ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Tuesday, January 9, 1996 TAG: 9601100106
SECTION: EXTRA PAGE: 6 EDITION: METRO
COLUMN: At Home With Technology
SOURCE: DAVID BUTLER
Q: My neighbor just installed a carbon monoxide detector in her home. Sounds like a good idea, but wasn't there some kind of recall or safety problem with these things?
A: Protecting your family against carbon monoxide (CO) is an excellent idea. Known as the "silent killer," CO is a colorless, odorless, tasteless gas that's nearly impossible to detect. CO poisoning can also be difficult to diagnose since symptoms are similar to other illnesses such as the flu. Chronic exposure can cause headaches, fatigue, nausea and dizziness.
Although there has never been a recall or safety problem with CO detectors, some units were prone to "nuisance tripping" at very low levels of carbon monoxide gas.
The Consumer Products Safety Commission recommends installing a least one CO detector per household, preferably near the sleeping area. CO is a byproduct of combustion. Major sources include furnaces, fireplaces, and LP or kerosene room heaters. New sealed-combustion appliances help isolate CO at the source. This is especially important for today's tightly built homes.
In October 1994, Chicago became the first major city to mandate CO detectors in all homes and apartments with combustion furnaces or appliances. During the first two months after the new ordinance went into effect, the Chicago Fire Department responded to nearly 6,000 carbon monoxide alarms. And during a rare atmospheric condition known as a "thermal inversion," residents reported more than 1,800 alarms within a 24-hour period!
Understandably, news reports from Chicago gave CO detectors a bad rap. But it's important to realize that those detectors were not defective. They were simply doing what they were designed to do. In the wake of this event there was general agreement that the detectors were too sensitive to small amounts of the gas.
Underwriters Laboratories has since revised its safety standards. To obtain UL approval, CO detectors must sound an alarm after exposure to 15 parts-per-million (ppm) for 30 days. The old standard required the alarm to trip after only eight hours' exposure at that level.
Depending on the model and sensor technology, some companies have redesigned their CO detectors to meet the new standard. This should greatly reduce nuisance alarms without compromising safety. Many models now feature a silence button. This allows an occupant to override the alarm when a low level of gas is detected. The alarm will still sound if dangerous amounts of CO accumulate.
CO detectors come in battery-powered and plug-in versions. Some models even have a continuous display of the current CO level (a great feature to have!). If your home has a hard-wired security system, you may want to consider a detector with output terminals for a central alarm panel.
So, to answer your question, there has never been a recall or safety problem with CO detectors. However, keep in mind that if the alarm does go off, experts urge you to remain calm. Unless you feel sick, it's not an emergency. A CO detector is giving you an early warning signal. At a minimum, you should have your furnace, appliances and fireplace checked for proper ventilation and operation.
To receive a list of companies that manufacture carbon monoxide detectors, please send $1.50 and a self-addressed envelope to David Butler F-546, Department TWN, 14713 Pleasant Hill Road, Charlotte, N.C. 28278-7927. The list includes toll-free phone numbers and a summary of each company's products.
Q: What's a thermal inversion? What causes it?
A: On December 22, 1994, unusually mild December in Chicago created a stagnant layer of warm air over a layer of cold air, called a thermal inversion. The layer of warm air didn't allow surface pollutants trapped in the cold air to disperse. Carbon monoxide levels reached 10 ppm - high enough to trigger many CO detectors. Summertime inversion layers sometimes contribute to unusually heavy smog in large cities such as Washington and Los Angeles.
LENGTH: Medium: 75 lines ILLUSTRATION: GRAPHIC: The above graph shows the cumulative effect of carbonby CNBmonoxide on a healthy adult.