4098 Smoke Detectors; Introduction; Smoke Detector Limitations - Simplex 4098 Applications Manual

4098 Smoke Detectors

Introduction

CAUTION: Install the detectors described in this publication in accordance with
Smoke Detector
The smoke detectors used with these bases are designed to activate and initiate emergency action,
Limitations
but do so only when used in conjunction with other equipment. They are designed for installation
in accordance with NFPA 72 National Fire Alarm Code.
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applicable NFPA standards, local codes, and the Authorities Having
Jurisdiction (AHJs). Failure to follow these instructions may result in
failure of the detector to initiate an alarm condition. The manufacturer
is not responsible for detectors that have been improperly installed,
tested, or maintained.
Smoke detectors do not work without power. AC or DC powered smoke detectors do not
work if the power supply is cut off for any reason.
Smoke detectors do not sense fires when smoke does not reach the detectors. Smoke from
fires in chimneys, in walls, on roofs or on the other side of closed doors may not reach the
smoke detector and alarm it.
A detector may not detect a fire developing on another level of a building. For this reason,
detectors should be located on every level of a building.
Smoke detectors have sensing limitations. Ionization detectors are better at detecting fast,
flaming fires than slow, smoldering fires. Photoelectric detectors sense smoldering fires
better than flaming fires. Because fires develop in different ways, and are often unpredictable
in their growth, neither type of detector is always best, and a given detector may not always
provide warning of a fire. In general, detectors cannot be expected to provide warning for
fires resulting from inadequate fire protection practices, violent explosions, escaping gases,
improper storage of flammable liquids like cleaning solvents, other safety hazards, or arson.
Smoke detectors cannot last forever. Smoke detectors contain electronic parts. Even though
detectors are made to last for many years, any of these parts could fail at any time. Therefore,
test your smoke detector system per NFPA 72 at least annually. Clean and take care of your
smoke detectors regularly. (See Chapter 5 of this publication for cleaning instructions.)
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