ISO 8216 and ISO 8217 standards describe the categories of marine fuels and provide detailed specifications, respectively. These specifications were developed to meet the requirements for marine fuels supplied on a world-wide basis for consumption on board ships. Internationally, a large number of residual fuel categories are available due to variations in crude oil supplies, refining methods, ship machinery characteristics and other local conditions. However, at a local or national level, the number of available categories can be limited.
While ISO 8217 takes into account various international requirements for such properties as flash point and sulfur, it is up to the user to identify and ensure compliance with all local, national and regional requirements.
ASTM D2069, adopted in 1991, was intended to be technically equivalent to ISO 8217. It was withdrawn in 2003.
Classification. The detailed classification of marine fuels into categories of products is based on the main applications and characteristics of the products. The classification is broadly broken down into distillate fuels and residual fuels.
The products 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 always 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.