The long-awaited latest guidance from the World Health Organization was released yesterday (10th October 2018). Of particular interest to Hayes McKenzie is the section specifically concerned with wind turbine noise. A quick flip to Section 34 on page 77 reveals that the WHO are conditionally recommending that turbine noise should not exceed an Lden of 45dB. Lden is the average noise level over one year, where noise during the evening is penalised with a +5 dB correction, and a +10dB correction applied for noise at night. In the case of wind turbine noise, which is continually varying from day to day, depending on the wind speed and direction, it will be almost impossible to establish compliance with this limit through measurement alone. As a means of ‘impact’ assessment, however, it has some distinct advantages which are discussed in Andy McKenzie’s paper for Acoustics Australia in 2012 and in a paper presented at the Institute of Acoustics Autumn Conference in 2015 by Andy along with fellow wind turbine noise specialist Andrew Bullmore. Both of these papers are available in the Publications – Our Published Papers section of this web site.
The new (2018) NPPF refers to noise at Paragraph 170(e) where it states that:
Planning policies and decisions shoud contribute to and enhance the natural and local environment by preventing new and existing development from contributing to, being put at unacceptable risk from, or being adversely affected by, unacceptable levels of soil, air, water or noise pollution or land instability.
It is considered further in general terms at Paragraph 180 and for minerals extraction at Paragraphs 204 and 205.
The wind turbine amplitude modulation assessment methodology developed by the IoA AM Working Group is now being followed by many acoustics practitioners around the world as it represents a unique way to evaluate AM at the blade passing frequency, and within specific frequency bands. This is crucial for minimising false identifications of wind turbine AM caused by variation of noise from other sources.
Review of the evidence on the response to amplitude modulation (AM) from wind turbines, with recommendations on control through the use of a planning condition. This follows on from the work of the UK Institute of Acoustics AM Working Group but unfortunately it is not the end of the story. The industry is still waiting for clarifications on the outcome of this latter piece of work and robust guidance as to how it should be implemented. The IoA Wind Turbine Noise Working Group, chaired by our very own Malcolm Hayes, is looking into this…..