The U.S. Coast Guard has published Policy Letter 03-21 which establishes that the Coast Guard considers the design and equipment standards of HSAC RP 161 to be at least as effective as the helicopter facilities regulations in 46 CFR Part 108, applicable to certain Mobile Offshore Drilling Units, floating Outer Continental Shelf facilities, and domestic vessels.
Source: USCG
Link: Acceptance of Helicopter Safety Advisory Committee (HSAC) recommended practice (RP) 161, new build helideck design guidelines