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"But my
furnace chimney looks fine on the outside."
Many chimneys venting gas or oil furnaces or hot water
heaters may appear to be in fine condition on the outside.
But inside it could be a completely different situation.
Yesterday's chimneys were not designed for venting today's
more energy efficient appliances. Let's take a close look at
what really counts...the inside.
Now look inside, see the problems?
A look at the inside of this same
chimney shows how acid-laden residue from the furnace has
attacked this flue. The original clay liner has eroded away;
pieces of it are even missing. (Old chimneys might not even
have a liner.) Mortar and bricks are loose and falling, and
moisture has leeched through to the home's interior walls.
With continued use, more erosion will take place, possibly
leading to leaks in the flue, complete flue blockage, or
possibly even carbon monoxide poisoning of the home's
occupants.
Chimney problems can cause illness and even loss of
lives.
It's happened thousands of times - illness, even death, from
carbon monoxide or sulfur dioxide poisoning. With
deterioration of the flue, the deadly gases can find their
way into your home through even the smallest cracks.
In severe cases, the chimney erosion will lead to partial or
complete internal collapse, blocking the flue and sending
these poisonous gases into the home.
But fortunately, the problems of a deteriorating gas or oil
furnace flue can be corrected without completely rebuilding
your chimney.
About
Carbon Monoxide
Consumer confidence in the convenience and safety of
today's home heating systems is usually well-placed. The oil
and gas heating industries have achieved impressive safety
records. Nonetheless, according to the U.S. Consumer Product
Safety Commission, over 200 people across the nation are
known to die each year from carbon monoxide poisoning caused
by problems in the venting - out of their homes - of toxic
gases produced by their heating systems. Other estimates for
total accidental CO poisoning are much higher. The Journal
of the American Medical Association, (JAMA Volume 261, No.8,
February 24,1989) estimates 1,600 deaths occur yearly.
In addition, around 10,000 cases of carbon
monoxide-related injuries are diagnosed each year. Because
the symptoms of prolonged, low-level carbon monoxide
poisoning mimic the symptoms of common winter ailments
(headaches, nausea, dizziness, fatigue, even seasonal
depression), many cases are not detected until permanent,
subtle damage to the brain, heart and other organs and
tissues has occurred. The difficulty of diagnosis also means
the numbers of people affected may be even higher.
What Is carbon Monoxide?
By now we all know that carbon monoxide is a very
dangerous, colorless, odorless gas, generally associated
with your home heating system, but for a little better
understanding, let's take a quick trip back to high school
chemistry class. The gas or oil you burn for home heating
are compounds known as hydrocarbons (hydrogen + carbon). In
your furnace these hydrocarbons are mixed with oxygen from
the air in your home, and burned to produce heat.. When your
furnace and chimney are working properly, the gas or oil is
burned more or less completely, and the resulting fumes are
mainly carbon dioxide (carbon + 2 oxygen atoms) and water
vapor. If your furnace doesn't get enough oxygen, either
because the house is too tight or the chimney isn't
functioning properly, carbon monoxide (carbon +1 oxygen
atom) is produced instead. It's the lack of that one little
oxygen atom that causes all the trouble.
What Carbon Monoxide Does To You
Too much carbon monoxide in your blood will kill you.
Most of us know to try to avoid this. Less well known is the
fact that low-level exposure to this gas also endangers your
health. One of the imperfections of our human bodies is
that, given a choice between carbon monoxide and oxygen, the
protein hemoglobin in our blood will always latch on to
carbon monoxide and ignore the life-giving oxygen. Because
of this natural chemical affinity, our bodies - in effect -
replace oxygen with carbon monoxide in our bloodstream,
causing greater or lesser levels of cell suffocation
depending on the intensity and duration of exposure.
The side-effects that can result from this low-level
exposure include permanent organ and brain damage. Infants
and the elderly are more susceptible than healthy adults, as
are those with anemia or heart disease. The symptoms of
low-level carbon monoxide poisoning are so easily mistaken
for those of the common cold, flu or exhaustion that proper
diagnosis can be delayed. Because of this, be sure to see
your physician about persistent, flu-like symptoms, chronic
fatigue or generalized depression.
If You Suspect A Problem
If you ever suspect a carbon monoxide problem,
immediately open doors or windows to ventilate the house and
get everyone outside for fresh air. Most utility companies
will respond to emergency calls and check your house and
heating system for the presence of carbon monoxide. Do NOT
reinhabit the house until you are certain there is no longer
a problem. If necessary seek medical attention, treatment is
very important. Have the heating system and the chimney
checked and serviced by reputable professionals like US
Chimney as soon as possible.
Why Is Poisoning From Carbon Monoxide On The rise?
1) Today's houses are more air tight due to energy
conserving measures. Consequently there is less fresh air
coming into a home and not as many pathways for stale or
polluted air to leave it. When furnaces and boilers are
starved of the oxygen needed to burn fuels completely,
carbon monoxide is produced. Many newer houses are so
airtight that powered exhaust fans in the kitchen and
bathroom can overcome the draft in the furnace chimney and
literally pull the toxic gases into the living space.
2) The new high-efficiency gas and oil furnaces, when hooked
up to existing flues, often do not perform at an optimum
level. The differences in performance create conditions that
allow combustion byproducts to more easily enter home living
spaces.
3) The above conditions join a number of older, on-going
problems including damaged or deteriorating flue liners,
soot build-up, debris clogging the passageway, and animal or
bird nests obstructing chimney flues.
Why Chimney Maintenance Is Important
When gas and oil burn in vented heating systems, the
dangerous fumes that are the by-products of combustion -
including carbon monoxide - are released into the chimney
through a connector pipe. Funneling these fumes out of the
living area is the primary purpose of a chimney. In addition
to carrying off toxic gases, chimneys also create the draft
(flow of air) that provides the proper air and fuel mixture
for efficient operation of the heating appliance.
Unfortunately, many chimneys in daily use in homes
throughout the country either are improperly sized or have
conditions that make them unable to perform their intended
function.
Gas
Natural gas is a clean-burning fuel, but today's
high-efficiency gas furnaces pose special problems. (see the
information pages on gas for a more complete discussion) The
fumes they produce are cooler and contain high levels of
water vapor, which cause more condensation than older
models. Since these vapors also contain chlorides picked up
from house-supplied combustion air, the flues are subjected
to more corrosive conditions than before and can quickly
deteriorate or plug up completely.
Oil
Oil flues need to be cleaned and inspected annually
because deposits of soot may build up on the interior walls
of the chimney. The amount of soot depends on how well tuned
the furnace is and whether the house provides sufficient air
for combustion. Excessive soot causes problems ranging from
inefficient furnace operation to completely blocked
chimneys.
To the extent that problems with either of these heating
systems interfere with the flow of toxic gases and particles
out of the house, they may also force carbon monoxide into
the home. They may cause a one-time, high-level exposure
situation or release smaller amounts more regularly over a
longer period. These problems should never be ignored.
Preventing Problems
In the United States, numerous agencies and
organizations now recognize the importance of annual heating
system inspection and maintenance in preventing carbon
monoxide poisoning. The U.S. Consumer Product Safety
Commission, the U.S. Environmental Protection Agency, the
National Fire Protection Association, the American Lung
Association - are some of the organizations that now
encourage the regular maintenance of home heating systems
and their chimneys in order to keep "the silent killer" at
bay.
A well tuned furnace or boiler, connected to a venting
system or flue that is correctly sized, structurally sound,
clean and free of blockages, will operate efficiently and
produce a warm and comfortable home. Carbon monoxide
detectors are now readily available and no home should be
without at least two, one near the furnace and one near the
sleeping area of the home. Detectors are NOT a substitute
for routine maintenance, but can be a lifesaver should
problems occur.
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