(1) Discharges led through the shell either from
spaces below the freeboard deck or from within superstructures and
deckhouses on the freeboard deck fitted with doors complying with
the requirements of Regulation 12 shall
be fitted with efficient and accessible means for preventing water
from passing inboard. Normally each separate discharge shall have
one automatic non-return valve with a positive means of closing it
from a position above the freeboard deck. Where, however, the vertical
distance from the summer load waterline to the inboard end of the
discharge pipe exceeds 0.01 L, the discharge may have two automatic
non-return valves without positive means of closing, provided that
the inboard valve is always accessible for examination under service
conditions; where that vertical distance exceeds 0.02 L a single automatic
non-return valve without positive means of closing may be accepted
subject to the approval of the Administration. The means for operating
the positive action valve shall be readily accessible and provided
with an indicator showing whether the valve is open or closed.
(2) In manned machinery spaces main and auxiliary
sea inlets and discharges in connexion with the operation of machinery
may be controlled locally. The controls shall be readily accessible
and shall be provided with indicators showing whether the valves are
open or closed.
(3) Scuppers and discharge pipes originating at
any level and penetrating the shell either more than 450 millimetres
(17½ inches) below the freeboard deck or less than 600 millimetres
(23½ inches) above the summer load waterline shall be provided
with a non-return valve at the shell. This valve, unless required
by paragraph (1), may be omitted if the piping is of substantial thickness.
(4) Scuppers leading from superstructures or deckhouses
not fitted with doors complying with the requirements of Regulation 12 shall be led overboard.
(5) All valves and shell fittings required by
this Regulation shall be of steel, bronze or other approved ductile
material. Valves of ordinary cast iron or similar material are not
acceptable. All pipes to which this Regulation refers shall be of
steel or other equivalent material to the satisfaction of the Administration.