Page 274 - Introduction to Marine Engineering

248 Fire fighting and safety

Accommodation
The accommodation areas will be made up almost exclusively of Class A
material requiring the use of water or soda-acid type extinguishers.
Electrical circuits however should be isolated before directing quantities
of water into an accommodation area. AH ventilation and exhaust fans
must be stopped and fire flaps closed. If hoses are employed a water
spray should be used in order to achieve the maximum cooling effect.
The accommodation will no doubt fill with smoke and therefore
breathing apparatus should be available.
The galley area presents a somewhat different fire hazard. Here Class
B materials, such as cooking oil, fat or grease, will be present requiring
the use of foam, dry powder or carbon dioxide extinguishers. A fire
blanket quickly spread over burning cooking utensils could extinguish a
potentially dangerous fire.

Machinery spaces

Machinery space fires will involve mainly Class B material requiring the
use of foam type extinguishers. Only the smallest of fires should be
tackled with hand extinguishers. The alarm should be quickly given and
the bridge informed. The ventilation fans should be stopped and fire
flaps closed. Any oil tanks close to the fire should be closed off and kept
cool by hosing with water. Foam-making equipment should be used on
the fire and foam spread over the tank tops and bilges. Water spray can
also be used to cool the surroundings of the fire, but a water jet should
not be used in the machinery space since it will move any burning oil
around and subsequently spread the fire. Only if the situation becomes
hopeless should the space be evacuated and gas flooding used. The
machinery space contains most of the fire fighting equipment as well as
the propulsion machinery. If it is vacated then control of the situation is
lost to a 'one-shot' attempt at gas flooding.
If evacuation is decided upon all personnel must be made aware of the
decision. The space must then be completely sealed against the entry or
exit of air and all oil supplies isolated at the tank valves. When all these
matters have been attended to, the flooding gas can be admitted and, if
the surrounding bulkheads hold to contain the fire, it will quickly go out.
Cooling of the boundary bulkheads should continue from outside the
space whilst flooding is taking place.
When the extinguished fire has been left long enough to cool down
the space can be re-entered. This should be done from the tunnel, if
there is one, or the lowest point remote from the seat of the fire.
Engineers wearing breathing apparatus may now enter, taking water
spray hoses with them to cool down any hot surfaces. Cooling and smoke
dispersal are the first priorities to provide an atmosphere in which