There is a safety standard for managing flour dust in places like bakeries for spontaneous combustion reasons: https://www.nfpa.org/product/nfpa-654-standard/p0654code
replyThis can happen to mulch as well if it's left in a very big pile for a long time.
replyRegularly happens to the same pile of mulch at a lot in Boston. No idea why they have been allowed to keep storing it.
replyhttps://www.universalhub.com/2026/mulch-fire-brings-all-jake...
If you have a big enough pile of organic matter, exothermic decomposition can lead to fire, if the conditions are right.
replyCommonly happens in grain silos, mulch piles, etc.
It really doesn't take that large of a pile of grass clippings or wood chips to get some steam coming out and a lot of steam if you disturb the pile.
Yep, many hay barns have caught fire because the hay was bailed while too wet and it is fermenting so vigorously.
replyHowStuffWorks used to be full of expert animations of automatic transmissions and helicopters around 2006 but they had a multipart article on spontaneous combustion, with anecdotes of 1890s people who retained too much ethanol.
replyHere it is: https://web.archive.org/web/20090510082422/http://science.ho... (3 pages, and refs)
replyHuman spontaneous combustion is a silly myth. Other kinds like oily rags and apparently fishmeal are very real.
replyMaybe it was more of being a middle schooler than a wider social phenomenon, but silly myths got a lot of play in the days before Google!
replyArguably even more now…
replyGrain dust and flour also come to mind. Essentially anything with the appropriate fuel/air mixture can combust, often explosively, even if we otherwise think of it as food!
replyThose events aren't spontaneous combustion, an ignition source is needed to cause a dust explosion with flour, grain, or sawdust. Spontaneous combustion of something like linseed oil happens with no external ignition source. Spontaneously combustible substances undergo exothermic reactions in normal conditions, e.g. when drying, curing, being exposed to air, or similar. They have low enough flash points that their own heat is enough to cause ignition, which is why you never hear about concrete spontaneously combusting despite having an exothermic curing process.
reply> which is why you never hear about...
replyIt might help that concrete is not combustible to begin with. Vs. (say) linseed oil definitely is.
Exactly. Grain dust is very dangerous because a small spark can make it explode, but the spark is absolutely necessary. If you leave a pile of oily rags in your garage and wait a few hours, your house could burn down. No spark needed.
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