Principle of Operation

The primary purpose of a fire indicator panel is to monitor each circuit, zone or point for any condition (alarm signal or other abnormal condition); display the status of that condition and to operate any required output or outputs according to the approved design of the system. These outputs are typically for the purpose of warning occupants on a fire alarm signal, notify the fire brigade, control the spread of heat, smoke or fire; or used for a wide variety of other purposes.
Before I go any further it’s important to define a couple of terms used in this article, to provide both context and explanation of their meaning;

CIRCUIT
A circuit comprises an unbroken path (usually a pair of wires) along which an electric current exists or is intended or able to flow. In fire alarm terms this generally means the wiring connecting one or more detectors to the fire panel.

ZONE
A zone is a group of one or more detectors, grouped by their common location or in the case of a collective circuit all of the detectors on that circuit. Another way to describe a zone is one of the following;

• One or more detectors on an single collective circuit or;
• One or more detectors, in a common location, defined in software on an addressable circuit.

Standards also limit the number of detectors a zone may comprise