Unified Interpretations


Unified Interpretations are adopted resolutions on matters arising from implementing the requirements of IMO Conventions or Recommendations. Such adopted resolutions can involve uniform interpretations of Convention Regulations or IMO Resolutions on those matters which in the Convention are left to the satisfaction of the Administration or vaguely worded.

Interpretations are circulated to Administrations concerned or are sent to IMO for information, as appropriate.


  1. IACS, as an international Non-Governmental Organization having observer status at IMO, works in co-operation with IMO in order to endeavour that regulations developed at IMO are clear, unambiguous and can easily be applied without the need of interpretations.
  2. However, interpretations may still be needed in cases where IMO regulations contain only functional requirements, allow alternative solutions to prescriptive requirements, are left to the satisfaction of Administrations or are generally or vaguely worded.
  3. The following Unified Interpretations (UIs) have been developed by IACS to assist the unified implementation of IMO regulations falling in the above-mentioned cases. It should be noted that the development of IACS Unified Interpretations (UIs) is not aiming at introducing additional requirements but at achieving uniform application of IMO regulations.
  4. IACS UIs are to be applied by IACS Societies to ships whose flag Administrations have not issued definite instructions on the interpretation of the IMO regulations concerned, in the course of statutory certification on behalf of those flag Administrations.

The technical backgrounds (development histories) of Unified Interpretations since 2004 can be found by following this link.

A list of the IACS working groups responsible for each Unified Interpretation may be found here.

UI SC93 Rev1 CLN

UI SC93 Enclosure of stern tubes on cargo ships (Chapter II-1, Regulation 12.10 (2006 Amendments)) - Rev.1 February 2010 Clean

UI SC94 Rev2 CLN

UI SC94 Mechanical, hydraulic and electrical independency of steering gear control systems (Chapter II-1, Regulation 29) - Rev2 - June 2016 Clean

UI SC95 New

UI SC95 Communication between Navigating Bridge and Machinery Space (Chapter II-1, Reg. 37) - 1994

UI SC96 Deleted

UI SC96 Capacity of an emergency fire pump Deleted in Nov 2005 because of SOLAS 2000 Amendments

UI SC97 Rev2 CLN

UI SC97 Connection of a pump to fire main (Reg. II-2/ - Rev.2 Nov 2005

UI SC98 Rev1 CLN

UI SC98 Fire hose nozzles of a plastic type material (Reg. II-2/ - Rev.1 Nov 2005

UI SC99 Rev2 CLN

UI SC99 Flexible bellows of combustible materials (SOLAS Reg. II-2/ - Rev2 August 2014 Clean

UI SC100 Rev2 Corr1 CLN

UI SC100 Rev.2 Corr.1 August 2014 Clean

UI SC101 Rev1 CLN

UI SC101 Main vertical zones (Reg. II-2/ - Rev.1 November 2005 Clean

UI SC102 Rev1 CLN

UI SC102 Cold Service (Reg. II-2/ - Rev.1 November 2005 Clean

UI SC103 Rev1 CLN

UI SC103 Insulation of machinery space boundaries (Reg. II-2/19.3.8) - Rev.1 November 2005 Clean

UI SC104 Deleted

UI SC104 Quick closing valve for emergency generator fuel tank Deleted in Nov 2005 because of SOLAS 2000 Amendments

UI SC105 Deleted

UI SC105 Relief valve in oil filling lines and safe positions for discharge of air and overflow pipes Deleted in Nov 2005 because of SOLAS 2000 Amendments.

UI SC106 Rev1 CLN

UI SC106 Galley exhaust duct (Reg. II-2/ - Rev.1 Nov 2005 Clean

UI SC107 Rev1 CLN

UI SC107 Continuous ceiling (Reg. II-2/ - Rev.1 Nov 2005 Clean

UI SC108 Rev1 CLN

UI SC108 Galley exhaust duct (Reg. II-2/ - Rev.1 Nov 2005

UI SC109 Rev1 CLN

UI SC109 Open Top Container Holds - Water Supplies (Reg. II-2/19.3.1) - Rev.1 Nov 2005

UI SC110 Rev1 CLN

UI SC110 Open Top Container Holds - Ventilation (Reg. II-2/19.3.4) - Rev.1 November 2005

UI SC111 Rev1 CLN

UI SC111 Open Top Container Holds - Bilge Pumping (Reg. II-2/19.3.5) - Rev.1 Nov 2005

UI SC112 Deleted

UI SC112 Pilot Transfer Arrangements Deleted in January 2002.

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