46 CFR §108.425

1. (a)Each length of fire hose in a fire main system must be—
   1. (1)Of 1 1/2 or 2 1/2 inch nominal hose size diameter;
   2. (2)Of 50 foot nominal hose size length; and
   3. (3)Lined commercial fire hose that meets Standard 19 of the Underwriters' Laboratories, Inc., (1971 edition) or Federal Specification ZZ-H-451f.
2. (b)Fire station hydrant connections shall be brass, bronze, or other equivalent metal. Couplings shall either:
   1. (1)Use National Standard fire hose coupling threads for the 1 1/2 inch (38 millimeter) and 2 1/2 inch (64 millimeter) hose sizes, i.e., 9 threads per inch for 1 1/2 inch hose, and 7 1/2 threads per inch for 2 1/2 inch hose; or
   2. (2)Be a uniform design for each hose diameter throughout the vessel.
3. (c)Each nozzle for a firehose in a fire main system must be a combination solid stream and water spray firehose nozzle that is approve under subpart 162.027. Combination solid stream and water spray nozzles previously approved under subpart 162.027 of this chapter may be retained so long as they are maintained in good condition to the satisfaction of the Officer in Charge, Marine Inspection.
4. (d)A combination solid stream and water spray firehose nozzle previously approved under subpart 162.027 of this chapter, must have a low-velocity water spray applicator also previously approved under subpart 162.027 of this chapter when installed in—
   1. (1)Machinery spaces containing oil fired boilers, internal combustion machinery or oil fuel units; and
   2. (2)Helicopter decks.