Fire Detection and Alarm Systems, Fixed Installations and Emergency Communications
Detection, fixed installations and communications are examined as one chain: the alarm must be raised, the right system released, and the right people told.
Detection
- Optical smoke detectors respond to visible smoke; ionisation units to sub-micron particles. Neither belongs in a galley or bathroom - use heat detectors there.
- Heat detectors are fixed-temperature (typically 57–74 °C) or rate-of-rise; flame detectors use UV or IR and react within seconds in machinery spaces.
- Manual call points sit at exits, and the alarm must repeat on the bridge and in the engine control room.
Fixed installations
- CO2 total flooding for machinery spaces: pre-discharge alarm, about a 20-second delay, evacuation and headcount, all openings sealed, and no re-entry until the space is ventilated and tested.
- Foam: deck foam on tankers, high-expansion in machinery spaces, low-expansion for spill blankets.
- Water: sprinklers in accommodation, drenchers on boundaries, water mist for machinery. A fire control plan and an international shore connection must be available.
Emergency communications
- General emergency alarm: seven short blasts and one long blast on the whistle and alarm bells. Abandon ship is a verbal order supported by more than six short blasts and one long blast.
- Internal: PA, sound-powered telephone, UHF portables, talkback. External: VHF Ch 16/DSC, EPIRB, 9 GHz SART, Inmarsat, IMO Standard Marine Communication Phrases.
Worked example
A smoke detector operates in a corridor at 03:00. The bridge acknowledges, notes the zone, sends a runner with a portable radio and a BA team with a charged hose. Silencing the alarm and logging 'false alarm' without an investigation is the error.
Traps
- Confusing the general emergency alarm with the abandon-ship signal.
- Dismissing a detector that keeps operating as 'just faulty'.
- Re-entering a CO2-flooded space because the fire looks out.