MARPOL Annex VI is the IMO's regulations against air pollution from ships. It sets limits for NOx from engines, sulfur in fuel, emissions in control areas (ECA), and – since 2023 – for the ship's energy efficiency and carbon intensity. Ecoxy provides the measurements and verification that document the ship's compliance with the requirements.
Annex VI to the MARPOL Convention came into force in 2005 and has since been tightened several times. It applies to all ships flying the flag of a state that has ratified the annex and is enforced by port state control (PSC) regardless of flag when the ship calls at a port in such a state.
The main provisions for a shipping company are:
In ECA areas, stricter requirements apply. Shipping companies operating in or to Northern Europe encounter several of them:
Practical consequence: A ship built after 2021 that sails between Norway, Denmark, and Germany must document Tier III – typically with SCR or EGR – and must be able to demonstrate during inspection that the treatment system works. This is where onboard measurements come in.
Certificates, fuel documentation, and measurements requested by the inspector
International Air Pollution Prevention Certificate issued to the ship after the first inspection and renewed every five years, with annual and intermediate inspections. It confirms that equipment, systems, and fuel management meet Annex VI.
One EIAPP certificate per engine over 130 kW, with Technical File and Record Book of Engine Parameters. NOx compliance is shown by parameter control or measurement onboard according to the NOx Technical Code.
Delivery notes with sulfur content are kept for three years, fuel samples for twelve months. When using a scrubber, approval and logging are required. SEEMP part III and verified CII report document carbon intensity.
Measurements and verification covering Annex VI from engine to report
Accredited measurement onboard according to the NOx Technical Code – for EIAPP, inspections, modifications, and documentation of SCR/EGR in Tier III areas.
Measurement of SO₂/CO₂ ratio for scrubber documentation, and of particles, CO, and CH₄ where emission permit or customer requires it.
Accredited verifier under EU MRV, EU ETS, and FuelEU Maritime – the European regulations that build on Annex VI.
We plan the measurements in line with the inspection windows of the classification society, so that the documentation is ready when the inspector arrives.
The NOx requirements in regulation 13 apply to the engine, not the size of the ship: all diesel engines over 130 kW are covered. An IAPP certificate is required for ships of 400 GT and above in international traffic; smaller ships must still meet the requirements but document it under the flag state's conditions.
IAPP applies to the ship and all Annex VI requirements collectively. EIAPP applies to one engine and only NOx. A ship with three engines has one IAPP and three EIAPPs.
Annex VI is the IMO's global regulation, while EU MRV, EU ETS, and FuelEU Maritime are the EU's regional additions for ships calling at European ports. The data overlaps – fuel consumption and emission factors – but the reporting and verification are different. See the page on MRV verification.
Port state control can hold the ship back until the deviation is corrected, and the flag state can impose fines. Lack of EIAPP, discrepancies between the engine and Technical File, and missing BDN are among the most common findings.
Tell us which requirement needs to be documented – NOx, sulfur, report verification – and which ships it concerns, and we will propose implementation within 24 hours on weekdays.
Accreditations and certifications
NA TEST 225
NA VV-003
Kiwa Certified
Kiwa ISO 14001
Achilles
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