Talon

The local ABC affiliate, WPVI, reported on someone who lost his house because nut he stored in his garage caught fire. He had left nuts in a metal bucket for his grandchildren to use for feed squirrels but, recently he covered this with another bucket to keep the dogs from getting into the nut. It's believed that the "trapped" oxygen caused it to combust.

Anybody have any idea how this actually happens? It wasn't at all clear from the report.


TALON

blame_the_gods

Nope, stumped.

Corwin

'Trapped' oxygen wouldn't burn very long.

Now... if the nuts were wet... and left undisturbed for a while... they could ignite. Any organic material produces heat when it decays. (If you ever drive past a garden center... look at the bark piles. If it isn't summer, they're probably steaming.) Leave it long enough, and give it a source of oxygen, and it can combust.

ImGod

The decay process releases heat. If you trap the heat it can eventually lead to combustion (i.e. get hot enough in a bucket with something covering it).

butswana

Maybe GOD(DOG) was punishing him.
What kind of nut(s) was(were) it(they)?

Talon

I searched WPVI's website but didn't find anything.

I know that decaying organic matter produces heat but, it actually caused enough heat to have a flame. I don't think the decay would cause that.

I will assume they were dry because the nuts were for current use. I don't think he's give rotten nut to his grandchildren.

[ February 28, 2002: Message edited by: Talon ]</p>

Corwin

It can easily produce that much heat. That's part of why you stir up compost heaps. (To let the heat out.) It becomes a problem when the material is enclosed and the heat builds up...

There was a web site I read where people were using a large composting room as a hot water heater. Interesting idea... but way too much work.

tronvillain

Talon:
Well, I definitely wouldn't want you in charge of storing hay, because it can.

He may not give rotten nuts to his grandchildren, but that doesn't mean the nuts were dry. The nuts may have had months to get wet and decay.

kwigibo

you might get a definitive answer in Science & Skepticism

repoman

While I haven't researched this topic, I believie it could be possible to combust from the composting. The only part about this that is mysterious is the question of how the bacteria/fungus/insects that are eating the nuts/leaves/hay can survive the extreme temperature.

One possible way may be that the eaters are eating in bands that are fairly warm, but they drive up the heat in the internal bands where live can't exist.
Darn, let me think about this. Is this even possible?

The simplest geometry I can think of is an onion, say with a 5 meter radius. So imagine that the surface the temp is about 40 C, and that it increases as you go deeper into the sphere. At a certain point the temp will be hot enough to stop life. So it is like having concentric spherical heat sources all layered together.
So the question is if you assume say 70 C as the hottest heat source, is it mathematically possible using a thermal energy balance to show that in layers inside that can be even hotter than 70 C? Or conversely, is it impossible?

HOWEVER, thinking about it a little more...
It may be possible that the compost material is oxidized in a sort of slowburn at temps higher than bacteria can live. That would be a heat source if so. It even may be that enzymes have been released into the pile that work at very high temps that predigest it for the lifeforms in that pile.