| Please be Aware of the Basic Safety Tips
KEEPING YOUR CHIMNEYS AND FLUES OPERATING PROPERLY
Chimneys Are Made to Protect You
A chimney is a structure made of masonry
or metal, which surrounds and supports a flue or multiple flues that vent products
of combustion from gas, oil, or solid
fuel appliances or fireplaces. The flue, then, is the inner part of the chimney,
the part that actually contains and vents the products of combustion. Flues can
be made of clay, as in the case of most masonry chimneys, or of metal, as in the
case of prefabricated or manufactured chimneys.
One way to think of a chimney and flue within it is to think of it as a structure
built to protect you. That is an important function of all chimneys no matter what
kind of appliance or fireplace they serve.
Remember, the main purpose of a chimney
is to vent the products of combustion from your home. That function is crucial
because the products of combustion contain
hazardous and noxious gasses. One of the hazardous gasses your chimney needs
to remove from your home is carbon monoxide.
Carbon monoxide is a colorless, odorless,
tasteless gas that can cause serious illness or death when it is present in sufficient
amounts. It is responsible
for hundreds of deaths and countless illnesses every year in homes across America.
In many cases carbon monoxide in the home originates in a furnace or other
burning appliance and finds its way into the house due to inadequate venting.
What
causes inadequate venting? There are several possibilities. One is that the flue
has become blocked. The blockage can come from debris falling into
the chimney
due to a deteriorating masonry chimney, or, it may be the result of nests
built there by animals or birds. Carbon monoxide can also seep into the house through
cracks or holes in flues and chimneys that moisture, chemical residue, or
chimney
fires have damaged.
The other important function of chimneys, especially those
serving solid fuel burning appliances like wood stoves or fireplaces, is to keep
excessive
heat
from combustible
materials that surround the chimney. Heat or flames from a chimney fire
can escape through cracks in the clay flue liner or through damaged or missing
mortar joints
of a chimney. They can then ignite surrounding combustible framing members
of a house.
Chimney fires occur within the structure of the chimney itself.
They happen when hot flue gasses or cinders ignite creosote accumulated on the
walls
of an unclean
chimney flue. Creosote is a natural byproduct of burning wood. It is
highly flammable and will accumulate on the inner walls of the flue under certain
burning conditions.
Even without the occurrence of a chimney fire, framing
members surrounding a chimney can have their molecular structure altered and
become more
flammable when exposed
to excessive heat over long periods of time. This process is known
as pyrolasis. Once wood is sufficiently pyrolized it can ignite at relatively
low temperatures
and becomes a significant fire hazard.
So, you see, a well structured chimney and flue are designed to offer
protection to your family and home from both the dangers of noxious
gasses such as
Carbon Monoxide, and from the high levels of heat present in the flue
gasses of
solid fuel burning appliances and fireplaces. But, like all structures,
they must
receive regular inspections and maintenance in order to maintain their
integrity and
to continue doing their job.
How To Maintain a Properly Functioning
Chimney
It is easy to understand from the information above why it is strongly
recommended that all flues and chimneys in use should receive annual
inspections. In
fact, you may want to consider more frequent inspections for chimneys
and flues that
receive heavy use, especially those venting hotter flue gasses that
contain creosote and soot produced by solid fuel burning fires.
A proper inspection of your chimney by a qualified chimney professional
should include a thorough examination of the external structure to
look for signs
of deterioration or weakness. Exterior staining due to flue gasses
seeping through
the chimney structure,
broken or spalled bricks, and deterioration of mortar joints are
all signs that your chimney may need repair.
A proper evaluation should also include a visual inspection of the
flue inside the chimney. Ideally, that internal inspection should
be done
with a video
inspection device. Such devices allow chimney professionals to detect
even small cracks
in the chimney liner that may not be seen by the naked eye. According
to the National
Fire Protection Agency code, cracked chimney liners constitute a
significant safety hazard and must be replaced.
All connections from
the burning appliance to the chimney should also be thoroughly inspected.
If the inspections described above indicate the possibility of a
chimney deficiency, then a more thorough inspection of the chimney
and the
structural members surrounding
it may be required.
However, regular annual inspections by a qualified chimney professional
should go a long way towards heading off serious chimney problems
and the need for
expensive repairs.
It is important to note, for an inspection to yield the best results,
the flues to be inspected will need to be cleaned first. Otherwise,
soot, creosote,
or
other residue might mask physical problems with the flue or flue
liner.
What You Can Do Between Inspections To Keep Your Chimney Operating
Properly
Make sure you have working carbon monoxide detectors in your home
and check them regularly. They should be located in the sleeping
areas
of your home
and preferably
on each floor. Carbon monoxide detectors can alert you to possible
problems within the venting systems of your furnace and gas hot
water heater and
keep you from
prolonged exposure to even low levels of carbon monoxide.
When using
wood burning appliances avoid banking the fires and closing the dampers in order
to prolong burning. Slower, cooler
burning wood
fires are
the primary
contributor of creosote in chimneys. Be certain to burn wood
that has been properly aged. Burning green wood also contributes to
creosote in chimneys.
Whenever possible burn your wood fires hot.
Hotter flue gasses prevent the condensation of creosote and pass more quickly
through the chimney.
They
are therefore useful
in preventing the accumulation of creosote in the flue. (If
you are using a wood stove, be sure to have a stove thermometer in
place
so you can
avoid over
firing
your stove.)
It is a good idea to treat your firewood with a
compound that will help keep creosote from accumulating in your chimney.
You can ask
your chimney
professional
for his
recommendation as there are several compounds on the market
created for this purpose.
Make periodic visual inspections of the external portions
of your chimney and any connections between burning appliances
and your
flue. Even
cursory visual
inspections
can alert you to problems like connectors that have come
loose
or a chimney that is deteriorating.
By having your chimney inspected by a qualified professional
on a regular basis and following the simple principles for
proper operation
of your
burning appliances,
you should enjoy years of trouble-free operation of your chimneys
and flues.
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