When a smoke detector senses particles of combustion, or a heat detector is activated through an increase in temperature, or a pull station is manually activated by an individual, an alarm condition is conveyed to the fire alarm control panel through the initiating circuit.  The fire alarm control panel then responds by activating the notification devices, sounding the horns and firing the strobes.  Monitored fire alarm systems can simultaneously alert building occupants and the Central Monitoring Station that there is an alarm condition at the protected premise.

If there is power failure in the building , the fire alarm system will be powered by a battery backup.  This battery backup is capable of functioning and activating an alarm for a specified length of time.  In addition, all Alarm equipment carry US UL (Underwriters Laboratories) and NFPA (National Fire Protection Association) approval on all components.  Fire Alarm systems are required to have a control panel and smoke detectors that are UL-approved to ensure that they are electronically compatible.

Unlike stand-alone residential smoke detectors which have reset buttons, fire alarm systems must be reset at the control panel.  Action must be taken to investigate the cause of fire before the system can be reset, ensuring the highest level of protection and safety.


Control Panel: The control panel provides the necessary circuits to power the fire alarm system.  It receives signals from detectors and transmits these signals to the notification devices. Control panels also supervise the system wiring and the primary power source to the panel.  Auxiliary power supplies in the control panel are required in the event of a power failure.

Initiating Devices

Smoke Detector:  Device that detects invisible and /or visible products of combustion.  Detectors can be photoelectric or ionization type and can also have a heat-sensing element.

Heat Detector:   Device that detects high temperatures or a certain change in temperature over a fixed time period (called rate-of-a rise detector) 

Pull Down Station:   Fire alarm box containing a glass plate, rod or pull element that mutually activated the alarm.

Notification Devices

Strobes and horns Bell:  Audible or visible devices used for signaling an alarm condition in a building.  Horns must be a certain decibel level over ambient noise to effectively alert building occupants to a fire.

Fire alarm strobes typically employ xenon tubes and light-efficient reflectors to pulse at a certain flash rate to signal warning of a fire.