SINS.BODYC 230311-20 15
Chimney Fires
The result of excessive creosote buildup is a chimney fi re.
Chimney fi res are dangerous. Chimney inside temperatures
can exceed 2000 degrees F. This causes much higher than
normal temperatures in the chimney and on its exterior surfaces
thus ignition of nearby or touching combustible material is more
likely during a chimney fi re. Proper clearances are critical dur-
ing such a fi re.
Chimney fi res are easy to detect; they usually involve one or
more of the following:
- Flames and sparks shooting out of the top of the chim-
ney
- A roaring sound
- Vibration of the chimney
In Case of a Chimney Fire
1. Prepare to evacuate to ensure everyone’s safety. Have a
well understood plan of action for evacuation. Have a place
outside where everyone is to meet.
2. Close air inlets on stove.
3. Call local fi re department. Have a fi re extinguisher handy.
Contact your local fi re authority for further information on
how to handle a chimney fi re. It is most important that you
have a clearly understood plan on how to handle a chimney
fi re.
4. After the chimney fi re is out, the chimney must be cleaned and
checked for stress and cracking before starting another fi re.
Also check combustibles around chimney and the roof.
- The services of a competent or certifi ed installer, (certifi ed
by the Wood Energy Technical Training program (WETT) - in
Canada, Hearth Education Foundation (HEARTH) - in U.S.A.,)
are strongly recommended.
Avoiding a Chimney Fire
There are two ways to avoid chimney fi res:
1. Do not let creosote build up to a point where a big chimney
fi re is possible.
2. Do not have fi res in the heater that may ignite chimney fi res.
These are hot fi res, such as when burning household trash,
cardboard, Christmas tree limbs, or even ordinary fuel wood;
(eg. with a full load on a hot bed of coals and with the air
inlet wide open).
Creosote
Formation and Need for Removal
When wood is burned slowly, it produces tar and other organic
vapours, which combine with expelled moisture to form creosote.
The creosote vapours condense in the relatively cool chimney
fl ue of a slow burning fi re. As a result, creosote residue accu-
mulates on the fl ue lining. When ignited, this creosote makes an
extremely hot fi re. The chimney connector and chimney should
be inspected at least once every two months during the heat-
ing season to determine if a creosote buildup has occurred. If
creosote has accumulated, it should be removed to reduce the
risk of a chimney fi re.
1. Highest smoke densities occur when a large amount of wood
is added to a bed of hot coals and the air inlet is closed. The
heated wood generates smoke, but without ample air, the
smoke cannot burn. Smoke-free, clean burning requires small
fuel loads, two or three logs at a time or 1/4 to 1/2 of a fuel
load and leaving the air inlet relatively wide open, especially
during the fi rst 10 to 30 minutes after each loading, when most
of the smoke generating reactions are occurring. After 30
minutes or so, the air inlet can be turned down substantially
without excessive smoke generation. Wood coals create very
little creosote-producing smoke.
2. The cooler the surface over which wood smoke is passing,
the more creosote will be condensed. Wet or green wood
contributes signifi cantly to creosote formation as the excess
moisture that is boiled off cools the fi re, making it difficult for
the tars and gasses to ignite, thus creating dense smoke
and poor combustion. This moisture-laden smoke cools the
chimney, compounding the problem by offering the smoke
the ideal place to condense.
In summary, a certain amount of creosote is inevitable and must
be lived with. Regular inspection and cleaning is the solution.
The use of dry, seasoned wood and ample combustion air will
help to minimize the buildup.
Содержание UL 1482
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