Resolution
MEPC.150(55)
GUIDELINES ON DESIGN AND CONSTRUCTION TO FACILITATE SEDIMENT CONTROL ON SHIPS
(G12)
(Adopted on 13 October 2006)
THE MARINE ENVIRONMENT PROTECTION COMMITTEE,
RECALLING Article 38(a) of the Convention on the
International Maritime Organization concerning the functions of the Marine
Environment Protection Committee conferred upon it by the international
conventions for the prevention and control of marine pollution,
RECALLING ALSO that the International Conference on
Ballast Water Management for Ships held in February 2004 adopted the
International Convention for the Control and Management of Ships’ Ballast Water
and Sediments, 2004 (the Ballast Water Management Convention) together with
four Conference resolutions,
NOTING that Regulation A-2 of the Ballast Water
Management Convention requires that discharge of ballast water shall only be
conducted through Ballast Water Management in accordance with the provisions of
the Annex to the Convention,
NOTING FURTHER that Regulation B-5.2 of the Ballast
Water Management Convention provides that, ships constructed in or after 2009
should, without compromising safety or operational efficiency, be designed and
constructed with a view to minimize the uptake and undesirable entrapment of sediments,
facilitate removal of sediments, and provide safe access to allow for sediment
removal and sampling taking into account Guidelines developed by the
Organization,
NOTING ALSO that resolution 1 adopted by the
International Conference on Ballast Water Management for Ships invited the
Organization to develop these Guidelines as a matter of urgency,
HAVING CONSIDERED, at its fifty-fifth session, the
draft Guidelines on design and construction to facilitate sediment control on
ships developed by the Ballast Water Working Group, and the recommendation made
by the Sub-Committee on Bulk Liquids and Gases at its tenth session,
1. ADOPTS the Guidelines on design and construction
to facilitate sediment control on ships as set out in the Annex to this
resolution;
2. INVITES Governments to apply the Guidelines as
soon as possible, or when the Convention becomes applicable to them; and
3. AGREES to keep the Guidelines under review.
Annex.
GUIDELINES ON DESIGN AND CONSTRUCTION TO FACILITATE SEDIMENT CONTROL ON SHIPS
(G12)
1.1 Regulation B-5.2 of the Convention requires that
ships described in Regulations B-3.3 to B-3.5 should, without compromising
safety or operational efficiency, be designed and constructed with a view to
minimize the uptake and undesirable entrapment of sediments, facilitate removal
of sediments and provide safe access to allow for sediment removal and
sampling, taking into account these Guidelines. Ships described in Regulation
B-3.1 of the Convention should, to the extent practicable, also comply with
Regulation B-5.2 taking into account these Guidelines.
1.2 The purpose of these Guidelines is to provide
guidance to ship designers, ship builders, owners and operators in the
development of ship structures and equipment to achieve the objectives of
paragraph 1.1 and thereby, reduce the possibility of introducing harmful
aquatic organisms and pathogens.
1.3 There may be a conflict between preventing
accumulation of sediments and preventing the discharge of harmful aquatic
organisms and pathogens.
2.1 Water taken up as ships’ ballast can contain
solid alluvial matter that, once the water is becalmed in a ship’s ballast
tank, will settle out onto the bottom of the tank and other internal
structures.
2.2 Aquatic organisms can also settle out of the
ballast water and can continue to exist within the sediment. These organisms
can survive for long periods after the water they were originally in has been
discharged. They may thereby be transported from their natural habitat and
discharged in another port or area where they may cause injury or damage to the
environment, human health, property and resources.
2.3 Regulation B-5.1 of the Convention requires that
all ships remove and dispose of sediments from spaces designated to carry
ballast water in accordance with the Ballast Water Management Plans. These
Guidelines are to assist ship designers, ship builders, owners and operators to
design ships to minimise the retention of sediment. Guidance on the management
of sediment is contained in the Guidelines for Ballast Water Management and the
Development of Ballast Water Management Plans (G4).
3.1 For the purposes of these Guidelines, the
definitions in the International Convention for the Control and Management of
Ships’ Ballast Water and Sediments (the Convention) apply.
3.2 Ballast Water Tank - for the purposes of these
Guidelines a ballast water tank is any tank, hold or space used for the
carriage of ballast water as defined in Article 1 of the Convention.
4. DESIGN FOR REDUCING
ACCUMULATION OF SEDIMENT
4.1 Ballast water tanks and their internal structure
should be designed to avoid the accumulation of sediment in a ballast tank. The
following should, as far as is practicable, be taken into account when designing
ballast tanks:
.1
horizontal surfaces to be avoided wherever possible;
.2
where longitudinals are fitted with face bar stiffeners, consideration should
be given to fit the face bar stiffeners below the horizontal surfaces to aid
drain off from the stiffeners;
.3
arrange for induced flows of water, either by pump forces or gravitational
forces, to wash along horizontal or near horizontal surfaces so that it
re-suspends already settled sediment;
.4
where horizontal stringers or webs are required, drainage holes to be as large
as possible, especially if edge toe-stops are fitted where horizontal stringers
are used as walkways, to encourage rapid flow of water off them as the water
level in the tank falls;