4
PACIFIC FP30 190712-28
Creosote
Formation and Need for Removal
When wood is burned slowly, it produces tar and other or-
ganic 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 accumulates on the fl ue lining. When ignited, this
creosote makes an extremely hot fi re. 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 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 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 the wood smoke is pass-
ing, 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 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 the buildup.
Chimney Fires
The result of excessive creosote buildup is a chimney fi re.
Chimney fi res are dangerous. Temperatures inside the chimney
can exceed 2000° F. This causes much higher than normal
temperatures on its exterior surfaces. Thus ignition of nearby
or touching combustible material is more likely during a chim-
ney fi re. Proper clearances are critical during 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 chimney
-A roaring sound
-Vibration of the chimney
In the event 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 fi re department. Have a fi re extinguisher handy.
Contact your local municipal or provincial 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 cracks before starting another
fi re. Also check combustibles around the 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 chimney
fi re is possible.
2. Do not have fi res in the heater that may ignite chimney
fi res. These are very hot fi res, 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.)
