Key learnings:
- Fire Detection and Alarm System Definition: A fire detection and alarm system detects smoke, heat, and flames, and includes manual call points for immediate help.
- Alarm System Importance: Alarms or bells are essential for alerting occupants during a fire.
- Types of Fire Detectors: The main types of fire detectors are smoke detectors, heat detectors, and infrared detectors.
- Coverage Areas: Fire detection systems cover areas like control rooms, equipment rooms, cable galleries, conveyors, and fuel oil tanks.
- Microprocessor Panels: These panels evaluate signals, transmit alarms, monitor circuits, and control functions like closing fire doors and shutting down ventilation systems.
Introduction of Fire Detection and Alarm System
Fire detectors are designed to detect one or more of the three characteristics of fire-smoke, heat and flame. Besides it every fire detection system must include manual call points (break glass), so that in the event of fire can be of immediate help.
During a fire, it is crucial to alert occupants through alarms or bells. This is done using the alarm system.
The fire alarm system is designed to provide 24/7 fire security for the entire power plant area.
A microprocessor-based addressable analogue fire alarm system is used to detect fires in various buildings and areas. The main fire alarm panel is in the central control room, with a repeater panel in the fire station.
The main fire alarm panel is located in the control building, with a repeater panel in the fire station. The number of annunciations depends on the plant’s specific requirements.
One (1) siren of 10 Km range is envisaged to provide warning in the event of fire.
In addition to it, PLC panel shall be provided at fire pump house and foam pump house.
Why Fire Detection and Alarm System Required
Fire detection and protection system is required for the following reasons:
- To detect fire in the area during the initial stage.
- To alert occupants, so that they escape the building safely.
- Summon trained personnel to take charge of controlling the fire as quickly as possible.
- To initiate automatic fire control and suppression system.
- To support and supervise the fire control and suppression system.
Type of Fire Detectors
- Smoke Detector
- Fire Detector
- Heat Detector
Area to be Covered under Fire Detection and Protection System
| Sl. No. | Fire Detection System | Area to be Covered |
| 1 | Smoke Detection System |
|
| 2 | Linear heat sensing cable detection system |
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| 3 | Quartzoid bulb heat detection system |
|
| 4 | Infra-red Detectors |
|
Design Philosophy of Fire Detection and Alarm System
- The PLC based control panel at pump houses shall indicate the status of each pump, system pressure, operation of hydrant or spray system, failure of starting of pumps, healthiness and failure of batteries/chargers, main supply, low level/very low level of water in the water supply system, status of compressors, selection station of batteries and chargers of panels and diesel engines etc. Alarms from these panels shall also be available at fire station in a repeater panel and at main fire panel alarm in control room.
- The PLC based addressable type panels at central Control rooms shall receive signal from sensor from various areas/equipments of the respective units.
- The Microprocessor based addressable panel shall evaluate the signals received from detectors, transmit the fire or trouble alarms (audio-visual) to prearranged points, supervise and monitor the complete fire detection and extinguishing circuits, initiate control functions like closure of fire doors, shutdown of draft fans, air conditioning and ventilation plant/equipment, closure of fire dampers in A/C and ventilation system etc. Opening smoke extraction vents, switching on smoke extraction equipment emergency lighting, tripping of transformer lockout relays etc.
- All the circuits from the detectors to the panels and the circuits from the panels to the actuating devices (such as solenoid valves, deluge valves, push buttons etc) shall be in closed loop type and in close watch for open-and-short-circuiting.
- Facilities shall be provided on the main fire alarm panel for sensitivity adjustment, isolation of detectors etc from the panel.
- Panel of fire detection, alarm monitoring and annunciation system shall operate on DC-supply, along with associated rectifier bank. Further each panel shall have the provision for batteries for charging.
- Each set of battery shall have the capacity for a period of 12 hours from the instant of charger/AC failure.
- Exit signs shall be painted o 18 gauge cold rolled sheet steel. This sheet should be suitable for fixing on walls or hanging from ceiling. Fire Exit/No Fire Exit shall be displayed on both sides of the Exit signs.
