WHY will hay burst into flames, if it gets wet, WITHOUT you having to light it with a match? I mean, what is the chemical process, that takes place(is it a reaction with the moist air, decaying straw, and such, that creates an exothermic reaction, and self-ignites the hay?) If anyone can answer this question, in SCIENTIFIC terms, please enlighten me(not just the old "spontanieous combustion", I KNOW that, but I want to know WHY.) I did not know that straw was pyrophoric, like phosporous is(meaning that it self-ignites in air).
A question for farmers OR chemists..
- Thread starter rca2000
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A little bit of farmer in my background, so I'll take a shot, though perhaps not as technical as you'd like -- when hay is wet, it can begin to ferment, a process that creates heat, thus potentially leading to combustion. Same thing can happen with silage. Never heard of this happening with straw, though I guess it could. When I worked on the farm as a kid, if we were stacking hay bales that were put up slightly wet, we'd spread salt between layers of the stack to absorb the water and reduce the likelihood of combustion.
There's a more technical explanation here:
www.nrsl.umd.edu/extension/ publications/haycombustionp1c.pdf
There's a more technical explanation here:
www.nrsl.umd.edu/extension/ publications/haycombustionp1c.pdf
cruisaire
PGA and Rainwater!
I'm neither a farmer nor a chemist, but the "fire triangle" says you need a fuel source (possibly methane from decaying hay), oxygen, and a spark source (in this case perhaps just the built-up heat that occurs as bacteria and other organisms are "working" in the hay). I know lumber yards wet down large piles of raw poles during warm weather and mulch piles are pretty hot inside from all the microbial work going on.
mhardy6647
Lunatic Member
yup, due to heat from microbial fermentation and/or chemical oxidation. Pile up some grass clippings in a big ol' heap and leave it for a while. Then, take your pitchfork (you DO have a pitchfork, right?) and work your way to the center. See how warm it is (not to mention how good it smells)?
I am told that in the Northern SF bay area (where Kingsford hails from) that the piles of peach pits used to make charcoal were always smolderin'.
I am told that in the Northern SF bay area (where Kingsford hails from) that the piles of peach pits used to make charcoal were always smolderin'.
merrylander
AK Member
In my youth I helped my cousin on his chicken farm. I can remember moving a pile of chicken manure+straw away from the building. This was December in Quebec and we were stripped to the waist and still sweating. The strong ammonia smell sure cleared your sinus'.
The fun thing about corn silage was in the spring. By this time the cows had eaten almost all the silage and the farmer was getting down to the stuff on the bottom. What with fermentation over the winter months the cows were not sure if it was silage or corn liquor. Funny as heck to watch a half gooned cow wander around the pasture.
Rob
The fun thing about corn silage was in the spring. By this time the cows had eaten almost all the silage and the farmer was getting down to the stuff on the bottom. What with fermentation over the winter months the cows were not sure if it was silage or corn liquor. Funny as heck to watch a half gooned cow wander around the pasture.
Rob
Randy Bassham
Active Member
IIRC the problem usually happens when the hay is put up too green without curing. The heat comes from decomposition and if it is wound or stacked too tight the heat has no place to go and keeps building until it's hot enough to light off. BTW the same thing happens when you leave a pile of rags saturated with organic oils or solvents such as turpentine or linseed oil they'll heat up pretty quick and catch fire. I don't think the problems happens with rags soaked in motor oil or grease. A few years ago I was out on the road and saw a large round bale blazing away and at least a half a dozen smoking and about to catch out in a large field, the weather was cold and rainy at the time..
bgadow
Me & My TV
Manure sheds, used around here to store chicken manure, often catch fire. Rumor has it that you could hide a dead body in that pile and it would be gone forever, eaten up bones & all by the bacteria or whatever.
The job I had shoveling chicken manure on the third story of a 3-story chicken house,well, not a dream job for sure. It was hot not because of the manure but because it was August. I can tell you that in the corners there just wasn't any oxygen that I could tell, just pure ammonia. There honestly wasn't anything there to breath.
The job I had shoveling chicken manure on the third story of a 3-story chicken house,well, not a dream job for sure. It was hot not because of the manure but because it was August. I can tell you that in the corners there just wasn't any oxygen that I could tell, just pure ammonia. There honestly wasn't anything there to breath.
The process is known as spontaneous combustion, and frequently occurs in hay piles as well as home mulching piles.
The hay starts to decompose, which releases a small amount of heat. If the hay or mulch is loosely packed, this heat can easily escape. If the hay is tightly packed in a thick layer or pile, the heat is trapped, and slowly builds up. It can actually get to the combustion point, and the hay will burst into flame.
That's why hay bales are usually stacked in a staggered pattern to allow for air circulation. The greener the hay, the worse the risk.
The hay starts to decompose, which releases a small amount of heat. If the hay or mulch is loosely packed, this heat can easily escape. If the hay is tightly packed in a thick layer or pile, the heat is trapped, and slowly builds up. It can actually get to the combustion point, and the hay will burst into flame.
That's why hay bales are usually stacked in a staggered pattern to allow for air circulation. The greener the hay, the worse the risk.
