Carbon Monoxide Detectors Alert Homeowners Before Gas Builds Up
Q. We switched to natural gas heat last year and are very happy with the new furnace, our monthly savings, and the comfort level in the home. Since then I’ve heard about more tragic deaths from carbon monoxide poisoning related to gas heaters. Are there actually more accidents occurring? I see advertisements for carbon monoxide detectors and notice them for sale in the local hardware stores. Do they work, should I have one, and how much do they cost?
A. Tragically, about 200 people in the United States die each year from accidental carbon monoxide (CO) poisoning, and another 5,000 require treatment at hospital emergency rooms. Many more people suffer from CO overexposure. Their condition may not be diagnosed or treated properly because symptoms are similar to the flu or common cold dizziness, headache, fatigue and sleepiness, nausea, vomiting, and confusion or disorientation. Even extremely low levels of CO can cause health problems, especially for elderly people; infants and young children; and individuals with cardiovascular disease, anemia and lung disease.
The fact that CO is colorless and odorless makes it all the more dangerous, because we can’t sense its presence ourselves. A specialized detector can alert you when CO is present, allowing you to take action before the CO gas builds up to dangerous levels.
For homes with combustion appliances, a detector provides relatively inexpensive insurance against what could potentially be a deadly situation. Combustion appliances include wood-burning fireplaces and wood stoves; and furnaces, water heaters, ovens, ranges and space heaters that use fossil fuels such as natural gas, propane, gasoline, coal, kerosene, oil or charcoal.
CO detectors look similar to smoke alarms, and they are available in models that operate on 120-volt household current or replaceable batteries. Prices range from around $40 up to $100 or more. Most hardware stores and home centers stock these devices.
The Consumer Product Safety Commission recommends that consumers purchase and install CO detectors that meet Underwriter Laboratories standards. (Look for the UL label on the product.)
These detectors not only alert you quickly to the presence of high levels of CO, they also respond at low levels. (Exposure to lower concentrations over time produces flulike symptoms in healthy adults and more severe illness in people with chronic health problems. The ability to detect lower levels protects against illness.) The alarm will sound in a short amount of time when CO concentrations are high, but it will take longer for the alarm to sound with lower CO levels.
While purchasing a CO detector makes good sense, it makes even better sense to prevent CO buildup from occurring. Keep your furnace tuned and maintained. Make certain adequate air for combustion reaches your furnace or water heater; don’t enclose them in mechanical rooms without grills or openings. Never operate unvented combustion appliances or charcoal grills indoors without adequate room ventilation.
Check for signs of flue spillage or backdrafting. To do so, visually inspect your furnace, water heater or other combustion appliance for signs of discoloration from flue gas spillage or backdrafting. Contact a professional service provider if you suspect problems with the safe operation of these appliances.
How CO gets into a home
Burning wood or the combustion of fossil fuels produce CO. A correctly tuned furnace with adequate air for combustion will produce very little CO. On the other hand, a significant amount of CO will be produced when there is incomplete combustion. Conditions that produce incomplete combustion include improperly tuned or faulty equipment or a restricted supply of air. A smoldering fire in a fireplace also could send CO into a room.
CO levels in homes with combustion appliances typically range from 0.5 ppm (parts per million) to 5 ppm, or about the same as outdoor air. CO concentrations above about 5 ppm should be investigated. The outdoor level of CO also affects the indoor level. The National Ambient (outdoor) Standard for CO is 9 ppm over an eight-hour period or 35 ppm for one hour of exposure. Due to heavy vehicle traffic and weather conditions, the CO level of outdoor air in some Washington cities can occasionally exceed these values.
Where to call with questions
If you have questions concerning health symptoms and you suspect it might be related to CO levels in your home, call your physician, local health department or health district, or the Washington State Department of Health (360) 664-8860. Other resources for information are the American Lung Association of Washington, (800) 732-9339, and the U.S. Environmental Protection Agency’s Region 10 office in Seattle, (800) 424-4372.
For questions about your furnace or other combustion appliances, call your service provider, mechanical contractor, or gas company.
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