46 CFR §169.734
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Each control cabinet or space containing valves or manifolds for the various fire extinguishing systems must be distinctly marked in conspicuous red letters at least 2 inches high: “CARBON DIOXIDE FIRE EXTINGUISHING SYSTEM,” “HALON EXTINGUISHING SYSTEM,” or “CLEAN AGENT EXTINGUISHING SYSTEM,” as appropriate.