NBN EN 1560:2011

This European Standard establishes a material designation system either by symbols or by numbers for cast iron.
The designation system by symbols is applicable to:
a) standardized cast iron materials (see 2.1);
b) non-standardized cast iron materials (see 2.2).
The designation system by numbers is only applicable to standardized cast iron materials (see 2.1).
NOTE The use of a designation system by symbols does not necessarily imply that the material is standardized.