Mandatory Code on Nox Emissions - Application of the Code

Annex VI requires that diesel engines with a power output of 130kW or more installed on ships after 1 January 2000 meet the requirements contained in a mandatory NOX Code. This also applies to diesel engines which are replaced or substantially modified (i.e., 10% increase in maximum continuous rating) after 1 January 2000. Emergency and lifeboat engines are excluded

Additionally, engines on ships that engage solely on voyages within the jurisdictional waters of the ship’s flag State may be exempted, provided that such engines comply with the flag Administration’s domestic NOX emission control requirements. The previous draft of this exemption clause was based on a threshold speed for high speed engines of 2000 rpm. Lobbying by the United States to lower the threshold to 1600 rpm – and thereby subject a greater amount of diesel engines used on board domestic ships to U.S. EPA requirements -- received general support. In order to obtain full agreement the above exemption was developed and accepted.

A proposal to extend the emission standards to existing engines was not supported, however, it was agreed that this matter could be considered in the future by the MEPC.