In order to comply with the new sulphur limit for fuel oil used on board ships taking effect from 1 January 2020, fuel oils with a sulphur content of 0.50% or less (hereafter, referred to as "compliant fuel oils") will be distributed globally for bunkering. Consequently, the number of occasions where fuels for main engines or auxiliary engines are changed from conventional fuel oils to compliant fuel oils and used will increase.

ClassNK has released a booklet containing precautions concerning the change-over to compliant fuel oils with an aim to provide crew members on board ships going to bunker and use compliant fuel oils with information focusing on the "compatibility" and "cold flow properties" of such fuels as well as the risks associated with such fuels and the measures to be taken to mitigate such risks.