Spontaneous oily rag combustion, hood grease fires

Awl --

Any thoughts on this, esp. on how likely this all is? Anyone with personal experience?

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says Yea on the possibility, for *uncovered* Linseed oil soaked rags. Also large Q's of pistachio nuts -- no foolin....

But what are the likelihoods? wrt to various oils, grease? Motor oils?

A very cautious shop-type friend says this happened to him, burned down part of his house.

Grease fires in vents are a little more understandable, given their proximity to exhaust heat and poss. sparks, but still seems like a long shot. But something to consider, esp. in an old house. I wonder what the buildup is like, with good modern filters. With old mesh washable filters, I saw no buildup in vents that had to be over 30 years old, altho not sure of the cooking hours on these vents.

But I do know that if I were freezing in the wilds with my oily rags and kitchen grease, hell would freeze over before I would be able to ignite this stuff. heh....

Reply to
Existential Angst
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A problem generally with "drying" oils -- oils that oxidize and generate heat. Especially the nut- and seed oils used for finishing wood; most vegetable oils, fats, and some others. The recommended storage for linseed-soaked rags used to be to keep them in a covered metal can.

Reply to
Ed Huntress

Only spontaneous combustion I ever saw with my own eyeballs was a big mound of bagged grass clippings, that were cut a hair on the damp side. A day of Indiana sun cooking them, then around 10 pm that night, a neighbor pounding on the door....

I'm sure it occurs elsewhere, otherwise they wouldn't sell all those red safety cans with the spring lids.

-- aem sends...

Reply to
aemeijers

The only factoid I remember. Is that petroleum oils are exempt from this. It's only natural oils like linseed which are a problem. Cooking grease is a maybe. Motor oil and wheel berring grease, not an issue.

Reply to
Stormin Mormon

I've heard that spread out flat is acceptable also. Such as hung over a clothes line, with plenty of exposed surface.

The metal can sounds like it would keep the heat in. Being actually more likely to combust.

Reply to
Stormin Mormon

On 12/9/2009 9:08 PM Stormin Mormon spake thus:

No. The reason one puts oily/solvent-soaked rags in a covered can is so there's not enough air to cause outright combustion, even if they do get hot enough to spontaneously do so.

The only time I witnessed spontaneous combustion was waaaay back when I was a temp worker at Standard Brands (anyone remember that chain?) in Tucson, when someone had thrown something oily or, more likely, soaked in paint thinner, into a dumpster, and it started smoldering. Of course, it gets pretty hot there. As someone else noted in this thread, not likely to happen in cold weather (but maybe it can happen even then?).

Reply to
David Nebenzahl

I wonder what the

Decomposition builds heat. Just about anything can burn. Leaves, wood chips, oily rags and etc. It mostly depends on the quanity and how they are stored. Most people don't have the large quanities stored that is required to produce enough heat to actually catch fire. But, keep in mind that it DOES happen.

Also, glass bottles that are laying aside a road on a sunny day can start a fire too. Ever fry and ant with a magnifing glass? It is rare, but it does happen.

Hank

Reply to
Hustlin' Hank

Thrown out of a hotel dining room once because of a fire in the cooking hood vent, after the wine arrived but before the food, so that was ok...

Never seen LInseed oil soaked rags SC, but the containers always bear the warning. I tend to burn any rags soaked in the oil after once off jobs to prevent surprises, and they do burn rather well.

Reply to
Steve

The idea of the can is to keep oxygen out, which prevents the generation of heat in the first place. Just slowing it down is enough. Spreading the rags out to dry is OK, too.

The only places I've run into this were the annual re-oiling of the deck on my uncle's 42-foot fishing boat, and varnishing a classic small yacht that was moored in the same place, which I used to help with every spring. It was

100% varnished brightwork above the gunwale. Traditional varnish is full of drying oil, too, and it's a bigger danger than linseed, because it usually contains drying enhancers that generate more heat. In both cases we had a couple of big instituional-sized potato chip cans that we used to hold the clean-up rags.
Reply to
Ed Huntress

Hay Barns are famous for burning down shortly after a load of slightly damp hay is loaded in.

When I was young, we had a house fire that started via spontaneous combustion of damp clothing in a metal clothes hamper that was installed flush in a wall. That was when I heard the term for the first time as my father was informed by the fire department as to the cause.

Reply to
salty

The metal container has to be one that shuts tightly to also deprive it of oxygen. Being metal, it would also contain any fire that started.

Reply to
salty

I have read of damp charcoal briquets stored in a locker on a boat spontaneously combusting.

Reply to
salty

Oxygen deprived -- that does make sense. Thanks.

Reply to
Stormin Mormon

Fires all the time in composting operation north of here for mushroom farmers.

Reply to
Frank

The culprit is oxidation of unsaturated fats:

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Unsaturated means a pair of carbon atoms double-bonded to each other rather than being connected by a single bond and having hydrogen attached to the other bonds. The double bond is less stable and oxygen can attack it, slowly at room temperature and faster as it heats up. If enough oxygen gets in but the heat doesn't dissipate the reaction can run away.

This dismisses cholesterol concerns and I don't believe all of it, but it does describe unsaturated fats in simple terms.

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Natural products are exempt from strict regulations on unproven advertising claims.

jsw

jsw

Reply to
Jim Wilkins

Right. That's the story for oils that will oxidize. You'll notice that several other posters have mentioned other things -- damp laundry, compost, etc. That's something else. That's biological decomposition, usually from bacteria. That generates plenty of heat, too.

Speaking of which, I put some high-nitrogen fertilizer in my compost pile on Sunday, because it's almost all leaves and it wasn't getting warm enough to suit me, and this morning it's sending up a plume of steam. I haven't stuck the rod into it yet to see how hot it is inside, but the steam usually means that the rod will be too hot to touch.

That can start a fire, and that's considered to be "spontaneous combustion," too. If it's really hot I'll mix it up and spray some more water on it to cool it down. But I'll have to check it closely for a few days now.

Then there's certain weirdos we see on the poltical shows on TV. I expect to see some of them burst into flame at any moment. That's another spontaneous combustion mechanism altogether -- more like being struck by lightning.

Reply to
Ed Huntress

One of these days I'll have to regale all with stories from my days as a fire investigator. The serial kitty litter arsonist that wasn't or the working fire IN the swimming pool.

Reply to
Kurt Ullman

Sure, work them in here. They sound like good ones.

Also, I'd like to hear someday from one of the firefighters who helped extinguish the Cuyahoga River fire in 1969. Putting out a burning river must stick in one's memory.

Reply to
Ed Huntress

Unsaturated vegatable oils will oxidize and if soaked into flammable materials and bulked up, can raise temperatures enough to ignite. Avoidance is to put oil-finish soaked rags in water, put them in an airtight container or spread them out so they aren't bulked up and let the material dry out. Petroleum oils don't have the same chemical structure.

I've not seen anything about grease fires in home cooking vent hoods, although some numb-nut left a fryer on the stove one night and caused a mass-evacuation of the apartment building when it caught fire. I have seen the aftermath of a hood fire in a restaurant, a BK about a mile up the road went up in flames when the fryer hood caught fire, burned the roof off. Took about a year to rebuild, too. Modern restaurant hoods are supposed to have wash-down features and extinguishers, not sure what happened at that place.

Stan

Reply to
stans4

Yes There are two different processes being discussed. When the hay in a barn or compost heats up it is due to thermophyllic bacteria or fungi. Without those critters it wouldn't happen. And the process in order to work needs a certain balance of nitrogen and carbon containing material. So piss on some rags and put them in a pile and you might get some heat but just wet rags won't work. Once the temperature and and volume reach a critical mass the oxidation of simple hydro carbons (like methane) take over and the living critters that started the process get fried. Eventually (as in a barn fire) the heat gets to the point all the hydrocarbons start to burn. Varnish soaked rags are strictly chemical reactions (no living critters involved).

Yeah I have tried high nitrogen fertilizer (30-10-10). I found it doesn't produce as good results as 10-10-10. No real proof of that other than how it seems to work better in the garden. Typically in the spring I can take a half a dozen bales of hay and a half pickup load of wood chips/bark/sawdust and if I get the mix just right I can turn it into nice black compost in about 10-14 days (turning it over every 3-4 days).

-jim

Reply to
jim

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