BS EN 1561:2011

1   Scope This European Standard specifies the properties of unalloyed and low-alloyed grey cast irons used for castings, which have been manufactured in sand moulds or in moulds with comparable thermal behaviour. This European Standard specifies the characterizing properties of grey cast irons by either

a) the tensile strength of cast samples , or

b) the hardness measured on the castings or on a cast-on knob.

If agreed by the manufacturer and the purchaser, the combination of both tensile strength
  from option a) and hardness from option b) may be specified. 
This European Standard specifies six grades of  grey cast iron  by a classification based on tensile strength measured on machined test pieces prepared
  from  cast samples  (see Table 1) and six grades of  grey cast iron  by a classification based on Brinell hardness (see Table 2). 
This European Standard does not cover technical delivery conditions for iron castings;
  see EN 1559‑1 [3] and EN 1559‑3 [4]. 
This European Standard does not apply to  grey cast irons  used for pipes and fittings according to EN 877 [5].