MCA releases a new consultation on MGN 657 requirements for fixed aerosol fire extinguishing systems for use in small vessel machinery spaces

Published on: 18 August 2022

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The MCA has released a public consultation with industries views sought for MGN 657 (M+F) Requirements for Aerosol Fixed Fire Suppression Systems for use in Small Vessel Machinery which publishes the test requirements for future approvals of these systems and requires that tests are witnessed by an Approved Body appointed by the MCA.

Aerosol fire extinguishing systems involve the release of a chemical agent to extinguish a fire by interruption of the process of the fire. The MCA has previously approved aerosol fixed fire suppression systems for use in small vessel machinery spaces through approval certificates based on the MCA’s MSF 1814 forms issued to suppliers of aerosol suppression systems. These certificates required the MCA approval of tests to show the safe and effective operation of the systems by live fire testing. This MGN (657) now formalises the process by publishing the test requirements for future approvals and to require the tests are witnessed by an Approved Body appointed by the MCA.

The approval certificate provides information on the vessel types that the system is accepted for as well as details of the installation requirements for that system. Requirements that are common to all aerosol fixed firefighting system installations are described in the draft MGN.


A UK Approved Body, as appointed under the Merchant Shipping (Marine Equipment) Regulations 2016, as amended, (“the Regulations”), in this context, is a body which may undertake approval of an aerosol fire suppression system test that complies with the requirements of these test procedures on behalf of the MCA. Further details on the UK Approved Bodies requirements can be found in MGN 554 “Marine Equipment – Procedure for becoming a UK Approved Body following the UK’s exit from the EU”, as amended, as well as in MIN 590 as Amended “United Kingdom conformity assessment procedures for marine equipment following the transition period”.

This consultation closes at 11:45pm on 30 September 2022.

The full consultation documents, including the daft of MGN 657 and the consultation response form can be accessed at

To provide feedback please complete aresponse form and email directly to

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