12.1.1 Where
fixed pressure water spray fire-extinguishing systems are provided
for the protection of spaces below the bulkhead deck, the following
provisions are to apply:
-
The drainage system
is to be sized to remove no less than 125 per cent of the combined
capacity of both the water spraying system pumps and the required
number of fire hose nozzles.
-
The required area
of the main and branch bilge pipes for the protected space are to
be adequate to ensure a maximum water flow of 2 m/s in each section
of the piping.
-
The drainage system
valves are to be operable from outside the protected space at a position
in the vicinity of the extinguishing system controls.
-
Bilge wells on
vehicle decks, ro-ro spaces and special category spaces shall be of
sufficient holding capacity and shall be arranged at the side shell
of the craft at a distance from each other of not more than 40 m in
each watertight compartment.
12.1.2 For
drainage of vehicle or cargo spaces by gravity, see
Pt 3, Ch 4, 9 Deck drainage. If led to a closed drain
tank, this tank is to be located outside the machinery spaces and
provided with a vent pipe leading to a safe location on the open deck.
12.1.3 On craft
with closed vehicle spaces, ro-ro spaces and special category spaces,
means are to be provided to prevent the blockage of drainage systems
from these spaces.