(i) For pipes of outside diameter over 60.3 mm a flattening test shall be conducted.  A section of the pipe not less than 63 mm is length shall be flattened cold between two parallel flat surfaces to a distance between the plates (H) as calculated by the formula given below, without showing any sign of a crack or flaw. 

H = (1+e) t / {e + (t/D)}      

where t  = specified thickness for pipe (mm)

          D = specified outside diameter of the pipe (mm)

          e = a constant, 0.08 for ferritic alloy steel.

(ii)  For pipe whose diameter equals or exceeds 254 mm, a bend test may be conducted instead of the flattening test.  The bend test specimens shall be bent at room temperature through 180 degree C without cracking on the outside of the bent portion.  The inside diameter of the bend shall be 25 mm.  Substitution of the bend test for the flattening test shall be subject to the approval of the purchaser.

(iii)  For pipes whose diameter exceed 635 mm and whose diameter to wall thickness ratio is 7.0 or less, the bend test described in clause (b) shall be conducted instead of the flattening test.