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 SC251 New

UI SC251 Controls of emergency bilge suction valve in periodically unattended machinery spaces (SOLAS regulations II-1/48.3) - October 2011

UI SC252 New

UI SC252 Controls for releasing carbon dioxide and activating the alarm in the protected space (FSS Code - October 2011

UI SC253 Rev1 CLN

UI SC253 Fire resistance requirements for fibrereinforced plastic (FRP) gratings used for safe access to tanker bows (IMO Res. MSC.62(67)) - Rev.1 May 2016 Clean

UI SC254 New

UI SC254 Fall Preventer Devices (MSC.1/Circ.1392 and Circ.1327) - April 2012

UI SC255 Corr1 CLN

UI SC255 Fuel pump arrangement required for ships to maintain normal operation of propulsion machinery when operating in emission control areas and non-restricted areas SOLAS II-I 26-3. (Partially) - Corr.1 November 2013 Clean

UI SC256 New

UI SC256 Date of Delivery under SOLAS and MARPOL Conventions - June 2012

UI SC257 Rev1 CLN

UI SC257 Pilot Transfer Arrangements (SOLAS V/23 as amended by Resolution MSC.308(88)) - Rev.1 October 2016 Clean

UI SC258 New

UI SC258 For Application of Regulation 3-11, Part A-1, Chapter II-1 of the SOLAS Convention (Corrosion Protection of Cargo Oil Tanks of Crude Oil Tankers), adopted by Resolution MSC.289 (87) The Performance Standard for Alternative Means of Corrosion Protection for Cargo Oil Tanks of Crude Oil Tankers - January 2013

UI SC259 Rev1 Corr1 CLN

UI SC259 For Application of SOLAS Regulation II-1/3-11 Performance Standard for Protective Coatings for Cargo Oil Tanks of Crude Oil Tankers (PSPC-COT), adopted by Resolution MSC.288(87) - Rev.1 Corr.1 October 2014 Clean

UI SC260 Rev1 CLN

UI SC260 Sample Extraction Smoke Detection System (FSS Code / Chapter 10 / as amended by MSC.292 (87)) - Rev.1 June 2015 Clean

UI SC261 New

UI SC261 Interpretation of Performance Standards for voyage data recorders (VDRs) (resolution MSC.333(90)) - May 2013

UI SC262 Rev1 CLN

UI SC262 Fixed Foam Fire Extinguishing Systems, Foamgenerating Capacity (FSS Code / CHAPTER 6 / and as amended by Res. MSC.327(90)) - Rev.1 May 2015 Clean

UI SC263 Deleted

UI SC263 Gaskets in fixed gas fire-extinguishing systems (SOLAS II-2/10.4, IMO FSS Code Ch 5) Deleted June 2014.

UI SC264 New

UI SC264 Non-combustible material as 'steel or equivalent' for ventilation ducts (SOLAS II-2, Reg. - December 2013

UI SC265 New

UI SC265 Code of safe practice for cargo stowage and securing – Annex 14 - December 2013

UI SC266 New

UI SC266 Revised guidelines for cargo securing manual and code of safe practice for cargo stowage and securing - scope of application - December 2013

UI SC267 Rev2 CLN

UI SC267 Implementation of the requirements relating to lifeboat release and retrieval systems (LSA Code Paragraph as amended by resolution MSC.320(89)) - Rev.2 September 2016 Clean

UI SC268 New

UI SC268 Arrangements for fixed hydrocarbon gas detection systems in double-hull and doublebottom spaces of oil tankers SOLAS Chapter II-2, Regulation - March 2014

UI SC269 New

UI SC269 Means of escape from the steering gear space in cargo ships New January 2015

Note: UI SC269 Rev 1 will come into force on 1 January 2018 and can be found in "Previous Revisions" 

UI SC270 Rev1 CLN

UI SC270 Fire pumps in ships designed to carry five or more tiers of containers on or above the weather deck (Res. MSC.365(93), SOLAS II-2/, II- 2/, II-2/, II-2/19.3.1 and IMO FSS Code Ch. - Rev.1 Dec 2015

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