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Carbon Monoxide Alarms at the End of their Life

January 27, 2012
 An Underwriter Laboratories (UL) standard UL 2034, entitled Single and Multiple Carbon Monoxide Alarms, establishes requirements for carbon monoxide (CO) alarms. The February 28, 2008 edition of the standard incorporates a major change that requires all CO alarms produced after August 1, 2009 to have an end-of –life signal. This is to activate once the device reaches its projected end-of-life. The specific product life is based on the design of the device.
A CO alarm will have three (3) signals – alarm, trouble, and end-of life. An activation for a CO alarm would be a series of four (4) rapid beeps followed by a five (5) second pause and then repeating. A trouble signal, indicating some type of fault or low battery, is a ½ second beep every 30-60 seconds – just like a low battery on a smoke alarm. The end-of life signal may be a distinct signal, or the same as a trouble alarm, providing that there is a visual indicator on the CO alarm to indicate that this is an end-of life alarm.
Depending on the manufacturer, some end-of-life signals can be silenced for up to 30 days, others can not. What is important is that when an end-of-life signal is sounded, the CO alarm must be replaced. This is true if the unit is a standalone CO alarm, or in a combination unit with a smoke alarm.
Since January of 2007, it has been an Illinois law to have a working CO alarm in all dwelling units. Many CO alarms now in service were made prior to the incorporation of the new requirements and will not have an end-of-life signal. As a result, many of these alarms may not function now, as designed. If your alarm does not have the end-of-life feature, was manufactured prior to August 2009, or you cannot find a manufactured date (located on the backside of the alarm) consult any paperwork that came with the unit or research the company’s website for further information. If none can be found, then serious consideration should be given to replacing the CO alarm.
Illinois law requires that CO alarms must be battery powered as a primary or secondary power supply. They cannot be solely electric powered.
For further information on CO or smoke alarms, contact the Palatine Fire Prevention office at 847-359-9029 or     


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