EN 10221 (Defects)

Class nominal diameter
dN  mm
the permissible maximum depth of the superficial discontinuities    mm
A 5 < dN  < 25 0,50
25 <   dN  < 150 0,02 x dN
B 5 < dN  < 12 0,20
12 <   dN  < 18 0,25
18 <  dN  < 30 0,30
30 <   dN  < 150 0,01 x dN
C 5 < dN  < 12 0,17
12 <   dN  < 30 0,23
30 <   dN  < 120 0,0075 x dN
D 5 < dN  < 12 0,15
12 <   dN  < 40 0,20
40 <   dN  < 60 0,005 x dN
60 <   dN  < 80 0,30
E 5 < dN  < 60 ª
         
ª this class of surface quality must be better than the D class. The prescription and the method of control must be agreed between the parts.