Unified Requirements


Unified Requirements are adopted resolutions on matters directly connected to or covered by specific Rule requirements and practices of classification societies and the general philosophy on which the rules and practices of classification societies are established.

Subject to ratification by the governing body of each Member Society, Unified Requirements shall be incorporated in the Rules and practices of the Member Societies, within one year of approval by the IACS General Policy Group. 

The existence of a UR does not oblige a Member Society to issue respective Rules if it chooses not to have Rules for the type of ship or marine structure concerned.

Unified Requirements are minimum requirements. Each Member remains free to set more stringent requirements.

The technical backgrounds (development histories) of Unified Requirements since 1999 can be found by following this link.

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

UR M54 Deleted


UR M55 Deleted

Planned maintenance scheme (PMS) for machinery - Deleted May 2001

UR M56 Rev3 CLN

UR M56 Marine gears – load capacity of involute parallel axis spur and helical gears - Rev.3 Oct 2015

UR M57 New

Use of ammonia as a refrigerant - 1993

UR M58 Deleted

Charge air coolers - Deleted Feb 2015

UR M59 New

UR M59 Control & safety systems for dual fuel diesel engines - 1996

UR M60 New

UR M60 Control and safety of gas turbines for marine propulsion use - 1997

UR M61 New

UR M61 Starting arrangements of internal combustion engines - Dec 2003

UR M62 Deleted

Rooms for emergency fire pumps in cargo ships - Deleted June 2014

UR M63 New

UR M63 Alarms and safeguards for emergency diesel engines - Jan 2005

UR M64 Rev1 CLN

UR M64 Design of integrated cargo and ballast systems on tankers - Rev.1 July 2004

UR M65 Rev1 CLN

UR M65 Draining and pumping forward spaces in bulk carriers - Rev.1 July 2004

UR M66 Rev3 CLN

UR M66 Type testing procedure for crankcase explosion relief valves - Rev.3 Jan 2008

UR M67 Rev2 CLN

UR M67 Type testing procedure for crankcase oil mist detection and alarm equipment - Rev.2 Feb 2015

UR M68 Rev2 CLN

UR M68 Dimensions of propulsion shafts and their permissible torsional vibration stresses - Rev.2 Apr 2015

UR M69 New

UR M69 Qualitative failure analysis for propulsion and steering
on passenger ships - June 2008

UR M71 Corr1 CLN

UR M71 Type Testing of I.C. Engines - Corr.1 June 2016

UR M72 Rev1 CLN

UR M72 Certification of Engine Components - Rev.1 Mar 2016

UR M73 Corr1 CLN

UR M73 Turbochargers - Corr.1 June 2016

UR M74 Rev1 CLN

UR M74 Installation of Ballast Water Management Systems - Rev.1 May 2016

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