Learned about it school, heard bout it happening but NEVER seen it before today!

[DR Buck]

Spontaneous combustion      

I went out early this morning to load the kiln and start a big milling job that I am behind on.    First thing I see is smoke coming from over in the corner of my log yard area.     Turns out my sawdust and bark pile was burning.    There wasn't anyone around yesterday or early this morning to start it burning.  All I can figure is it was caused by spontaneous combustion. Never seen it happen before today.  Fortunately no harm was done and I let it burn all day today.   Makes me want to make sure I clean the sawdust out of the barn every day.

[Ron Wenrich]

I've seen it several times in bark piles.  It usually happens in the winter and by being driven on with dump trucks.  The compaction and the heat usually sets it off.  They're next to impossible to put out.  The piles have to be pulled apart and doused with water. 

I've seen sawdust piles much larger than yours never catch on fire.  They get really warm, and its a good place to warm your feet in the winter.  They've all been circle mills.  Your dust may be a lot finer.  But, we've had a trailer load of fire sit for up to a week or more that never catches.

Your pile will burn for months.  There was one in NY that burnt for 20 years.  Of course, the guy kept adding to the pile. 

[bandmiller2]

Squirrels playing with matches.Sawdust piles are weird they will heat, and sometimes hold snow and ice all summer I've uncovered chunks of snow in august.Guess its good form to blow the dust as far from the mill as you can.Anyone know the volume of sawdust needed to have dangerous heat ?? Frank C.

[Chris Burchfield]

It is actually an uninhibited chemical chain reaction according to the National Fire Protection Association.  I've seen individual piles of horse poop begin as a smoldering fire.  I've seen mulch do the same thing.  As the organics begin to break down by action of the microbes, it generates heat.  Undisturbed, it will continue to gen heat until an ignition temperature is reached.  When mixed with oxygen it will produce an open flame.

[Burlkraft]

That happened to a friend of mine.......

We was just standin' there talkin' and he burst in to flames  :  :  :  :

[Chuck White]

I would guess that the same thing could happen with the larger compost bins that some people have for their gardens.

Makes you want to keep it cleaned out from under the mill.  ;)

[Dave Shepard]

I wonder if keeping a sawdust pile watered down would help prevent it by limiting oxygen and aiding the composting process?

[Texas Ranger]

That happened to a friend of mine.......

We was just standin' there talkin' and he burst in to flames  :  :  :  :

Was that cause of horse poop or sawdust? 8)

[DR Buck]

That happened to a friend of mine.......

We was just standin' there talkin' and he burst in to flames  :  :  :  :

Now that's just not true.  :   You don't have that many friends   ;) and I've seen them all logged into the forum already today.     :D :D :D :D :D :D :D :D :D :D

[bandmiller2]

If your full of poop beware. Frank c.

[Magicman]

Had it to happen to me.  The "duff" pile (bark, sawdust, etc) started and set fire to a stack of stickered lumber.  Lost the entire stack.

[Sprucegum]

I don't have the paperwork at hand but I was told that in Alberta it is against the law to pile sawdust more than 3 feet high for that very reason.

[GaryinMississippi]

That happened to a friend of mine.......

We was just standin' there talkin' and he burst in to flames  :  :  :  :

I've done a slow burn before, but I've never burst into flames.

[Tim L]

I've seen a pile of laundered mop heads combust in a hospital laundry.

[CHARLIE]

I wonder if keeping a sawdust pile watered down would help prevent it by limiting oxygen and aiding the composting process?

I don't think so since it is damp or moist sawdust or hay that generates the heat.

Back in the mid 1970s, I remember driving past a large stack of hay bales (the rectangular bales) in a field about 4:00pm and smoke was coming from them.  We were headed to another town to attend a play.  On the way home, about 10:00pm we passed those bales and they were burning really good. Large flames. 

Farmers are taking a risk if they put wet hay in their barns.

[Brad_bb]

Some moisture will aid the microbe action.  I wonder if it's like corn, if corn is too wet it will rot and produce alcohol an can eventually lead to a fire.