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.