This International Standard specifies the requirements for petroleum fuels for use in marine diesel engines and boilers, prior to appropriate treatment before use. The specifications for fuels in this International Standard can also be applicable to fuels for stationary diesel engines of the same or similar make and type as those used for marine purposes. This International Standard specifies four categories of distillate fuel, one of which is for diesel engines for emergency purposes. It also specifies six categories of residual fuel. NOTE 1 For the purpose of this International Standard, the term “petroleum” is used to include oil from tar sands and from shale. NOTE 2 Appropriate guidance about fuel treatment systems for diesel engines is published by the International Council on Combustion Engines (CIMAC)[4]. NOTE 3 Requirements for gas turbine fuels used in marine applications are specified in ISO 4261[5]. NOTE 4 For the purposes of this International Standard, the terms “mass %” and “volume %” are used to represent the mass and volume fractions respectively.