What to do if you have a Chimney Fire

About a month ago we had a chimney fire - or at least we think so!

It was a bit frightening!

I had just fired up the wood stove and it was burning at a nice 450 to 500 degrees when after a two hours there was a curious bang (still not sure from where or why) and then the smoke detector suddenly rang!

While there wasn't any visible smoke -- there were other telltale signs that something was amiss.  The flue thermometer shot right up to 900 degrees, there was a strange "whooshing" sound in the stove pipe and the flue thermometer was curiously tilted.  It appeared that the inside of the double-walled stove pipe had shifted down pulling the thermometer down with it.

I immediately shut the damper down which reduced the fire in the stove, and then quickly surveyed the chimney in the attic to be sure the fire was contained.  Then we just waited it out.

After about 5 minutes the "Whooshing" subsided and the flue temperature came rapidly down to below 400 degrees.  We let the fire burn itself out and the thermometer slowly returned to its original horizontal position.  We didn't us the woodstove for the remainder of the weekend just in case.

What should you do to Prevent a Chimney Fire?
The primary cause of chimney and stove pipe fires is the build-up of creosote in the chimney.  The best way to avoid creosote is to avoid creating the circumstances where creosote can be formed and deposit itself on the inside of the chimney.  The way to do that is:
  • Always burn well seasoned, dry firewood
  • Always keep the flue temperature between 400 and 800 degrees
How to protect in case of a Chimney Fire?
I thought I was using seasoned wood and I watched the temperature.  But we still had a chimney fire.  So it is best to ensure that you build a chimney system that can withstand just such an invitability:
  • Use a stainless steel double-walled insulated chimney
  • Use a double-walled stove pipe to connect the stove to the chimney
  • Use the correct parts to connect the stove pipe to the chimney
    (My suggestion is that you get and use all three from the same manufacturer so they all interface well)
  • Be sure to have an appropriate chimney cap with a spark arrester
  • Install a flue thermometer in the flue pipe (and in the correct location)
  • Purchase a fire extinguisher and store it visibility near the wood stove.
What to do during a Chimney Fire?
If you have built a modern chimney systems like suggested above, you will likely easily survive a chimney fire.  In fact many of the newer chimney systems are constructed to survive many such fires.  As long as the fire is contained inside the chimney system you will be safe -- the chimney fire will burn itself out.  The real problem is when poorer materials are used or the chimney is improperly installed, and the fire escapes the confines of the chimney.  But do you do when you have a chimney fire:
  • Do NOT panic!
  • Immediately shut the air damper on the wood stove - do not open the stove - the whole idea is to starve the fire of oxygen!
  • Check the entire chimney system to ensure the fire has not escaped - if it has -- evacuate immediately! (The most like location where the fire will escape is somewhere in the attic and you will not be equipped to fight such a fire!)
  • Otherwise, wait out the fire, carefully watching the flue temperature - it will tell you when the fire is out.
After the Chimney fire:
You have just had a chimney fire and it may be a sign that there is somethng wrong in your chimney.  Be safe:

  • Do not start another fire until you have had the chimney inspected and cleaned by a professional chimney sweep
  • Replace any damaged chimney elements
Replacing the Stove Pipe
To be on the safe side the following weekend I replaced the stove pipe with a new one.  I'll describe that process in the next post and what I found when I inspected the chimney.

Related Posts:

Cottage on the Edge: How to Install a Flue Gas Stove Pipe Thermometer
Adding to the Wood Pile - Do's and Don't for what you can/should burn

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