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Sawdust spontaneous combustion?

Started by Czech_Made, June 16, 2016, 09:02:54 AM

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Czech_Made

Anybody had it happen?  The sawdust I left under the sawmill was smoldering yesterday.  I know it can happen to coal - long story, learned it in the army - but sawdust?

One more thing to be nervous about. >:(

Bandmill Bandit

Ive not had it happen my self BUT ive seen the results of it a few times.

Natuaral or added moister in any organic material will create the conditions for "heating" to occur, some times enough to reach combustion AND the same heat causes decay in the material which produces methane. Can be a dangerous mix
Skilled Master Sawyer. "Skilled labour don't come cheap. Cheap labour dont come skilled!
2018 F150 FX4, Husqvarna 340, 2 Logright 36 inch cant hooks and a bunch of stuff I built myself

kderby

I am about to move a sawdust pile. 

One neighbor said he would not let me use his loader because when the pile catches on fire, he would be liable.

If this is an issue I would like to learn about it.

Kderby

Czech_Made

As I said, I seen it before.  Here, I dug this out:


    Charcoal – high
    Fish meal – high
    Linseed oiled rags – high
    Brewing grains – moderate
    Latex foam rubber – moderate
    Hay – moderate
    Manure – moderate
    Wool wastes – Moderate
    Baled rags – low to moderate
    Sawdust – possible
    Grain – low


I know of linseed oil rags from my dad.

Hilltop366

I do remember my grandfather spreading salt over the loose hay in the barn, suppose to be it helped prevent spontaneous combustion.

Magicman

I had a customer that piled up a mixture of cleanup which included sawdust, bark, edging scraps, etc.  It ignited and burned most of the nearby stickered lumber.  Yup it can happen, but my thoughts are that a pile of pure sawdust would be much less likely to combust.
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

Chuck White

Quote from: Hilltop366 on June 16, 2016, 11:24:12 AM
I do remember my grandfather spreading salt over the loose hay in the barn, suppose to be it helped prevent spontaneous combustion.

Up here in this area most will spread salt on top of baled hay as each tier is stacked in the barn.
~Chuck~  Cooks Cat Claw sharpener and single tooth setter.  2018 Chevy Silverado and 2021 Subaru Ascent.
With basic mechanical skills and the ability to read you can maintain a Woodmizer  LT40!

Ron Wenrich

I've seen several bark piles catch on fire.  They are usually the ones that are piled high and compacted by driving trucks or loaders on them.  They usually vent in the winter time when the weather is cold.  Takes a long time to put them out and lots of water.

I've heard of sawdust piles catching fire, but I'm not sure its spontaneous.  I've seen some pretty high piles of sawdust that have never caught on fire.  You will get heat from the decomposition process, but the wood is too wet to catch.  Steam will come off when you open up a sawdust pile.  Dry wood would be more prone, but the decomposition process is shut off from lack of moisture and heat levels would remain low. 

We've had sawdust catch on fire, but mostly from welding or someone smoking. 
Never under estimate the power of stupid people in large groups.

Blackgreyhounds

It is very easy to get a very small spark of metal, static electricity or coal or something eles into a pile of combustibles like sawdust, that can linger for many days before catching "on fire."  So maybe not technically spontaneous, but certainly looks like it.  I'd always be careful around any pile of sawdust, especially if it is dry.  This could easily happen when vacuuming up sawdust into a plastic shop-vac, etc.

Ianab

Spontaneous combustion certainly can happen. It usually needs moisture to start some decay, (or a chemical reaction like curing varnish) which creates heat, and then sets fire to drier material surrounding it.

Growing up and making hay on the farm we would always watch for bales that had a plug of wet green grass, that might have been caught in a damp hollow and not dried like the rest of the crop. That was a potential fire risk once it was compressed into a bale and surrounded by dry hay.

But it takes a very exact set of circumstances to set it off. Too much air and the heat is carried away before ignition. Not enough air and lack of oxygen slows any reaction.  I read a Uni study a while back where the students studied combustion in varnish soaked rags, trying different combinations of rags, tins and varnish. Of about 40 experiments, 3 of them actually caught fire. Which proved the phenomenon is real, but wont always happen.

With drier sawdust it's more likely to be hot metal fragments from a machinery or electrical failure getting blown into the stack or bin. Or welding, smoking, hot exhaust pipes etc.  Not true spontaneous combustion, but the end result is the same.

Either way, fire is a real risk around any sawmill.
Weekend warrior, Peterson JP test pilot, Dolmar 7900 and Stihl MS310 saws and  the usual collection of power tools :)

Carson-saws

I know that mulch piles can reach over 120 degree F and was a disagreement or still may be in regard to quarantine of Ash.  The mulch producers say the internal pile heat is enough to destroy the pest yet was not allowed to be shipped outside "QZ"  Maybe Ron Scott has some insite on this.  I have seen "smoldering piles" as well and know that in a woodshop with a dust collection system it is recommended to "ground" the tube to help avoid combustion through static ignition. 
Let the Forest be salvation long before it needs to be

KirkD

Quote from: Chuck White on June 16, 2016, 12:28:42 PM
Quote from: Hilltop366 on June 16, 2016, 11:24:12 AM
I do remember my grandfather spreading salt over the loose hay in the barn, suppose to be it helped prevent spontaneous combustion.

Up here in this area most will spread salt on top of baled hay as each tier is stacked in the barn.
I have done hay all my life and if hay is so wet when put in bales that it needs salt it should not go in a barn. It will still mold and not be good feed.
Wood-mizer LT40HD-G24 Year 1989

KirkD

We have a Kingsford Briquettes factory here in Springfield and they have a dozer and a hoe working the piles all day turning them to keep them from catching on fire and dry it out. Same thing at the forest products plant that sells bark and sawdust for landscaping.
Wood-mizer LT40HD-G24 Year 1989

lewis

I worked in a alder mill and the sawdust pile would catch on fire every sept.but the pile was 20-30 feet deep

thecfarm

Salt? New one to me. We put hay up for many years. Let it dry in the field and all is good.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

Bandmill Bandit

I did have a bit of a left over straw bale stack burn one summer that started on its own but it wast a real big stack. Might of had around 500 or so bales left in the stack.

It was far enough away from everything so we just let it burn.
Skilled Master Sawyer. "Skilled labour don't come cheap. Cheap labour dont come skilled!
2018 F150 FX4, Husqvarna 340, 2 Logright 36 inch cant hooks and a bunch of stuff I built myself

Farmerjw

What I worry about in my woodshop is sucking a piece of metal through the dust collector (ie: nut, bolt, washer, screw, etc.)  It could cause a spark going through the blower, but it could also land in the sawdust red hot from being banged around and this would be a great catalyst for a fire.
Premier Bovine Scatologist

Czech_Made

During my mandatory military service - standing guard protecting socialism against the aggressive NATO  ;D ;D ;D - we had a pile of coal dust that got rained on.

Dumb officer - there were some real idiots in the Czechoslovakian army - made soldiers move that pile, about a truckload, to a coal bunker.  In a day, thick smoke was coming out of the coal bunker.  When we were shoveling it out again, there were numerous pockets of smoldering/burning coal. 

ppine

Fine sawdust in the air is also an explosion hazard.

I worked at a coal mine in AZ which had a fire for 2 years.

Some plants only use compressed air tools to avoid electrical sparks.
Forester

Percy

I was told by an old timer that alot of sawmill fires are started by the sawmill loan papers and the insurance policy rubbing together in the drawer  ;D
GOLDEN RULE : The guy with the gold, makes the rules.

Czech_Made

Quote from: Percy on June 17, 2016, 08:33:49 AM
I was told by an old timer that alot of sawmill fires are started by the sawmill loan papers and the insurance policy rubbing together in the drawer  ;D

You don't say  ;D ;D

Ron Wenrich

Quote from: ppine on June 17, 2016, 08:23:56 AM

I worked at a coal mine in AZ which had a fire for 2 years.


We've had a mine fire burning in Centrailia, PA since 1962.  The government bought most of the homes in the town and tore them down.
Never under estimate the power of stupid people in large groups.

Magicman

If I had to work outside this afternoon I am sure that I would spontaneously combust.   ::)
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

Percy

Quote from: Magicman on June 17, 2016, 01:44:18 PM
If I had to work outside the afternoon I am sure that I would spontaneously combust.   ::)
:D :D
GOLDEN RULE : The guy with the gold, makes the rules.

Kbeitz

Quote from: Ron Wenrich on June 17, 2016, 11:52:24 AM
Quote from: ppine on June 17, 2016, 08:23:56 AM

I worked at a coal mine in AZ which had a fire for 2 years.


We've had a mine fire burning in Centrailia, PA since 1962.  The government bought most of the homes in the town and tore them down.

Pictures of Centrailia, PA ... I live just a few miles from there...



 



 



 



 



 



 


Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

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