Wrinkle bends in steel pipe.

(a) A wrinkle bend may not be made on steel pipe to be operated at a pressure that produces a hoop stress of 30 percent, or more, of SMYS. (b) Each wrinkle bend on steel pipe must comply with the following: (1) The bend must not have any sharp kinks. (2) When measured along the crotch of the bend, the wrinkles must be a distance of at least one pipe diameter. (3) On pipe 16 inches (406 millimeters) or larger in diameter, the bend may not have a deflection of more than 1 1/2 ° for each wrinkle. (4) On pipe containing a longitudinal weld the longitudinal seam must be as near as practicable to the neutral axis of the bend. [35 FR 13257, Aug. 19, 1970, as amended by Amdt. 192-85, 63 FR 37503, July 13, 1998]