Fire Alarm

A fire alarm system is a set of electric/electronic devices/equipment working together to detect and alert people through visual and audio appliances when smoke/fire is present. These alarms may be activated from smoke detectors, heat detectors, water flow sensors, which are automatic or from a manual fire alarm pull station.

Fire alarm control panel (FACP) AKA fire alarm control unit (FACU); This component, the hub of the system, monitors inputs and system integrity, controls outputs and relays information.

Primary power supply: Commonly the non-switched 120 or 240 Volt Alternating Current source supplied from a commercial power utility. In non-residential applications, a branch circuit is dedicated to the fire alarm system and its constituents. “Dedicated branch circuits” should not be confused with “Individual branch circuits” which supply energy to a single appliance.

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Secondary (backup) power supplies: This component, commonly consisting of sealed lead-acid storage batteries or other emergency sources including generators, is used to supply energy in the event of a primary power failure.

Initiating devices: This component acts as an input to the fire alarm control unit and are either manually or automatically actuated. Examples would be devices pull stations, heat detectors, or smoke detectors. Heat and smoke detectors have different categories of both kinds. Some categories are beam, photo electrical, aspiration, and duct.

Notification appliances: This component uses energy supplied from the fire alarm system or other stored energy source, to inform the proximate persons of the need to take action, usually to evacuate. This is done by means of a flashing light, strobe light, electromechanical horn, “beeper horn”, chime, bell, speaker, or a combination of these devices. The System Sensor Spectralert Advance Horn makes a beeping sound and electromechanical sound together.

Building safety interfaces: This interface allows the fire alarm system to control aspects of the built environment and to prepare the building for fire, and to control the spread of smoke fumes and fire by influencing air movement, lighting, process control, human transport and exit.

Magnetic Smoke Door Holders: Wall or floor mounted solenoids or electromagnets controlled by a fire alarm system or detection component that magnetically secures spring-loaded self-closing smoke tight doors in the open position. Designed to de-magnetize to allow automatic closure of the door on command from the fire control or upon failure of the power source, interconnection or controlling element. Stored energy in the form of a spring or gravity can then close the door to restrict the passage of smoke from one space to another in an effort to maintain a tenable atmosphere on either side of the door during evacuation and fire fighting efforts in buildings.

Duct Mounted Smoke Detection: Smoke detection mounted in such a manner as to sample the airflow through duct work and other plenums specifically fabricated for the transport of environmental air into conditioned spaces. Interconnection to the fan motor control circuits are intended to stop air movement, close dampers and generally prevent the re circulation of toxic smoke and fumes produced by fire into occupant spaces.

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Emergency Elevator Service: Activation of automatic initiating devices associated with elevator operation are used to initiate emergency elevator functions, such as recall of associated elevator cab(s). Recall will cause the elevator cabs to return to the ground level for use by fire service response teams and to ensure that cabs do not return to the floor of fire incidence. Phases of operation include primary recall (typically the ground level), alternate/secondary recall (typically a floor adjacent to the ground level – used when the initiation occurred on the primary level), illumination of the ‘fire hat’ indicator when an alarm occurs in the elevator hoist way or associated control room, and in some cases shunt trip (disconnect) of elevator power (generally used where the control room or hoist way is protected by fire sprinklers).

Public Address Rack (PAR): An Audio public address rack shall be interfaced with fire alarm system, by adding signaling control relay module to either rack power supply unit, or to main amplifier driving this rack. the purpose is to “mute” the BGM(background music) of this rack in case of emergency in case of fire initiating true alarm.