a) The intactness of machinery space bulkheads and of
tunnel plating required to be of watertight construction
is not to be impaired by the fitting of scuppers discharging
to machinery spaces or tunnels from adjacent compartments
which are situated below the freeboard deck.
b) Such scuppers may, however, be led into a strongly constructed
scupper drain tank situated in the machinery
space or tunnel, but close to the above-mentioned adjacent
compartments and drained by means of a suction
of appropriate size led from the main bilge line through
a screw-down non-return valve.