46 C.F.R. § 52.05-20

Radiographic and ultrasonic examination of welded joints must be as described in PW-11 of Section I of the ASME BPVC (incorporated by reference; see § 52.01-1). Parts of boilers, fabricated of pipe material such as drums, shells, downcomers, risers, cross pipes, headers, and tubes containing only circumferentially welded butt joints, must be nondestructively examined as required by § 56.95-10 of this subchapter.