46 C.F.R. § 52.05-1
General (modifies PW-1 through PW-54)
Boilers and component parts, including piping, that are fabricated by welding must be as indicated in PW-1 through PW-54 of Section I of the ASME BPVC (incorporated by reference; see § 52.01-1) except as noted otherwise in this subpart.