Pyrolosis revisited

A USAF Captain was killed by an exploding tire that she was holding in here lap because it wouldn't fit in the trunk of the Lexus. She was on vacation in Scotland and they had some tire trouble, a bulge in the tire. They put on the doughnut, and about 100 miles later the tire exploded killing her. After reading the thread on pyrolosis, I wonder if that's what caused the tire to explode. Even not knowing about pyrolosis, I still would rather have a suitcase in my lap than a dirty tire. More people should be made aware of this.

http://www.upi.com/Top_News/US/2010/04/03/USAF-officer-survived-IED-killed-by-tire/UPI-80581270334814/

Doesn't sound like pyrolysis would be possible as the story describes the event - but who knows?

I've read several detailed investigative reports on deaths from tire explosions involving pyrolysis. Every one them involved certain factors including #1 a tire heated to a degree that it charred and volatile gasses formed, #2 an oxygen source on the inside of the tire, and #3 there was a source of ignition.

This person was holding a bulging tire inside the car. Even if, let's say it had been overheated from use and had internal volatile gasses - it would need oxygen and a source of ignition to cause pyrolysis. Now, if it ruptured and was open to air, and the guy had a lit cigarette next to it - then maybe?

I suppose it could have just been an ordinary blowout, and picked the wrong time to do it. Doesn't seem like it would be fatal, however.

i dont know the scientific name for it but i've seen a couple dozen radial tires that havent been touched in years simply blow out sitting in the sun...thats another reason i dont like the damn things...never have.

If you watch the Bridgestone video, there"s no heat applied directly to the tire. Only a very small amount could possibly get to the tire from conduction, I"m sure you would be able to put your hand to the edge of the rim and feel almost no heat.
There"s oxygen inside the tire to allow some combustion, but I believe pyrolosis can occur without it. And I wouldn"t think that a car tire would have enough psi to kill you normally, although most people don"t have them in their laps.
As for the cigarette, it would not have mattered, because it would have no influence on the inside of the tire. The tire blew all the windows out when it blew, so I think there was more than the normal 35psi in there.

#1 Pryolysis is the process of the tire-rubber being overheated and emitting explosive gasses.
Not "warm to the touch." It has to be much hotter. Most pryo-tire explosion investigations have found tire rubber that had gotten so hot it had almost caught fire from a torch or welder. The misleading issue is - often the tire on the outside does not feel hot, so the hot-spot internally goes un-noticed.

#2 That explosive gas has to be trapped inside the tire.

#3 If there is enough heat present, a blast of oxygen has to hit it allow an explosion to take place - not much different than how a diesel engine works with a glow-plug.

#4. If there is NO heat anymore, nothing can happen without an external source of heat to ignite the mix. Thus my mention of a cigarette.

As to the story with the guy with the tire on his lap? Sounds like a normal blow-out to me - but no real facts are provided. If the tire had been over-inflated, it certainly could kill somebody at close range. I was in a shop where a guy got killed when he filled a tire - to what we think was 180 PSI. That was a "blow-out" and not a "tire-explosion." A blow-out only has the force of the PSI involved. A tire-explosion has igniting gasses involved and can easily exceed 1000 PSI.

The Bridgestone video, nor any other video has much use unless all the facts are provide. I've read many full-scale investigative reports of pyro-tire explosions.

I was just speculating about pyrolosis being the cause in this case.
But my question to you is how is a blast of oxygen or a cigarette going to ignite a blast in a sealed container?? (the tire)
To my understanding, pyrolosis is a chemical reaction, which can be anerobic. (no oxygen)

Like I said, I've read through several detailed investigative reports on deaths from tire explosions. I am not an expert, just a careful reader.

That article about the guy with the tire on his lap that got killed? I don't believe there is any way that was a pryolysis explosion. From what little facts were put into the story, it was probably just a blow-out. If the tire had been a problem leaker, and maybe somebody overinflated it, and then a blowout-blister started, and then he had it on his lap - and then it blew to pieces with him maybe only 1 foot away? A simple blow-out could of killed him.

But to guess some more about the factless story? Lets say the tire had gotten severely overheated to a point where the rubber was near ignition and explosive fumes were created by pyrolysis. He then puts it on his lap and it has a huge blister ready to pop. Lets say he has a lit cigarette in his mouth. Then it DOES pop and there is a rush of explosive gas coming out of the tire that blows into his face - needing #1 an ignition source and #2 oxygen. Seems it would have both very quickly and the trail of gas leaving the tire would be like a fuse hooked to a bomb.

Seems simple enough to me - in theory. But as I said, no real facts were given.

There are many detailed accident reports on the Web to read, if you so desire. I'd believe what's in them before belieiving what seems to happen according to some idiot newspaper reporters or what's shown in videos.