Airborne noise from ships: a comparative review of classification society regulations and evaluation methods

In recent years, airborne noise generated by ship machinery and exhaust systems has become an increasingly relevant environmental concern. However, beginning in 2019, several classification societies, such as RINA, DNV, Lloyd’s Register, Bureau Veritas, and the Korean Register, have introduced new class notations aimed at minimizing airborne noise emissions from ships. These voluntary notations are designed to regulate and limit ship noise, particularly in port areas (at low or zero speed). This paper reviews these protocols developed by key classification societies, including Lloyd's Register ([2019]. Procedure for the Determination of Airborne Noise Emissions from Marine Vessels. Lloyd’s Register Group Limited.), DNV ([2019]. Part 6, Chapter 7, Section 8 – External Airborne Noise Emission – QUIET.), RINA ([2021]. Noise Emissions in Port Area Outboard and Inboard, Part F, Chapter 6, Section 04 (updated July 2024).), ABS ([2022]. Guide for the Classification Notation – Underwater Noise and External Airborne Noise.), and the Korean Register ([2023]. Guidance for External Airborne Noise from Ships.), which have recently introduced guidelines for measuring and limiting airborne noise emissions from marine vessels. The analysis focuses on these voluntary class notations’ requirements, technical standards, and applicability to different types of ships, emphasizing the effectiveness of their measurement protocols. Key differences will be highlighted in scope, implementation challenges, design implications, and gaps within current regulatory frameworks. Addressing these issues from a regulatory perspective could enhance the protection of both human and marine environments, advancing the maritime sector toward greater sustainability.