Fire detection onboard the ship?

When fire breaks out:

1. Activate fire alarm or emergency alarm, as soon as noticing of breakout of fire.
2. Find the origin of fire, CE and all ER members informed.
3. Restrict it, and extinct it on the spot with portable extinguishers and by other means.
4. Verify the class of fire and decide the type of extinguishing agents, which should be used.
5. Initial attack must be backed-up with second more substantial means of attack.
[i.e. Semi-portable or Fire main, follows after portable ones.]
6. Water must be used prudently, since ship’s stability can be affected.
7. Fixed installation is a back-up, used as a last resort. Usage of fixed installation in ER fire can cause loss of power and steering, for a long period of times.
8. Fixed fire fighting installation system can be used as initial attack on cargo hold fire.
9. Fire must be confined to the space, in which originated; [by controlling flow of air, by cooling adjacent bulkheads, and by directing extinguishing agents onto fire].
10. Finally after fire is out, overhauling begins, and check structural damages.
11. All fire fighting equipment replenished.
12. Cause of fire to be determined, and action taken to prevent re-occurrence of same type of fire.

If fire is considerable and immense:

1. Sound fire alarm system.
2. Evacuate all ER staff, count them and assign them as per Muster List.
3. Remote stopping of all fuel pumps, to be done.
4. Remote closing of all quick closing valves, to be done.
5. Remote closing of all skylight doors and ER watertight doors, to be done.
6. Remote closing of all ER ventilation dampers, to be done.
7. Prime mover and all machinery to be stopped.
8. All ER entry and exit doors, to be closed perfectly.
9. All ER ventilation fans, to be stopped manually.
10. Fixed installation system, to be operated by CE or 2/E in proper manner.

Fixed fire Detection and Alarm System:

a) This system with manual call points must be able to operate immediately at all times.
b) Must have two sources of power supply, and visual and audible alarms for power failure.
c) Control panel should be located on Bridge.
d) Heat, smoke or other products of combustion, flame or any combination of these may operate detector.

Types of Detector:

Smoke detector:
1. Installed at stairways, corridor, escape route within Accommodation Space.
2. Also used in Cargo space and Machinery space
3. Maximum floor area per detector = 74 m².
4. Max. distance apart = 11 meters.
5. Max. distance away from bulkhead = 5.5 m.
6. Photocell or light scattering types.

Heat Detector:
1. Maximum floor area per detector = 37 m².
2. Max. Distance apart = 9 meters.
3. Max. Distance away from bulkhead = 4.5 m.
4. Used Bi-metal strip.
5. Fitted in boiler room, laundry, Control Room, Galley.

Flame Detector:
1. Ultra Violet or infrared.
2. Fitted near fuel handling equipment.

Combustible Detector:
1. Fitted in galley, ER fwd bulkhead adjacent to p/p room under floor plate.

Heat Detector:

• There may be 3 types; fixed temperature, rate of temperature rise, or a combination.
• Rate of rise detector do not respond and give alarm if temperature gradually increases, e.g. moving into tropical regions or heating switched on.
• Tested by portable electric hot air blower.

Rate of temperature rise Detector:

a) Pneumatic Type:

1. Increase in temperature increases the air pressure inside thin copper hemi-spherical bulb, if the airs bled through two-way bleed valve is sufficient, diaphragm will not move up and close the contacts.
2. If rate of temperature rise causes sufficient pressure build-up inside the bulb to close the contact, alarm will be given.
3. Temperature adjustment screw is provided to close the contacts at a predetermined temperature, giving alarm. (Temperature setting vary from 55°C to 70°C.)

b) Bi-metal Coil Type:

1. Two bi-metal coils are attached to a vertical support bracket and upper coil is better insulated from heat than lower coil.
2. When temperature increases lower coil will move to close the gap (between two contacts) at faster rate than upper coil moves to maintain the gap.
3. If rate of temperature rise is sufficient, the gap will close and alarm given.
4. A fixed temperature stopgap is provided at upper coil to close the contact giving alarm.  

c) Fixed Temperature Detector:

• Quartzoid Bulbs fitted into Sprinkler System are fixed temperature detectors, used for spaces other than engine and boiler rooms.

Flame Detector: (Infra-red) 

1. Flame has a characteristic flicker frequency of about 25 Hz, and this fact is used to trigger an alarm.
2. Flickering radiation from flames reaches detector lens/filter unit, which only allows infra-red rays to pass and be focused upon cell.
3. Signal from cell goes into amplifier, which is tuned to 25Hz, then into time delay unit and alarm circuit.
4. To minimize false alarms, fire has to be present for predetermined period.
5. Suitable for machinery spaces, but not in boiler room.
6. Obscuration by smoke renders it inoperative.
7. Tested by means of a naked flame.

Smoke Detectors:

1. Light Scatter
2. Light Obscuration
3. Scatter and obscuration combined.

Light Scatter Type: 

1. Photo-cell is separated by a barrier from a semi-conductor, intermittently flashing light source, are housed in an enclosure, allowing smoke but not light inside.
2. When smoke is present in the container light is scattered around the barrier onto photocell and an alarm is triggered.
3. Could give early warning of fire.
4. Photocell and light sources are vulnerable to vibration and dirt.
5. Tested by means of cigarette smoke.

Fire control plan:

1. General arrangement plan must be permanently exhibited onboard, for the guidance of officers.
2. Positioned outside the deck house [opposite to gangway of both sides] in a permanently watertight enclosure for assistance of shore fire brigade.

Fire Control Plan includes:

• Fire control stations.
• Various fire sections, enclosed by both Class A and Class B divisions.
• Particulars of fire detection and alarm system.
• Sprinkler installation and fire extinguishing appliance.
• Means of escape.
• Ventilation system, including positions and numbers of fan controls and dampers.