1 If the bilge drainage system for cargo spaces
is additional to the system served by pumps in the machinery space,
the capacity of the system should be not less than 10 m3/h
per cargo space served. If the additional system is a common system,
the capacity need not exceed 25 m3/h. The additional bilge
system need not be arranged with redundancy. Whenever flammable or
toxic liquids are carried, the bilge line into the machinery space
should be isolated either by fitting a blank flange or by a closed
lockable valve.
2 If bilge drainage of cargo spaces is arranged
by gravity drainage, the drainage should be either lead directly overboard
or to a closed drain tank located outside the machinery spaces. The
tank should be provided with vent pipe to a safe location on the open
deck.
3 Enclosed spaces outside machinery spaces containing
bilge pumps serving cargo spaces intended for carriage of flammable
or toxic liquids should be fitted with separate mechanical ventilation
giving at least six air changes per hour. Electrical equipment in
the space should comply with the IACS Unified Interpretation SC 79.
If the space has access from another enclosed space, the door should
be self-closing.
4 Drainage from a cargo space into bilge wells
in a lower space is only permitted if that space satisfies the same
requirements as the cargo space above.