Chimney Fire

[WV Sawmiller]

   On our way home from babysitting the grandkids and running errands in town my wife and I saw a large column of black smoke ahead. Got there and found huge flames shooting out of a big rock chimney on a neighbors house. I jumped out and ran to make sure there was nobody inside and found an 88 y/o man inside. Other neighbors gathered quickly and we tried to smother the flames with several boxes of baking soda and such. Nobody had a fire extinguisher nor did the man have an outside hose bib or water hose.

   The man had a wood heater hooked to the fireplace and it was poorly sealed with >1" gaps between the stove pipe and rocks. He had a roaring fire of locust wood burning.

   We got a ladder and passed buckets of water up to another neighbor on the roof to wet the shingles down. Mortar, superheated rocks and cinders were spitting out of the chimney. Eventually the built up creosote in the chimney burned out and the fire died down. A relative was with the neighbor and was going to stay till he knew everything was safe. Our main concern whether there was cracked mortar and flames available to the ceiling out of our sight.

   I have had chimney fires in the past and lined the flue with stainless steel liners to prevent recurrences or repair damages (cracks) in the mortar, rock or bricks. This was a good reminder to keep your chimney cleaned and fire fighting devices immediately available. I hope each of you who heat with wood in a fireplace or wood heater keep this in mind and check on your chimneys and fire extinguishers.



 
When we took this picture the flames had largely died down. When first seen they were 3' above the topcap on the chimney. Note the flames showing about halfway down the house where the mortar has cracked and fallen out and you can see the open flames. I wonder what it looks like on the opposite side hidden in the attic.

[red]

I was told not to shoot fire extinguisher into chimney. But to shoot fire extinguisher into heavy duty black garbage bags and drop into chimney. Under perfect circumstances.  Of course when in the moment you only have seconds to make decisions. But a standard fire extinguisher will not get down the chimney far enough . I have also heard people talk of a rumbling train noise inside the house. Scary Stuff

[WV Sawmiller]

Red,

   I can attest to the roaring noise from a chimney fire I witnessed in Jacksonville NC when I was stationed/lived there.

   I was thinking of the fire extinguishers for any wood that might catch fire. I have also been warned about putting water in the chimney while burning because it can cause the hot rocks/bricks/blocks to crack allowing the flames to reach the wood. One neighbor says soak a blanket and throw it in the heater and it will suck the moisture up into the chimney and extinguish the flames.

   I am not sure what the best way actually is to put out the flames but welcome suggestions.

   I suspect many times the fires actually go unnoticed and just burn themselves out. The times when they crack the chimney and mortar and set the house on fire is the problem. The flames are similar to an old tire burning. Once they catch up they are very hard to put out.

[DDW_OR]

old adage, an ounce of prevention is worth a pound of cure.
my dad used a wood furnace with metal chimney. first thing each morning he made a HOT fire to burn the creosote build up from the previous day.

this new place has an old log cabin that had many, many, many cold fires. the inside of the brick chimney was blocked by creosote making it unusable.

we are putting in a Central Boiler 750 to heat the new house, green house and future hot tub. the record low was -1 degree in December 1972. records go back to 1929.
may also use the CB to heat a Kiln.

[Chuck White]

I believe the first thing to do in case of a chimney fire is to close the draft door on the stove or furnace, that will start things calming down.

Make sure everyone in the house is awake and ready to vacate.

I don't burn wood anymore, but I still have a fire extinguisher sitting on the floor at the head of our bed!

Lots of folks keep a fire extinguisher right where they would expect a fire to start!  WRONG!!!!!!

[submarinesailor]

I believe the first thing to do in case of a chimney fire is to close the draft door on the stove or furnace, that will start things calming down.

Make sure everyone in the house is awake and ready to vacate.

I don't burn wood anymore, but I still have a fire extinguisher sitting on the floor at the head of our bed!

Lots of folks keep a fire extinguisher right where they would expect a fire to start!  WRONG!!!!!!

Chuck - I agree with everything you said.  I have a CO2 in the master bedroom and a dry powder by the front door.

Bruce

[WV Sawmiller]

I believe the first thing to do in case of a chimney fire is to close the draft door on the stove or furnace, that will start things calming down.

Make sure everyone in the house is awake and ready to vacate.

I don't burn wood anymore, but I still have a fire extinguisher sitting on the floor at the head of our bed!

Lots of folks keep a fire extinguisher right where they would expect a fire to start!  WRONG!!!!!!

Thanks. A major problem with this fire was we could notsmother the fire by shutting the heater up and such because the stove pipe was not sealed will where it went into the chimney rocks. I guess we might could have tried sealing it with a wet blanket or such.

[Peter Drouin]

Green wood and chimney cap will do it every time.

[WV Sawmiller]

Green wood and chimney cap will do it every time.

Peter,

   My chimney cap is the metal mesh type. I had just cleaned it out a couple weeks ago as a matter of fact. I guess in the winter when using the wood heater regularly we could remove it but would not want it uncovered the rest of the year.

   One of the commonly used and preferred woods here is locust because it burns with a hot fire and very little ash residue. It does generate a lot of creosote though and the fact it burns so hot makes it more likely to ignite built up creosote.

   When I clean my stove pipe I often take it off and outside and actually burn it out. (Since this is the safety part of the forum I will not suggest a splash of gas as a great ignition tool to set off the built up creosote.)

[John Mc]

The species of wood has very little to do with whether you get creosote formation. IT's the condition of the wood (green or dry) and the way you burn it (trying to choke it off and starve it for air, particularly in the earlier stages of the burn cycle).

[WV Sawmiller]

The species of wood has very little to do with whether you get creosote formation. IT's the condition of the wood (green or dry) and the way you burn it (trying to choke it off and starve it for air, particularly in the earlier stages of the burn cycle).

J Mc,

   Thanks for the info. I knew dry wood was the standard but I did think some woods like locust and any evergreen would generate more creosote than good dry hardwood like oak, maple, ash, etc.

[John Mc]

I've burnt a fair amount of locust myself, and not had a problem with it. And it's a myth that burning white pine causes creosote. Assuming you've got a decent stove installation, if it's dry and burned properly it will burn cleanly. Often the problem with pine is that it burns so quickly that people try to choke off the air supply to make it last longer.  Burned properly, the only problem it will cause is more frequent trips to your wood pile, since pine has far fewer BTUs per cord than most hardwoods.

[DDW_OR]

.............Assuming you've got a decent stove installation......
........ people try to choke off the air supply to make it last longer............

Those are the major cause of chimney fires

[Ianab]

The species of wood has very little to do with whether you get creosote formation. IT's the condition of the wood (green or dry) and the way you burn it (trying to choke it off and starve it for air, particularly in the earlier stages of the burn cycle).

J Mc,

   Thanks for the info. I knew dry wood was the standard but I did think some woods like locust and any evergreen would generate more creosote than good dry hardwood like oak, maple, ash, etc.

An issue with pine is probably that people try and burn it the same as hardwood. Loading up the firebox normally. But it burns really fast, with a lot of heat, for a short time. So they close the damper to get a longer burn time, create a smoky fire, and that creates the creosote.

If you load a smaller load, more often, and keep a small hot fire burning it wont create creosote problems. But of course that's a hassle, and hence why pine etc is less popular for firewood.

[Peter Drouin]

Look at the smoke coming out, If it's blue the wood is green if it's white the wood is dry. The thing with a cap, it will slow down the hot smoke with the creosote suspended in it and cool and stick the inside of the chimney.
And outside chimney is a trouble maker to start with. Lot of times you will have condensation on the onside, and that will rot the chimney from the inside out.

Always put the chimney on the inside of the house. Start the thing below the cellar floor on a footing. So if some rain goes down it the water will go into the ground . I have seen chimney block started on the cellar floor and the rain will weep the nasty out from under it and make a big mess. 
And never a cap.

[drobertson]

I've only seen on, years ago as a kid, the next door neighbors had one, big glow with a roar, never will forget that,  and it looks like you can see flame through the mortar cracks jut above where the wide part transitions to the narrow going up, scary stuff, that flue need some serious inspections now.

[Chuck White]

Look at the smoke coming out, If it's blue the wood is green if it's white the wood is dry. The thing with a cap, it will slow down the hot smoke with the creosote suspended in it and cool and stick the inside of the chimney.
And outside chimney is a trouble maker to start with. Lot of times you will have condensation on the onside, and that will rot the chimney from the inside out.

Always put the chimney on the inside of the house. Start the thing below the cellar floor on a footing. So if some rain goes down it the water will go into the ground . I have seen chimney block started on the cellar floor and the rain will weep the nasty out from under it and make a big mess. 
And never a cap.

My first (original) chimney did exactly that.  It was block with a flue inside, on the outside of the house!
Trouble is, they get cold and condense the creosote.  I've never liked chimney caps on wood burners!

My current chimney is stainless steel and I have an oil fired furnace and an oil fired water heater plumbed to it!

[John Mc]

Interior chimney (in the center of my house). Wish I'd had the stainless liner put in when it was built, but I didn't. So it's a masonry liner inside a stone chimney. I have a chimney cap, and have had zero problems with it. Heat primarily with wood, clean once a year, and get about 1 quart of crud off the inside of a 24' tall chimney.  Without the chimney cap, I was just getting too much rain down the inside of the chimney during heavy storms. Just about everyone around here seems to have a cap, other than some of the really old homes. It doesn't seem to be an issue if you burn dry wood, burn it properly, and have a well-designed system that draws properly.

[WV Sawmiller]

Interior chimney (in the center of my house). Wish I'd had the stainless liner put in when it was built, but I didn't. So it's a masonry liner inside a stone chimney. I have a chimney cap, and have had zero problems with it. Heat primarily with wood, clean once a year, and get about 1 quart of crud off the inside of a 24' tall chimney.  Without the chimney cap, I was just getting too much rain down the inside of the chimney during heavy storms. Just about everyone around here seems to have a cap, other than some of the really old homes. It doesn't seem to be an issue if you burn dry wood, burn it properly, and have a well-designed system that draws properly.

John,

   Have you checked on having a stainless liner added to your existing chimney? You might be surprised how little it costs and how easy it is to do. Its worth checking and a real feel good addition. Good luck

[submarinesailor]

Many years ago I read an article/study the University Of Georgia did about burning firewood and and creosote build up.  It stated that there was less than 3% difference between SEASONED wood types.  The biggest difference was the burning of wet/green wood.

Here is one of their more recent articles:  Burning fresh cut wood, or green wood, can l leave buildup on your chimney and flu. The high moisture content of green wood is going to allow a lot of the creosote in wood to go up in smoke and form residues on flues, chimneys, and stovepipes. 

Over time, a build-up of creosote could start a chimney or flu fire.  The sticky, gum-like resins in pine firewood have given some people the impression that it causes more creosote residues to build-up than hardwood. Research has found this is not true.  The buildup on fireplace or wood heater walls, chimneys, and flue pipes seems more a result of burning wood at relatively low temperatures.  Burning poorly seasoned wood favors creosote buildup, because evaporating water cools the burning process.   When wood is heated, some of its chemical makeup is first changed to a gas and later ignited if the fire is hot enough. If the fire's not hot enough, these chemicals become part of the smoke. And if they contact a surface cool enough, they'll condense back to a liquid or a solid there.  Over time, this layer of creosote becomes thick enough that a hot fire will ignite it in place, causing a chimney fire.

Filling a wood stove at night and closing the damper to reduce airflow can keep a fire burning all night with no more wood, but it also is likely to form more creosote.  Avoid using low damper settings for extended times.  Burning small amounts of seasoned wood at high temperatures is one solution to the problem, but doing that by hand makes for busy and sleepless nights. An alternative solution is automatic-fed wood-pellet stoves. 

Always run a wood stove or fireplace within the manufacturer's recommended temperature limits. Too low a temperature increases creosote build-up, and too high a temperature may eventually cause damage to the chimney and result in a chimney fire.  Add only enough wood to keep the fire at the desired temperature.  And remember, dry well-seasoned wood is important for an efficient heat source as well as safety.  Regular chimney inspections and cleanings are also key to preventing creosote build-up.

Bruce

[thecfarm]

I had one once. Some snow from the roof blocked off the oxygen just for a few seconds and the fire was out. 

[Brucer]

The article Bruce posted should be mandatory reading for anyone who wants to burn wood.

When I built my house I installed a Fisher stove, with a temperature indicator on the chimney. I found we couldn't have a decent size fire, except in the coldest weather. Either the house we get way too hot, or else the dampers had to constantly adjusted to keep a small fire in the proper temperature range. The problem was, the Fisher was too big for the house, and also didn't have a big enough range of adjustment.

My neighbour had installed an identical stove, and he just got a fire going in the morning and then turned the dampers way down before going to work. One day as I was driving home from work I had to pull over for the fire truck. Then I found myself following the truck as it wound it's way through town. As I got closer and closer to my house, I started to worry. Then a sigh of relief. It was my neighbour's house that had flame shooting out of the chimney.  Fortunately they got it out before it set fire to the house. Unfortunately the water damage inside was pretty bad.

In 1998 I replaced the Fisher stove with a modern convection stove with secondary and teriary combustion controls. I can turn it right down once the fire has got established. I usually have to brush a little creosote out of the chimney every 3 years or so.

Did I mention that I burn very dry wood?

[John Mc]

Brucer, what you experienced with your Fisher stove is a common problem with wood stoves. People install a system that is just too big for their normal heating load. The problem is made worse by the fact that wood combustion just doesn't like to be "turned down" the way you can with oil/natural gas/propane: you generally can't run a wood stove at 10 or 20% and expect an efficient, clean burn.

It seems counter-intuitive, but you can often meet more of your heating needs by NOT sizing a wood stove or boiler for your peak heat loads. Make it a little undersized, and supplement the heat on those couple really cold weeks of the year with something else (or just live with it a bit cooler in your house). The smaller stove will be usable further into the "shoulder" heating seasons in the Spring and Fall, without driving you out of the house. If you size for peak heating loads, you often end up using the supplemental heat system more often, since your stove is too big for the milder days.  Some wood boiler systems address this by having a large heat reservoir - generally a large water storage tank, often buried. This lets them run the boiler full out at high fire, where it is most efficient and heat up the house and the storage tank, then shut the boiler down and run off the reserve tank until it drops too low. The wood stove version of this would be something like a well-designed masonry heater: you fire it up, burn a good hot fire and use that to heat up a lot of thermal mass. Let the fire die, and the mass slowly radiates heat into the room. You regulate the heat by how often you build a fire, not by turning down the fire to a low setting.

[goose63]

When I put my wood stove in I used triple wall Stainless insulated pipe with a cap cost me $ 200 the same pipe for my little shop was $ 100 FOR A 2 Ft peace last fall clean it once a year.

The Stainless pipe is worth it 

[Chuck White]

When I put my wood stove in I used triple wall Stainless insulated pipe with a cap cost me $ 200 the same pipe for my little shop was $ 100 FOR A 2 Ft peace last fall clean it once a year.

The Stainless pipe is worth it

Peace of mind is a big deal!   ;)

[Farmerjw]

My parent's first woodburning stove was a Franklin.  The most inefficient, wood burner (and it burnt a lot without returning much heat).  When they remodeled the front of the house they bought a "Mama Bear" stove.  Think the Papa Bear was larger and there was a smaller one.  The lady told my folks they didn't need the Mama Bear based on house plan and insulation.  Based on the Franklin they "knew" better.  Well that Mama Bear would run you out of the house without breaking a sweat.  They replaced the Franklin with a much smaller wood burner that pretty much heated the whole house with a little help from the Mama Bear on the coldest of days.  Technology changes really made a difference.  The amount of heat felt and wood burnt was amazingly different. 

[WV Sawmiller]

   I was working in southern Norway '87-'89 and noticed they used a lot of small wood burning room heaters. In the USA I have always seen larger central area woodburners more commonly used. I know I have a great big one down in the basement. In Norway the wood was generally cut into sections about 1' long and if they were 4" in diameter they would split them 4 ways. Our Norwegian daughter (Former exchange student) showed me the technique they use to see if the wood was dry enough was to blow through it. Most of the wood they burned was birch. They would drag the trees to a landing, set up a bunch of rollers, and roll them to a cut off saw (Buzz saw type) run by a PTO on a tractor. Looked pretty dangerous to me. They would palletize and shrink wrap the wood to make up about 1 cubic meter for sale.

   Being a Socialist country they also had community councils who oversaw certain services. One of these was chimney sweeping. You would get a notice when the sweep would be there and you needed to be there or have someone to assist and allow access. I guess part of that was because the homes were largely built of wood and close together in tight clusters in the valleys and a fire in one was a risk for several.

[jdonovan]

if you've got a sizeable chimney fire going, then discharging a dry chem into the fire box should get the powder to get pulled up the chimney.

if you want to be pre-ready, get some zip top bags filled with dry chem and you can drop them from the top. The heat melts the bag open, and they they disperse the powder near the bottom and gets carried up by the draft.

If you use water, the result is almost always a cracked flue due to spot cooling where the water stream hits. Cracked flue's are better than losing a home, but is about the bottom of the list for extinguishing choices.

In the picture, it looks like about 1/3 up on the left I can see flame through some missing mortar.

[WV Sawmiller]

In the picture, it looks like about 1/3 up on the left I can see flame through some missing mortar.

   Yes. I mentioned that in the caption under the picture. Mortar was probably an inch thick there. Dropping powder down the chimney would have been impossible when we first arrived as flames were shooting out 3-4 feet. By the time we took the picture the flames had largely died down.

[Brucer]

Brucer, what you experienced with your Fisher stove is a common problem with wood stoves. People install a system that is just too big for their normal heating load....

I actually sized the Fisher appropriately for the size of the house. I have an air circulation system that moves the hot air from ceiling level to the rest of the house. What I overlooked was the fact that the Fisher is a radiant stove and the heat is transferred to every surface that's in line with the stove. I also didn't realize the limited output range with their damper system.

The stove I replaced the Fisher with is a convection stove. Most of the heat rises directly upward to be captured by the circulation system. It also has 5 times the output range. As far as overall heat output, it's actually the same size as the Fisher was.

With my Fisher stove I could only burn about half a cord of wood a year if I didn't want to risk a chimney fire. With my current Pacific Energy stove I burn 3 cords a year and that's all I need for daytime heating.