46 C.F.R. § 54.15-1
General (modifies UG-125 through UG-137)
(a) All pressure vessels must be provided with protective devices as indicated in UG-125 through UG-136 Section VIII of the ASME BPVC (incorporated by reference; see § 54.01-1) except as noted otherwise in this subpart.
(b) The markings must be in accordance with this chapter for devices covered by § 54.15-10.