Fire and Gas System Maintenace and calibration
The Fire and Gas system (FGC) is designed to provide early warning and location of fires in their initial stages, flammable gas leakage or accumulation up to the lower explosive limit (LEL%), and toxic gas likely to be present up to the occupational exposure limit (OEL). The system uses detectors such as manual call points, fire detectors, or toxic gas detectors. All incoming detector field circuitry interfaces with the Fire & Gas control panel (F&GCP) through detector interface modules.
The F&GCP acts on information from a certain number of inputs that agree, known as a 'voting' system. Output interface modules receive outputs from the processing unit and provide to output circuits (Relays), providing electrical isolation between the plant and F&GCP and providing the required power for operation. Output devices can be alarms or control circuits.
Protected plants are typically divided into fire areas, each with its own detection, alarm, control, and extinguishing system. If both fire and gas detection are required, these systems share common control panels. Manual initiation of critical control actions overrides any software-based system.
The type of a Fire & Gas control panel and associated detectors/outputs depends on the controller's type. Addressable type systems have addressable detectors individually identified at the F&GCP via a data highway, while traditional type systems have detectors that change the value of the electrical current in its loop via normal wiring connections. Zones on the F&GCP identify each loop as a zone, which could include one or more traditional detectors.