Fire - safety decision time

August 2002 Fire & Safety

Many building owners have no problem frequently replacing carpet, furniture, lighting, communications systems, computers and other furnishings.

But they have trouble deciding when to upgrade a fire alarm system, despite the important functions it performs - life safety functions like occupant notification as well as the monitoring or control of other critical systems like fire pumps or HVAG systems are silent sentinels, keeping watch over occupants and property both day and night; they automatically make the premises safer during a fire. Yet we take them for granted.

Finite lifespan

There are many reasons why systems are not replaced. Some common obstacles to system replacement include cost or failure of an owner to understand the importance of the system.

A fire alarm system has a finite life span - the problem is determining when it is over. Here are the things to watch out for:

What is the expected life of a fire alarm system? When should a fire alarm system be replaced? The answer is different for nearly every case. Most fire alarm systems have an expected life span of about 12 to 15 years, if the system is properly maintained and tested on a regular basis. However, there is no reason that a fully functioning system cannot operate for far longer. Some systems have been known to last more than 20 years.

The decision to replace an aging fire alarm system is complex, and the outcome of that decision differs greatly depending on a large number of variables. First and foremost, a fire alarm system is a life safety system and must be reliable - that is, it must have the ability to perform the tasks it was designed to accomplish with a minimal number of nuisance alarms, trouble signals or failures to alarm under specified conditions. Fire alarm system reliability is affected by four major variables: components, design, installation, and maintenance.


Fire alarm systems are manufactured from electronic components readily available in the marketplace at the time of manufacture. However, as time passes and technological advances make some electronic components obsolete, it is often difficult or impossible to find 'form, fit and function' replacements for the original components. Component failure rates vary somewhat, depending on the manufacturer and the processes used. However, most modern electronic components have very low failure rates. At some point in time, however, parts are either to expensive or are not available. That can render the system inoperative, which can lead to serious life safety concerns, and generally signals the end of the system.

Design and installation

Poor design of fire alarm system can lead to increased nuisance alarm rates, increased maintenance costs, inoperability, and in some cases, fines. A fire alarm system must be properly designed and installed; otherwise overall system reliability and occupant confidence in the system will be eroded. In many cases, a system is tailored to the owner's fire protection goals. When a system is being designed, a fire protection engineer should be involved to be sure that the system is adequate for the tasks expected of it.

When a system is improperly designed or installed, symptoms of unreliability may not always be readily apparent. For example, smoke detectors mounted on very high ceilings or near air supply registers may not provide a timely alarm response. However, smoke detectors mounted in dusty or humid areas will be prone to nuisance alarms. Flaws in existing systems can be determined through an inspection by a qualified engineer.


Proper maintenance is crucial to the effectiveness of a fire alarm system. Some owners don't understand the benefits of adequately maintaining a system that is seemingly never used. They must be shown why a system needs to be maintained in order to provide a safe environment. In some cases, replacement is the solution to maintenance issues.

Poorly designed, installed or maintained systems can result in numerous alarms. Older systems that are at the end of their expected life span can also result in nuisance alarms. These nuisance alarms can cost the owner (or tenant) large amounts of money due to lost production while employees are standing outside waiting for the alarm to be cleared. The direct costs of nuisance alarms are easy to put into rands, because the variables can be measured and costs can be calculated. Of course, nuisance alarms do not include malicious false alarms caused by disgruntled employees or vandals. Indirect costs are generally more difficult to measure. Occupants become jaded by numerous nuisance alarms and begin ignoring them. The 'cry wolf' syndrome can end in tragic results, with potentially huge costs, both direct and indirect.

Changing conditions

Even if a system is still functioning as designed, there may be a need to replace it because of changes in the building itself or the way it is used. Owners may outgrow a system by adding to the premises, by changing the occupancy type or by changing the fuel loading characteristics. A system designed for a specific hazard may no longer be appropriate if the fuel type or loading is changed following a renovation or expansion. Original system design must be matched to the goals of the owner, applicable codes and standards, and the conditions in the premises. Any deviation from the original building plan without a review of the fire alarm system may render the system incapable of meeting established goals.

Another time to consider replacing a fire alarm system is when a poor installation needs to be corrected. Take, for example, a system installed 12 years ago that has dozens of smoke detectors improperly installed under a floor in a computer mainframe room. As installed, the detectors will collect dust and dirt in the sensing area. They will be prone to nuisance alarms and may or may not properly actuate during a fire. Lives could be lost if a fire occurred. Correction of the improperly installed detectors may be a simple matter, but the relative age of the system may make it appropriate to replace the entire system. What's more, owner goals may have changed since the system was installed - another reason for an upgrade.

Benefits and costs

It is important to bear in mind that new technology may also be more effective, easier to maintain and less expensive than like-for-like replacement. Changes in technology often lead to enhancement features. One example is analog detection, which offers much greater system performance and flexibility than was available just five or 10 years ago. These new features may be more appropriate for the current needs of a facility.

The current generation of equipment also offers software maintenance features, such as automatic sensitivity testing of detectors and drift compensation, which can dramatically reduce operating costs. Trouble signals are indicated when a detector becomes too 'dirty' to properly function. This technology can offer considerable cost savings in maintenance budgets, especially for facilities with large numbers of inaccessible detectors, such as those installed on high ceilings or mounted on ducts.

Consideration for the long-term maintenance needs of a project should be factored into the design objectives. However, many system owners fail to recognise that maintenance and testing of a fire alarm system is a significant cost spread over the life of the system. Fire alarm system maintenance is not optional and must be considered in the cost analysis. Therefore, the costs must be included in the annual maintenance programme.

Making the decision

So when should a fire system be replaced?

Clearly, there is no 'one size fits all' answer to this question. Each case must be evaluated individually. Whenever a fire alarm system is being designed, upgraded, inspected or analysed, it is crucial that the occupancy, owner's goals, codes and standards and other requirements are evaluated by a qualified engineer to be sure the system meets the needs of the building and the occupants.

Fire alarm systems have a finite life span. The goal is to have a safe, functional, and reliable system to protect the occupants and property. Determining when to replace the system is not that difficult, but requires some careful research, analysis and thought.

For more information: Shane Nefdt, Honeywell-TeqTrader, 011 403 3002.

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