IACS: Machinery Installations - Service Tank Arrangements

The International Association of Classification Societies (IACS) has issued a Unified Interpretation document referring to the service tank arrangements.

This document (UI SC123 REV5 CLN) has been released on 1 July 2023.

According to SOLAS Regulation II-1/26.11, every new ship is required to have two fuel oil service tanks for each type of fuel used for propulsion and vital systems, or a comparable setup.

These tanks should have a minimum capacity of 8 hours at the highest continuous power output of the propulsion system and the standard operating load of the generator system while at sea.

The following explanations provide guidance on the compliance and acceptable "equivalent arrangements" for commonly used fuel systems.

A service tank is specifically meant for storing fuel that meets the necessary quality standards for immediate use.

This fuel must be of a grade and quality that aligns with the specifications outlined by the equipment manufacturer.

Importantly, a service tank should be exclusively designated for this purpose and not repurposed for any other use.

The utilization of a settling tank, with or without purifiers, or relying solely on purifiers, along with just one service tank, does not meet the criteria for being considered an "equivalent arrangement" in place of the mandated two service tanks.

This Unified Interpretation is intended for application by IACS Members and Associates to all ships that fall under the relevant SOLAS Regulation.

IACS Members are required to uniformly adopt Revision 5 of this Unified Interpretation for ships that are contracted for construction on or after July 1, 2024.

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