Avoiding False Alarms

Many electrical contractors will attest to the fact that fire alarm systems offer a nice addition to their primary electrical business. Most can also tell a horror story or two about the number of costly and unpaid service calls due to false alarms from fire alarm systems. Some contractors even decide the false alarm issue provides a significant enough reason to keep them from accepting a fire alarm system installation. Others may complain that they lost a longtime customer due their inability to repair a faulty alarm.

Unfortunately, these systems seem to cause twice as much aggravation as any other part of your business. When you install a fire alarm system, you must not only satisfy the requirements of the electrical inspector, you must also meet the demands of the fire inspector who won’t allow an owner to occupy a building until the system passes inspection.

Can you do something to reduce or possibly eliminate these problems and keep performing fire alarm system installations? Of course. In fact, as the fire alarm system installer, you probably have the most impact on reducing false alarms.

First you must understand the three factors that cause false alarms: poor design, poor installation and poor maintenance.

Of these three items, poor installation and poor maintenance lead the field in causing false alarms. Where does the electrical contractor start in his or her quest to reduce problems caused by what should be a profitable and addition to their primary business? Two areas come to mind and both rely on similar actions that you probably already follow in your primary electrical business: training your electricians to understand fire alarm system installations and a good understanding of the Code—in this case the National Fire Alarm Code, NFPA 72-2002.

NPFA 72 serves as the primarily an installation document. And, it defines what the contractor must do to avoid false alarms and contains the minimum installation requirements for fire alarm systems. The Code defines what most people call a “false alarm” somewhat differently. Instead it defines a “nuisance alarm” as “any alarm caused by mechanical failure, malfunction, improper installation or lack of proper maintenance, or any alarm activated by a cause that cannot be determined.”

NFPA 72-2002 begins by requiring that the fire alarm system designer select initiating devices of the manual or automatic type to minimize nuisance alarms. If, as a contractor, you intend to also design the system, then you need to know the proper use of each type of initiating device. The Code also requires that the contractor install such devices properly.

You should certainly understand the environmental concerns that affect detector installations. Specifically, you cannot install electronic devices like smoke detectors or electronic heat detectors in any area where the following ambient conditions exist:

(1) Temperature below 32 F

(2) Temperature above 100 F

(3) Relative humidity above 93 percent

(4) Air velocity greater than 300 feet/min.

Electrical and mechanical influences and aerosols and particulate matter found in protected spaces can also affect smoke detectors. You should locate detectors to minimize the influences of aerosols and particulate matter from sources such as showers, combustion products and chemical fumes, cooking equipment, fireplaces and paint spray. Similarly, you should also minimize the influence of electrical and mechanical factors, such as electrical noise. While you most likely cannot isolate environmental factors totally, an awareness of these factors during system layout, design and installation favorably affects detector performance.

As a contractor, you are well aware of the pressure brought to bear as the project nears completion. The general contractor and owner clamor for completion of the finish work so that the building may pass final inspection and occupants may move into the space. When you assume responsibility for the fire alarm system, you take on the one major system that, if not completed on time, will keep the building from opening. Because the fire alarm system often becomes an add-on, unless you have become well aware of Code specifics, you may become pressured to install and activate the fire alarm system prematurely. Sadly, this will almost guarantee false alarms from smoke detectors. Additionally, NFPA 72-2002 requires that you not install the smoke detectors until after the completion of the construction cleanup of all tradespeople, unless otherwise required by the authority having jurisdiction. If, as a contractor, someone requires you to install the system before the other tradespeople complete their work, then you should inform the GC or owner that the smoke detectors must be cleaned and retested afterward.

This pressure to finish the job may also tempt you to “throw” more electricians at the project to meet deadlines. Unfortunately, due to the more complicated issues with fire alarm systems, you will likely spend more valuable time troubleshooting the problems caused by workers unfamiliar with the system. EC

MOORE, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a co-editor of the current National Fire Alarm Code Handbook. Moore is a principal with Hughes Associates Inc. at the Warwick, R.I., office. 


About the Author

Wayne D. Moore

Fire/Life Safety Columnist
Wayne D. Moore, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a principal member and past chair of NFPA 72, Chapter 24. Moore is a vice president with JENSEN HUGHES at the Warwick, R.I., office. He c...

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