Do wood chips spontaneously combust?

[ragkar]

A guy was warning me about this for wood chips and shredded leaf piles but I have my doubts. Everyone knows about fires in lumber mills and graineries but that's due to dust. And I recall reading about occasional forest fires that are caused by spontaneous combustion of decayed vegetation.
But when I was researching my compost heap I recall seeing advice that the compost heap should be at least three feet deep or the bottom layers won't get warm enough to support fermentation.
I'm thinking that if I keep my wood chip pile less than two feet tall, the danger is nil. But my shredded leaf compost pile (oaks) would have to be around three feet tall for it to work.

 

[Bird]

I wish I could remember where I read the stories recently about that, perhaps the Dallas Morning News. At any rate, there had been a fire in a playground in a city park or at a school and they had wood chips under the swings and other playground equipment. So someone apparently thought it was spontaneous combustion of the wood chips and they were considering removing all the wood chips and replacing them with something else. But the last thing I read about it was that they had decided it was not spontaneous combustion and the wood chips were safe.

 

[RobertN]

I wish I could remember where I read the stories recently about that, perhaps the Dallas Morning News. At any rate, there had been a fire in a playground in a city park or at a school and they had wood chips under the swings and other playground equipment. So someone apparently thought it was spontaneous combustion of the wood chips and they were considering removing all the wood chips and replacing them with something else. But the last thing I read about it was that they had decided it was not spontaneous combustion and the wood chips were safe.

Cigarette butts are usually the issue. However, the place where I work has extensive landscapeing, with lots of bark/chips. Every year they get at least a little bark fire. In addition, they sometimes put a spray on the bark/chips to preserve them, and lower the fire danger. However, it is flammable and has a tendency towards combustion immediately after application.

They had a good one going a couple months ago. Multiple engines responded...

 

[texasjohn]

I think it is possible, but very unlikely... I know I've seen piles of chips at least 14 feet high... and the pile sat there for years, thru rain, etc...

Perhaps just the right conditions, moisture, materials, insulation versus oxygen levels, etc. would produce a smoldering situation which, again,under the right conditons could blaze up...

Hay bales when baled too green can heat up a lot... but primarily it destroys the feed quality of the hay, not producing a blaze.

Net... I do not recall ever reading of anyone simply having a chipper, making a pile of chips and it catching on fire..... it is possible that a call to the local fire department would give you their opinion .... and they are sensitive to causes and fequency of fires across a broad area.

 

[BigE_]

Wood chips aren't going to spontaneously combust unless you start adding other things like manure. I was just reading in the paper a couple of days ago about a place that was burning what they called hog fuel. They had a problem with their incinerator and got a backlog of the fuel, which then did the spontaneous combustion thing and has been burning for over a month. I guess it smells pretty bad due to the decomposing stuff in there.

The bark chips fires that I have seen have all been due to a cigarette being thrown in there. It ticks me off to no end when I see the butts being tossed out of the car (burning or not).

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!

 

[BigE_]

Here's the story:
Everett wood chip fire burns for months, upsets neighbors

THE ASSOCIATED PRESS

EVERETT, Wash. -- Neighbors of a burning pile of wood waste in northeast Everett have had about enough of the lingering stink that has punctuated their lives since August.

"You can't get away from it and it's absolutely nauseating," said Riverside resident Doug Yearout.

Tissue maker Kimberly-Clark, which owns the burning pile, is combating the problem by moving it around, hauling truckloads of the wood to its pulp mill on Everett's waterfront and extinguishing flare-ups 24 hours a day

"We're doing as much as we can to consume as much of that pile now as possible," said Chris Eisenberg, manager of mill which produces about 1 million rolls of tissue products a day.

The material, called "hog fuel," is made of bark and other wood scrap. It fuels a co-generation boiler at the mill to create steam. The steam is used in paper-making and generates enough electricity for about 21,000 homes.

Eisenberg said the boiler, owned by the Snohomish County Public Utilities District, had a major malfunction in late June, which forced the company to stop burning the wood scraps.

While Kimberly-Clark waited for the boiler to be repaired, shipments of the wood fuel continued and the pile grew to 120,000 tons, about double the normal winter stockpile.

When the boiler was repaired on Sept. 20, the company started hauling away about 1,000 tons of the scrap wood a day.

The scraps are piled at a storage yard and former sawmill, along with piles of logs and wood chips used in the pulping process, on property proposed by the city for a possible University of Washington branch campus.

The pile started composting, building up heat, and eventually ignited in August.

"It's not just the type of thing you can just pour water on," said Larry Altose, a spokesman for the state Department of Ecology. "It's more complicated than that."

The smoky burn has prompted odor and air quality complaints to the Department of Ecology and the Puget Sound Clean Air Agency.

Yearout, a veterinarian, lives just west of the burning pile on a maple-lined bluff.

"It just permeates. The clothes stink, the house stinks, you can't open the windows and ventilate it," Yearout said. "It's like being by a camp fire all the time with the wind blowing in the wrong direction."

Yearout said he has complained to the company and state regulators, and is growing impatient. He recently put flyers on mailboxes informing neighbors of his efforts to have the fire extinguished.

Kimberly-Clark is investigating ways to minimize the impact on neighbors, Eisenberg said, adding that the smoldering waste should be cleared within the next few months.

Kristi Kramer, Yearout's partner and a civil engineer, said she doesn't believe everything possible is being done to get the fire put out once and for all.

"If Joe Blow homeowner burns during a burn ban, he gets a ticket right away," she said. "And here a corporation is able to affect our health adversely and not have to do anything. And that's what I'm frustrated with."

 

[BigE_]

So, I stand corrected -- you get enough of the wood chips in one place and they start decomposing, you can have a fire.

 

[N80]

Piles of sawdust can and do combust! I have never seen it happen but I've heard about it and seen evidence of it.

I used to hunt on a plantation down on the Ashley river near Charleston. There were enourmous piles of sawdust from the last time it was cut which had to have been at least 50 and probably 75 years before. The first evidence you could see was that on cool days these piles would steam. I'm not talking about steaming in the sun, the sun did not reach these piles. But there would be streams of steam coming up in multiple places. And in these places you could feel the heat of the decomposing pine sawdust.

The second thing is that in these piles there would be little hollowed out 'chambers' and the insides of them would be charred sawdust. And believe me, these things were three to four miles off any paved road....no cigarette fires.

It always smelled like burning pine around these piles.

So, I know they can generate heat and smolder enough to char the sawdust. But, never actually saw one combust. It was always damp and humid on this plantation. A drier climate might be more condusive to spontaneous combustion.

 

[scott_vt]

Afternoon Ragkar,
In my 25 years as a volunteer firefighter I have gone to exactly 2 fires started from wood chips. They were both very minor and the piles were a few feet deep ! So yes it can happen but it is quite rare and you will probablly get alot of smoke from smoldering and very little fire IMO !

 

[Mickey_Fx]

Seems to me if woodchip piles were a real problem, you wouldn't see mts of woodchips at papermills or even at wood mills where things like chipboard are made.

Lived in a town where Western Craft (brown wraping paper) had a large mill and their wood chip pile was at least 50' high. Duracraft also had a large chipboard mill in same town with large piles of woodchips. Used to drive by a paper mill on way to work and now drive by several other paper mills driving to the kids house. Have been doing this for about 40 yrs and don't recall a fire at any of these places.

Maybe other factors come in to play but I don't know.