Life savers: carbon monoxide detectors offer peace of mind for homeowners and are mandatory for some builders - Carbon Monoxide Detectors

Building Products, Sept-Oct, 2003 by Sharon O'Malley

And Wikstrom says that eventually there will be one in every new home. "We produce products that save people's lives," he says. "As you get greater and greater education about the dangers of carbon monoxide, they will be coded in as smoke alarms are now throughout the country."

A Trio of Detectors Here are the three most common carbon monoxide detection technologies:

CHEM-OPTICAL DETECTORS, known as "gel cells" or biomimetic alarms, mimic the body's response to carbon monoxide. Gel-coated discs darken in the presence of CO and trip the detector's alarm. These inexpensive detectors won't sound the alarm in the presence of common household gases. Still, some complain that they are not as precise as detectors that operate on other technologies because high and low temperatures and humidity can trip their alarms. Biomimetic sensors work best when indoor relative humidity and temperatures are controlled.

ELECTROCHEMICAL SENSORS are usually battery powered. Electrodes in an electrolyte solution generate energy when they react with CO. These detectors respond quickly to CO, but their sensors last only about two years and can die without warning the home-owner. Electrochemical detectors usually include a continuous digital readout, a lighted display, and a memory feature that allows the homeowner to check CO levels that occurred in their absence.

METAL OXIDE OR SEMICONDUCTOR SENSORS were the first kind on the market. Heated tin dioxide reacts with carbon monoxide to determine levels of the toxic gas. Because the tin oxide is heated every few minutes, the unit needs a lot of energy to operate, so these detectors have to be plugged into an electrical outlet. While they can't run on batteries alone, they come with battery backups in case of a power outage. Metal oxide sensors respond quickly to CO but can be tripped by common household chemicals, and can degrade in the presence of high humidity.--S.O'M.

Kidde. To avoid confusing an abruptly awakened homeowner, this carbon monoxide/fire detector has a voice warning system that announces, "Fire! Fire!" or "Warning! Carbon monoxide!" during an emergency. When its battery begins to run low, the unit will chirp once, and then resort to the voice message. "Low battery!" and flash red lights. The single test/reset button tests the smoke and CO sensors simultaneously. 800-880-6788. www.kidde.com. Circle 185.

First Alert. This 120-volt AC plug-in carbon monoxide detector can be tested using a standard TV or VCR infrared remote control. A back-up 9-volt battery keeps the unit running during power outages. Its peak memory feature allows it to record its last highest CO level reading until reset, even if the air clears, the maker claims 630-851-7330. www.firstalert.com. Circle 186.

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Invensys. Using one interconnect wire, the Firex 7000 carbon monoxide detector can be connected to additional smoke and CO alarms. The Smart Quiet Alarm locator silences all interconnected smoke and CO alarms except the trigger alarm for up to 10 minutes to help identify the alarm source, says the company. A ramp-up horn starts out at a low volume during tests to protect the user's hearing. This combination smoke/CO detector is available in both battery-operated and 120-volt AC versions. 630-260-3402. www.icca.invensys.com. Circle 187.