IACS: Unified Requirements for ship systems: starting arrangements, compressed air supply, and essential services

The International Association of Classification Societies (IACS) on 1 February 2024 published four revised Unified Requirements and one new. We bring you the overview of the five here in one place.

Requirements for uninterruptible power system (UPS) units

UR E21 (Rev2) comes into force on 1 July 2025.

These rules cover UPS units application, design, construction, location, performance, and testing. They ensure UPS units provide uninterrupted power for various purposes, such as emergency services, and comply with specific standards and regulations. It also incorporates definitions for UPS components and specifies testing requirements to verify their suitability for different environments.

Speed governor and overspeed protective device

UR M3 (Rev7) comes into force on 1 January 2025.

The document specifies the adjustment limits for engine speed governors and overspeed protective devices, as well as requirements for electronic speed governors and actuators. Additionally, it details the governing characteristics of generator prime movers, including speed variations and load demands. The document also provides guidelines for emergency generator sets and governing characteristics for generators operating in parallel.

Bridge Control of Propulsion Machinery

UR M43 (Rev1) comes into force on 1 January 2025.

These regulations include provisions for preventing overload and prolonged running in critical speed ranges, independence of the bridge control system, automatic sequencing of operations, and automatic inhibition of remote starting under hazardous conditions. Additionally, requirements for slow-turning devices for steam turbines and provisions for alarm systems in case of bridge control system failure are specified.

Starting Arrangements of Internal Combustion Engines

UR M61 (Rev3) comes into force on 1 July 2025.

The document includes specifications for mechanical starting arrangements, such as air starting, and electrical starting arrangements. For air starting, provisions are made for air compressor capacity, starting air receivers, and the number of consecutive starts. For electric starting, the document specifies the use of separate batteries, their capacity, and their continuous maintenance.

Capacity and availability of compressed air for essential services

UR M84 comes into force on 1 July 2025.

The document specifies that arrangements for compressed air supply must ensure sufficient availability for essential services at all times, including during normal operation, maintenance, and in the event of system failure. Additionally, it states that if compressed air is sourced from the engine starting air system, it must not reduce the capacity and availability required for engine starting as per UR M61.

For more information, please see the document below (available only to subscribers):

Requirements for Uninterruptible Power System (UPS) Units

Speed Governor and Overspeed Protective Device

Bridge Control of Propulsion Machinery

Starting Arrangements of Internal Combustion Engines

Capacity and Availability of Compressed Air for Essential Services