A fixed fire extinguishing system for special category spaces
should be at least as effective in controlling a flowing petrol fire
as a fixed pressure water-spraying system complying with the following:
(a) The nozzles should be of an approved full
bore type. They should be arranged so as to secure an effective distribution
of water in the spaces which are to be protected. For this purpose,
the system should be such as will provide water application at a rate
of at least 3.5 litres per square metre per minute (0.07 gallons per
square foot per minute) for spaces with a deck height not exceeding
2.5 metres (8.2 feet) and a capacity of at least 5 litres per square
metre per minute (0.1 gallons per square foot per minute) for spaces
with a deck height of 2.5 metres (8.2 feet) or more.
(b) The water pressure should be sufficient to
secure an even distribution of water.
(c) The system should normally cover the full
breadth of the vehicle deck and may be divided into sections provided
they are of at least 20 metres (66 feet) in length, except that in
ships where the vehicle deck space is subdivided with longitudinal
“A” Class divisions forming boundaries of staircases,
etc., the breadth of the sections may be reduced accordingly.
(d) The distribution valves for the system should
be situated in an easily accessible position adjacent to but outside
the space to be protected which will not readily be cut off by a fire
within the space. Direct access to the distribution valves from the
vehicle deck space and from outside that space should be provided.
Adequate ventilation should be fitted in the space containing the
(e) The water supply to the system should be provided
by a pump or pumps other than the ship's required fire pumps which
should additionally be connected to the system by a lockable non-return
valve which will prevent a back-flow from the system into the fire
(f) The principal pump or pumps should be capable
of providing simultaneously at all times a sufficient supply of water
at the required pressure to all nozzles in the vehicle deck or in
at least two sections thereof.
(g) The principal pump or pumps should be capable
of being brought into operation by remote control (which may be manually
actuated) from the position at which the distribution valves are situated.