Carbon Monoxide and Heating Systems
Carbon Monoxide and Heating Systems:
* According to the U.S. Consumer Product Safety Commission, in
2002, heating systems contributed to 55 percent of the 188
reported (non-fire) carbon monoxide deaths. * Carbon monoxide is
estimated to be the number one cause of poisoning deaths in the
U.S.
* Between 1995 and 1999, it is estimated that 10,200 more than
7,800 non-fatal cases of CO poisoning (associated with consumer
products) were reported in U.S. hospitals.
* Many CO poisoning cases are misdiagnosed as flu or cold
symptoms.
Where does CO come from?
Carbon monoxide is a colorless, odorless gas produced as a
result of incomplete combustion of appliances such as boilers,
furnaces, wood-burning stoves, water-heaters and gas cooking
stoves (especially when used as a space heater), as well as
automobiles. CO presents a direct danger when, under certain
circumstances, the toxic gas no longer flows freely out a
flue-vent or chimney and begins back-drafting into your home.
Who's most at risk of CO poisoning?
It is estimated that 1 in 20 homes in cold-weather climates are
capable of producing the conditions that result in CO poisoning.
These conditions can range from a broken or obstructed flue to
less obvious situations, such as an overly tight home,
inadequate combustion air or extra-powerful exhaust vents.
Automobiles idling in an attached garage - even with the garage
door wide open - can raise CO to dangerous levels inside the
home if there is not a completely sealed air barrier between the
garage and the inside of the house. Children, the elderly,
individuals with respiratory problems and pets are at risk for
CO poisoning at levels as low as 30 parts per million (ppm),
however most commercially available CO detectors will not alarm
until levels reach 70 ppm.
How do you know if your home has the potential for CO?
The surest way to test your home is to have a thorough building
performance audit performed, which includes a procedure called a
combustion appliance zone (CAZ) worst-case depressurization
test. The procedure tests your combustion appliances while the
home is placed under severe, worst-case conditions. The test is
relatively inexpensive.
How do you prevent CO?
Carbon monoxide can be kept out of a home by maintaining proper
draft of your combustion appliances. Basic maintenance
activities that include a regular visual inspection of your flue
pipe for signs of aging and keeping the flue clear and
unobstructed are helpful. More importantly, any time you change
the pressure or air-flow characteristics of a house (i.e. adding
ventilation, strengthening air-sealing or insulation
properties), worst-case testing should be performed to ensure
that the upgrades have not compromised the draft of the
combustion appliances.
Will a CO detector protect my family?
Every house should be equipped with a working CO detector,
however it should be used as the last line of defense and not
the sole means to protect your family. A New York state Health
Department bulletin advises, "a carbon monoxide detector is not
a substitute for regular maintenance of CO sources." Most
detectors available at local home centers will not alarm until
CO levels reach as high as 70 ppm. The state Health Department
considers a home dangerous if CO levels of 35 ppm persist for up
to one hour, and only 9 ppm for levels sustained over an
eight-hour period.
A professional-grade, low-level monitor is highly recommended
for homes where children, the elderly, people with respiratory
ailments or pets live.