At present, the scientific basis for setting the stand-off distance threshold is unclear, resulting in diverse approaches nationally and internationally. Annoyance effects from wind turbine for the non-infrasonic component have been published. Health effects including nausea, dizziness, and headaches have been reported and assumptions for linking those effects to the infrasonic component are being increasingly suggested. The noise spectra generated by a wind farm has two components; an infrasonic component and a non-infrasonic component. For all the components, the sound power level, the rate of decay with distance, and finally the effects for a given sound pressure level on a nearby resident are different. The non-infrasonic component decays at a rate with distance representative of a spherical sound source. The infrasonic component decays at a rate with distance much lower than a spherical sound source and close to the decay rate of a cylindrical propagation condition. Explanations for the reasons of a much lower rate of attenuation for the infrasonic component are given. These effects in combination inform the methodology proposed to determine noise stand-off distances from a wind farm.
Sound & Vibration Research and Review, Brisbane, Australia
Principal, Noise Measurement Services Pty Ltd, Brisbane, Australia
20th International Congress on Sound & Vibration, Bangkok, Thailand, 7-11 July 2013
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