ISO DIS 18406

Description / Abstract: This International Standard describes the methodologies, procedures, and measurement systems to be used for the measurement of the radiated underwater acoustic sound generated during pile driving using percussive blows with a hammer.

A major motivation for undertaking measurements of percussive pile driving is as part of an assessment of impact on aquatic fauna required by regulatory frameworks. This standard describes a generic approach to measurements that can be applied to different regulatory requirements.

This standard is suitable for measurement of percussive pile driving undertaken for offshore installation of foundations (e.g. monopiles, jackets, tripods etc.) used in construction of offshore wind farms, oil and gas platforms, and other inshore structures such as bridge foundations and aquatic renewable energy devices. This standard does not cover measurement of the sound radiated by vibropiling or sheet piling. This standard does not cover piling in water of depth less than 4 m or greater than 100 m.

The procedures described herein provide guidance on making measurements to satisfy the following objectives:

- To monitor source output during piling, for example for regulatory purposes;

- To provide consistency in comparison of piling noise from different construction projects;

- For validation of modelling or predictions.

This standard covers only the measurement of the sound field radiated during percussive pile driving. The scope of this standard does not include the assessment of exposure metrics, or the use of exposure criteria. No attempt is made to prescribe a methodology for generating maps of the acoustic field in the vicinity of the source. In the normative part of the standard, requirements and procedures are described for measurement of the sound field at specific ranges from the pile being driven.

In this part of the standard, no procedure is provided for determination of an acoustic output metric that is independent of the propagation path between source and receiver (such as a source level). Ideally such a metric would have some predictive utility (for example, in calculating noise impact zones and noise maps). However, some information on the determination of a possible acoustic output metric is provided in an informative annex (Annex A).

The standard covers only the measurement of sound pressure in the water column. The scope does not include measurement of sound particle velocity or seabed vibration. This exclusion does not imply that such measures are unimportant; indeed, their importance in assessing the impact on aquatic life is recognised. However, at the time of drafting, measurement of these quantities is not yet mature enough for standardization.