Keep This Door Locked on Security Alert Sign

Keep This Door Locked on Security Alert Sign – MS0050

This MS0050 mandatory sign instructs crew and personnel to keep a specific door locked whenever a security alert is in effect aboard the vessel. Featuring the ISO 7010 blue circular mandatory-action pictogram alongside clear, bold text, the sign leaves no ambiguity about the required action during heightened security conditions, helping enforce access-control procedures at critical points throughout the ship.

Manufactured from durable, photoluminescent material, this sign remains legible in low-light and blackout conditions, an essential feature for maritime environments where security drills and real alerts can occur at any hour. Its rigid construction and UV-resistant printing ensure it withstands the harsh marine atmosphere of salt spray, humidity, and temperature extremes without fading or delaminating.

Why Keeping This Door Locked on Security Alert Matters

Unauthorised access to restricted areas is one of the most significant vulnerabilities a vessel can face during a security alert. Under the ISPS (International Ship and Port Facility Security) Code, ships are required to implement access-control measures that escalate with the declared security level. A door left unlocked during a Level 2 or Level 3 security alert can undermine the entire vessel security plan, allowing unauthorised entry to sensitive spaces such as engine rooms, cargo holds, bridge access points, or crew accommodation. Clear, standardised signage like this MS0050 sign ensures that every crew member, contractor, and visitor immediately understands which doors must remain locked and reinforces the ship’s documented security procedures without relying on memory alone.

Compliance and Certification

This sign is produced in accordance with the ISO 7010 international standard for graphical safety symbols, ensuring the pictogram is instantly recognisable to multilingual crews regardless of nationality. It supports compliance with a vessel’s Ship Security Plan under the ISPS Code and complements the broader safety management framework required by the ISM Code. Maintaining correct, durable signage at all points of restricted access is also consistent with the safety-of-life obligations set out under SOLAS, the International Maritime Organization’s convention governing safety and security aboard ships. Fitting compliant signage at every relevant doorway is a straightforward, low-cost way to demonstrate due diligence during flag-state and port-state control inspections.

Installation Recommendations

Mount this sign at eye level directly on or immediately beside the door it references, ensuring it is visible to anyone approaching from either side where practical. Clean the mounting surface thoroughly before applying to ensure maximum adhesion in humid marine conditions, and consider mechanical fixing (screws or rivets) in addition to adhesive backing for doors subject to vibration, slamming, or frequent traffic. Position the sign away from areas where paint, grease, or corrosion could obscure it over time, and include it in routine safety-sign inspections so that any wear is identified before it can compromise legibility.

• ISO 7010 compliant mandatory-action pictogram with bold, legible text
• Photoluminescent material for visibility during blackouts and low-light security musters
• Durable, UV- and corrosion-resistant construction suited to harsh marine environments
• Supports ISPS Code access-control procedures and vessel security plans
• Compact size for easy mounting on doors and adjacent bulkheads

Vessels operating under a documented Ship Security Plan should ensure every restricted door referenced in that plan carries clear, durable signage of this kind, cross-checked during internal security drills and external audits. Replacing faded or damaged signage promptly, and keeping a small stock of spares aboard, helps ensure that access-control instructions remain visible and enforceable at every security level, from routine operations through to a declared security alert.

Keep every restricted door on your vessel clearly marked and compliant with the MS0050 Keep This Door Locked on Security Alert Sign – a small investment that reinforces your ship’s security procedures and supports crew accountability during heightened alert conditions.

For related shipboard signage, browse our Hazard Signs and Fire Fighting Signs categories to complete your vessel’s IMO/SOLAS-compliant safety signage program.