BWM Convention Experience-Building Phase: Outcomes
Updated
The Experience-Building Phase (EBP) was a structured IMO programme, agreed under resolution MEPC.290(71), to gather data on the practical implementation of the BWM Convention during its early years without penalising ships and equipment makers for teething problems. It collected data on system performance, sampling and analysis, and challenging operating conditions, feeding a review of the Convention and its guidelines. Its findings have driven refinements such as clearer commissioning testing and contingency guidance.
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Key takeaways
- The Experience-Building Phase, agreed under MEPC.290(71), gathered real-world data on BWM Convention implementation from 2017 onward.
- It collected data on system performance in challenging waters, on sampling and analysis reliability, and on failures and contingencies.
- It surfaced gaps between type-approval test conditions and real operating conditions, especially in low-salinity and low-UVT water.
- A key outcome was mandatory commissioning testing under MEPC.325(75), effective 1 June 2022, which is indicative not a full D-2 validation.
- The phase also informed clearer contingency and temporary non-compliance guidance for system failures.
- Its lasting lesson is that transparent reporting of genuine difficulties is treated more constructively than concealment.
What Was the Experience-Building Phase?
The EBP was established by the Marine Environment Protection Committee to run through the initial period after the Convention entered into force in 2017. Its purpose was to collect real-world data on how the Convention and its systems performed in service, so the regulatory framework could be refined on evidence rather than assumption.
It was deliberately structured as a data-gathering and lesson-learning exercise, not an enforcement holiday, but it did embody a pragmatic recognition that early adopters should not be unfairly penalised for problems that arose from the framework's immaturity rather than from negligence. This encouraged transparent reporting of difficulties.
The phase had a defined data-gathering and analysis structure, with a plan for collecting information, a trial period, and a subsequent analysis leading to a review of the Convention text and guidelines. It brought together flag states, port states, industry and equipment makers around a common evidence base.
What Data Did It Gather?
The EBP collected information on the performance of installed treatment systems in actual service conditions, including how they coped with challenging water such as low salinity, low temperature, high turbidity and low UV transmittance, which were known weak points not fully captured by type-approval testing.
It also gathered data on sampling and analysis, both indicative and detailed, to understand how reliably compliance could be verified in the field and how consistent results were between methods and laboratories. This was important because inconsistent sampling outcomes undermine fair enforcement.
Reports of system failures, contingency situations and operational difficulties fed the phase, building a picture of where the framework caused practical problems. The emphasis on honest reporting of difficulties, without immediate penalty, was designed to surface issues that would otherwise stay hidden.
What Problems Did It Surface?
A recurring theme was performance in challenging waters. Systems that passed type approval within a defined envelope sometimes struggled in real ports with sediment, low salinity or poor UV transmittance, highlighting a gap between test conditions and operational reality.
Sampling and analysis proved less straightforward than hoped. Differences between indicative and detailed methods, and between laboratories, raised questions about how a ship should be judged non-compliant and about the fairness of enforcement based on a single indicative result.
The value of commissioning testing became clear: systems that were type approved could still be poorly installed or commissioned, so a check on the specific installation was needed. This informed the development of mandatory commissioning testing.
What Changed as a Result?
One tangible outcome was the introduction of mandatory commissioning testing for newly installed systems under resolution MEPC.325(75), effective from 1 June 2022, confirming through indicative biological sampling that an installed system works in the ship's actual conditions. It is important to note this is indicative testing, a one-time installation check, not a full D-2 compliance validation.
The EBP also fed clearer guidance on contingency measures and the treatment of temporary non-compliance, giving operators a defined path when a system fails rather than a binary compliant-or-detained outcome. This reflected the phase's finding that failures happen and need a proportionate framework.
More broadly, the phase informed the ongoing review of the Convention and its guidelines, including work on how challenging water quality is addressed, how sampling and analysis should be conducted and interpreted, and how the regulatory framework can be made more robust and consistent.
Why Does the EBP Still Matter to Operators?
The refinements the EBP produced shape day-to-day compliance now. Commissioning testing is a fixed requirement for new installations, and contingency guidance is what an operator relies on when a system fails, so understanding their origin helps crews apply them correctly.
The EBP's central lesson, that transparent reporting of genuine difficulties is treated more constructively than concealment, remains the right posture. A documented, notified system fault handled through contingency measures is far better received than a hidden non-compliant discharge, a principle that survived the phase into normal enforcement.
The phase also signalled that the framework will keep evolving as evidence accumulates, so operators should expect further refinement of sampling standards, challenging-water guidance and possibly the Convention text itself, and should track MEPC developments rather than assume the rules are static.
How Should Operators Use These Lessons?
Treat the type-approval envelope as a hard operating limit, because the EBP confirmed that challenging waters are where systems fail; if uptake water is outside the certified salinity, temperature or UV transmittance, use an alternative method or contingency rather than pushing the system.
Ensure new installations are properly commissioned and that the commissioning test is documented, and keep in mind that it confirms installation function rather than guaranteeing ongoing D-2 compliance, which still depends on correct operation and maintenance.
Sea Clean applies these lessons in service, as an authorized Headway agent and a brand-agnostic supporter of other makes, supporting commissioning, verifying calibration, supplying parts and consumables, and coordinating independent ISO 17025 sampling; we are not ourselves an accredited laboratory. In Norway and the North Sea region we can typically attend within 0 to 24 hours.
Frequently asked questions
What was the Experience-Building Phase?
It was an IMO programme agreed under resolution MEPC.290(71) to gather data on how the BWM Convention worked in practice during its early years, feeding a review of the Convention and its guidelines. It gathered evidence without unfairly penalising early adopters for framework teething problems.
Did the EBP mean I did not have to comply?
No. It was a data-gathering and lesson-learning exercise, not an enforcement holiday. Ships still had to meet the applicable standard, but genuine difficulties reported transparently were treated constructively rather than punitively.
What came out of the Experience-Building Phase?
Key outcomes include mandatory commissioning testing under MEPC.325(75), clearer contingency and temporary non-compliance guidance, and ongoing review of challenging-water and sampling issues. It confirmed that type-approval conditions can differ from real operating conditions.
Is commissioning testing a D-2 compliance check?
No. Commissioning testing under MEPC.325(75) is indicative and confirms, once, that an installed system functions in the ship's actual conditions. It does not replace the type approval or ongoing in-service verification of D-2 compliance.
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