Do wood chips spontaneously combust?

[orezok]

Remember the old movie "Fahrenheit 451". It was titled for the temperature at which paper combusts. I imagine wood is about the same.

 

[AlanB]

Fuels and Chemicals and their Ignition Temperatures

I think, and I am guessing at this point though, that anything like large piles of wood etc, are not "pure" or such, and those impurities will raise or lower the autoignition temp accordingly.

Picturing large piles of wood chips etc. I just doubt that other things would not be in there as well.

 

[BigE_]

Heating with Wood: Principles of Combustion, from the Montana State University Extension Service

 

[N80]

Heating with Wood: Principles of Combustion, from the Montana State University Extension Service

I'm not sure this reasonably describes what happens in a wood chip or sawdust pile. They are describing the second stage of combustion in a wood burning fireplace. Very big difference.

Someone else in this thread has already cited a much lower number for spontaneous combustion. I'd like to see their source.

Bottom line is, piles of sawdust and woodchips do combust. Ample evidence had been cited for that. If it has to be 450 degrees for that to happen, then it must reach 450 in those piles. I think that is highly unlikely though and suspect that for whatever reason, whether its impurities or differeing properties for sawdust and decaying chips, that these piles ignitie at far lower temps than 450 degrees.

 

[orezok]

It's highly likely that during the decomposition of the wood and other items in the pile, that some combustible gas such as methane is given off. That byproduct could ignite at a much lower temperature and then ignite the other products.

 

[BigE_]

My somewhat educated guess is that the decaying wood produces gases that ignite at much lower temperatures. Once those gases ignite, I'm sure it is easy to reach the 540 degrees cited in the article above for the actual wood to burn.

 

[BigE_]

Guess orezok and I had the same thought at the same time....

 

[Rara Avis]

My somewhat educated guess is that the decaying wood produces gases that ignite at much lower temperatures. Once those gases ignite, I'm sure it is easy to reach the 540 degrees cited in the article above for the actual wood to burn.

The actual wood doesn't burn, its the gases...

Pyrolysis: The process also occurs when burning compact solid fuel, like wood. In fact, the flames of a wood fire are due to combustion of gases released by pyrolysis, not combustion of the wood itself. Thus, the pyrolysis of common materials like wood, plastic and clothing is extremely important for fire safety and fire fighting.

 

[Doc_Bob]

I have tons of wood chips ever year. They never ever came close to burning.
Don't worry.
Bob

 

[dillo99]

Well this isn't about wood chips but it is kind of funny. A buddy of mine loaded a farm wagon with fresh hay and they decided to park it in their metal storage barn - with lots of other equipment. Luckily, they put it in the middle of the barn and it was not near anything else. They weren't in the barn again for about 2 weeks - they opened the door and found a pile of ash and metal wagon parts. They never knew if the thing just smoldered down to nothing or if there was a blaze. Lucky that nothings else caught fire.

On the not funny side: My uncle lost a 150 year old barn about 3 years ago to a hay fire. That one was very sad as it basically sent him out of the dairy business and shut down a 80 year old family business. I would think that if hay can spontaneously combust, wood chips can as well - but it may be a big less likely just because they are probably harder to ignite.

 

[LBrown59]

Reminds me of one time I was on my motorcycle sitting at a stop light, and the car behind me tossed a lit cig out the window. I hopped off the bike, walked back, picked up the lit cig, said "It looks like you dropped this" and tossed the thing back in through their open window! Walked back to the bike and drove off. Don't know if it got the message across, but it really made me feel good!

With the kooks we have out there now a days this would be a good way to get your head blown blown off by some nut.