Possible Wiki Item - What To Do With A Runaway Stove

BrotherBart said:

kd460 said:

Getting into this late, but, I think a CO2 extinguisher may help. At least for those stoves that have the air inlet accessable. Blast the CO2 into the air inlet to calm things down (similiar to what Gibbonboy mentioned).

This happens to be the only way to shut down a runaway diesel engine as well. Some even have a C02 injected system plumbed into the air intake in case of a runaway.

What about a simple test? Get a fire going good and hot (within reason) and test your unit by dampering it down. See what happens. At least you will have a general idea of whether dampering down may work or not in case of a runaway. KD

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Story about the Diesels. I used to work for a truck leasing company. Sitting in the Service Manager's office one day I hear a V-8 Detroit Diesel start up right outside the door. The RPMs started up and just kept going. It ran right through the governor and never missed a beat heading for explosion time. The faster it went the more air that Roots blower packed into it. The old Service Manager took the cigar out of his mouth, calmly stood up, walked out in the shop and picked up a new bundle of red shop rags and tossed it, still tied in a bundle, into the intake pipe. He then walked back in his office without even looking back.

That sucker stopped dead.

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Yes, I have heard of this as well. Don't think the turbo, the intercooler, the intake and valves/cylinders liked all those pieces of cloth either-but it works! Probably that old Detroit was a naturally aspirated 2 stroker without an intercooler. Those suckers can actually run backwards! Sounds like this guy has dealt with a few runaways in the past!

Found an interestig article here: http://www.backwoodshome.com/articles/frandsen36.html that states using rock salt for a chimney fire? I wonder if this would work for a runaway fire as well. KD

Really great thread - it's good to know ahead of time what to do.

I'm thinking that the sand idea sounds the easiest and the least risky - what do you suggest for delivery? I assume most of us aren't keeping shovels and playground sand on our hearth..


How does a paper lunch sack full of sand sound? open door, toss it in and close the door? bag burns and the sand spreads out?

-TNB

BrotherBart said:

Turner-n-Burner said:

Really great thread - it's good to know ahead of time what to do.

I'm thinking that the sand idea sounds the easiest and the least risky - what do you suggest for delivery? I assume most of us aren't keeping shovels and playground sand on our hearth..


How does a paper lunch sack full of sand sound? open door, toss it in and close the door? bag burns and the sand spreads out?

-TNB

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I now have two boxes of baking soda near each stove. Two for a buck at the dollar store.

This thread was inspired by my old insert developing a crack in the firebox and running away twice in the same week last month. Why twice? The patch broke. I now have lots of baking soda, a new stove and the offending party is sitting on concrete blocks out back. A four cubic foot fire box full of oak, a glowing stove top and pipe and a thermometer pegged over 1,000 is not a pretty sight.

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BB what did you do when you realized that it was running away?
i've had a few 800 degree pipes with crackling but i shut the primary and secondary air and closed the baffle and wait fo it to drop.

if i seen over a 1000 i think i'd have to go wipe after that. this usally happens when i load it up before bed. then you have to wait....... then you don't get a good night sleep.

I think Elks sand method would be the safest.Last year I really had one crankin towards 800 in my f3cb and I just opened the door for maybe 30 seconds than shut the air off,shut the door and i think it had a kind of fireplace effect where the cool air draft from the room chased the heat up the chimney.I actually had to open her back up soon thre after-Pat

Hi guys...I have to weigh in on this even though I'm a newbie. Some of you responded to my cries for wood stove help a couple of weeks ago when I was having a runaway problem w/ my Jotul Oslo. (Love this stove!)...

Anyway, my nerves are much more steely now and the stove and I have come to some sort of understanding. That, and I've stopped burning either 15 year old firewood that had been stacked in the back room since before my mom owned the house. (I'm not kidding, that stuff was that old and drier than a popcorn fart.) The other thing that I stopped burning was a stove full of 8 year old black locust. Geez, it's a wonder we got through that week unscathed.

My newbie moral of the story is - burn the right thing and the stove becomes MUCH more predictable and steady. No more zooming up to 750+ from 350. I get a nice steady 500 - 600 and I'm tickled.

Thanks to all who helped me out the other week. You guys are champs.

Shut every air opening completly.

-Mike

kd460 said:

Getting into this late, but, I think a CO2 extinguisher may help. At least for those stoves that have the air inlet accessable. Blast the CO2 into the air inlet to calm things down (similiar to what Gibbonboy mentioned).

This happens to be the only way to shut down a runaway diesel engine as well. Some even have a C02 injected system plumbed into the air intake in case of a runaway.

What about a simple test? Get a fire going good and hot (within reason) and test your unit by dampering it down. See what happens. At least you will have a general idea of whether dampering down may work or not in case of a runaway. KD

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what about plumbing a CO2 tank into the cold air intake? The CO2 tanks for kegerators and such are somewhat expensive to buy, but really cheap to recharge.

A common house hold item is salt.
It works well to help put out fires. Of course clean up after and the affects on metal are not welcome.
A not so common item is a roadside flare.
I believe I heard of these being able to put out fires. I do not know if this is true, perhaps someone here knows?
Maybe it is because it uses up the Oxygen. Or produces massive amounts of CO2. Either way it would have to be done carefully as depending on the type of flare it may bring it's own problems. Too much heat, it may not be able to be extinguished itself.
Of course some minor damage to the stove or cleanup is much better then losing the home to fire.
Long ago there was a form of Halon extinguisher used. Great idea. Put out the fire, saved the equipment, hurt or killed the people. But help was cheap, equipment expensive, just good business.

coldinnj said:

<snip>
Long ago there was a form of Halon extinguisher used. Great idea. Put out the fire, saved the equipment, hurt or killed the people. But help was cheap, equipment expensive, just good business.

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Those halon systems are still in use in some places, and in others have been replaced with CO2 setups that do the same sort of thing. Two places I've seen them commonly used are computer rooms and the engine rooms on commercial marine vessels. In both cases there would be serious problems trying to put out the fire with water or dry chemicals. Oxygen starvation is really the only effective way to go from the point of putting out the fire, not just saving the equipment. (and in a vessel or a high rise computer room, putting out the fire could also SAVE the lives of lots of "cheap help".

Every setup of the sort that I saw had safety features up the wazzoo to prevent accidental discharge, and "wake the dead" alarms to warn any people inside to evacuate NOW. The alarm was supposed to sound for at least 30 seconds to a minute before the system would dump, which was about twice as long as it would take to evacuate the space.

Yes it was possible to get killed by one of those systems, but it was not easy.

Gooserider

Aggreed Gooserider. I'm aware they are still in use. Especially in Computer centers. Just bringing up the point that originally, long ago, when they were first used the preventive measures to save human life were not taken or accounted for well. Now they are. The old decision that I would hope never to have to make and trust others who are better equipped to decide then I: Who or how many do we sacrifice to save the others. I give much respect to those who have to make that decisin and would not want to trade places with them.

BeGreen said:

My understanding was that halon is no longer made in the US by law due to stratospheric ozone depletion (16 times CFC11!). I have installed a couple small halon systems in boat engine rooms. We were told with the last boat (1991) that it would be illegal to manufacture after 1993. Is this not the case?

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There is supposedly no new halon being made in the US - I've heard there is at least some level of black market importing, sort of like the demand for Canadian toilets with the real 5 gallon flush that does...

However most of the halon on the market is considered "fossil" material that still exists since it was made before the cutoff date, but can't be readily disposed of. So they allow it to still be used in fire suppression systems since that effectively keeps it out of the environment unless there is a real fire and a system gets dumped. Since fires are (hopefully) very rare events, the amount released in any given year is to small to do appreciable harm (especially since most of the alleged harm was hype to begin with...)

Of course, as the available supply gets used up, the remainder gets more expensive, which drives the search for cheaper alternatives when possible. Nowadays, many applications use CO2 instead - it works almost as well and costs less...

Gooserider

I saw some "sicko" using Coal, near the Wood pile, to try and bait a Stove into becoming a Runaway recently. I had to use a Poker to chase him away. Boy did it make me Piping Hot. I wanted to Shake him & then kick him in the Ash. It really Stirred things up. The hole idea just Grates on me. Sorry ust wanted to Vent. If you see the guy take him out to the Wood shed and Split his lip. Well thats it for this quick Log on.

A CO2 system...

http://mb-soft.com/public/extingui.html

Two things would worry me about a CO2 system.

First is the potential thermal shock problem. CO2 when it dumps produces drastic cooling (even dry ice is possible), indeed it is often considered that it puts out fires as much by cooling as it does by displacing oxygen. Normally this isn't a big deal, but I wonder how much damage might occur to over heated chimney materials from being suddenly cooled several hundred degrees - and what this would do to the chimneys ability to preserve its fire integrity. Probably less of a problem in a steel chimney than a masonry one, but still an issue, and what would it do to a cast iron or soapstone stove body?

The second thing I'd be conserned about is whether the pressure generated by dumping a large volume of CO2 into the confined space of a chimney and firebox might also pose a problem to door hardware, window glass and the like....

I haven't done any testing, but those are items that would make me nervous.

I like the idea earlier of having some containers of powder from a dry-chemical fire extinguisher to toss into the stove. I had a fire-extingusher that had lost pressure, so I took it apart and dumped the powder into a couple of quart yogurt containers (note, do this outside, it's MESSY!) which I then taped shut and put near the stove. I figure if I get a runaway I can open the door long enough to lob those containers in, then slam it. The containers will melt, and dump the powder on the fire.... The stuff is light enough that the draft will also carry it up the flue and put out anything in the chimney, without pressurizing or over cooling the fire system.

Hopefully I never get to test this, but it should work!

Gooserider

CO2 extinguisher is a poor choice for wood fire extinguishing. CO2 gas has almost no cooling ability and the gas is quickly carried up the chimney. ABC dry chem, is a better choice but the blast of coals from either would be dangerous when the door is open for someone not experienced.

The best choice would be loggers dry chem toss bags. Bailey's sell them, they are dry chem in a bag that you throw at a fire.

Next thing, I've only ever run old air-tights so if they get to 1000 F or so I will turn the air vents down. I try not to go over 900 F flue temps and normally stay about 600 F, never have glowing stove or pipe at those temps (only at 1000). I have had a little air tight red hot including the cast doors by burning pine scraps at a building site. I unfortunatly didn't have a thermometer on that one but I suspect it was pretty darn hot.

My current install has 20 ft of single wall leading to 6 ft of 2100 F insulated stuff in a straight shot all in heated space. The stove has a 7" outlet but I installed a reducer with the 6" pipe because I knew the 7" could lead this stove into a runaway overdraft. I can open the stove anytime during a burn without risk to me and the stack temps drop quickly due to the air bypassing the fire and going straight up the stack.

Again, all old air-tight experience with tall high-draft chimneys burning hot fires, never have creosote except the cap.

slowzuki said:

CO2 extinguisher is a poor choice for wood fire extinguishing. CO2 gas has almost no cooling ability and the gas is quickly carried up the chimney. ABC dry chem, is a better choice but the blast of coals from either would be dangerous when the door is open for someone not experienced.

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I agree on the blast, and the idea that the CO2 would go up the chimney quickly... OTOH, I've used a CO2 extinguisher on a "training fire" and noticed that it did cool the material quite a bit - momentarily produced frost on it. The CO2 in an extinguisher is actually liquid, and cools greatly when it flashes from a liquid to a gas as you pull the trigger. Some of this comes from the cooling effect of gas expansion, some from the heat absorbed by the phase change from liquid to vapor. I don't know how much of that cooling would take place in a chimney fire, but I know that it's enough that if you dump a CO2 extinguisher at someone frostbite is possible.

My comments on the CO2 extinguisher was intended as a response to the pointer that .5a/B made, saying that I did't think it was an optimal solution. I will give that paper's author some credit for dealing with the blast problem - he proposed having a fitting on the pipe that would allow one to inject the fire extinguisher without actually opening the stove.

The best choice would be loggers dry chem toss bags. Bailey's sell them, they are dry chem in a bag that you throw at a fire.

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Never seen those, but there was a suggestion earlier in this thread about getting some dry-chem powder in a ziplock bag - presumably about the same thing. My plastic containers might be a bit slower to release the powder, but are less likely to get accidentally spilled, and mine have the added advantage of being free.... (I'm cheap! :coolgrin: )

Next thing, I've only ever run old air-tights so if they get to 1000 F or so I will turn the air vents down. I try not to go over 900 F flue temps and normally stay about 600 F, never have glowing stove or pipe at those temps (only at 1000). I have had a little air tight red hot including the cast doors by burning pine scraps at a building site. I unfortunatly didn't have a thermometer on that one but I suspect it was pretty darn hot.

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I've never had the stove glow, but I've had the pipe glowing several times. My setup has the rear vent exit stove going into a "T" that is hooked onto the bottom of the chimney liner My magnetic thermometer sits on the upright arm of the "T" right after the bend (call it the armpit...) This is much lower than reccomended but is the only accessible place I can put it. I try to run at least one load a day up to just shy of the redline on the thermomemter (~475*F) - sometimes it goes over. Things start to glow shortly after that. I don't know just how accurate that POS dial thermometer is, but it seems to agree roughly with when the snap switch on the flue exit from the stove turns the blower on.

My current install has 20 ft of single wall leading to 6 ft of 2100 F insulated stuff in a straight shot all in heated space. The stove has a 7" outlet but I installed a reducer with the 6" pipe because I knew the 7" could lead this stove into a runaway overdraft. I can open the stove anytime during a burn without risk to me and the stack temps drop quickly due to the air bypassing the fire and going straight up the stack.

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Again, all old air-tight experience with tall high-draft chimneys burning hot fires, never have creosote except the cap.

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This is a Pre-EPA semi-airtight, seemingly high draft chimney, about 28' of 6" liner inside a masonry chimney that is on the inside of an exterior wall. The only time I ever get smoke back is when loading the hot stove and I have the door open I will get some smoke out the upper spin damper - NOT out the door. The upper spin damper is about the same height as the top of the stove vent exit, and it ONLY smokes if the door is wide open. As soon as I shut the door, the smoke stops and I get heavy suction through both spin dampers, but especially the lower one.

Gooserider

I haven't read the entire thread so someone may have already said this, but I'll say it anyway: I've heard that if you get a chimney fire, one way to deal with it is to get your dry-powder fire extinguisher, open the stove door, discharge the ENTIRE fire extinguisher into the stove/flue, and then slam the door shut again. Supposedly the heat of the stove/fire will cause the dry powder (sodium bicarbonate) break down and release CO2 which wil kill the fire.

Throwing water onto a hot fire is a good way to get yourself killed because it releases a lot of hot steam that will cook you in about half a second flat. Firefighters know about this -- that's why they get down near the floor and spray "pulses" of a fine mist of water upward into the hot smoke to cool it and allow the resulting steam to dissipate before it builds up.

The extinguisher does get cold, and the air is cooled when discharging CO2 for all the reasons you list but the CO2 has little mass and is quickly evaparated from the area it is applied. One ends up chasing a fire around where the dry chem stays in place on an area. A stove has quite a bit of thermal mass. I'd still try it if it was all that is available.

Unfortunately water is the best agent to be used but it has to be applied carefully. A mist spray into the base of a chimney would be absolutely ideal, something like a 1/16 or 1/8" orifice at household pressures. I don't know of any chimneys with this setup but I have seen a chimney with a manual sprinkler installed at the top. I'd worry the thermal shock of cranking that sucker on may damage the masonry chimney it was in.

Fire departments tend to carry the dry chem toss packs now and they just go up on the roof and toss them down.

OTOH, I've used a CO2 extinguisher on a "training fire" and noticed that it did cool the material quite a bit - momentarily produced frost on it. The CO2 in an extinguisher is actually liquid, and cools greatly when it flashes from a liquid to a gas as you pull the trigger. Some of this comes from the cooling effect of gas expansion, some from the heat absorbed by the phase change from liquid to vapor. I don't know how much of that cooling would take place in a chimney fire, but I know that it's enough that if you dump a CO2 extinguisher at someone frostbite is possible.

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DoubleClutch said:

I haven't read the entire thread so someone may have already said this, but I'll say it anyway: I've heard that if you get a chimney fire, one way to deal with it is to get your dry-powder fire extinguisher, open the stove door, discharge the ENTIRE fire extinguisher into the stove/flue, and then slam the door shut again. Supposedly the heat of the stove/fire will cause the dry powder (sodium bicarbonate) break down and release CO2 which wil kill the fire.

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That would be more effective than some approaches, but it has one problem - you are blowing a large volume of gas into the fire along with the dry chem. Granted the gas is supposed to be Nitrogen, which is flame suppressing in and of itself. However that gas going into a mostly closed box, and isn't going to go up the chimney as fast as the extinguisher is going to be blowing it out. It has to go somewhere, and that somewhere wll be back out the door at you, along with any loose embers, ashes and other possibly burning material that is light enough to blow around. You are now standing with an empty extinguisher in a room with a bunch of embers scattered around - you may have put out the chimney fire, but you may not have improved the overall situation. :bug:

That is why I argue in favor of something that can be thrown into the stove without putting any pressure into it at the same time - The fire is best kept in the metal box, even if it is over enthusiastic there.

Gooserider