'Like a bomb': Exploding tire that killed L.A. County firefighter was a little-known risk

[mahatmakanejeeves]

'Like a bomb': Exploding tire that killed L.A. County firefighter was a little-known risk

Rebecca Ellis
Sat, August 24, 2024 at 6:00 AM EDT
5 min read

No one knew the burning construction vehicle could become a bomb. … Not the driver who tried to douse it with an extinguisher. Not the workers who sent water gushing onto the engine. And not Andrew Pontious, an L.A. County firefighter dispatched to the Palmdale quarry on June 14.

Pontious had sprayed water near the vehicle for about two minutes when one of its nearly 7-foot tires exploded, according to a Fire Department analysis completed this month. … Hunks of rubber and steel shot the length of a football field. Pontious, 53, died instantly.

“It was like an IED,” David Pontious, Andrew’s brother who worked at the same Palmdale fire station before retiring this spring, said, referring to an improvised explosive device, as a roadside bomb in a war zone is known.

It’s common for tires to blow out in a fire, with pressure building until the air whooshes out with a loud pop. … But, sometimes, the tire doesn’t blow — it explodes. The air inside the tire combines with the heat, starting a chemical reaction powerful enough to create a violent shock wave. The larger the tire, the bigger the blast.

{snip}

[yourout]

1. Stored energy sources are many times unrecognized..

Points of danger.
Capacitors. Hydraulic accumulators. Compressed air storage.

[Jerry2144]

2. Springs, things under tension

Are also potential hazards

[PufPuf23]

4. Propane tanks in wildfires. nt

[ret5hd]

3. Simple fix for those fighting fires on such equipment:

Puncture the tires first: sharp rod, bullet, I dunno...just release the pressure.

[CoopersDad]

6. Deflate tires at the valve for the most controlled release.

Piercing the tire could lead to too rapid a release, aka and explosion.

But yeah, don't let them sit there and burn!

[ret5hd]

7. you gonna go up there and push that little stem in...

while the fires burning?

[CoopersDad]

8. I would hope to take out the valve stem with a rifle shot.

eom

[BlueWaveNeverEnd]

5. I remember this.

[sl8]

9. Study: "Exploring the chemical aspects of truck tire blowouts and explosions"

https://doi.org/10.1016/j.ssci.2007.10.004

Abstract

Truck tire blowouts and explosions, which account for a non-negligible number of occupational accidents with severe outcomes particularly in the transportation industry, are the subject of a literature review aimed at identifying the different processes involved, with a special focus on the chemical aspects of the phenomena. Tire blowouts and explosions associated with heat input are the result of the contribution of the thermal expansion of the air inside the tire, the thermal weakening of the tire structure, and three potential chemical reactions, namely pyrolysis, thermo-oxidation and combustion, leading to the degradation of the tire polymer matrix. Tire pressure and air temperature data recorded during a torch-induced tire explosion experiment were analyzed and show a sharp transition at 97 °C between an initial pure thermal air expansion regime and a second regime, also linear and attributed to a combination of air expansion and reactions of thermo-chemical degradation of the tire materials. The findings also highlight the difficulties that are encountered when trying to devise preventive and corrective measures against tire blowouts and explosions.

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