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©PACIFIC ENERGY FIREPLACE
PRODUCTS LTD.
Chimney Smoke and Creosote
Formation
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 flue of a slow burning fire. As a result, creosote
residue accumulates on the flue lining. When ignited, this
creosote makes an extremely hot fire. The chimney connector
and chimney should be inspected periodically (at least once
every two months) during the heating season to determine if
a creosote buildup has occurred. If creosote has accumulated
(3 mm. or more), it should be removed to reduce the risk of
a chimney fire.
1. Highest smoke densities and emissions 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 fuel load and leaving the air
inlet relatively wide open, especially during the first 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 the wood smoke is
passing, the more creosote will be condensed. Wet or green
wood contributes significantly to creosote formation as the
excess moisture that is boiled off cools the fire, making
it difficult for the tars and gases 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 annoying smoke
emissions and creosote buildup.
Chimney Fires
The result of excessive creosote buildup is a chimney fire.
Chimney fires are dangerous. Chimney inside temperatures
can exceed 2000°F(1093˚C). 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 fire. Proper clearances
are critical during such a fire.
Chimney fires are easy to detect; they usually involve one or
more of the following:
-Flames and sparks shooting out of the top of the chimney
-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 inlet on stove.
3. Call local fire department. Have a fire extinguisher handy.
Contact your local municipal or provincial fire authority for
further information on how to handle a chimney fire. It is
most important that you have a clearly understood plan
on how to handle a chimney fire.
4. After the chimney fire is out, the chimney must be cleaned
and checked for stress and cracks before starting another
fire. Also check combustibles around the chimney and
the roof.
- The services of a competent or certified installer, (certified
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 fires:
1. Do not let creosote build up to a point where a big chimney
fire is possible.
2. Do not have fires in the heater that may ignite chimney
fires. These are hot fires, such as when burning household
trash, cardboard, Christmas tree limbs, or even ordinary
fuel wood; (e.g.. with a full load on a hot bed of coals and
with the air inlet excessively open.)
NOTE: WE STRONGLY RECOMMEND THAT SMOKE AND
CARBON MONOXIDE DETECTORS BE INSTALLED IN
THE AREA WHERE THE HEATER IS TO BE INSTALLED.
If smoke detectors have been previously installed, you may
notice that they are operating more frequently. This may be
due to curing of stove paint or fumes caused by accidentally
leaving the fire door open. Do not disconnect the detectors.
Safety
