46 C.F.R. § 52.20-25
Setting (modifies PFT-46)
(a) The method of supporting firetube boilers must be as indicated in PFT-46 of Section I of the ASME BPVC (incorporated by reference; see § 52.01-1) except as noted otherwise in this section.
(b) The foundations must meet the requirements of § 52.01-130.