Fireplace and Chimney Cleaning
Most folks consider their fireplaces and
chimneys to be indestructible parts of their home that require
little or no maintenance. While masonry work is generally as close
to maintenance-free as you can get, fireplaces and chimneys are more
than just works of masonry: they are a part of your home's heating
system, which must effectively exhaust fumes from your fireplace,
furnace and water heater.
Relatively minor but regular maintenance
efforts can help your chimney operate safely for an indefinite
period of time. In the U.S., many people are poorly informed about
the importance of basic chimney maintenance. This lack of
understanding causes a substantial number of preventable deaths and
injuries each year.
Beyond the safety issue, neglect of
chimneys leads to very expensive major repairs that would not be
necessary if the chimney were properly maintained.
The three most serious problems that result
from poorly maintained chimneys are:
- Carbon monoxide poisoning
- Chimney fires
- Premature failure of the fireplace and
Carbon Monoxide Poisoning
Carbon monoxide poisoning claims about
4,000 lives a year in the U.S., and a significant number of these
deaths are the result of poorly maintained chimneys. In addition,
about 10,000 people are made ill by lower levels of exposure to
Carbon monoxide is a by-product of
combustion. The less complete the burning (combustion), the more
carbon monoxide is generated. Gas hot water heaters, gas and oil
furnaces, fireplaces, and wood stoves all generate carbon monoxide.
One of the reasons carbon monoxide is so
deadly is that you generally can't see or smell it: rarely do its
victims have any warning. Low levels of poisoning tend to cause
flu-like symptoms, so that people think they are just catching a
cold. More advanced poisoning can cause vomiting and headaches and
even death. Carbon monoxide is deadly because it tricks the body
into thinking it is oxygen. The body actually prefers carbon
monoxide, choosing it over oxygen when both are present in the
Once in the body, carbon monoxide goes
everywhere in the body, including the brain. Children, in
particular, are quite susceptible to brain damage after relatively
low levels of exposure.
With chimneys, fireplaces and furnaces,
most carbon monoxide problems occur because of improper exhausting
of fumes. Such problems are almost entirely avoidable through
regular professional chimney inspection.
Another major threat posed by inadequate
maintenance is chimney fires. As fires burn, they generate smoke. As
the smoke rises up the chimney, it comes into contact with the
relatively cooler interior of the chimney (the flue), where some of
the smoke condenses, like steam on a glass of cold water. The
resulting condensed smoke is called creosote. Creosote is a black or
brown gummy substance that builds up on the flue. Once a sufficient
amount of creosote builds up, it can catch fire. The resulting
chimney fire can range from being barely noticeable to being so
dramatic that it sounds like a low flying jet.
The danger in chimney fires comes from the
extremely high temperatures generated, which can severely damage the
mortar in the chimney and even ignite nearby burnable surfaces. The
first fire in a chimney may not even be noticed or, if noticed, may
instill a false confidence in the owner (noticing that they had one
chimney fire and seeing no harm done, they conclude that the hazard
doesn't apply to their circumstances).
In many cases, the first chimney fire can
cause cracks and loosen mortar joints that then provide the next
fire with an avenue to reach the roof timbers and other combustible
Typically, chimney fires that spread to the
rest of the house do so very quickly and consume the entire house
before being brought under control. The high temperatures cause them
to spread extremely fast, often trapping people in upper story
A third major danger from poorly maintained
chimneys is failure of the basic structure itself. As discussed
above, chimney fires can damage the mortar joints and cause cracks
that crumble further with continued "small" chimney fires.
Even before the second chimney fire has the
opportunity to penetrate the cracks caused by the first, carbon
monoxide can escape the chimney and leak into the living quarters of
the home. Brain damage and death can occur before anyone has even
noticed a problem.
As frightening and fierce as the potential
fireplace and chimney hazards are, they are almost entirely
preventable. The Chimney Safety Institute recommends that homeowners
who light fires in their fireplaces three or more times a week
during the heating season should have their chimneys inspected and
cleaned once a year.
If unseasoned wood is burned in the
fireplace, twice-a-year cleaning and inspection may be necessary,
because unseasoned wood usually burns at a lower temperature than
seasoned wood, causing more smoke and therefore more creosote.
Some people assume that because they don't
have fires continuously during the winter, they don't have to worry
too much about creosote buildup. This may be far from the truth. The
colder the flue, the greater the condensation, so creosote buildup
is the greatest at the beginning of a fire, in the time before the
flue has fully heated up.
The Chimney Safety Institute also
recommends that if you use the chimney, wood stove, or free-standing
fireplace less than three times a week, you should have the chimney
inspected at least once a year and cleaned if necessary.