PVC for airlines. I was only correcting misinformation saying the pipes were rated for 10bar of liquid pressure and 10 bar air pressure was higher.

 

[Shadowdog500]

?.. Hitting the pipe with a ladder will produce a different result if water (at the same pressure) is in the line instead of air? I think not.

Air is compressible. At 135 PSI the compressor and air lines are holding over 9 times thier volume under pressure. Once the pipe breaks with air in the system the air will expand rapidly to over 9 times its compressed volume and will send parts of scrapnel out like a hand grenade.

Water is not compressible, once the pipe breaks there will be no expansion of the water and parts will not be flying everywhere.

This is why they pressure test tanks with a fluid instead of a gas.

Chris

 

[coldh2o]

You two should get a room. Regardless of the science you are making it sound like it is safe to use PVC because it is rated at a certain pressure for liquid not gas.

When a gas builds pressure it compresses, therefore you have a larger volume of gas trying to escape then a non compressible fluid. In other words if a liquid breaks the PVC you would get wet, if a gas breaks the PVC you would get injured or killed by shrapnel.

I never ONCE said it was safe to use PVC for airlines. I was only correcting misinformation saying the pipes were rated for 10bar of liquid pressure and 10 bar air pressure was higher.

+1. Neither did I say PVC air lines were a good thing, nor did I dispute the fact that compressed air carries much more potential energy than a fluid at the same pressure.

 

[banditbigdog]

Posted this a while back,

http://www.wave3.com/story/17113807/...uries-reported

LOUISVILLE, KY (WAVE) - Emergency crews were on the scene of an explosion at a duct work factory in Fairdale Thursday afternoon.

Fairdale fire chief Don Wittry said several workers suffered facial, head and arm injuries at Shape Manufacturing at 1987 South Park Road. Six of them were taken to a hospital. Wottry did not believe any of them were admitted.

Wittry said a 300-yard PVC pipe filled with compressed air exploded across the entire length of the building, sending shrapnel from the shattered pipe onto the workers' heads. It was not immediately clear what caused the pipe, which Wittry described as 6 to 8" in diameter, to burst.

There was no fire associated with the explosion.


OSHA, the Kentucky Fire Marshal, and health department officials investigated the explosion. The building will be inspected to make sure it is safe.

 

[taumac]

^^^^This^^^^



To me, using PVC is nothing but cutting corners for a DIY'er. Go the extra and use some actual pipe that you KNOW won't explode into shrapnel.

I can understand not having the money for a rapid air system but a cheap way of doing a air system is using a 100ft of air line pvc or rubber and using that for the system but still people use PVC.

 

[Scott r c]

Other than the oil (good call), I'll ask again, how are any of those different for liquid or air? Hitting the pipe with a ladder will produce a different result if water (at the same pressure) is in the line instead of air? I think not.

One more time: I don't use or advocate PVC for air lines, but at the same pressure, why does it matter if the internal fluid is water or air?

Its just a dangerous experiment that evidently you need to experience first hand to figure out. There is a huge difference in breaking a line with 100psi of water vs. a line with 100psi of air. I have broke both.

 

[LS6 Tommy]

I don't consider myself to be an overly intelligent man, but sometimes I feel like a Genius. This is turning into one of those times..

Tommy

 

[csargents1546]

Science and specs. Aside. DO NOT USE PVC FOR AIR LINES. If osha say not to do it as it is dangerous. There is a strong possibility that they might actually know what they are talking about. We are thankful no was injured. When my pvc system that was installed by the previous owner blew. It knocked stuff off the wall on the other side of a 32 foot garage. That is an indication of the amount of potential energy stored in an 80 gallon air tank at 150 psi.
Imagine for a moment. Worker goes to plug in an air line. Said worker has a hammer in his other hand. Hammer slips, hits the line just a little. Said line is running 100 psi. Said line is connected to two large 120 gallon air tanks. 240 gallons of air stored at 100 psi. When that air releases all of that stored energy as 240 gallons expands by 9 time the volume as the air expands. 240 gallons becomes 2160 gallons of air at regular atmospheric pressure. Those numbers scare the hell out of me and hopefully anyone else considering using pvc.

 

[csargents1546]

To the moderator. Can we put the osho bulletin up as a sticky at the beginning of the tool section?

 

[DekeT]

Wrong. As noted by others, pressure is pressure, regardless of the medium.

Wrong for you. You took my statement out of context. The pressure rating to which I was referring was allowable liquid pressure printed on the side of the pipe and not gas pressure. I was clarifying that the print was for liquid and not gas. Don't know how you inferred something else.

 

[Lotek]

Re: Home Depot Clearance Thread 2015

No need for insults. Some were just not informed when they installed it. I had it in my old house for 6 years and in my current for 4 years. Wasn't aware of the issues until after installed at the new place.

But the insults and abuse do serve a purpose, they get your attention...

 

[djjsr]

Wittry said a 300-yard PVC pipe filled with compressed air exploded across the entire length of the building, sending shrapnel from the shattered pipe onto the workers' heads. It was not immediately clear what caused the pipe, which Wittry described as 6 to 8" in diameter, to burst.

A 6" pipe that's 900 feet long has a volume of 1322 gallons. That must have been one hell of a boom!

 

[coljar]

My head must be made out of PVC, because I think it's going to explode.

 

[nine4gmc]

My head must be made out of PVC, because I think it's going to explode.

Try burying it between buildings, that should help!

 

[why worry]

I read through all of the comments and TOTALLY agree PVC is not to be used for compressed air or gases. The one thing not mentioned is the why.. As I recall the reason the plastic manufactures found was due to the compressed gases actually drying out the PVC hence causing it to be dry and brittle. When a nick or impact occurs then the stored energy of the compressed gases comes into play and a disaster occurs.
Dave

 

[bcos]

Metal wins !

 

[Ironhorse74]

So can someone help me design my pvc air system?

Brad

Some ******* had to ask.

 

[Cypherian]

What would you have me infer from this chart? That pvc is good for hundreds of psi pressure?

Only that the engineering Information says it can hold it however, this falls into the just because it is supposed to be able to doesn't mean you should. My truck is rated for 6500 lbs towing just because it is supposedly capable doesn't mean It won't blow an engine, transmission etc if I did tow 6500 lbs up to the top of a mountain in Colorado

Cypher

 

[58Yeoman]

My name is Phil. I used pvc pipe for air lines in my last garage (28x28), for almost nine years. I have not used pvc in over 7 years. I was dumb. I was lucky. I took it all down when I sold the house. I didn't install any in my new place (24x40). Now I just pull the hose out of the reel. I didn't know that pvc could explode like that, and was lucky I didn't find out until I started reading about it here.

Someone said that there should be a sticky on the tool section; I think there should be a sticky warning people on every section. Some people don't go to the tool section.

 

[404]

I don't consider myself to be an overly intelligent man, but sometimes I feel like a Genius. This is turning into one of those times..

Tommy

You are just noticing that common sense and doing some research are going extinct.

 

[coldh2o]

Wrong for you. You took my statement out of context. The pressure rating to which I was referring was allowable liquid pressure printed on the side of the pipe and not gas pressure. I was clarifying that the print was for liquid and not gas. Don't know how you inferred something else.

Not trying to derail the thread, but this discussion points to a big part of the whole misunderstanding with thinking PVC for air lines is ok - there is no distinction in the pressure rating (nor can there be because again, a psi is a psi) therefore no difference in labeling (show me in the OP photos where the pipe is labelled for liquid).

So if someone goes to buy pipe and has no understanding or knowledge of the difference in potential energy between compressed gas and fluids, they simply look for a pipe with a psi rating greater than the system pressure. Why not have manufacturers label PVC "liquid only" or "not for air"? Maybe some do, I can't recall. But then we get into bigger issues of admitting liability, nanny state handholding, etc.

 

[MoparTrucks]

PVC air lines are alive and well in my area where there are no inspections of commercial operations that I can tell and since Missouri is not an OSHA state we don't even have the threat of an OSHA inspection to bear.

I was at a local Dodge dealer last week buying a part and noticed they had PVC air lines all over their shop and when I was talking to the parts manager about it just in conversation he said they had had two instances of them bursting in the last year.....did they replace them with metal? Nope, just replaced the burst sections!

To me its like seat belts, I am the EMS Captain for our Fire Dept and see the results of the fact that Missouri has one of the lowest compliance rates with mandatory seat belt laws in the nation. You can show statistics, you can show photos, you can cite science and physics but there will be no persuading some people that "bracing yourself" won't work in even a minor crash and that cars do not typically explode in a flaming ball in an accident (everyone seems to know of someone who was trapped by a seat belt and burned to death despite the relative extreme rarity of such an event).

Same goes for PVC air lines, I doubt those who use PVC air lines will change their ways just because its a bad idea by virtually every metric, after all, everyone knows of those who have them and haven't had them burst yet.

 

[Jackfre]

The other thing about this system is the poor lay-out. When you install pipe for anything you should look at how the material is to flow. Try to minimize the fittings. For air in an HVAC system you can't read the air flow accurately unless you are at least 5 pipe diameters away from the last tee or 90. Air, water, gas, steam, all roll when coming out of a fitting. For instance the drop on the galv shown in the pics could have been a straight drop with the two tees one below the other and another tee added at the bottom for drain blow down. That would have saved one 90* bend and not have cork-screwed the air to the outlets. I can't say that the lay-out was the cause, but I would say it is a contributing factor.

 

[ilovevocs]

 

[TheEquineFencer]

FWIW: The cold pipe they used burst without much problem....

 

[softailgarage]

https://www.youtube.com/watch?v=IVO4_hUvFs

FWIW: The cold pipe they used burst without much problem....

Thats a bad link, "video does not exist"

I've said it once, I'll say it again, In California it is ILLEGAL to install PVC air lines in a commercial structure...there is a reason for that.

 

[Kevin54]

That is what people don't get: liquid is incompressible and is why it is used for lifting. Air copmresses and stores like a spring. Just say no to PVC. RApid air is fast and eay

Wrong for you. You took my statement out of context. The pressure rating to which I was referring was allowable liquid pressure printed on the side of the pipe and not gas pressure. I was clarifying that the print was for liquid and not gas. Don't know how you inferred something else.

So many contradictions in this thread about liquids being incompressible or being compressible. You can compress a liquid, and different liquids will compress differently. A lot of the compressibility depends on the viscosity of the fluids. If a liquid was not compressible, we would all be able to run water in a brake system in a car, but because of the difference rates as to which a liquid is compressible, hydraulic fluid is the better choice.

from a physics site:

You can compress water, or almost any material. However, it requires a great deal of pressure to accomplish a little compression. For that reason, liquids and solids are sometimes referred to as being incompressible.

To understand what happens, remember that all matter is composed of a collection of atoms. Even though matter seems to be very solid, in actuality, the atoms are relative far apart, and matter is mostly empty space. However, due to the forces between the molecules, they strongly resist being pressed closer together, but they can be. You probably have experienced compressing something as hard as steel. Have you ever bounced a steel ball bearing off a sidewalk? When you do that, the 'bounce' is due to compressing the steel ball, just a tiny little spot that comes into contact with the sidewalk. It compresses and then springs back, causing the bounce.

The water at the bottom of the ocean is compressed by the weight of the water above it all the way to the surface, and is more dense than the water at the surface.

A consequence of compressing a fluid is that the viscosity, that is the resistance of the fluid to flow, also increases as the density increases. This is because the atoms are forced closer together, and thus cannot slip by each other as easily as they can when the fluid is at atmospheric pressure.

From a Hydraulic/Pneumatic website: http://hydraulicspneumatics.com/200.../Article/False/70094/TechZone-HydraulicFluids

Despite the frequent assumption that hydraulic fluid is incompressible, the fact remains: All fluids have some degree of compressibility. Granted, fluid compressibility may be neglected in systems that do not require tight control of response and where operating pressure and fluid volume are moderate. However, when applying high pressure to a large volume of fluid, a significant amount of energy can be expended to compress the fluid — essentially squeezing the fluid's molecules closer together.

The result can be delayed response — a loaded actuator may not move until upstream fluid has been compressed, and the energy stored in the fluid may cause the actuator to continue moving after its control valve has closed. Bulk modulus is a property that indicates the compressibility of a fluid. With many of today's hydraulic systems operating at pressures 5000 psi and higher, ignoring bulk modulus can compromise response time of a system.

Bottom line......Don't Use PVC for an air line.

 

[bullnerd]

Had that **** explode on me at two different shops, one shop twice in a week, and they still wouldn't replace it!

Thats enough info for me not to use it.

 

[TheEquineFencer]

Thats a bad link, "video does not exist"

I've said it once, I'll say it again, In California it is ILLEGAL to install PVC air lines in a commercial structure...there is a reason for that.

try it now...

 

[Strouty]

I've said it once, I'll say it again, In California it is ILLEGAL to install PVC air lines in a commercial structure...there is a reason for that.

That is because PVC used for air is known to cause cancer. It has nothing to do with the common sense that is can and will explode without warning.

 

[coldh2o]

That is because PVC used for air is known to cause cancer.

Particularly when genetically modified...