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.
- 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.
- 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.
- 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.
- 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.
List of UIs
List of IACS UIs; the IMO instruments they refer to; when they were submitted to the IMO; and the outcome of the IMO's consideration
Latest update 19 Sep 2017.
IMO Chemical Code
UI CC1 Rev2 CLN
UI CC1 Interpretation of sub-section 3.9(b), BCH Code - Rev.2 Feb 2007
UI CC2 Rev1 CLN
UI CC2 Interpretation of paragraph 4.9.2, BCH Code - Rev.1 Feb 2007
UI CC3 Rev1 CLN
UI CC3 Interpretation of paragraph 4.11.2, BCH Code - Rev.1 Feb 2007
UI CC4 New
UI CC4 Venting System on Chemical Tankers - June 2002
UI CC5 New
UI CC5 Fire protection and fire extinction IBC Code Chapter 11 - September 2008
UI CC6 New
UI CC6 Lining approved for use with acids – IBC Code item 15.11.2 - April 2011
UI CC7 New
UI CC7 Unprotected openings - June 2016
Interpretations of the COLREG
UI COLREG1 Rev1 Corr1 CLN
UI COLREG2 Deleted
UI COLREG2 Interpretation to COLREG 1972 Rule 23 (a) Deleted 1st January 2009 to coincide with MSC.253(83).
UI COLREG3 Rev1 Corr1 CLN
UI COLREG3 Interpretation to COLREG 1972 Annex 1, Section 3 (b) - Rev.1 Corr.1 Jan 2010
UI COLREG4 Corr1 CLN
UI COLREG4 Interpretation to COLREG 1972 Rule 27(b)(i) - Corr.1 July 2007
Fire Test Procedure
UI FTP1 New
UI FTP1 Adhesives used in A or B class divisions - June 2000
UI FTP2 New
UI FTP2 Pipe and duct penetrations - June 2000
UI FTP3 Rev2 CLN
UI FTP4 Rev1 CLN
UI FTP4 Fire resistant windows on tankers (Appendix A.I to resolution A.754(18)) - Rev.1 August 2006 CLN
UI FTP5 New
UI FTP5 Testing and approval of “A” class divisions – fastening of insulation material and details of joints (IMO Res. A.754(18) / IMO FTP Code Part 3) - June 2010