(b)Each field bend must comply with the following:
(1)A bend must not impair the serviceability of the pipe.
(2)Each bend must have a smooth contour and be free from buckling, cracks, or any other mechanical damage.
(3)On pipe containing a longitudinal weld, the longitudinal weld must be as near as practicable to the neutral axis of the bend unless—
(i)The bend is made with an internal bending mandrel; or
(ii)The pipe is 12 3/4 in (324 mm) or less nominal outside diameter or has a diameter to wall thickness ratio less than 70.
(c)Each circumferential weld which is located where the stress during bending causes a permanent deformation in the pipe must be nondestructively tested either before or after the bending process.