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Chimmeys |
Having an adequate chimney for your fireplace plays a vital role in
the success of a good burning fire. A chimney has two primary
functions - first, to carry undesirable combustion, also known as
smoke, out of the house and second, to provide the draft that feeds
air to the fire to keep it burning. The draft of the chimney comes
from rising hot air. As the air flows up the chimney, many factors
come into play to include:
Chimney Height
Bends in the Chimney
Chimney Location
Construction of Chimney
Tightness of House
When it comes to the height of the chimney, a tall chimney will
produce more draft than that of a short chimney. For the diameter,
this too has an effect on the draft. If a chimney is too wide, you
could experience a problem in allowing smoke to cool excessively,
which would slow down the draft. You want the diameter to be similar
to the flue outlet diameter. Keep in mind that your chimney diameter
should never be more than three or four times the cross-sectional area
of the stove outlet. If you happen to have a chimney that is
oversized, you should consider adding a liner with a flue that is
smaller in diameter.
The location of the chimney is also important. By adding your chimney
to the indoors rather than outside, you can use the warmth of the
chimney as additional heat. Each chimney has to have turns, which
lowers the draft. As a guideline, every 90-degree turn cuts off five
feet of effective chimney height. In other words, a 12-foot chimney
that has two turns has an effective chimney height of two feet.
The construction of your chimney is also an interesting factor. A
round chimney flue will draft better than a rectangular or square
chimney. You should also consider having an insulated chimney that
will make it easier for the draft and will stay warmer longer. When
it comes to the tightness of your home, every appliance you currently
have for heat has to have air to support combustion. If your house is
too tight, there may not be adequate air to feed the fire.
Most people have no idea the importance a chimney plays but when it
comes time to build or update your fireplace, keep this information
in mind.
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