Yes.
For example, regulation 4 of Annex VI (in force 1 July 2010) provides that the flag State Administration of a Party State may allow any fitting, material, appliance or apparatus to be fitted in a ship or other procedures, alternative fuel oils, or compliance methods used as an alternative to that required by Annex VI if such fitting, material, appliance or apparatus or other procedures, alternative fuel oils, or compliance methods are at least as effective in terms of emissions reductions as that required by Annex VI, including any of the standards set forth in regulations 13 and 14.
