ISO 8217:2017 specifies the requirements for fuels for use in marine diesel engines and boilers, prior to conventional onboard treatment (settling, centrifuging, filtration) before use. The specifications for fuels in this document can also be applied to fuels used in stationary diesel engines of the same or similar type as those used for marine purposes. ISO 8217:2017 specifies seven categories of distillate fuels, one of which is for diesel engines used for emergency purposes. It also specifies six categories of residual fuels. For the purposes of this document, the term "fuels" is currently used to include the following: - hydrocarbons from petroleum crude oil, oil sands and shale; - hydrocarbons from synthetic or renewable sources, similar in composition to petroleum distillate fuels; - blends of the above with a fatty acid methyl ester(s) (FAME) component where permitted. NOTE 1 Appropriate guidance about fuel treatment systems for diesel engines is published by the International Council on Combustion Engines (CIMAC)[5]. NOTE 2 Requirements for gas turbine fuels used in marine applications are specified in ISO 4261[6]. NOTE 3 For the purposes of this document, the terms "mass %" and "volume %" are used to represent the mass and volume fractions respectively.