Chimney Safety Alert
--Reprinted from Consumer Product Safety Commission document #5017
In 1982, wood-burning appliances accounted for more fires, more fire deaths, and
greater property damage than any other kind of heating fuel -- about 140,000 fires,
250 deaths and $257 million in property damage. These losses represented 20 percent
of all residential fires in the U.S., 5 percent of all fire deaths, and 8 percent
of estimated property damage.
CPSC research indicates that most wood heating fires involve the chimney and not
the appliance itself. The majority of these fires are contained within the chimney
and cause no damage to the house. The Commission is concerned, however, not only
about the chimney fires that did ignite other parts of the house, but also about
the potential future hazard from the continued use of chimneys whose structural
integrity has been compromised by a chimney fire. This is especially true in light
of the fact that many contained chimney fires are not reported to the fire services;
in fact, consumers may not even be aware that a chimney fire has occurred.
Therefore, the Consumer Product Safety Commission is issuing a special safety alert
concerning chimneys used with wood burning stoves, fireplaces, and fireplace inserts.
The Commission urgently warns consumers to be aware of the potential fire hazards
associated with these chimneys.
Now that the nation has entered the heating season, the Commission strongly urges
you, if you have a stove or fireplace, to check the chimney for any damage that
may have occurred in the past heating season. If it is difficult to examine the
chimney, a local chimney repairman, chimney "sweep," or dealer can help. Have any
damage repaired NOW.
Most fires involving either masonry or prefabricated metal chimneys occur because
of improper installation, use, or maintenance. The Commission staff has identified
the following common causes of fires:
- Improper chimney installation too close to wood framing.
- Installation of thermal insulation too close to the chimney.
- Improperly passing the stovepipe or chimney through a ceiling or wall, causing ignition
of wood framing.
- Structural damage to the chimney caused by the ignition of creosote (a black tar-like
substance that builds up inside the chimney in normal use).
Structural damage to metal prefabricated chimneys that results in wood framing being
exposed to excessive temperatures or leakage of potentially toxic gases to the interior
of the home can take the following forms:
- Corrosion or rusting of the inner liners of metal chimneys.
- Buckling, separation of the seam, or collapsing of the inner liner of metal chimneys.
(This can result from too hot a fire, especially in high-efficiency stoves and in
fireplace inserts, or from a creosote fire.)
Structural damage also occurs in masonry chimneys, often associated with deterioration
or improper installation of the chimney. The tile inner liner and the surrounding
brick or block structure may crack and separate, perhaps as a result of the ignition
of creosote that has built up in the chimney. Many old chimneys do not have a tile
liner. If your chimney does not have a liner, the addition of a properly installed
liner is advisable. Also, a clay liner should be sealed with refractory cement.
Even when the heating appliance is properly installed, people with either metal
or masonry chimney systems should frequently check the chimney for creosote deposits,
soot build-up, or physical damage. This involves only a simple visual examination,
but it should be done as often as twice a month during heavy use. If you see heavy
creosote buildup, suspect a problem, or have had a chimney fire, a qualified chimney
repairman or chimney "sweep" should perform a complete safety inspection. They can
arrange for any necessary repairs or creosote removal, which must be done before
the heating appliance is used again.
There are products now available which, according to recent tests conducted by independent
laboratories, show promise for reducing the production of creosote and harmful pollutant
emissions. Advance wood stove designs appear to provide more complete combustion
of the fuel. Catalytic combustors appear to achieve similar results, and are available
with new stoves or as separate components which can be installed between the flue
gas exit and the chimney connector of existing stoves.
The Commission advises owners of all chimneys to:
- Be sure that the chimney and stovepipe were installed correctly in accordance with
the manufacturer's recommendations and local codes. If there is any doubt, a building
inspector or fire official can determine whether the system is properly installed.
- Minimize creosote formation by using proper stove size and avoiding using low damper
settings for extended periods of time.
- Have the chimney checked and cleaned routinely by a chimney "sweep" at least once
a year. Inspect it frequently, as often as twice a month if necessary, and clean
when a creosote buildup is noted.
- Always operate your appliance within the manufacturer's recommended temperature
limits. Too low a temperature increases creosote buildup, and too high a temperature
may eventually cause damage to the chimney and result in a fire.
- Frequently look for signs of structural failure.
If you have had a fire or other safety problem with your chimney, or would like
additional information, call the Commission's toll-free Hotline 800-638-CPSC.
The U.S. Consumer Product Safety Commission protects the public from the unreasonable
risk of injury or death from 15,000 types of consumer products under the agency's
jurisdiction. To report a dangerous product or a product-related injury, you can
go to CPSC's forms page and use the
first on-line form on that page. Or, you can call CPSC's hotline at (800) 638-2772
or CPSC's teletypewriter at (800) 638-8270, or send the information to
info@cpsc.gov. Consumers can obtain this publication and additional publication
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