How the Fire Alarm System Works

Fire Alarm System

The fire alarm system is made up of a number of devices working together to detect and warn people of fire. These alarms may be activated automatically from smoke detectors, heat detectors, or through manual fire alarm activation devices such as manual call points or pull stations.

The fire alarm system components include The control panel – the system hub monitors inputs and system integrity, controls outputs, and relays information. Primary power supply; supplied in the form of 124V or 240V AC from the power company.

How Fire Alarm System Works

The fire alarm system can be set off automatically by smoke detectors, heat detectors, or manually. These sensors are programmed to detect certain levels of heat or smoke that could be an indication of fire.

Once a fire is discovered by this system, it tells the occupants of a building about the fire by making lots of noise and flashing lights.

Aside from notifying and warning occupants of fire, automated fire alarm systems can also:

  • Shut down the air handling fans and the smoke dampers in the air ducts to prevent the spread of smoke and flame.
  • Turn on a deluge sprinkler system to extinguish a fire
  • Activate a preaction sprinkler system to allow it to extinguish the fire.
  • Unlock doors to allow exit
  • Lock doors to prevent entrance
  • Close smoke barriers or smoke curtains to prevent the spread of smoke or flame
  • Activate fire suppression systems, etc.

Read Also: 9 Fire prevention and fire fighting devices and how to buy them

Types of Fire Alarm Systems

There are basically two (2) types of fire alarm systems:

1. Heat detector:

This device responds to a rise in temperature and gets activated in case of a fire. It triggers an alarm by either melting a low-fusing alloy or bending a bimetallic strip. They are intended to minimize property damage by reacting to the change in temperature caused by a fire. They are mostly fixed in garages, kitchens, etc.

2. Smoke detector:

A smoke detector is a device that senses smoke, typically as an indicator of fire. The smoke detectors are of two (2) types – Optical smoke detectors and ionize smoke detectors. The optical smoke detector acts like an electronic eye while the ionized smoke detector acts like an electronic nose. All smoke detectors consist of two basic parts – A sensor to sense the smoke and a very loud electronic horn to wake people up.

Regardless of the type of detector or alarm selected, the proper placement and maintenance of the device are crucial. Follow all manufacturer’s instructions for placement, testing, and maintenance. The NFPA suggests battery replacement at least once a year on battery-equipped units and a monthly detector test to verify the alarm function.

NOTE: Alarm installation and maintenance must always be done by a competent person.


A fire alarm system is a safety device designed to detect fire and alert people in a building to the danger. It consists of smoke and heat detectors, alarms, and sometimes sprinklers. When smoke or high temperatures are detected, the system sounds an alarm to initiate an evacuation and can also notify emergency services. These systems are invaluable in preventing injuries and minimizing damage by creating timely awareness and response to fire incidents.

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