Tire explodes while filling

[Sean88gt]

Holy shit! Where the fuck is Matt at? I need a scientific explanation for dumbasses.

[CJ]

Holy shit! Where the fuck is Matt at? I need a scientific explanation for dumbasses.

The welding causes the tire to go through pyrolysis. This isn't a tire blow out. That was a tire explosion. Usually it's in excess of 1000psi pressure.

Check this shit out:

http://www2.worksafebc.com/PDFs/investigations/IIR2005108320019.pdf

An investigation about a heavy machinery mechanic that was killed by an exploding tire from exactly the above video. I'll isolate the relevant section:

A tire explosion is an explosive reaction involving energy many orders of magnitude greater than that of a tire blow-out. A shock wave creating pressure in excess of 1000 psi is what causes the tire to rupture in a tire explosion. Tire explosions usually occur when the equipment is stationary. (See the Appendix for definitions related to the explanations below.)
The most common cause of tire explosion involves pyrolysis of a section of rubber compound, usually the tire’s inner liner, due to a heat/energy source. The most common sources of heat/energy are:

• Equipment contact with high voltage power lines
• Tire or equipment fires
• Application of heat to tire components, such as welding and heating with a blow torch or overheated brakes
• Lightning strike
Pyrolysis of rubber produces flammable gases such as methane, styrene, butadiene, hydrogen, and other hydrocarbons. An explosion will occur if all of the following conditions exist concurrently:
• There is an explosive concentration of flammable gases.
• There is an adequate concentration of oxygen to support combustion of the flammable gases.
• There is an ignition source.
• There is sufficient molecular energy to sustain the explosive reaction.

If the other three conditions exist, then the flammable gases will explode if there is a hot spot of sufficient temperature to auto-ignite the gas mixture. A flame or spark is not required if the host-spot temperature exceeds the auto-ignition temperature of the gas mixture.
The evidence gathered at the scene indicates that there was a fire inside the tire before the explosion. Air samples analyzed at the lab did not show presence of flammable and/or combustible substances in the compressor reservoir. Furthermore, if any such substances had been present in the tire chamber, the fire would have started during the welding process, creating smoke that would come out the valve stem and alert Mechanic 1 to a problem.
Mechanic 1 was a conscientious worker and would most likely not have inflated the tire after welding if smoke was pouring out of the valve. Therefore, since the tire was being inflated when it failed we can assume any fire inside the tire began after the process of inflation began.
The new weld was more extensive than the others. The inside of the rim next to the bead by the welded area showed heat discoloration. The tire bead over this area was badly charred. In the charring process

(pyrolysis) the flammable gases were trapped inside the tire. The air fill valve is close to the welded area. As air is introduced, some passes by the hot spot in essence, fanning smoldering rubber and eventually resulting in a fire inside the tire. This most likely created further chemical breakdown of the rubber inside the tire chamber, producing more flammable gas. With the further introduction of air through the airing up process, the explosive limit of the mixture is reached and the mixture exploded inside the tire. The burning gases moved on both sides of the initiating area. When the explosive burning gases met at the top of the tire approximately 180 degrees from the explosion source, the shock wave blew open the tread.
The tire explosion created four flaps of the tire (see Photo 12). The force of the explosion was such that those flaps were folded over and down (see Photo 13). The tire flaps that folded over both sides of the rim had yellow paint, indicating that the flaps hit the rim so hard that the paint came off. One of the flaps struck the worker on the head.

Mechanic 1 was standing or crouching close to the rim, possibly checking the pressure gauge. The explosion caused the tire to split into four flaps that peeled backward. The flaps that peeled over the rim hit the rim with such a force that yellow paint from the equipment came off. One of the flaps peeled backward and down approximately 46 inches, striking the worker and causing fatal head injuries.

After the incident, Mechanic 1 was lying next to the exploded tire. A broken air hose was blowing air. Parts of the broken air chuck were lying on the ground. There was a bottle of soap solution with the cap on and a small hand spray pump lying next to the exploded tire.
The glass from the log stacker windows was scattered in a radius of approximately 60 feet. Most of the mobile equipment in the yard suffered damage to the windows. There were some large pieces of tire rubber scattered around the yard. The building suffered damage, including large holes (caused by large pieces of flying rubber) in the walls and most of the plywood under the overhang on the east side was knocked out. Some of the equipment that was stored inside the building was damaged.
The explosion was heard by some people in town several miles away.
A close examination of the site indicated that the concussion from the explosion was mostly at level of 6 feet and higher.

Summary: don't even THINK about welding a wheel with the tire still attached.

[CJ]

That is fucking nuts.

[Sean88gt]

Dammit man! Does that count as internal combustion?

[CJ]

Dammit man! Does that count as internal combustion?

yes, and boom bitch.

[91CoupeMike]

Explosive decompression.

[Chili]

He is definitely lucky to be alive...

The Army always made us use a cage when airing up tires. Fortunately we never needed the cage to save someone.

That.. When I was at Fort Bliss there was stained concrete in our motorpool that was supposedly the result of a decapitation due to not using a cage. They used to point it out to everyone when working in there.

[Juiced4v]

Taking my chet to the tire shop next time.

[CJ]

lofl @ 2:34

[sig239]

Best tire shop story ever. A Naynay is filling a split rim, and it comes apart, taking the hat off his head, but not hurting him. Owner comes out screaming to use the cage next time. Next split rim that comes in, the shop owner watches as the Naynay crawls into the cage and tries to work the rim thru the cage. He still laughs about it 20 years later.

That shit had me rolling,