Chimney fire and CO2?

I don't have any first hand experience with CO2 fire extinguishers for chimney fires, so take whatever I say with a grain of salt.

My guess is that if you can flood the firebox with enough CO2, such that the chimney fire is deprived of oxygen, then of course the fire will go out. The problem I anticipate is sustaining the oxygen deprivation. The chimney will be drawing like crazy when it gets hot enough for a chimney fire. Many people report it sounding like a freight train! So as soon as you stop the CO2 flow, you'll get a rush of air up the chimney and the fire will be likely to take right off again.

This thread does raise the question of what is the best course of action if you have a chimney fire? Maybe a CO2 extinguisher is a good option. I don't know.

It makes a hell of a mess but stops the fire. Shut off all air supplies to the fire after while you run for a bucket of water.

Dont ask me how I know - new ext was around $40 as well.

bob

Co2 would not be efficient in this scenario. It might certainly bring it under a bit more control, but here is the issue. Co2 extinguishers are an instantaneous thing, so once you stop putting in co2 that's it. The coals, and anything that has started to burn and is still hot will more than likely ignite again in a very short period of time. This is why you don't see people selling co2 extinguishers for general home use, sure they don't make a mess, but they have their limits. Others types of extinguishers actually break the chemical reaction or slow it down enough to be effective, and keep working to an extent even after you stop applying it.

IMO your best fire extinguishing agent to have on hand in this case is 1) those sticks they sell you can toss in the stove, 2) a bucket of sand or ash, 3) an abc dry chemical fire extinguisher.

Personally I just have an abc fire extinguisher for general house use. Sure it will make a mess, but its better than the alternative.

English BoB said:

It makes a hell of a mess but stops the fire. Shut off all air supplies to the fire after while you run for a bucket of water.

Dont ask me how I know - new ext was around $40 as well.

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I am assuming the mess was from the co2 extinguisher blowing the ash everywhere? the co2 extinguisher it self leaves zero mess.

TheRambler said:

I am assuming the mess was from the co2 extinguisher blowing the ash everywhere? the co2 extinguisher it self leaves zero mess.

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Correct - plus hot coals with the ash.

Do not leave the door ajar when starting the fire and leave the room.

bob

I did experience a chimney fire in an old traditional fireplace. It was scary as hell. I dumped a bucket of water on the fire and that worked to put it out. Spent the rest of the weekend cleaning up the resulting billow of ash that got EVERYWHERE.

I have a couple bags of the commercial "throw this in your fire and it will kill it all" stuff I keep near the fireplace. I assume it chemically creates an environment which starves the flue of oxygen.

You will crack your stove using water or co2 extinguisher, CO2 comes out extremely cold (like frost bite if it gets on you cold)

Ohhhhhhh . . . a topic that I know quite a bit about . . . huzzah.

I would not use a CO2 fire extinguisher on a woodstove fire.

a. CO2 extinguishers are typically not rated for an A-class type of fire (i.e. ordinary combustibles such as paper, plastic . . . and wait for it . . . wood.)

b. CO2 extinguishers do not have the penetrating power -- as mentioned once you stop applying CO2 if there is still oxygen, fuel and an ignition source hot enough to light the combustibles it will re-light.

c. All extinguishers have a certain amount of force behind them to expel whatever agent is in the can so to speak . . . CO2 extinguishers have a decent amount of force though and there is a good chance hot coals, ash, smoke, etc. could spill out and travel a fair distance in your home by using this extinguisher . . . and to a lesser degree . . . other extinguishers.


Me . . . I would avoid having these types of fires . . . and before anyone says "Yeah, but FirefighterJake that's easier said than done. What I need to know is what to do if I have a fire and need to put it out. Just saying, don't have one doesn't answer the question as to what to do." True . . . but then again if you run your woodstove right (i.e. watch the temps, don't load 'er up with small splits, don't leave the air control open all the way and then wander off to go watch TV, clean your chimney on a regular basis, etc.) . . . truthfully you really shouldn't need to worry about putting out a fire . . . or at least it should be a very rare event.

Now I cannot lie and say I've never had an "Oh crap. That fire looks like it is getting into the red zone" moment. I've had some hot fires (but no "This will surely burn my house down" types of fires) . . . but I have never had to extinguish the fire. What I have done is severely restrict the incoming air using a piece of aluminum foil over the incoming air, I've cooled down the stove and flue with a fan blowing directly on to it to wick away the heat and watched it very, very carefully as the heat has come down to "OK I can now go to sleep" levels.

OK, so you're still unconvinced and really want to know what to do if you have to kill the fire in your stove.

a. Sand or ash . . . fire needs oxygen. Suffocate the fire by dumping a whole bunch of ash or sand on it and usually it will dampen right down or go out.

b. Open up the door . . . this effectively turns the high efficiency wood heating appliance into a relatively inefficient fireplace.

c. If you really, really, really want to stop the fire I would use an ABC rated dry chemical extinguisher . . . but just be very miserly with the amount of powder and force you use to extinguish the fire and watch to make sure no hot coals or embers go skittering out the open door and on to or under any combustibles.


I am not a big fan of water . . . well I mean I like drinking water . . . especially the water in my home . . . I am not a big fan of Poland Springs Water . . . but this is a discussion for another time. I especially do not like the idea of folks throwing water on to a fire in their stove for two reasons:

a. The possibility of thermal damage. Water when heated turns to . . . basic chemistry here folks . . . steam. And does anyone remember which has more volume: water in the liquid form or gaseous form? Gaseous form? The concern here is that both the expansion of the water when it turns to steam and quick change in temp could result in damage to the stove or chimney. When we put out a chimney fire in a traditional brick and mortar chimney with a clay liner and use water . . . 9 times out of 10 the chimney is toast . . . why . . . thermal damage from the steam conversion and thermal shock.

b. Stoves and chimneys can be replaced though . . . people . . . not so easily . . . although my wife did replace her ex-husband with me so I guess technically people can be replaced. So nix that last part . . . however . . . the possibility of being burned from the conversion of water in its liquid form to steam is a very real possibility . . . and burns hurt. I've never been burned on the job, but I did get a wicked bad burn while in Freeport . . . not the Freeport of LL Bean fame though . . . the Freeport of Bahamas fame . . . and let me tell you a nasty secondary burn is not much fun.

To add to the above-when water changes to steam it expands approx 1650 times it's original volume.

I agree with everyone here that CO2 is not a good choice, it will likely knock the fire out, but it will instantaneously restart. I do see people talk about chimney fires, then the talk is bout the wood stove fire and how to put it our, not how to put out the chimney fire. You can knock out the chimney fire without fully killing the stove fire, and you can kill the stove fire totally and still have a burning chimney.

To use a dry chemical extinguisher to put out a chimney fire, aim it up the chimney, not at the fire in the stove. The draft will draw the chemical up into the chimney. Empty the extinguisher into the chimney. Close the door, close the draft. Often times this is all it takes if you catch it in time and/or if there is not an overabundance of buildup in the chimney.

I know people here advise against using water to kill the fire, but water has been used to put out fires for a very long time. Waded up newspaper, soaked in water quickly, tossed into the stove, shut the door, works great. The stove heat evaporated the water to steam, it rises into the chimney and the fire is knocked out. I would not recommend a bucket of water tossed into the stove for a number of reasons.

motoguy said:

I have a couple bags of the commercial "throw this in your fire and it will kill it all" stuff I keep near the fireplace. I assume it chemically creates an environment which starves the flue of oxygen.

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I have a chimney. You light it like a road flare. Seames crazy that you need to light this, and then throw the whole thing in the fire.

I like the bag idea, simple, anyone can do it. What are they called? Any one try one?

CHIMFEX.
http://www.chimfex.us/about-chimfexr.html

I keep a few around "just in case".

bholler said:

for an over fire yes for a chimney fire absolutely not.

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Yes . . . thank you for the clarification . . . this would be a very, very bad thing for a chimney fire.