Resource Documents: Noise (670 items)
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Author: Cooper, Steven; and Chan, Christopher
Abstract: An issue exists around the world of wind farms that comply with permit conditions giving rise to noise complaints. Approval limits are normally expressed in A-weighted levels (dB(A)) external to residential receivers. The distance from the wind farm to residential receivers can result in diffculty in establishing the dB(A) contribution of the wind farm, as the overall noise includes background noise that can provide masking of the wind turbine noise. The determination of the ambient background at a receiver location (without the influence of the wind farm) presents challenges, as the background level varies with the wind and different seasons throughout the year. On-off testing of wind farms does not normally occur at high wind farm output and limits this approach for acoustic compliance testing of a wind farm. The use of a regression analysis method developed more than 20 years ago is questioned. Anomalies with respect to compliance procedures and the regression method of analysis based on real-world experience are discussed.
Steven Cooper and Christopher Chan
The Acoustic Group, South Windsor, Australia
Acoustics 2020, 2, 416–450; doi:10.3390/acoustics2020024
Author: Court of Common Pleas, Carbon County, Pa., Civil Division
28. Atlantic Wind has failed to produce sufficient evidence and failed to sustain its burden to show that the proposed Wind Turbine project will comply with section 402.A.54.p of the Zoning Ordinance.
29. As Atlantic Wind has failed to meet its burden of proof and persuasion regarding the specific requirements of the Zoning Ordinance for wind turbines, no presumption has arisen that Atlantic Wind’s proposed use is consistent with the health, safety and general welfare of the community.
30. Although we find that no burden has shifted to the Objectors to present evidence and persuade this Court that the proposed use will generate adverse impacts not normally generated by such use and that these impacts would pose a substantial threat to the health and safety of the community, the Objectors presented credible expert testimony and scientific evidence that the proposed use will have a detrimental effect on the health, safety and welfare of the community. …
38. The current principal use of the proposed Project Area is for the production of potable water.
39. The proposed wind turbine project would be an additional principal use in the Project Area. ( Zoning Ordinance, section 306.B.1).
40. Unless Bethlehem Authority ceases to use the Project Area for the production of potable water, the Wind Turbine Project would constitute a second principal use within a residential district in violation of section 801.B.2 of the Zoning Ordinance.
41. As Atlantic Wind does not meet the requirements of the Zoning Ordinance relative to the proposed use and does not challenge the validity of the Zoning Ordinance nor seek to have the property re-zoned, the application for a special exception to permit wind turbines in an R-1 zoning district must be denied.
42. Having failed to meet its burden of production and persuasion concerning its request for a special exception to permit wind turbines in an R-1 zoning district, Atlantic Wind’s second request for a special exception to permit an operations and safety building as a use not specifically provided for (and not prohibited) in any of the zoning districts is rendered moot and denied.
43. Having failed to meet its burden of production and persuasion concerning its request for a special exception to permit wind turbines in an R-1 zoning district, Atlantic Wind’s request for an interpretation of the Zoning Ordinance relative to the proposed permanent meteorological towers being permitted as either integral parts of the wind turbine use or as accessory uses or structures which are customary and incidental to the wind turbine use is rendered moot and denied.
44. Having failed to meet its burden of production and persuasion concerning its request for a special exception to permit wind turbines in an R-1 zoning district, Atlantic wind’s request for a special exception to permit the permanent meteorological towers as a use not specifically provided for (and not prohibited) in any of the zoning districts is rendered moot and denied. …
As Atlantic Wind has failed to demonstrate that the sound produced by the proposed wind turbines will not exceed forty-five (45) A-weighted decibels and that there will be only one (1) principal use on the proposed project area, Atlantic wind has failed to meet its burden of persuasion that the proposed wind turbine project will comply with all the objective requirements for a special exception to be granted under the Penn Forest Township Zoning Ordinance. Therefore, the deemed approval of Atlantic Wind’s application for a special exception must be vacated and we will enter the following
ORDER OF COURT
AND NOW, to wit, this 21st day of April, 2020, upon consideration of Appellants’ land use appeal and the oral argument of counsel thereon, our review of the record created before the Penn Forest Township Zoning Hearing Board and the Referee appointed by this Court, the briefs of the parties, and the report of the Referee, and in accordance with our Memorandum Opinion bearing even date herewith, it is hereby ORDERED and DECREED as follows:
1. The land use appeal of Phillip C. Malit sch and Christopher Mangold is GRANTED;
2. The deemed approval of the application of Atlantic Wind, LLC, for a special exception under the Penn Forest Township Zoning Ordinance is VACATED; and
3. The application of Atlantic Wind, LLC for special exceptions under the Penn Forest Township Zoning Ordinance is DENIED.
Download original document: “Malitsch and Mangold v. Penn Forest Township Zoning Hearing Board”
Laboratory study on the effects of wind turbine noise on sleep: results of the polysomnographic WiTNES study
Author: Smith, Michael; et al.
Study Objectives: Assess the physiologic and self-reported effects of wind turbine noise (WTN) on sleep.
Methods: Laboratory sleep study (n = 50 participants: n = 24 living close to wind turbines and n = 26 as a reference group) using polysomnography, electrocardiography, salivary cortisol, and questionnaire endpoints. Three consecutive nights (23:00–07:00): one habituation followed by a randomized quiet Control and an intervention night with synthesized 32 dB LAEq WTN. Noise in WTN nights simulated closed and ajar windows and low and high amplitude modulation depth.
Results: There was a longer rapid eye movement (REM) sleep latency (+16.8 min) and lower amount of REM sleep (−11.1 min, −2.2%) in WTN nights. Other measures of objective sleep did not differ significantly between nights, including key indicators of sleep disturbance (sleep efficiency: Control 86.6%, WTN 84.2%; wakefulness after sleep onset: Control 45.2 min, WTN 52.3 min; awakenings: Control n = 11.4, WTN n = 11.5) or the cortisol awakening response. Self-reported sleep was consistently rated as worse following WTN nights, and individuals living close to wind turbines had worse self-reported sleep in both the Control and WTN nights than the reference group.
Conclusions: Amplitude-modulated continuous WTN may impact on self-assessed and some aspects of physiologic sleep. Future studies are needed to generalize these findings outside of the laboratory and should include more exposure nights and further examine possible habituation or sensitization.
Michael G Smith, Mikael Ögren, Pontus Thorsson, Laith Hussain-Alkhateeb, Eja Pedersen, Jens Forssén, Julia Ageborg Morsing, Kerstin Persson Waye
University of Gothenburg, Chalmers University of Technology, Lund University, Sweden
Sleep, 25 March 2020, doi: 10.1093/sleep/zsaa046
Download original document: “A laboratory study on the effects of wind turbine noise on sleep: results of the polysomnographic WiTNES study”
Author: West, Michael
Despite their generally positive reputation as sources of clean, safe energy, Industrial Wind Turbines (IWTs) do have their critics. For years, residents living in the vicinity of IWT clusters have reported a variety of physical ailments which they attribute to the sounds and vibrations emanating from wind turbines (Kelley, 1985; CBC.ca, 2011). Noise bylaws, setback distances and other regulations applied to IWTs appear to be based on analysis methods used historically with industrial applications, where noise tends to be constant or semi-constant and in the audible range. The noise generated by IWTs is quite different – spiky and high amplitude – like an exploration seismic source pulse, and mainly found in low frequencies not detectable by human hearing (i.e. infrasound or “below hearing”). This article looks at the signals generated by IWTs from a geophysicist’s perspective. …
The analysis of the operating IWTs on the ground and the seismic and air-pulse recordings confirms that large horizontal axis Industrial Wind Turbines act like airgun seismic sources that create low frequency pulses approximately once per second. The audible part of the air pulse makes a sound like “whump” so, as per geophysical industry tradition, we should name the IWT a “whumper” seismic source (as opposed to a thumper or puffer which would require a faster rise-time on the pulse). Most of the amplitude of the pulse exists at frequencies below the audible range, so a person stopping by the roadside to listen to an IWT may not hear anything and is likely to think that they make no significant “noise” at all.
Two aspects of IWT-generated noise do not appear to have been adequately accounted for in the creation of regulations for the IWT industry: that the noise contains many spurious, high amplitude spikes, and that it is mainly found in the low, infrasonic frequencies. An impulsive noise source such as an IWT requires amplitude measurements over short time windows like 1 second and little or no averaging of data during analysis. Long analysis time windows and averaging amplitude over 1/3 octave band frequency ranges is an acoustics industry testing method appropriate only for higher frequency “whirring” machines like diesel generators or milling machines. Current Ontario Government regulations do not include testing frequencies lower than 31.5 Hz. “Noise” testing procedures for regulation of IWTs should be revised to include all low frequencies created by the IWTs because the low frequency events contain the most power and highest amplitudes.
Conversion of non-weighted peak pulse amplitudes from the microphone recording in Figure 9, at 550 meters offset in 20 kph winds including the full frequency range to 1 Hz, revealed peak Sound Pressure Levels of 65 dB or more. Additionally, the SPL noise limit specification should not be increased with increased wind speed as this makes no sense. Governments and agencies tasked with the regulation of IWT installations should review and revise their testing protocols, so that regulations that reliably protect the health of people and animals living in the vicinity of IWTs can be implemented.
Michael West, P. Geoph., B.Sc., GDM
Canadian Society of Exploration Geophysicists | Recorder, Jun 2019, Vol. 44, No. 04
Download original document: “The Industrial Wind Turbine Seismic Source”