46 C.F.R. § 78.47-13 Fire detecting and manual alarm, automatic sprinkler, and smoke detecting alarm bells.
Title 46 - Shipping
(a) The fire detecting and manual alarm automatic sprinklers, and smoke detecting alarm bells in the engine room shall be identified by at least 1 inch red lettering “FIRE ALARM”, “SPRINKLER ALARM” or “SMOKE DETECTING ALARM” as appropriate. Where such alarms on the bridge or in the fire control station do not form a part of an easily identifiable alarm cabinet, the bells shall be suitably identified as above. (b) [Reserved]
Title 46: Shipping
PART 78—OPERATIONS
Subpart 78.47—Markings for Fire and Emergency Equipment, Etc.
§ 78.47-13 Fire detecting and manual alarm, automatic sprinkler, and smoke detecting alarm bells.

