UK: Guidance for Fixed Aerosol Fire Systems in small vessels

UK Maritime and Coastguard Agency has issued a Marine Guidance Note - MGN 657 (M/F) regarding requirements for Fixed Aerosol Fire Extinguishing Systems for small vessel machinery spaces.

This MGN was published on 27 February 2024.

Introduction/Background

The approval process for Fixed Aerosol Fire Extinguishing Systems in small vessel machinery spaces has shifted to UK Approved Bodies from the MCA. This change streamlines the approval process and ensures compliance with international guidelines.
The testing requirements outlined in this the (Marine Guidance Note) are based on guidelines established by the International Maritime Organization (IMO), specifically the Maritime Safety Committee (MSC) Circular 1270. These guidelines ensure that approved systems meet rigorous standards for fire suppression effectiveness.
New approval certificates will provide comprehensive information, including the types of vessels the system is approved for and specific installation requirements. This transparency enhances safety and regulatory compliance for small vessels.

General

Fixed Aerosol Fire Extinguishing Systems operate by chemically interrupting the fire process, effectively extinguishing fires in enclosed spaces.
There are two main methods of applying aerosol agents: Condensed Aerosols, which are generated through pyrotechnic means, and Dispersed Aerosols, which are stored under pressure and released using valves, pipes, and nozzles.
While formal definitions are provided, understanding them intuitively can aid in addressing safety considerations during installation, operation, and maintenance.

UK Approved Bodies and Certifying Authorities

UK Approved Bodies, appointed under relevant regulations, are responsible for approving Fixed Aerosol Fire Suppression Systems. These bodies ensure that tests comply with established procedures, as detailed in the Appendix of this MGN.
More information on the requirements for UK Approved Bodies can be found in related marine equipment regulations and notices.
The Certifying Authority, which may include the MCA acting on behalf of the Secretary of State, authorizes the use of approved systems on vessels. This authority ensures that systems meet safety, toxicity, and environmental standards.

Fixed Aerosol Fire Extinguishing Systems Approval

UK Approved Bodies issue approval certificates following the successful completion of tests outlined in the Appendix. These certificates demonstrate a system's effectiveness in extinguishing fires but do not automatically approve them for use on vessels.
Initial certification is valid for five years and requires satisfactory testing. Subsequent recertifications are based on further testing every five years, with a retest required after 15 years or after major design changes.
Major design changes trigger retesting, ensuring that any alterations to the system do not compromise its effectiveness or safety.

Vessel Installation Requirements

Installation of systems on vessels follows specific guidelines outlined in this MGN and manufacturer's manuals. These guidelines ensure proper placement, operation, and maintenance of the system.
The calculation of protected space volume and aerosol concentration is crucial for effective fire suppression. These calculations inform the design and installation process, enhancing the system's efficacy.
Safety measures, including isolation switches, control panels, and safety notices, are essential for ensuring safe operation and maintenance of the system on board vessels.

Installation, Commissioning, and Maintenance Requirements

Installation, commissioning, and maintenance of Fixed Aerosol Fire Extinguishing Systems must be carried out by authorized personnel using approved components and in accordance with manufacturer instructions.
Regular inspections and servicing are necessary to ensure the system's continued effectiveness and compliance with regulatory standards.
Comprehensive record-keeping of installation, commissioning, servicing, and inspections is vital for regulatory compliance and safety. Additionally, adherence to the manufacturer's guidelines and conditions of approval ensures optimal system performance and longevity.

Also, the Appendix of this MGN details guidance on the fire test approval procedures for Fixed Aerosol Fire Extinguishing Systems for use in small vessel machinery spaces.

It includes definitions of terms related to aerosol fire extinguishing systems, details about the test enclosures and required fire tests, principal requirements for the systems, information about the test report and certificate, and references to relevant guidelines and codes.

The document specifies that the test enclosure should be constructed within a 20-foot ISO steel container and provides details about the mock-up of an engine and the placement of trays and cans for the fire tests. The required fire tests include open pool fires, hidden spray fires, hidden pool fires, combined fires, and a wood crib fire.

The document also outlines the principal requirements for the components of the aerosol systems, including design density, agent quantity, storage container design, handling and disposal, valves, generators/nozzles, actuation and control systems, alarms and indicators, enclosure integrity, and more.

The test report should include information about the test laboratory, client, manufacturer, product description, test method, test results, and conclusions.

On successful completion of the tests, a Certificate of Inspection and Tests will be issued, stating that the aerosol system is suitable for installation in normally unoccupied spaces of vessels of less than 24 meters load line length.

All regulations can be found at legislation.gov.uk

For more information, please see the document below (available only to subscribers):