As an electrical contractor who installs fire alarm systems regularly, you likely have experienced costly call backs due to system false alarms. You would expect that, with the new technology available, you would never experience these problems. At least, that is what the fire alarm equipment salesman told you.

In fact, a widely held belief in the fire alarm community states that the more modern fire alarm systems, using the addressable/analog design architecture, provide far more reliable performance than the older “conventional” systems. However, no statistically valid, peer-reviewed research substantiates this belief. Clearly, the smoke detectors of 20 years ago represented a “false alarm” problem. As the population of smoke detectors increased, the number of unwanted alarms reported to municipal fire services across the country reached epidemic proportions. Complaints galvanized the leading fire alarm manufacturers into action, and they developed new technologies. The addressable/analog architecture currently employed for most systems seems to have provided a lower incidence of unwanted alarms.

However, as documented in a recent report published in October 2010 by the National Fire Protection Association, U.S. fire departments responded to 2.177 million false alarms in 2009. Although this indicates a decrease of 2.9 percent over the previous year, it means false alarms accounted for one out of 10 calls to which fire departments responded.

Although an issue may exist with how fire departments record what they label as the causes of false alarms, the report shows a decrease of false alarms due to system malfunctions (32.1 percent of all false alarms) by almost 9 percent over those in 2008. However, the report attributes 45 percent of all false alarms to what those reporting labeled as “unintentional false alarm.” Those reporting describe these unintentional false alarms as the actuation of a device accidentally and included responses to carbon monoxide detectors.

All these statistics show that your installations still have a high probability of false alarms, causing a significant loss to your profit margin.

The major causes of false alarms today remain the same as they have been for years: poor installation and maintenance. Poor installation can take on many forms, from miswired devices to continuing to attempt installations of technologically challenging equipment without paying for assistance from the manufacturer or authorized distributor.

NFPA 72 2010, the National Fire Alarm and Signaling Code, clearly states the requirements for proper installation of the devices associated with a fire alarm system. Consistently assigning the same technicians to install fire alarm systems makes good business sense. So does choosing a brand of fire alarm systems that is both reliable and has strong technical support from the manufacturer or its authorized (and trained) distributor. Unfortunately, the perfume of the low-cost equipment may outweigh the stench of the poor, false-alarm prone installation.

The practice of installing smoke detectors in areas that are obviously unfriendly environments is one avoidable cause of unintentional false alarms. For example, the drawings show a smoke detector in the center of a room, but the heating, ventilating and air conditioning (HVAC) contractor has already installed ductwork and has located a vent exactly where the smoke detector belongs. Installing the smoke detector adjacent to the vent, regardless of whether it is a supply or return vent, will have a detrimental effect on the smoke detector’s function. For this reason, the code states that, in spaces served by air-handling systems, you must not locate detectors where airflow prevents detector operation. Now, this clearly references that the vent can affect the ability of the detector to detect smoke. However, an additional problem arises if the vent is a supply. Such a vent can cause dust that accumulates in the detector to “cloud” when the HVAC system turns on. This, ultimately, would actuate the detector. If the vent is a return, it can draw dust into the detector. In either case, an unintentional false alarm will occur.

Poor maintenance of the fire alarm system is another leading cause of false alarms. The code clearly states the property, building or system owner is responsible for the maintenance of the system, but the owner rarely sees the code. As a contractor, you have the responsibility to make the owner aware of this requirement, and of course, implementing a contract to do this work will also prove profitable to you.
As a professional contractor and adviser to your customer on fire alarm systems, you must ensure the system is installed and maintained in accordance with NFPA 72 2010, the National Fire Alarm and Signaling Code. Do so and you will go a long way toward eliminating unwanted, unnecessary or false alarms and those costly call backs.


MOORE, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a past chair of the NFPA 72 Technical Correlating Committee. Moore is a principal with Hughes Associates, Inc. at the Warwick, R.I., office. He can be reached at wmoore@haifire.com.