This paper describes a case study in which low frequency noise (LFN) was suspected of causing disturbance in a semi-rural location close to an industrial estate. Previous attempts using conventional acoustic measurement techniques to resolve the case, or even prove the existence of a real acoustic problem, had proved unsuccessful. The study does not involve wind turbine noise directly, but the work done and resulting findings provide insight into identifying the problem of LFN and predicting annoyance.
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Lincoln Township in Wisconsin sent a survey to its residents to help assess the impacts of 22 turbines installed by Wisconsin Public Service Corporation (WPSC) and Madison Gas and Electric (MG&E), which went online in June 1999. A summary of the survey comments received is provided in the attached document. After the wind turbines went online, the Lincoln Township Board of Supervisors approved a moratorium on new turbine construction.
Dr. David M. Lipscomb PhD provided this testimony before the State of Washington Energy Facility Site Evaluation Council involving the risks of noise emissions from then proposed Sumas Generating Plant on human health. An excerpt of the testimony is provided below. The full testimony can be downloaded by clicking on the link at the bottom of this page.
This WHO document on the Guidelines for Community Noise is the outcome of the WHO- expert task force meeting held in London, United Kingdom, in April 1999. It bases on the document entitled “Community Noise” that was prepared for the World Health Organization and published in 1995 by the Stockholm University and Karolinska Institute.
The document critically reviews the adverse effects of community noise, including interference with communication, noise-induced hearing loss, annoyance responses, and effects on sleep, the cardiovascular and psychophysiological systems, performance, productivity, and social behavior. Noise measures or indices based only on energy summation are not enough for the characterization of most noise environments. This is particularly true when concerned with health assessment and predictions. It is equally important to measure and display the maximum values of the noise fluctuations, preferably combined with a measure of the number of noise events, and to assess whether the noise includes a large proportion of low frequency components.
This paper, presented at the Windpower ’87 Conference & Exposition in San Francisco by N.D. Kelley, a physicist at the Solar Energy Research Institute in Golden, Colorado validates the fact that turbines (both upwind and downwind) produce low-frequency sound emissions that can negatively impact humans within their homes. Although modern wind turbines are different from those studied in 1987, the research is significant in that it demonstrates the need to test for low-frequency sound emissions and to do so inside buildings.
This report summarizes extensive research by staff of the Solar Energy Research Institute and its subcontractors conducted to establish the or1g1n and possible amelioration of acoustic disturbances associated with the operation of the DOE/NASA MOD-1 wind turbine installed near Boone, North Carolina. Results have shown that the most probable source of this acoustic annoyance was the transient, 'unsteady aerodynamic lift imparted to the turbine blades as they passed through the lee wakes of the large, cylindrical tower supports. Nearby residents were annoyed by the low-frequency, acoustic impulses propagated into the structures in which the complainants lived. The situation was aggravated further by a complex sound propagation process controlled by terrain and atmospheric focusing. Several techniques for reducing the abrupt, unsteady blade load transients were researched and are discussed.
This document has been prepared by Terry Matilsky, Professor of Physics at Rutgers University. For almost 40 years, he has been funded by NASA and other federal agencies to do data analysis from various scientific satellites; to examine what information tells us about a phenomena, and draw rational and solid, scientific conclusions from them.