46 CFR § 108.477
Fire hydrants
April 15, 2021
(a) If a fixed foam extinguishing system has outlets in a main machinery space, at least 2 fire hydrants, in addition to the fire hydrants required by §108.423 of this subpart, must be installed outside the entrances to the space with each at a separate entrance.
(b) Each hydrant must have enough hose to spray any part of the space.
(c) Each hydrant must have a combination nozzle and applicator.