Fire alarm system

           A fire alarm system is designed to detect the un wanted presence of fire by monitoring environmental changes associated with combustion.

TYPES :

  1. Manual
  2. Automatic

PURPOSES :

  • Notify the occupants of the vicinity about outbreak of fire as soon as it starts.
  • To evacuate to a place of safety.
  • To alert fire services department to get to work for control spread of fire and to put the same out

COMPONENTS

  1. Fire Alarm Control Panel:

  • It is an electric panel that is the controlling component of a fire alarm system The panel receives information from environmental sensors designed to detect changes associated with fire, monitors their operational integrity and provides for automatic control of equipment and transmission of information necessary to prepare the facility for fire based on predetermined sequence.
  • Panels usually have a number of signaling line circuit loops. 
  • Each device on loop has its own address. 
  • So the panel knows the state of each individual device connected to it. .

Common addressable input devices include :

 

  • Smoke Detectors.
  • Heat Detectors (Rate of Rise and Fixed Temperature)
  • Manual Call Points (MCPs)
  • Notification Appliances (Audible or Visible)
  • Fire Sprinkler System inputs.
  • Switches for Flow Control, Pressure Control, Isolating.

Common addressable output devices are known as Relays and include :

  • Warning System/Bell*
  • Door Holders relays.
  • Control function relays.

Relays are used to control variety of functions such as :

  • Switching fans on or off.
  • Closing / Opening of doors.
  • Activating fire suppression systems. 
  • Activating notification appliances. 
  • Shutting down equipments.

ZONES : 

          Zones are made by dividing an area or building into different sections and placing each device in the building in a different zone.

 

Initiating Devices :

  • Manually actuated devices & such as MCPs are installed near every vulnerable location
  • (Break Glass – Push bottom type) as identified, o    Automatically activated devices include different types of fire detectors.
  • Emergency voices Alarm Communication System
  • Pre recorded.
  • Manual (Public Address system)
  • These are used to alert occupants for orderly evacuation.