2.2.1 Ships performing ballast water exchange
in accordance with regulation D-1 of the Convention shall do so with
an efficiency of at least 95 per cent volumetric exchange of ballast
water.
2.2.2 For ships exchanging ballast water by the
pumping-through method, pumping through three times the volume of
each ballast water tank shall be considered to meet the standard.
Pumping through less than three times the volume may be accepted provided
the ship can demonstrate that at least 95 per cent volumetric exchange
is met.