Conventional Fire Panels

 

Fig.1     Conventional Fire Panel

Conventional panels have a number of zones, which are wired radially from the panel. 

The panel will indicate which particular zone activates and the whole zone must then be searched for the particular device that activated.  

There will be at least two bell circuits, which will come on together when the panel activates.

Any interfacing to other equipment can be done using relays on the bell circuits or the fire contacts on the panel itself.

Both the alarm zones and the bell circuits have end-of -line monitoring resistors so that a fault can be displayed if the cables are damaged or a detector removed.  

Conventional panels and detectors are the cheapest type of fire detection system available and are best suited for small simple buildings where the zones to be searched are small and where false alarms have no significant consequences.

Limitations:

Only a zone is identified at the panel as being in alarm.

The detectors used are simple two-state devices.

 Faults are only identified by an LED .

The panel cannot be interrogated for information .

Thresholds cannot be adjusted or verification times set.

Individual devices cannot  be masked at the panel