MEPC 53/24/Add.1 

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ANNEX 2 

RESOLUTION MEPC.124(53) 

Adopted on 22 July 2005 

GUIDELINES FOR BALLAST WATER EXCHANGE (G6) 

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-4 of the Annex to the Ballast Water Management 

Convention addresses the conditions under which ballast water exchange should be conducted, 

taking into account Guidelines developed by the Organization, 

NOTING ALSO that resolution 1 adopted by the International Conference on Ballast 

Water Management for Ships invites the Organization to develop these Guidelines as a matter of 

urgency, 

HAVING CONSIDERED the draft Guidelines for ballast water exchange developed by 

the Ballast Water Working Group and the recommendation made by the Sub-Committee on Bulk 

Liquids and Gases at its ninth session, 

1. ADOPTS the Guidelines for ballast water exchange, 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. 
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ANNEX 

GUIDELINES FOR BALLAST WATER EXCHANGE (G6) 

1 INTRODUCTION 

1.1 The purpose of these Guidelines is to provide shipowners and operators with general 

guidance on the development of ship specific procedures for conducting ballast water exchange. 

Whenever possible ship owner and operators should enlist the assistance of classification 

societies or qualified marine surveyors in tailoring ballast exchange practices for various 

conditions of weather, cargo and stability. The application of processes and procedures 

concerning ballast water management are at the core of the solution to prevent, minimize and 

ultimately eliminate the introduction of harmful aquatic organisms and pathogens. Ballast water 

exchange offers a means, when used in conjunction with good ballast water management 

practices, to assist in achieving this solution. 

1.2 Ballast water exchange introduces a number of safety issues, which affect both the ship 

and its crew. These Guidelines are intended to provide guidance on the safety and operational 

aspects of ballast water exchange at sea. 

1.3 Given that there are different types of ships, which may be required to undertake ballast 

water exchange at sea, it is impractical to provide specific guidelines for each ship type. 

Shipowners are cautioned that they should consider the many variables that apply to their ships. 

Some of these variables include type and size of ship, ballast tank configurations and associated 

pumping systems, trading routes and associated weather conditions, port State requirements and 

manning. 

Application 

1.4 The Guidelines apply to all those involved with ballast water exchange including, 

shipowners and operators, designers, classification societies and shipbuilders. Operational 

procedures and guidance reflecting the issues rose in these Guidelines should be reflected in the 

ships ballast water management plan. 

2 DEFINITIONS 

2.1 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 and: 

.1 “Ballast Water Tank” – means any tank, hold, or space used for the carriage of 

ballast water. 

3 RESPONSIBILITIES 

3.1 Shipowners and operators should ensure, prior to undertaking ballast water exchange, that 

all the safety aspects associated with the ballast water exchange method or methods used onboard 

have been considered and that suitably trained personnel are onboard. A review of the safety 

aspects, the suitability of the exchange methods being used and the aspects of crew training 

should be undertaken at regular intervals. 
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3.2 The Ballast Water Management Plan is to include the duties of key shipboard control 

personnel undertaking ballast water exchange at sea. Such personnel should be fully conversant 

with the safety aspects of ballast water exchange and in particular the method of exchange used 

on board their ship and the particular safety aspects associated with the method used. 

3.3 In accordance with Regulation B-4.4 of the Convention if the master reasonably decides 

that to perform ballast water exchange would threaten the safety or stability of the ship, its crew 

or its passengers, because of adverse weather, the ship’s design, stress, equipment failure, or any 

other extraordinary condition a ship shall not be required to comply with Regulations B-4.1 

and B-4.2. 

.1 When a ship does not undertake ballast water exchange for the reasons stated in 

paragraph above, the reasons shall be entered in the Ballast Water Record Book. 

.2 The port or coastal State concerned may require that the discharge of ballast water 

must be in accordance with procedures determined by them taking into account 

the Guidelines for additional measures including emergency situations (G13). 

4 BALLAST WATER EXCHANGE REQUIREMENTS 

4.1 Exchange of ballast water in deep ocean areas or open seas offers a means of limiting the 

probability that harmful aquatic organisms and pathogens be transferred in ships ballast water. 

4.2 Regulation D-1 of the Convention requires that: 

.1 ships performing ballast water exchange in accordance with this regulation shall 

do so with an efficiency of at least 95 per cent volumetric exchange of ballast 

water; and 

.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 described in paragraph 1. 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. 

4.3 There are three methods of Ballast Water exchange which have been evaluated and 

accepted by the Organization. The three methods are the sequential method, the flow-through 

method and the dilution method. The flow-through method and the dilution method are 

considered as “pump through” methods. 

4.4 The three accepted methods can be described as follows: 

Sequential method – a process by which a ballast tank intended for the carriage of 

ballast water is first emptied and then refilled with replacement ballast water to achieve at 

least a 95 per cent volumetric exchange. 

Flow-through method – a process by which replacement ballast water is pumped into a 

ballast tank intended for the carriage of ballast water, allowing water to flow through 

overflow or other arrangements. 
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Dilution method – a process by which replacement ballast water is filled through the top 

of the ballast tank intended for the carriage of ballast water with simultaneous discharge 

from the bottom at the same flow rate and maintaining a constant level in the tank through 

out the ballast exchange operation. 

5 SAFETY PRECAUTIONS ASSOCIATED WITH BALLAST WATER 

EXCHANGE 

5.1 Three methods of carrying out ballast water exchange at sea have been identified as 

acceptable by the Organization. Each has particular safety aspects associated with it that should 

be considered when selecting the method(s) to be used on a particular ship. 

5.2 When identifying the ballast water exchange method(s) for the first time for a particular 

ship, an evaluation should be made which should include: 

.1 the safety margins for stability and strength contained in allowable seagoing 

conditions, as specified in the approved trim and stability booklet and the loading 

manual relevant to individual types of ships. Account should also be taken of the 

loading conditions and the envisaged ballast water exchange method or methods 

to be used; 

.2 the ballast pumping and piping system taking account of the number of ballast 

pumps and their capacities, size and arrangements of ballast water tanks; and 

.3 the availability and capacity of tank vents and overflow arrangements, for the flow 

through method, the availability and capacity of tank overflow points, prevention 

of under and over pressurization of the ballast tanks. 

5.3 Particular account should be taken of the following: 

.1 stability which is to be maintained at all times and not less than those values 

recommended by the Organization or required by the Administration; 

.2 longitudinal stress, and where applicable torsional stress values, not to exceed 

permitted values with regard to prevailing sea conditions; 

.3 exchange of ballast in tanks where significant structural loads may be generated 

by sloshing action in the partially filled tank to be carried out in favourable sea 

and swell conditions such that the risk of structural damage is minimized; 

.4 wave-induced hull vibrations when carrying out ballast water exchange; 

.5 limitations of the available methods of ballast water exchange in respect of sea 

and weather conditions; 

.6 forward and aft draughts and trim, with particular reference to bridge visibility, 

slamming, propeller immersion and minimum forward draft; and 

.7 additional work loads on the master and crew. 
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5.4 Having undertaken an evaluation for a particular ship and the exchange method or 

methods to be used, the ship should be provided with procedures, advice and information 

appropriate to the exchange method(s) identified and ship type in the Ballast Water 

Management Plan. The procedures, advice, and information in the Ballast Water Management 

Plan, may include but is not limited to the following: 

.1 avoidance of over and under-pressurization of ballast tanks; 

.2 free surface effects on stability and sloshing loads in tanks that may be slack at 

any one time; 

.3 maintain adequate intact stability in accordance with an approved trim and 

stability booklet; 

.4 permissible seagoing strength limits of shear forces and bending moments in 

accordance with an approved loading manual; 

.5 torsional forces; 

.6 forward and aft draughts and trim, with particular reference to bridge visibility, 

propeller immersion and minimum forward draft; 

.7 wave-induced hull vibrations when performing ballast water exchange; 

.8 watertight and weathertight closures (e.g. manholes) which may have to be 

opened during ballast exchange must be re-secured; 

.9 maximum pumping/flow rates – to ensure the tank is not subjected to a pressure 

greater than that for which it has been designed; 

.10 internal transfers of ballast; 

.11 admissible weather conditions; 

.12 weather routeing in areas seasonably affected by cyclones, typhoons, hurricanes, 

or heavy icing conditions; 

.13 documented records of ballasting and/or de-ballasting and/or internal transfers of 

ballast; 

.14 contingency procedures for situations which may affect ballast water exchange at 

sea, including deteriorating weather conditions, pump failure and loss of power; 

.15 time to complete the ballast water exchange for each tank or an appropriate 

sequence thereof; 

.16 continual monitoring of the ballast water operation; monitoring should include 

pumps, levels in tanks, line and pump pressures, stability and stresses; 

.17 a list of circumstances in which ballast water exchange should not be undertaken. 

These circumstances may result from critical situations of an exceptional nature or 
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force majeure due to stress of weather, known equipment failures or defects, or 

any other circumstances in which human life or safety of the ship is threatened; 

.18 ballast water exchange at sea should be avoided in freezing weather conditions. 

However, when it is deemed absolutely necessary, particular attention should be 

paid to the hazards associated with the freezing of overboard discharge 

arrangements, air pipes, ballast system valves together with their means of control, 

and the build up of ice on deck; and 

.19 personnel safety, including precautions which may be required when personnel 

are required to work on deck at night, in heavy weather, when ballast water 

overflows the deck, and in freezing conditions. These concerns may be related to 

the risks to the personnel of falling and injury, due to the slippery wet surface of 

the deck plate, when water is overflowing on deck, and to the direct contact with 

the ballast water, in terms of occupational health and safety. 

5.5 During ballast water exchange sequences there may be times when, for a transitory 

period, one or more of the following criteria cannot be fully met or are found to be difficult to 

maintain: 

.1 bridge visibility standards (SOLAS V/22); 

.2 propeller immersion; and 

.3 minimum draft forward. 

5.6 As the choice of acceptable ballast water exchange sequences is limited for most ships, it 

is not always practicable to dismiss from consideration those sequences where transitory noncompliance may occur. The practical alternative would be to accept such sequences provided an 

appropriate note is placed in the Ballast Water Management Plan to alert the ship’s master. The 

note would advise the master of the nature of the transitory non-compliance, that additional 

planning may be required and that adequate precautions need to be taken when using such 

sequences. 

5.7 In planning a ballast water exchange operation that includes sequences which involve 

periods when the criteria for propeller immersion, minimum draft and / or trim and bridge 

visibility cannot be met, the Master should assess: 

 .1 the duration(s) and time(s) during the operation that any of the criteria will not be 

met; 

 .2 the effect(s) on the navigational and manoeuvring capabilities of the ship; and 

 .3 the time to complete the operation. 

5.8 A decision to proceed with the operation should only be taken when it is anticipated that: 

.1 the ship will be in open water; 

.2 the traffic density will be low; 
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.3 an enhanced navigational watch will be maintained including if necessary an 

additional look out forward with adequate communications with the navigation 

bridge; 

.4 the manoeuvrability of the vessel will not be unduly impaired by the draft and trim 

and or propeller immersion during the transitory period; and 

.5 the general weather and sea state conditions will be suitable and unlikely to 

deteriorate. 

5.9 On oil tankers, segregated ballast and clean ballast may be discharged below the water 

line at sea by pumps if the ballast water exchange is performed under the provisions of 

Regulation D-1.1 of the International Convention for the Control and Management of Ships’ 

Ballast Water and Sediments, provided that the surface of the ballast water has been examined 

either visually or by other means immediately before the discharge to ensure that no 

contamination with oil has taken place. 

6 CREW TRAINING AND FAMILIARIZATION 

6.1 Appropriate training for ships’ masters and crews should include instructions on the 

safety issues associated with ballast water exchange based upon the information contained in 

these Guidelines. Instruction should be provided on the ships’ Ballast Water Management Plan 

including the completion of required records. 

6.2 Ships’ officers and crew engaged in ballast water exchange at sea should be trained in and 

be familiar with the following as appropriate: 

.1 the ship’s ballast pumping and piping arrangements, positions of associated air 

and sounding pipes, positions of all compartment and tank suctions and pipelines 

connecting them to ship's ballast pumps and, in the case of use of the flow through 

method of ballast water exchange, the openings used for release of water from the 

top of the tank together with overboard discharge arrangements; 

.2 the method of ensuring that sounding pipes are clear, and that air pipes and their 

non-return devices are in good order; 

.3 the different times required to undertake the various ballast water exchange 

operations including the time to complete individual tanks; 

.4 the method(s) in use for ballast water exchange at sea if applicable with particular 

reference to required safety precautions; and 

.5 the need to continually monitor ballast water exchange operations. 

7 FUTURE CONSIDERATIONS IN RELATION TO BALLAST WATER 

EXCHANGE 

7.1 These Guidelines may be revised and updated in the light of possible technical evolutions 

with the ballast water exchange methods and of new ballast water management options. 

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