Page 273 - Introduction to Marine Engineering

Fire fighting and safety 247

Halons, while being excellent fire extinguishing gases, have a greater
ozone depleting potential than CFCs. IMO has adopted amendments to
the SOLAS Convention banning any new installations of halon systems
on ships, which are now in force. IMO is further urging annual leakage
inspections for existing installations and actively considering the
phasing-out of all existing systems in the near future.

Fire fighting strategy
Fighting a fire on board ship may amount to a life or death struggle; to
enter into such a conflict unprepared and unarmed is to invite failure.
The 'armaments' or equipment available have been described. Now
comes the matter of being prepared.
A basic strategy should be followed in all fire fighting situations. This
will involve four distinct aspects, which are locating, informing, containing
and finally extinguishing a fire.
A fire may be located by detection devices fitted in the various spaces
in a ship or simply by smelling or seeing smoke. Alert personnel,
whether on watch or not, should always be conscious of the danger of
fire and the signs which indicate it. Certain areas are more liable to
outbreaks of fire and these should be regularly visited or checked upon.
Once detected the presence of a fire must be made known quickly to
as many people as possible. It is essential therefore that the bridge is
informed of the location and extent of the fire. A small fire might
reasonably be immediately tackled by the finder but attempts should be
made whilst fighting the fire to attract attention. Shouting 'Fire',
banging on bulkheads, deliberately setting off equipment alarms in the
vicinity, all are possible means of attracting attention. Anyone finding a
fire must decide whether to fight it immediately or whether to leave it
and inform others first. The more people who know of a fire the greater
the efforts that can be brought to bear upon it. If in doubt—inform!
Ships are built to contain fires in the space where they begin. Fire
resisting bulkheads and decks are positioned at appropriate distances in
order to limit the spread of fire, and it remains for fire fighting
personnel to ensure that these barriers are secure whilst attempting to
fight the fire. All doors and openings should be closed, all ventilation
and exhaust fans stopped, and flammable material isolated from the
space. It should be remembered that a fire exists in three dimensions
and therefore has six sides, so it must be contained on six sides.
A small fire can usually be easily extinguished but it can also quickly
become a big fire, so the fire extinguishing must be rapid if it is to be
effective. Fire fighting strategy will vary according to the location of the
fire. The various areas and their particular problems will now be
examined.