October 2020

The IMO revised G8 guidelines has entered into force

DESMI Ocean Guard CompactClean has been approved since September 2018

The DESMI Ocean Guard CompactClean BWMS was one of the first BWMS to achieve IMO type approval according to the IMO BWMS code. The approval was issued on 21st September 2018 and includes no operational limitations of the BWMS in terms of salinities, water temperatures or holding times.


“We have had focus on the IMO BWMS code for quite some time now”, says Rasmus Folsø, CEO DESMI Ocean Guard A/S. 

“Our customers need the best solution, which is prepared for the future and has the right approvals. Total compliance and operability with no limitations is essential”.


According to Rasmus Folsø this focus is rewarded by the customers: 

Rasmus Folsø, CEO, DESMI Ocean Guard

"Total compliance and operability with no limitations is essential”

“Throughout 2020 we have experienced a solid increase in our order intake, and our position as one of the market leaders has been cemented”.

The evolution of the IMO G8 Guideline into the BWMS Code, and what it means

An important part of the IMO ballast water convention has since day 1 been the Guideline for approval of Ballast Water Management Systems (BWMS), also called G8.


More formally that Guideline was called MEPC.174(58), and it was adopted on 10 October 2008. Although this early guideline contained significant and detailed descriptions of tests to be completed and procedures to be followed in order to issue an IMO type approval to a BWMS, it over the years became apparent that the guideline could be improved. Shipowners were increasingly experiencing that BWMS approved according to this guideline did not always perform as expected when installed and operated on their vessels.


In an effort to make the type approval requirements for Ballast Water Management Systems (BWMS) more robust, the original IMO Guidelines for approval of ballast water management systems (G8) (MEPC.174(58)) were revised and on 28 October 2016 these revised G8 Guidelines (MEPC.279(70)) were adopted by IMO.

This revised Guidelines included several clarifications and also more stringent requirements to the required type approval tests, all with the aim to ensure more robust and better performing BWMS. Some of the more significant new requirements were:


  1. Landbased testing required in all three salinities if the BWMS should be approved for use in all three salinities.
  2. During shipboard testing the BWMS should be installed in a manner that would allow it to be used for all the vessel’s ballast operations in the 6 months test period.
  3. It should be documented that the BWMS were used for all the ship’s ballast operations during the shipboard testing period, and not just the 5 required shipboard tests.
  4. Test facilities should be independent of the BWMS manufacturer.

Already at the time when the revised G8 MEPC.279(70) was adopted several administrations and shipowner organizations were concerned about the fact that the revised G8 was just a guideline. This concern gathered momentum and on 13th April 2018 the BWMS code (MEPC.300(72)) was adopted. This is basically the revised G8, but no longer a guideline but a mandatory code.

When the BWMS code was adopted IMO also agreed that type approval according to this would be mandatory for all BWM systems installed on vessels after October 28, 2020. Following is specified in the BWMS code:

Before 28 October 2020:

Systems approved under the former G8 guidelines (MEPC.174(58)) not later than 28 October 2018 can still be installed ("installed" means the contractual/actual date of delivery of the ballast water management system to the ship). No upgrades to these systems will be necessary.

28 October 2020 and after:

If the installation of a ballast water treatment system falls on or after 28 October 2020, the system to be installed must be type approved according to the BWMS Code requirements.

Installation of a system without revised G8 or BWMS Code type approval will not be permitted for global use.

Ready for the future?

“Many BWMS has been sold over the years and more are to come – and there is no doubt that we as suppliers has an obligation to ensure that our customer’s systems are prepared for the future and have full compliance worldwide.

Therefore, I am happy that our focus on compliance has resulted in a market leading position where we do not only have the required IMO BWMS Code type approval in place, but also US Coast Guard type approval, and that these approvals are leading the way in the market in terms of allowing global operation of CompactClean without any problematic operational limitations. 

A BWMS should be operational throughout a vessel’s lifetime, and with CompactClean we have achieved just that”, concludes Rasmus Folsø.