# Did I Have a Chimney Fire?



## 2coldHere (Jan 26, 2011)

Weird thing happened yesterday. I haven't been using my woodburning fireplace insert for weeks. It was real cold, and the cold air was falling down my chimney and creeping into the living room thru the stove, also bringing the stinky chimney smell in with it. I got tired of havig cold feet and smelling the chimney all the time and decided to build a fire to warm up the stove & chimney and stof the seeping cold & smell.

I was in a hurry and my wood was green (and had ice & snow on it), so I used some diesel fuel as an accelerator to get it going (go ahead and yell at me, but I do it all the time).

The fire got going really strong and the flames were licking up thru the flue.

I started noticing a hissing noise, and it turned into a boiling liquid noise. sounded just like a big frying pan full of cooking oil being boiled real hard on top of a stove; only it was somewhere inside my fireplace insert area.

At first I thought maybe it was all the water from the ice, snow, and green wood I was burning; then I wondered if it might instead be that the creosote in the chimney had turned liquid and was dripping down & boilding/burning inside. I also wondered if maybe I'd put too much diesel in, and maybe the boiling sound was the excess liquid fuel sizzling on the bottom of the stove's plate steel belly.


Does creosote do that (turn to liquid)? I've never had that problem before. I closed the flue and cut off the air supply reql quick and the boiling sound went away; then I ended up finally just letting the fire die out because it wasn't hot enough to keep the wood burning, and I didn't want a chimney fire.

Thought I'd ask about the "liquid creosote" thing. Thanks.


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## Mike PA (Jan 26, 2011)

Two things: Green/ wet wood hisses when burned. You can hear the hiss pretty easily. Second, creosote will make a noise as it heats up and cooks or burns off. Sort of a crackling noise, kind of like rice crispies in milk. It may sound like small pebbles or stone landing on a steel plate. I think the sound you described is the creosote heating up, but not necesarily burning. 

A true chimney fire sounds more like a jet at take-off and the draft up your fireplace woul dbe tremendous.


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## CrappieKeith (Jan 26, 2011)

Whatever it was I'd be brushing out that flue pipe.


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## 1harlowr (Jan 26, 2011)

CrappieKeith said:


> Whatever it was I'd be brushing out that flue pipe.


 
:good:


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## CrappieKeith (Jan 26, 2011)

...too add...please stop burning green wood. Stop using diesel to light it. Drywood lights so much easier and it gives you so much more heat.

You are so flirting with the devil...you are just begging for your home to start on fire!


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## jerrycmorrow (Jan 26, 2011)

TreeCo said:


> .......and cleaning out behind that insert!


 
you might be surprised what you find behind the insert. if you haven't cleaned it you will have tons of creosote, right there by the fire box.


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## r&r (Jan 26, 2011)

Would one of those creosote logs you can get from the grocery store help? I clean my chimney out pretty often but creosote builds up in the flue pipe between my stove and chimney. Would one of those creosote removing logs work for that? Anybody used one of those before?


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## jerrycmorrow (Jan 26, 2011)

r&r said:


> Would one of those creosote logs you can get from the grocery store help? I clean my chimney out pretty often but creosote builds up in the flue pipe between my stove and chimney. Would one of those creosote removing logs work for that? Anybody used one of those before?


 
my wife uses one but i don't put much stock in it. nothing works like a stiff brush to the flue and flat surfaces as well as burning cured wood and a hot fire.


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## jerrycmorrow (Jan 26, 2011)

could be better than nothing though in a tight spot


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## PasoRoblesJimmy (Jan 26, 2011)

*Chimney fire*

A chimney fire will cause your stove pipe to turn bright red, shake and vibrate. It will sound like a freight train going through your house.

Wet/green wood and diesel can kill you and and your family from carbon monoxide poisoning. It is also setting you up for a future chimney fire or setting your house on fire.


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## mga (Jan 26, 2011)

since you haven't used it for a couple of weeks, it was probably condensation on the flue pipe vaporizing off.

not knowing your set up, is your flue pipe insulated? if not, it could be condensation on the outside of the pipe. again, i don't know your set up, so it's a guess.

also, if you're not going to use your wood burner for a long period of time, don't you shut the damper? leaving it open allows the warm air of the house to meet the cold are outside and that forms condensation. even the cold air falling down the flue pipe gets warmer as it drops.


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## CrappieKeith (Jan 26, 2011)

mga said:


> since you haven't used it for a couple of weeks, it was probably condensation on the flue pipe vaporizing off.
> 
> not knowing your set up, is your flue pipe insulated? if not, it could be condensation on the outside of the pipe. again, i don't know your set up, so it's a guess.
> 
> also, if you're not going to use your wood burner for a long period of time, don't you shut the damper? leaving it open allows the warm air of the house to meet the cold are outside and that forms condensation. even the cold air falling down the flue pipe gets warmer as it drops.


 
Exactly....nice point!


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## ziggo_2 (Jan 26, 2011)

CSL or Chimney sweeping logs work.....that is to say if you follow the instructions. Mine said to put it in when the fire is reduced to coals and leave it alone (nothing else with it) Then when its done, resume burning as usual and after a about a week *brush the chimney* .

What im saying is that these CSL's are only for helping, they will not clean the chimney alone. I think it even says that on the box. Ive only used one the one time in the winter, I had a pretty thick glaze in the chimney and it helped loosen it up. My chimney was almost spotless when I was done.

This year its been falling down on its own so all i have to do is scoop out the clean out. I will give it a good brushing in the fall before heating season.

You would be very impressed the difference between burning dry wood and wet wood. Also you should have the wood inside for a week before burning it. I understand we all get in a hurry sometimes, I would NEVER use diesel to start the fire in my house....thats just plain stupid.


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## jerrycmorrow (Jan 26, 2011)

don't think the op likes the feedback


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## 2coldHere (Jan 26, 2011)

*boiling oil sound*

it's not that I didn't like the feedback: I haven't been online till just now since I posted.

re: burn dry wood instead of the cheap green wood I bought. Please, bring me some for free! I'd love to burn nice seasoned dry hardwood! Anybody with a nice truckload, please bring it here and stack & cover it for me for free! I can't buy it 'cause I'm broke and on a pension; and can't stack much of it because of a disability; but my teen boy can stack some. Again, free clean dry hardwood COME ON DOWN I'd love to have you!

re: don't burn diesel. Problem is, I can't get the green, wet, ice-filled frozen wood to light and STAY lit without it. Youngest is allergic to all the molds/mildews on the wood & bark so I can't store it inside to dry/pre-warm it either.

re: don't I close my flue? yes. But it's made of steel and doesn't seal well. I have a 1966 "mood fireplace". The flue is steel built into concrete block. The chimney is ceramic block built into concrete block and faced with brick. I inserted a plate steel Buck Stove wood burning fireplace insert and it also has a steel flue/closer. Weeks of cold & sub-zero temps with lots of snow and no fire burning; and my guess is the boiling sound was probably condensation from the freshly-hot chimney.

Thanks for the comments about what a chimney fire would sound like. it didn't sound quite like that, but the flames were rushing up the flue pretty good.

My best solution: win the lottery. Then I can either buy a nice new wood stove and nice clean/dry hardwood; or a nice new fuel efficient boiler for the baseboard heating I already have; or better yet, I can move to San Diego and forget about all this fire stuff (except for when the hillsides burst into flames each October because of the arsonists).


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## Dalmatian90 (Jan 27, 2011)

> I started noticing a hissing noise, and it turned into a boiling liquid noise. sounded just like a big frying pan full of cooking oil being boiled real hard on top of a stove; only it was somewhere inside my fireplace insert area.



If it wasn't accompanied by a roaring sound...no, you probably didn't have a chimney fire.

You came as close as is possible to having one without having one. The creosote was moments away from igniting.



> Does creosote do that (turn to liquid)?



Yes.

Chimney with cracked / no liners and mortar in poor shape will allow the creosote to seep out. A fire in the chimney will then follow this like a fuse into the void spaces around the chimney, with a high potential to ignite the walls or attic.

It looks like someone is squeezing roofing tar out of the joints. 

Image grabbed randomly off the internet:






To expand this a bit...

Creosote starts off as a liquid. It's formed by smoke condensing as the smoke cools in the chimney. Steam, since it condenses at a relatively low temperature, can be a big culprit -- as water condenses, it "scrubs" hydrocarbons and unburned particles (soot) out of the smoke. The original non-EPA airtight stoves like Fishers also see more condensation because they don't shove as much air (and heat) up the chimney, giving the smoke more time to cool and condense. The EPA stoves reduce the amount of unburned fuels going up the chimney, plus their finicky on not having moist wood, both of which help a lot to reduce creosote build up. 

I don't believe, but I'm not certain, when you find in on the exterior of a chimney within a structure, that it's formed by the original liquid water/smoke mix. I believe when that tar like creosote comes out, it's because it's been heated (not necessarily by a chimney fire, but at least by hot flue temps) to a point where it can flow.

Grrrr...I can't find my own photos that I have showing classic condensation on the walls of a building from a structure fire. When conditions are right, you see the same effect on the walls in buildings that were on fire, and when you see the fresh condensation it looks like a heavy, maybe slightly oily looking, dew with soot mixed in. It's the same idea as creosote forming in a chimney, hydrocarbon and unburned particles being deposited but this case on the walls, and only one time instead of in layer after layer from cycle after cycle of fires in the wood stove.

Here's another image grabbed at random from the interwebs:


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## mga (Jan 27, 2011)

> re: don't I close my flue? yes. But it's made of steel and doesn't seal well. I have a 1966 "mood fireplace". The flue is steel built into concrete block. The chimney is ceramic block built into concrete block and faced with brick. I inserted a plate steel Buck Stove wood burning fireplace insert and it also has a steel flue/closer. Weeks of cold & sub-zero temps with lots of snow and no fire burning; and my guess is the boiling sound was probably condensation from the freshly-hot chimney.



i was always under the impression that when installing an insert into an existing fireplace that a steel flue liner is required from the top of the chimney down to the unit.

if i read that right, you just slipped one in the opening.....?


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## 2coldHere (Jan 27, 2011)

*Wood Just Isn't For Me*

GREAT post Dalmation; thank you very much for the insight. You've supported my fear that I did come very close to a chimney fire. I know I used almost twice as much diesel this time than I ever have before (nearly a whole canteen cup full -- military guys will know what I mean).

The heat w/wood like your life depends on it was a good quote too.

re: insert needing a sleeve? The owner's manual of my insert/stove (Regular Buck Model 27000) says it can be mounted in existing masonry chimneys without a separate add-on pipe; says the add-on pipe system allows the insert to be used as a stand-alone stove. House/chimney was built in 1966, stove built in 1970's, I figure they're same-era and I used the stove's install instructions. My local (later-developed) building code might require a chimney insert but I didn't bother with that: I figure if decades' worth of Buck Stove users followed the manual without trouble, then so can I.

I think a combination of things added together to cause this near-chimney-fire. Over and over again on this site I've seen how important it is to start off with good quality, well-seasoned hardwoods that are kept covered & dry. I'm poor and I bought cheap wood, and got what I paid for: crappy wood that doesn't want to light and doesn't want to stay lit unless it's real hot. That tempted me to use diesel, which I wouldn't need (or want) to do if my fire would start the normal way with just some decent kindling under it. Add the weeks of non-use, the prior use of this same crappy wet wood that probably has built up a thick layer of crispy creosote inside my chimney this winter, and the cold weather we've been having.... and "whoosh", three bad decisions add together to form a near fire.

I think my wood burning days are limited. I don't like doing it. Costs too much for all the stuff (stove, wood splitter, and then all the wood), hurts my body to process the wood, makes a damn mess all over the house & yard, hogs a lot of space on my yard, ticks off the neighbors with the smoke, and tempts me to do stupid things (like start cheap wet wood alight with diesel) that might burn down my house. Once I do get the stove going the heat is nice, but it cooks only one room and I have to set up fans to blow the air around the house: causing my youngest to have allergy & asthma attacks to the molds/mildews/plant spores that are inside the crappy wood I bought. 

The only good it's done for me is to give my cats someething to do because they love exploring the woodpiles (little critters set up home in them).

I come to this same conclusion each time I really think about it: I'm better off not burning wood but instead running some new natural gas lines and installing some unvented space heaters; plus somehow trying to figure out how to sell enough stuff or make enough money to buy a more fuel efficient natural gas boiler so I can keep the thermostat turned up.


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## Mike PA (Jan 27, 2011)

Wood heat is not for everyone. But there is definitely a learning curve involved with it and we all make mistakes, especially early in our burning careers. Maybe wood burning isn't for you this year, but save the wood you bought and use it next year, after it has time to dry. If you must buy wood, buy a year ahead (you will know it is dry) and get that teenage boy to do some stacking. Burning dry wood will greatly help to eliminate your troubles, but periodic cleaning is also needed.

I hate to see someone give up, as it really can be a great alternative to gas, oil, or electric, but it isn't for everyone. It really requires some work and attention to detail that not everyone is able or wants to do. Good luck and be safe.


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