§192.315 Wrinkle bends in steel pipe.

(a)  A wrinkle bend [a bend in the pipe that: (1) Was formed in the field during construction such that the inside radius of the bend has one or more ripples with: (i) An amplitude greater than or equal to 1.5 times the wall thickness of the pipe, measured from peak to valley of the ripple; or (ii) With ripples less than 1.5 times the wall thickness of the pipe and with a wrinkle length (peak to peak) to wrinkle height (peak to valley) ratio under 12. (2) (i) If the length of the wrinkle bend cannot be reliably determined, then wrinkle bend means a bend in the pipe where (h/D)*100 exceeds 2 when S is less than 37,000 psi (255 MPa), where (h/D)*100 exceeds (47000—S)/10,000 +1 for psi [324—S)/69 +1 for MPa] when S is greater than 37,000 psi (255 MPa) but less than 47,000 psi (324 MPa), and where (h/D)*100 exceeds 1 when S is 47,000 psi (324 MPa) or more. (ii) Where: (A) D = Outside diameter of the pipe, in. (mm); (B) h = Crest-to-trough height of the ripple, in. (mm); and (C) S = Maximum operating hoop stress, psi (S/145, MPa).] may not be made on steel pipe [any pipe or tubing used in the transportation of gas, including pipe-type holders.] to be operated at a pressure that produces a hoop stress of 30 percent or more, of SMYS [specified minimum yield strength is: (1) For steel pipe manufactured in accordance with a listed specification, the yield strength specified as a minimum in that specification; or (2) For steel pipe manufactured in accordance with an unknown or unlisted specification, the yield strength determined in accordance with § 192.107(b).].

(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 11/2° 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]