IACS Unified Requirement and Unified Interpretation

This page provides the text of newly established IACS Unified Requirements (UR) and Unified Interpretations (UI) as well as their most recent revisions and corrigenda. Recent revisions and changes have been underlined for easy reference.
Texts of the IACS Unified Requirements and Unified Interpretations are made available on this page for the period of one year following the date of adoption. Texts of all current UR/UI can be found on the IACS website (http://www.iacs.org.uk).

IACS Unified Requirements

IACS Unified Requirements are the minimum class requirements shared among all IACS Member Societies. Unless an application date is specified, Unified Requirements are to be incorporated in the Rules and practices of each IACS Member Society within one year of their adoption by IACS.

IACS Unified Interpretations

IACS Unified Interpretations were created with a view to the uniform implementation of IMO conventions among all IACS Member Societies and provide interpretations of IMO Conventions which are vaguely worded or have been left to the satisfaction of each Administration.

The outlines of technical resolutions adopted by IACS are available at the links shown below.

Implementation Dates

The Implementation dates of the Unified Requirements (UR) and Unified Interpretations (UI) are shown in the "Implementation Date" column of the tables. However, as each UR / UI has its own implementation scheme, e.g. contract basis, keel laying basis, etc. please confirm the implementation dates included in the texts.

Unified Requirements and Unified Interpretations will be incorporated into the ClassNK Rules / Guidance and apply to ships classed with ClassNK.

UR Abbreviations

A : Mooring and Anchoring C : Containers D : Mobile Offshore Drilling Units
E : Electrical and Electronic Installations F : Fire Protection G : Gas Tankers
I : Polar Class K : Propellers L : Subdivision, Stability and Load Line
M : Machinery Installations N : Navigation P : Pipes and Pressure Vessels
S : Strength of Ships W : Materials and Welding Z : Survey and Certification

UI Abbreviations

CC : IBC Code / BCH Code COLREG : COLREG FTP : FTP Code
GC : IGC Code / GC Code GF : IGF Code HSC : HSC Code
LL : Load Line MODU : MODU Code MPC : MARPOL
PASSUB : Passenger Submersible Craft SC : SOLAS TM : Tonnage Measurement

IACS Unified Requirement

Resolution Revision Adoption Date Title Implementation Date
UR M74 Rev.3 Mar. 2025 Ballast Water Management Systems 1 Jan. 2027
UR F45 Rev.1 Mar. 2025 Installation of BWMS on-board ships 1 Jan. 2027
UR F44 Rev.3 Corr.1 March 2025 Fore peak ballast tanks and space arrangements on oil & chemical tankers ---
UR W7 Rev.5 Feb. 2025 Hull and machinery steel forgings 1 Jan. 2027
UR Z11 Rev.7 Feb. 2025 Mandatory Ship Type and Enhanced Survey Programme (ESP) Notations 1 Jan. 2027
UR E15 Rev.5 Jan. 2025 Electrical Services Required to be Operable Under Fire Conditions and Fire Resistant Cables 1 Jul. 2026
UR F43 Del Jan. 2025 Installation requirements for analysing units for continuous monitoring of flammable vapours ---
UR W35 Rev.2 Feb. 2025 Requirements for NDT Service Suppliers 1 Jan. 2027
UR W10 Rev.3 Feb. 2025 Spheroidal graphite iron castings or ductile iron castings 1 Jan. 2027
UR W9 Rev.3 Feb. 2025 Grey iron castings or flake graphite iron castings 1 Jan. 2027
UR Z15 Rev.4 Jan. 2025 Hull, Structure, Equipment and Machinery Surveys of Mobile Offshore Units 1 Jul. 2026
UR M25 Rev.5 Dec. 2024 Astern power for main propulsion 1 Jan. 2026
UR I3 Rev.2 Corr.1 Dec. 2024 Machinery Requirements for Polar Class Ships ---
UR Z17 Rev.21 Jan. 2025 Procedural Requirements for Service Suppliers 1 Jul. 2026
UR Z17 Rev.20 Nov. 2024 Procedural Requirements for Service Suppliers 1 Jan. 2026
UR W27 Rev.3 Corr.1 Dec. 2024 Cast Steel Propellers ---
UR W24 Rev.5 Corr.1 Dec. 2024 Cast Copper Alloy Propellers ---
UR M86 New Nov. 2024 Monitoring and Safety Functions for Exhaust Gas Cleaning (SOx) Systems 1 Jan. 2026
UR M10 Rev.5 Nov. 2024 Protection of internal combustion engines against crankcase explosions 1 Jan. 2026
UR H1 New (Withdrawn) Jan. 2024 Control of Ammonia releases in Ammonia fuelled vessels Withdrawn in November 2024
UR M85 New Nov. 2024 Type approval testing of synthetic materials for aftmost propeller shaft bearings 1 Jan. 2026
UR M52 Rev.3 Nov. 2024 Length of aftmost propeller shaft bearing 1 Jan. 2026
UR Z17 Rev.19 Oct. 2024 Procedural Requirements for Service Suppliers 1 Jan. 2026
UR P4 Rev.8 Sep. 2024 Production and Application of Plastic Piping Systems on Ships 1 Jan. 2026
UR S35 Corr.1 Sep. 2024 Buckling Strength Assessment of Ship Structural Elements ---
UR Z1 Rev.10 Sep. 2024 Annual and intermediate classification survey coverage of IMO Resolution A.1186(33) ---
UR M46 Rev.4 Aug. 2024 Ambient conditions – Inclinations and Ship Accelerations and Motions 1 Jan. 2026
UR E10 Rev.10 Aug. 2024 Test Specification for Type Approval 1 Jan. 2026
UR F44 Rev.3 Sep. 2024 Fore peak ballast tanks and space arrangements on oil & chemical tankers 1 Jan. 2026
UR Z7.1 Rev.15 Corr.1 May 2024 Hull Surveys for General Dry Cargo Ships ---
UR Z7 Rev.29 Corr.1 May 2024 Hull Classification Surveys ---
UR S10 Rev.7 Corr.2 May 2024 Rudders, Sole Pieces and Rudder Horns ---
UR C7 New May 2024 Approval and Certification of Container Securing Systems 1 Jul. 2025
UR C6 New May 2024 Requirements for Lashing Software 1 Jul. 2025
UR W8 Rev.4 Mar. 2024 Hull and machinery steel castings 1 Jan. 2025
UR E21 Rev.2 Feb. 2024 Requirements for uninterruptible power system (UPS) units 1 Jul. 2025
UR M61 Rev.3 Feb. 2024 Starting Arrangements of Internal Combustion Engines 1 Jul. 2025
UR M84 New Feb. 2024 Capacity and availability of compressed air for essential services 1 Jul. 2025
UR M47 Del. Feb. 2024 Bridge control of propulsion machinery for attended machinery spaces ---
UR M43 Rev.1 Feb. 2024 Bridge control of propulsion machinery 1 Jan. 2025
UR M3 Rev.7 Feb. 2024 Speed governor and overspeed protective device 1 Jan. 2025
UR M78 Rev.2 Jan. 2024 Reciprocating Internal Combustion Engines Fuelled by Natural Gas 1 Jan. 2025

 

IACS Unified Interpretation

Resolution Revision Adoption Date Title Implementation Date
UI GF22 New Mar. 2025 Gas Fuel Vent Pipes – Single walled construction in Machinery spaces 1 Jul. 2026
UI SC89 Rev.5 (Withdrawn) Dec. 2024 Ventilation of Cargo Spaces Withdrawn in December 2024
UI SC305 New Dec. 2024 Single essential propulsion components and their reliability 1 Jan. 2026
UI SC191 Rev.9 Nov. 2024 IACS Unified Interpretations (UI) SC 191 for the application of amended SOLAS regulation II-1/3-6 (resolution MSC.151(78)) and revised Technical provisions for means of access for inspections (resolution MSC.158(78)) 1 Jul. 2025
UI SC190 Rev.2 Nov. 2024 IACS Unified Interpretations (UI) SC 190 for Application of SOLAS Regulation II-1/3-6 (Res MSC.134(76)) and Technical Provisions on Permanent Means of Access (Res MSC.133(76)) 1 Jul. 2025
UI SC307 New Nov. 2024 Hydrocarbon Gas Detection and Bilge High Level Alarms in Cargo Pump-Rooms 1 Jan. 2026
UI SC306 New Nov. 2024 Valve piercing ship’s collision bulkhead 1 Jan. 2026
UI SC269 Rev.2 Nov. 2024 Means of escape from the steering gear space in cargo ships 1 Jan. 2026
UI SC11 Rev.2 Nov. 2024 Precautions against shock, fire and other hazards of electrical origin 1 Jan. 2026
UI SC5 Del Nov. 2024 Emergency source of electrical power in passenger ships ---
UI SC4 Del Nov. 2024 Emergency source of electrical power ---
UI GF21 New Oct. 2024 CO2 fire extinguishing systems in methyl/ethyl alcohol fuelled vessels machinery spaces 1 Jan. 2026
UI SC259 Rev.1 Corr.2 Oct. 2024 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) ---
UI SC304 New Oct. 2024 Code on noise levels onboard ships - calibration of sound instruments 1 Jul. 2026
UI SC99 Rev.2 Corr.1 Sep. 2024 Flexible bellows of combustible materials ---
UI SC211 Rev.1 Sep. 2024 Protection of fuel oil tanks and designation of fore peak spaces 1 Jan. 2026
UI MPC131 New Jul. 2024 Unified Interpretation on the application of the amendments to Appendix IX of MARPOL Annex VI adopted by MEPC.385(81) 1 Nov. 2024
UI SC303 New Jul. 2024 Harmonization of Industrial Personnel Safety Certificate with SOLAS Safety Certificates 1 Jul. 2025
UI SC156 Rev.3 Jul. 2024 Doors in watertight bulkheads of cargo ships and passenger ships 1 Jul. 2025
UI GF20 New Jun. 2024 Arrangements of fuel tanks in methyl/ethyl alcohol fuelled vessels 1 Jul. 2025
UI SC302 New May 2024 Interpretation of SOLAS Regulation II-2/11.4.1 Pertaining to Crowns of Machinery Spaces of Category A 1 Jul. 2025
UI LL62 Rev.1 Corr.2 Jun. 2024 Side Scuttles, Windows and Skylights ---
UI SC277 Rev.1 May 2024 Escape from machinery spaces on cargo ships 1 Jul. 2025
UI SC276 Rev.1 May 2024 Escape from machinery spaces on passenger ships 1 Jul. 2025
UI SC301 New May 2024 SOLAS Regulations II-2/9.7.2 and 9.7.5.1 – Separation of ducts from spaces 1 Jul. 2025
UI SC266 Del. Feb. 2024 Revised guidelines for cargo securing manual and code of safe practice for cargo stowage and securing– scope of application ---
UI SC249 Rev.2 Jan. 2024 Implementation of SOLAS II-1, Regulation 3-5 and MSC.1/Circ.1379 1 Jan. 2025