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 SC162 Rev1 CLN

UI SC162 Emergency fire pumps in cargo ships - General (Reg. II-2/ - Rev.1 Nov 2005

UI SC163 Rev2 CLN

UI SC163 Emergency fire pumps in cargo ships - sea suction and sea valve (FSS Code, Ch. 12, (SOLAS Chapter II-2, Reg.10, (SOLAS Chapter II-2, Reg.10, - Rev.2 Sept 2009

UI SC164 Rev1 CLN

UI SC164 Emergency fire pumps in cargo ships - priming (FSS Code, Ch. 12, - Rev.1 Nov 2005

UI SC165 Deleted

UI SC165 Electrical cables for the emergency fire pump (Reg.II-2/ Deleted Dec 2014.

UI SC166 Rev1 CLN

UI SC166 Waste receptacles (SOLAS 2000 Amendments (MSC.99(73)), Reg.ll-2/4.4.2) - Rev.1 Nov 2005

UI SC167 Rev1 CLN

UI SC167 Electrical distribution boards (Reg. II-2/,, and - Rev.1 Nov 2005

UI SC168 Rev1 CLN

UI SC168 Hydrants for dangerous goods (SOLAS 2000 Amendments (MSC.99(73)), Reg.ll-2/ - Rev.1 Nov 2005

UI SC169 Corr1 CLN

UI SC169 Foam systems positions of aft monitors (SOLAS 2000 Amendments (MSC.99(73)), Reg.ll-2/10.8 and FSS Code Ch. - Corr. Feb 2003

UI SC170 Rev1 CLN

UI SC170 Low pressure CO2 systems (FSS Code Ch.5.2.2) - Rev.1 Nov 2005

UI SC171 Rev2 CLN

UI SC171 Interpretation of the term "First Survey" - Rev.2 Aug 2008

UI SC172 Rev1 CLN

UI SC172 Monitoring the concentration of hydrocarbon gases in cargo pump rooms on oil tankers (Chapter II-2, Reg (Res MSC.99(73)) - Rev.1 Nov 2005

UI SC173 New

UI SC173 Safety Devices in Venting Systems (Reg.II-2/ - July 2003

UI SC174 Rev1 CLN

UI SC174 A 60 Front Insulation of Tankers (Reg.II-2/ - Rev.1 Aug 2006

UI SC175 New

UI SC175 Combustible Gaskets in Ventilation Duct Connections ( Reg.II-2/ ) - July 2003

UI SC176 Rev1 CLN

UI SC176 Fixed Local Application Fire Extinguishing System (Reg.II-2/10.5.6) - Rev.1 May 2004

UI SC177 New

UI SC177 Lubricating Oil and other Flammable Oil System Arrangements — Retroactive Application of Regulations II- 2/15.3 and 15.4 of SOLAS (2001 Edition) - July 2003

UI SC178 Rev1 CLN

UI SC178 Emergency Fire Pumps in Cargo Ships (FSS Code, Ch. 12, FSS Code, Chapter 12, paragraph Suction heads - Rev1 April 2011 Clean

UI SC179 Rev2 CLN

UI SC179 Dewatering of forward spaces of bulk carriers (Chapter XII, Regulation 13.1 (Resolution MSC 134(76)) and IMO interpretation of SOLAS Regulation XII/13 (MSC/Circ.1069)) - Rev.2 March 2011 Clean

UI SC180 Rev3 CLN

UI SC180 Hold, ballast and dry space water level detectors (Chapter II-1/25 and Chapter XII/12) and Performance Standards for Water Level Detectors on Bulk Carriers and Single Hold Cargo Ships other than Bulk Carriers (Resolution MSC.188(79)) SOLAS Regulation II-1/25 and SOLAS Regulation XII/12 - Rev3 March 2012 Clean

UI SC181 Withdrawn

UI SC181 BRIDGE DESIGN, EQUIPMENT ARRANGEMENT AND PROCEDURES Withdrawn pending further development work

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