2.1 Oil tankers delivered on or before 31 December
1979, as defined in regulation
1.28.1, may, in accordance with regulation 30.6.5 of Annex I
of MARPOL, discharge dirty ballast water and oil-contaminated water
from cargo tank areas below the waterline, provided that a part of
the flow is led through permanent piping to a readily accessible location
on the upper deck or above where it may be visually observed during
the discharge operation and provided that the arrangements comply
with the requirements established by the Administration which shall
at least contain all the provisions of these specifications.
2.2 The part flow concept is based on the principle
that the observation of a representative part flow of the overboard
effluent is equivalent to observing the entire effluent stream. These
specifications provide the details of the design, installation and
operation of a part flow system.