46 CFR § 78.47-17
Fire extinguishing system controls
April 15, 2021
Each control cabinet or space containing valves or manifolds for a fire extinguishing system must be distinctly marked in conspicuous red letters at least 2 inches high: “[CARBON DIOXIDE/STEAM/FOAM/WATER SPRAY/MANUAL SPRINKLING/AUTOMATIC SPRINKLING/CLEAN AGENT—as appropriate] FIRE SYSTEM.”.
[USCG-2006-24797, 77 FR 33877, June 7, 2012]