CHIMNEY FIRES
There is no one
easy answer to chimney fires, as many situations are different. Flue
fires in a real, brick chimney are a real problem, as the draft controls
necessary to shut off the flow of oxygen to the chimney are simply not
present, and the mortar between the bricks could be old and cracked.
Generally, in the
case of the brick chimney flue fire, the easiest way to put out the
fire is to throw a glass of water directly on the fire: the water will
flash into steam, rise up the chimney and inhibit oxygen, and snuff
out the fire. Sometimes a second glass of water is needed, but not often.
(Note: The steam can damage a chimney and it must then be inspected
before use.)
Some people have reported success in putting out chimney flue fires with
a mug or drinking glass full of salt thrown on the wood, but I have
not tried this.
Airtight stoves
and tight fitting, stainless steel, insulated stove pipe are a different
matter entirely. Due to the nature of the stoves (particularly if they
have an automatic draft control for temperature regulation) they WILL
build up a layer of creosote in the chimney, and that creosote WILL
burn. If a flue fire gets started in an airtight stove, a small glass
of water thrown on the fire will flash to steam and inhibit the flue
fire, BUT it may also severely damage the stove: glass doors can break,
the steel or cast iron may not be able to adjust to the temperature
difference and crack, etc.
Everyone with an airtight stove should have their own chimney cleaning
brush and rod, and then plan on inducing a controlled chimney flue fire
once a month. The use of dried potato peels or newspaper -- but
absolutely no wood! -- will raise the temperature of the flue
sufficiently to induce a controlled "burn" that is simply a flash of
heat in the chimney. A chimney temperature gauge should be on the
stovepipe about 5 feet above the stove (if possible) and when the
temperature reaches about 500 degrees, all dampers should be shut down
and the fire starved of fuel and oxygen. The residual oxygen in the
stove will keep the fire going until the temperature reaches 550 degrees
or so, the go out and rapidly cool down. The dampers may then be open to
induce a flush of cool air through the pipe, so it cools down faster --
in a half hour the pipe will be just slightly warm to the touch.
What the controlled
flue fire does is convert the gooey, tar-like creosote into a fluffy
carbon deposit that DOES NOT adhere to the walls of the stove pipe.
One stroke with the chimney cleaning brush produces huge flakes of fluffy
carbonized creosote that will fall down into the stove, where it can
be easily removed.
We heated exclusively
with wood using the same stove and stove pipe for twelve years, and
once a month in the heating season I would induce a flue fire (on a
day it wasn't raining), wait an hour, then go up on the roof and stroke the
stove pipe with the cleaning brush (a brass brush, not a plastic one).
This regular cleaning stops the creosote build up at a certain point,
removes it cleanly, and prevents a super, uncontrolled flue fire that
can be dangerous.
Now that my
back is really bad and we heat with kerosene space heaters, we only need
to use the wood stove as a back up heat source for an occasional fire.
That does not mean I can ignore the chimney, though! All it means
is that I have to clean the chimney less often.
NOTE:
Words have a precise meaning. Waiting until a chimney is so
clogged with creosote to induce a chimney fire is dangerous.
Creosote is gummy, and the recommendation that chimneys only be cleaned
with a plastic bristle brush means the goo is simply inconvenienced a
little - an unintentional chimney fire is almost guaranteed.
Similarly, a statement of "let a professional handle it" ignores the
many people who simply cannot afford to hire a professional chimney
sweep, and we all know that those stoves and a badly creosoted chimney
will still be used.
NOTICE OF A DIFFERENT OPINION ON CHIMNEY CLEANING
December 21, 2007
Cleaning the chimney
serving a stove by having a "controlled burn" is extremely dangerous and
could easily cause a house fire. This is NOT recommended by the National
Fire Protection Association, the Chimney Safety Institute, or the
Midwest Chimney Safety Council. What IS recommended is an annual or
twice-annual inspection and sweeping by a professional, CSIA Certified
Chimney Sweep or at the very least, sweeping it yourself once a month
and having an inspection by a professional once a year who is trained to
see dangerous damages. The idea is to avoid chimney fires altogether,
which can and do cause internal damages to chimneys making them
unsuitable for further use. A second fire may very well escape the
chimney and spread to the rest of the house. What this person is saying
is very irresponsible and could cause loss of property and life if
people take his/her advise.
For more information please visit www.midwestcsc.org, www.csia.org, or
www.nfpa.org.
Sincerely,
Marge Padgitt
Educational Director
Midwest Chimney Safety Council
Independence, MO 64050
NOTICE:
Chimney fires, flue fires, are dangerous. No matter what you do or
how you do it, flue fires can still occur. No once accepts
liability for the actions of others (including "professionals"), and in
the case of wood stoves and chimneys attached thereto you are on your
own and must use discretion and care in the use of a wood stove.
