Installing fire alarm systems to code is only half the job fire technicians face. General maintenance throughout the years of a fire alarm’s lifetime is just as important. Best of all, you can make good money while providing a valuable, required service.

To address the issue, the National Fire Protection Association (NFPA) has originally established a comprehensive set of standards that addressed every conceivable aspect of fire protection, including maintenance (NFPA 72, Section 7-1.6, 1999 Edition).

The NFPA section provides a detailed description of how to check batteries, fuses, generators, central office connections, remote annunciators, heat detectors, digital alarm communicator transmitters (DACTs), notification appliances, smoke detectors and more. If you install fire alarm systems, then you need to obtain this document.

Smoke Detectors Save Lives

Although heat detectors, fire pulls and all the other devices that go into a fire alarm system are important to the fire detection mission, perhaps the most important to life safety is that of automatic smoke detection.

It is their ability to detect microscopic-sized smoke particulates that make automatic smoke detection devices so important, especially in residential settings. Today, 94 percent of all U.S. households have at least one smoke detector.

Check Detectors Routinely

There are essentially two ways for fire technicians to test their clients’ smoke detectors. The first is a functional check and the second is a test that verifies smoke detector calibration.

A functionality test essentially acts as a go-no, go test. The bottom line: either it will work or it will not. There is no middle ground. Although this may be effective to some degree, it fails to provide an overall indication of a smoke detector’s real health.  This is because a functional test cannot spot oncoming problems where smoke detector sensitivity readings have nearly reached the no-go threshold.

A smoke detector sensitivity test is a quantitative means of determining whether the sensory apparatus within a smoke detector is operating at a prescribed level of efficiency. This rating is expressed as a percentage that pertains to the degree of obscuration of light that occurs between a light source and a photosensitive sensor before an alarm occurs. This percentage must be displayed on the smoke detector base, with the actual sensitivity reading on the test instrument being permanently recorded.

Using Approved Testing Methods

The first rule of thumb when testing smoke detectors is to check the installation and maintenance instructions that came with the detectors. Second, follow NFPA 72 in how you test and how often.

The first test method provides a functional check. This one relies on the use of an aerosol spray that simulates smoke. In the fire detection industry, this product is often referred to as smoke in a can, or canned smoke.

When using canned smoke, the fire technician must maintain a specified distance between the smoke detector and aerosol can (usually two to three feet). Otherwise, spraying close to the detector can leave a wet residue within the smoke chamber and other portions. This will cause problems, as the residue will inevitably collect airborne dust and dirt.

The second general method used when checking smoke detectors verifies calibration. There are several ways to do this, as outlined by Section 7-3.2.1, NFPA 72, 1999.

Smoke detector manufacturers also deal with sensitivity testing by offering a special calibration test meter that connects directly to the smoke detector with a cord. Although this method will work fine, such a tool can only be used on one manufacturer’s smoke detector products.

A similar arrangement is available by using a magnet or a button on the detector itself. In both instances, if the sensitivity of the smoke detector is within listed limits, it will go into alarm. Otherwise, there may be a problem with the smoke detector.

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