Thursday, June 14, 2007

Can parking your SUV on a pile of leaves really cause it to go up in flames?

Who's asking: Kathleen McLaughlin Jacobson, Los Angeles, CA

Kathleen asks this in response to the "Sopranos" series finale, during which this happened to AJ's vehicle.

But it's an example of how popular entertainment can save lives, because this can and does happen. I've seen it -- not with an SUV, but a sporty little European roadster. Parked in a Middleburg hayfield on a dry October afternoon, it went up in flames before anyone even realized it was smoking.

It was a steeplechase race meeting. My friends and I were sitting around on a blanket in the midfield, drinking wine and passing a hat for dollar bets, when we saw the black cloud rising from the parking lot. It was between races, so the whole crowd moved over to see what was going on: the two-seater was burning merrily away, and everyone who'd parked anywhere nearby rushed to move their cars before the fire could spread. The fire department responded quickly, and no other cars burned, although the five or six surrounding the burning car were probably totaled by smoke and water damage.

What causes this is the catalytic converter, a portion of the car's exhaust system that forces the car's exhaust through platinum-rhodium and platinum-palladium catalysts in order to remove carbon monoxide and nitrogen oxides. This process turns toxic gases into carbon dioxide and water, and as with any process that compresses gases, it gets hot. Really hot. 1800F hot.

This is why you shouldn't drive your car through a pile of dry leaves, and you shouldn't park any vehicle over something that might be a fire hazard. Most of us know instinctively that parking in a pile of dry leaves isn't a great idea -- but SUV drivers don't always know they're parking over flammable materials, because the cars are so much higher off the ground. Also, some SUV drivers seem to think that "off-road" means "nature-proof," as if these vehicles were somehow exempt from the normal rules of physics.

I'm not a fan of SUVs ... unless you're a park ranger. Some people in Maine genuinely need them. No one in Los Angeles does, and certainly -- as he discovered -- AJ Soprano didn't.


Bill said...

OK, so at least it's not the most obvious thing in the world. The show seemed to be implying that A.J. was a moron for not knowing this -- A.J. IS a moron, but for other reasons.

Kathleen said...

Thanks Clair. I had no idea and I do drive an SUV. Now I've got a whole new phobia...thankfully big piles of leaves are in short supply in LA. I do admit to feeling like an AJ-level moron due to the way Tony and Carmela were carrying on. Kinda pulled me out of the know...before that other thing pulled me out of the show.-Kathleen

Karen Olson said...

I think this would be great for a Mythbusters episode.

AnswerGirl said...

I don't want to overstate the risk; cars' undercarriages are shielded to prevent direct contact between hot engine parts and whatever's underneath. But catalytic converters can throw sparks, and undercarriage coverings can crack or come off.

You're right, Karen, "Mythbusters" should do this.

Moira said...

I never knew that about SUVs. But I do know that a hideous pea-green Dodge Dart can spontaneously combust in the parking lot of your local Jr. High while your parents are signing you up for gymnastic lessons during the Carter administration.

I think my mother and three sisters willed the car's demise. It was so ugly. We hated it! My dad was trying to be practical. That was the end of that -- back to big ol' Buicks.