12.2.1 The height
of air pipes from the upper surface of decks exposed to the weather,
to the point where water may have access below is normally to be not
less than:
- 450 mm on the freeboard deck;
- 300 mm on the superstructure deck;
- these heights being measured above deck sheathing, where fitted.
12.2.2 Lower
heights may be approved in cases where these are essential for the
working of the craft, provided that the design and arrangements are
otherwise satisfactory.
12.2.3 An increase
in the height of air pipes may be required or recommended by individual
Administrations when air pipes to fuel oil and settling tanks are
situated in positions where sea water could be temporarily entrapped,
e.g. in recesses in the sides and ends of superstructures or deckhouses,
between hatch ends, behind high sections of bulwark, etc. This may
entail an increase in tank scantlings and will be specially considered.
12.2.4 Air pipes
are generally to be led to an exposed deck. Alternatively, air pipes
from cofferdams or void spaces may terminate in the enclosed 'tween
deck space on main vehicle decks, provided the space is adequately
ventilated and the air pipes are provided with weathertight closing
appliances.
12.2.5 Where
air pipes are led through the side of superstructures, the opening
is to be at least 2,3 m above the summer load waterline.