The Alarm That Cried Wolf

False alarms take up a good bit of police and fire department resources. Low-voltage specialty companies have long struggled with this issue, as local law enforcement and fire departments have decidedly cracked down on those with chronic false trips. Recently, Freetown, Mass., made a public statement regarding the false alarm ordinance it passed in 1994.

“Fire Chief Carlton Abbott Jr. shared false alarm statistics pertaining to the [1994] bylaw,” said Kim Ledoux, correspondent with the Standard-Times newspaper of New Bedford, Mass. “Fiscal 2003–04 showed 699 false alarms. During 2004–05, the year the department started enforcing the bylaw, the number of false alarms dropped to 534. By 2005–2006, the number of false alarms was down to 449.”

The situation has become so bad that leaders in some communities, such as Las Vegas, have adopted a no-response policy. The city of Henderson, Nev., is one of those communities. A Feb. 18, 2008, Las Vegas Sun article reported that there must be a visible indication of a fire before the Henderson fire department will respond. Previously, an alarm was sufficient to trigger a call from the security company to the fire department for response.

This policy is being applied to burglar alarm systems across the nation, and misapplication of smoke detectors is one of the most prevalent causes of false fire alarms. Thus, electrical contractors (ECs) that work in the fire and burglar alarm market must be mindful of the problem.

ECs fighting false alarms should thoroughly know the detectors they use. It’s important to know how they work, how to install them and the kinds of things that can cause false alarms.

For example, passive infrared (PIR) motion detectors can be prone to false alarms when the headlights of a motor vehicle suddenly strike them at night. Although the newer PIRs are better designed and able to repel this kind of interference, it is best to mount them in a corner where it’s not possible for this to occur.

Door switches also can be a source of false alarms when they are applied incorrectly. Surface magnetic door switches, in particular, when used on metal doors, can be troublesome because the steel in the door acts to defer some of the magnet’s flux away from the reed switch in the switch portion of the pair. Over time, the presence of the steel door will lessen the power of the magnet, reducing the holding force on the reed switch. This can eventually lead to false alarms. One solution is to use a larger, wide-gap magnetic switch.

It would be wise for the EC to partner with a manufacturer and one or more suppliers that provide proven support by way of education and telephone advice. If possible, send lead technicians to seminars and other training opportunities. The Internet also offers a host of educational resources, but you have to look for them.

COLOMBO is a 32-year veteran in the security and life safety markets. He currently is director with and a nationally recognized trade journalist located in East Canton, Ohio.

About the Author

Allan B. Colombo

Freelance Writer
Allan Colombo is a 35-year veteran in the security and life safety markets. He is director with and a nationally recognized trade journalist in East Canton, Ohio. Reach him at

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