The classification of marine fuels is based on the main applications and characteristics of the products. The classification is broken down into distillate fuels and residual fuels.
The marine fuels are designated by a code that consists of:
- the initials ISO,
- the letter F (for petroleum fuels),
- the category of fuel, consisting of three letters:
- the first letter of this category is the family letter (D for distillate or R for residual);
- the second letter, M, designates the application “Marine”,
- the third letter, X, A, B, C, …, K, which indicates the particular properties in the product specification (ISO 8217),
- for residual fuels, a number which corresponds to the maximum kinematic viscosity, in mm2/s, at 50°C.
For example a product may be designated in the complete form, e.g. ISO-F-RMA 10, or in abbreviated form, e.g. F-RMA 10.