Failing to maintain your wood stove or fireplace properly can lead to a chimney fire. Chimney fires occur when combustible deposits on the inner walls of the chimney ignite. These combustible deposits, called "creosote," are a natural byproduct of woodburning. A fire hazard exists if 1/4 inch of creosote (or more) coats the inner walls of the chimney.
Preventing Chimney Fires
Chimney fires do not occur in clean, intact, properly installed chimneys. Have a professional chimney sweep clean and inspect your appliance at least once a year. More frequent cleanings may be required, based on the type of wood burned, the type of appliance, and the frequency of use. In general, pre-1990 stoves, or any appliance that is used frequently, will require more than one cleaning per year.
Detecting a Chimney Fire
The first indication of a chimney fire is usually the noise – a roaring sound that grows louder as the fire’s intensity increases. Clouds of black smoke and sparks will be seen exiting the top of the chimney; in severe fires, flames can extend several feet above the chimney.
What to do
In case of a chimney fire, follow these steps:
- Call the fire department immediately.
- Alert others in the building to evacuate.
- Close the appliance’s dampers and/or the primary air inlet controls, limiting the fire’s air supply and reducing its intensity. If there is a barometric damper in the chimney connector, plug or close the opening in the barometric damper.
- Open the appliance door just enough to insert the nozzle of a 10 lb. dry chemical fire extinguisher rated for Class ABC fires. Discharge the entire contents of the extinguisher into the appliance and shut the door.
- If possible, wet down the roof and other outside combustibles to prevent fires ignited by shooting sparks and flames.
- Closely monitor all combustible surfaces near the chimney. During severe chimney fires, these surfaces can become hot enough to ignite.
After a chimney fire, have the chimney inspected by a professional chimney sweep or wood stove/fireplace installer; choose a professional who has earned credentials from the National Chimney Sweep Guild, Chimney Safety Institute, or the National Fireplace Institute®. Do not use the chimney until it has been inspected by a professional. The excessive heat produced by a chimney fire can crack chimney walls, damage chimney liners, and damage some types of factory-built chimneys. If not repaired, these damages create a greater possibility for any subsequent chimney fire to spread beyond the confines of the flue to the house.