Detection
of fire includes the early warning and initiation of protection systems for the safety of occupants, and immediate action
of the fire brigades for the control of fire. The early detection of fire is initiations by fire alarm systems.
There are two kinds of fire alarm system.
MANUAL
SYSTEM
The activation of the manual fire alarm system
rely on detection by the occupants of the presence of fire. Building occupants can detect when a fire has occurred by means
of smell, sound, and sight.
However, the effectiveness of human detection
of fire is the least reliable. People’s response to fire is dependent on various factors. It could be fast if the person
in the vicinity of fire has an active presence of mind. It could be disastrous if they are not met.
A manual fire alarm box are provided in the natural
path of escape from fire and should be readily accessible, unobstructed and clearly visible.
AUTOMATIC
SYSTEM
Even though most fires are likely to be discovered
by the occupants in an occupied area before a detector is activated, automatic detectors can provide early warning when the
building is unoccupied or when the occupants are inactive. The automatic fire alarm systems detect a fire by sensing the presence
of the products of combustion such as smoke, heat, flame, etc.
The system should have sufficient number of signals
that are clearly audible to all persons in the building. Alarm sounding devices should be distinctive in quality and pitch
from all other sounding devices and shall not be used for any purpose other than that of sounding fire alarms or calling fire
drills.