Persistent floating products under MARPOL Annex II
The 2021 regime for slick-forming cargoes: the regulation 1.23 definition, the regulation 13.7.1.4 prewash and the four European sea areas where it applies.
A persistent floating product is a cargo that floats on the sea surface, resists evaporation and does not dissolve, forming a slick that persists long after discharge. MARPOL Annex II regulation 1.23, inserted by IMO resolution MEPC.315(74) and in force from 1 January 2021, defines it by four properties together: density not more than that of sea water at 1,025 kg/m3 at 20 degrees C, vapour pressure not more than 0.3 kPa, solubility not more than 0.1 percent for a liquid or 10 percent for a solid, and kinematic viscosity greater than 10 cSt at 20 degrees C.
Regulation 13.7.1.4 requires an appendix VI prewash for a category Y persistent floater with a viscosity of 50 mPa.s or more at 20 degrees C and, or, a melting point of 0 degrees C or more, identified by the entry 16.2.7 in column o of IBC Code chapter 17. The residue and water mixture goes to a reception facility at the port of unloading until the tank is empty.
The rule is regional rather than global. Regulation 13.9 lists the areas: North West European waters, the Baltic Sea area, Western European waters and Norwegian waters. Note that the high-viscosity test in regulation 1 is taken at the unloading temperature while the persistent floater test is taken at 20 degrees C, so a cargo can meet one and not the other. The full article will cover the cargoes affected, the revised Procedures and Arrangements Manual format and the enforcement practice in the designated areas.