This information note examines the revision to the ETSU-R-97 method of deriving noise conditions for wind farm planning permissions from background noise measurements, as proposed in an article in the Acoustics Bulletin of the Institute of Acoustics (IoA).[1] We have used actual wind speed data to model the impact of the revision on noise conditions and likelihood of noise complaints from neighbours.
The revision is designed to correct for site-specific wind shear that was erroneously assumed to be constant between two heights in the ETSU-R-97 guidance. The impact of this assumption is shown graphically in Appendix 1. However, in this note we show that the Acoustics Bulletin revision increases the uncertainty of the background noise curves and reduces confidence in the reliability of noise conditions based on them.
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