Compost igniting?? Is it really possible?

Question

Has anyone heard of a compost heap heating up so much it actually starts fire? Seems pretty unlikely to me, but with the ammonia coming off of it, who knows...

Answer 1

I've never heard of a compost pile doing it but it is definitely possible. Around here hay is a problem. If farmers and ranchers bale or stack hay when it is green or wet, the bale composts in place and the resulting methane can be ignited by spontaneous combustion or even static electricity generated by the wind blowing through tall grass next to a bale. If we see a bale 'smoking' (actually water vapor) in the cool morning air we move them to a patch of bare ground or feed them immediately to the hogs (they love it but it can make cattle and horses sick) After machines (engine exhaust and overheating bearings etc.) and lightening it is the third major cause of fire in our area, ahead of man made. RScott

Answer 2

Yes, it's true. There's a lot of heat and gas made as byproducts of the decaying matter.

let me share my story....

bought a compost "machine" (really a plastic bin) put composting stuff in it. One day, my husband is smoking fish and decides he's gong to put the ashes (which he swears are totally not even hot or burning) from the smoker into the compost pile to help save the earth (unbeknownst to me of course).

Next thing I see is a bunch of smoke outside and I ask him what's that? "oh, just the smoker". Uh......No it's the compost bin totally up in HUGE flames melting out vinyl fence too. I'm shocked it didn't catch the onto the house because it's near the house and that's how big the fire was from a "little" compost pile.

He didn't think that would happen. Dummy....

Answer 3

Yes, spontaneous combustion is the most common cause of compost fires.The combination of organic materials with low moisture contents in a large unmonitored pile with limited air exchange is a prescription for spontaneous combustion.
Biological activity generates heat within organic matter. Its temperature is controlled by heat loss through evaporation of moisture, aeration and sometimes mechanical turning. The moisture content of a pile may become too low, reducing the effectiveness of the material to cool through evaporation and thus causing the temperature to rise above above 70 to 80°C (the point at which microorganisms die or become dormant, and the biological heating stops).

The critical moisture range that supports spontaneous combustion is roughly 20 to 45 percent, while the optimal range for composting is typically 50 to 60 percent. Large piles may inhibit air exchange, therefore not allowing the material to cool.

Typically, composting materials ignite at temperatures between 150 and 200°C. As the temperature rises, the speed of temperature increase also rises. For example, heat is generated about 16 times faster at 100°C than at 60°C because the reaction rate approximately doubles with each 10°C rise in temperature.

From that point to the temperature at which organic materials ignite (150°C and higher), heat-releasing chemical reactions take over. These actions include chemical oxidation, slow pyrolysis (chemical decomposition brought about by heat) and condensation of gases within dry charred particles.

Compost fires can also be caused by lightning strikes, heat from equipment or vehicles, sparks from welding activities, wildfires and arson.
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex10721
Hope this was helpful.

Answer 4

Yes, it is possible. Temperatures of composts can get very high and wind and high ambient temps. These can help raise internal temperatures within a compost pile to the ignition point. Generated methane can ignite, not so much the ammonia.

Answer 5

Certainly possible. Most of the dancing devils in the marshes are small balls of methane fire called fire damp travelling from gas pit to gas pit.

I have seen a pile of waste iron powder from a metallurgical factory catch fire after remaining damp for a few days. The heat of chemical reaction, the insulating nature of the heap, and methane cause it.

Answer 6

Its called spontaneous combustion I have seen it occur in a hay stack when the hay stored was too green so yes it could happen.~~

Answer 7

Angel had it right... it has VERY little to do with the gasses of decomposition... it's the internal temperature reaching flash-point.

Answer 8

yes it is possible.