New European underwater noise measurement standard developed in the AQUO project

The acoustic impact of ships has gained growing attention during the last few years. The Europe-an Union within the MSFD and associated TG Noise has assigned the anthropogenic noise from shipping as one of the contributors to a downgrading of the environmental status. The assessment and the corresponding mitigation measures would have to be proposed by 2016 and put in force by 2020. Therefore, it is vitally important for the ship industry and regulatory bodies to have available measurement procedures enabling the correct estimation of underwater noise radiated by vessels. Some international standard bodies such as ANSI and ISO have already developed and are still developing procedures for civil applications to quantify the underwater noise emission of ships. However, there are aspects of these procedures that are not yet consolidated from a technical point of view like the uncertainty associated to the procedure, and topics that are not yet addressed, like measurements in shallow waters. In this regard, the AQUO project, in the scope of the FP7 Europe-an Research Framework, set as one of its targets the development of a new European standard for underwater noise measurements adapted to both, shallow and deep waters with a special emphasis on the assessment of the uncertainties. This paper is a follow-up to the one previously written by TSI identifying the sources of uncertainties of the current measurement procedures. It will firstly present the measurement procedure resulting from the research done in the AQUO project. Thanks to the collaboration agreement signed by BV and TSI, this procedure has been largely adopted by Bureau Veritas in its new rule note (NR 614) titled Underwater Radiated Noise. Finally, the paper will also present the outcomes of the theoretical and experimental studies of its associated sources of deviation trying to provide realistic values for the uncertainty and repeatability of the measurement procedure. Due to its impact on marine life, the abatement of the Underwater Radiated Noise by ships has become the most out-standing novelty and difficult challenge that the Shipbuilding industry has ever faced. Therefore, the industry is trying to provide new solutions in order to comply with the new directives and requirements having been recently developed and promoted by the EU, Marine Institutions and the scientific community.