CO2 Horn Sign

CO2 Horn Sign – IMO Fire Control Symbol FS0206

The CO2 Horn sign is a mandatory IMO fire control symbol used to mark the location of a CO2 alarm horn, on board a vessel. Recognised under IMO Resolution A.654(16) and reproduced to ISO 17631, this pictogram allows crew, surveyors, and shore-based emergency responders to identify a CO2 horn position instantly, regardless of the language they speak.

The symbol depicts the text “Co2” above a red and grey horn or loudhailer graphic, denoting the audible alarm that sounds automatically before a fixed CO2 fire-extinguishing system discharges into a protected space. This design forms part of the internationally standardised library of fire control symbols found on fire control plans, damage control plans, and general arrangement drawings across commercial vessels, offshore installations, and naval ships.

Why the CO2 Horn Location Matters

A CO2 horn gives crew a short but critical warning window to evacuate a machinery space, cargo hold, or paint locker before the fixed CO2 system floods the compartment and displaces the breathable oxygen inside it. Because a CO2 release without adequate warning can be fatal to anyone left inside the space, crew need a clear, instantly recognisable sign to identify a CO2 horn location without delay.

Because rapid, unambiguous identification of fire-fighting equipment and warning devices is so important during a fire emergency, SOLAS Chapter II-2 and the Fire Safety Systems Code require clear signage marking the position of every CO2 horn, so crew unfamiliar with a particular vessel, relief officers, and visiting surveyors can find them without delay. This sign is typically mounted directly above or beside the horn itself, and is also reproduced on the fire control plan posted at the gangway and bridge.

Compliance and Certification

This CO2 Horn sign is manufactured to comply fully with IMO Resolution A.654(16) and ISO 17631 symbol requirements, ensuring the pictogram, colour scheme, and proportions match the standard expected during port state control inspections, classification society surveys, and SOLAS compliance audits. Non-standard or incorrectly proportioned signage is a common source of survey deficiencies, so every FS0206 sign is checked against the current IMO symbol register before it leaves our warehouse.

Manufactured from durable photoluminescent, self-adhesive vinyl, this sign charges under normal ambient lighting and glows for an extended period in the dark, ensuring the CO2 horn location remains identifiable even during a blackout or power failure. This self-luminous performance is especially valuable in engine rooms and cargo spaces where visibility can drop sharply during a fire event.

Installation Recommendations

For best results, mount this sign at eye level directly above or beside the CO2 horn it identifies, in a position that stays visible and unobstructed by cabling, fittings, or nearby equipment. Clean the mounting surface thoroughly to remove any dust, oil, or moisture before applying the self-adhesive backing, ensuring a permanent bond that will hold up to the conditions typical of a machinery space location.

Vessels undergoing a fire control plan update, newbuild fit-out, or SOLAS compliance retrofit should ensure this sign is included alongside the complete suite of IMO fire control symbols so that the printed fire control plan matches the physical signage installed throughout the ship. Surveyors routinely cross-check the fire control plan against signage actually fitted onboard, making consistency between the two a key focus area during flag state and classification inspections.

Key features of this CO2 Horn sign include:

• Complies with IMO Resolution A.654(16) and ISO 17631 fire control symbol standards
• Photoluminescent vinyl construction for visibility during power loss or low-light conditions
• Self-adhesive backing for fast, permanent installation on panels and bulkheads
• Waterproof and saltwater resistant for long-term use throughout the vessel
• Matches the standard pictogram used fleet-wide on fire control plans for consistent crew recognition

This sign is a small but essential part of a compliant fire control plan. Every sign we supply is checked for compliance before dispatch. Order your CO2 Horn sign today to keep your vessel’s fire control plan and physical signage fully aligned, supporting crew safety, SOLAS compliance, and a smooth outcome at your next port state control or classification survey.

For more information on the international symbol standards referenced above, see the International Maritime Organization resolution library. Browse our full range of Fire Fighting Signs for more IMO-compliant fire control signage for your vessel.