Turbine noise dissected; Expert says low frequencies are produced

By stoplenchwickwindfarm | February 28, 2009


Wind Watch: Turbine noise dissected; Expert says low frequencies are produced

Go here for the original post: http://www.wind-watch.org/news/?p=23251


LAFARGEVILLE — At its meeting Tuesday night, the Orleans wind committee got confirmation from an expert that turbines produce low-frequency noise and could cause health problems.

The committee held a conference call with Richard R. James, principal consultant at E-Coustic Solutions, Okemos, Mich. Mr. James has more than 35 years’ experience and worked on revising the International Electrotechnical Commission’s standard for measuring turbine sound levels. He worked with George W. Kamperman, consulting engineer in acoustics at Kamperman Associates Inc., Wisconsin Dells, Wis., on creating a guide to siting wind turbines for local governments.

Mr. James said low-frequency sound and infrasound, the lowest-frequency sound, are felt, not heard.

“Typically, they are not even measured,” he said. “They are not very common in nature, but a few examples are distant thunder and tornadoes.”

In creating guidelines for siting, Mr. James reviewed noise standards and studies from around the world. Many noise regulations for wind turbines are based on measurements that weigh audible noise, or dBA.

“But there are still hundreds of complaints of low-frequency noise annoyance in those communities,” Mr. James said. “We decided we needed to include a low-frequency noise measure in the standard.”

In their siting guide, Mr. James and Mr. Kamperman said audible sound from turbines should not exceed 5 decibels above pre-construction ambient noise levels. Low-frequency noise should not exceed 5 decibels above the pre-construction measurement. Those limits, they said, should be met at nonparticipating landowners’ property lines.

“It’s a standard for communities that could be enforced with instruments that most acoustic engineers have access to,” he said.

He said walls and windows block audible noise well but do not block low-frequency sound.

Mr. James also said low-frequency noise causes health problems.

“We’ve known since the 1950s that sound outside the home can cause sleep disturbance,” he said. “We also know noise, sleep and health are related.”

He said that sleep disturbance, vibro-acoustic disease and wind turbine syndrome have been connected with low-frequency noise.

“It’s clear that the majority of sound energy from a turbine is in the low-frequency range, but none of the information from a wind developer ever describes that fact,” Mr. James said. “None of the data for the lower frequencies is collected or figured as part of their tests.”

Mr. James said communities should have their ambient-noise levels tested by qualified engineers before a wind farm is developed.

The committee next will meet at 7 p.m. March 10 at the town office, when Keith D. Pitman, president and chief executive officer of Empire State Wind Energy, will present information on wind development and Charles E. Ebbing, facilitator and retired acoustic engineer with Carrier Corp., will talk about low-frequency noise and annoyance.

By Nancy Madsen
Times Staff Writer

Watertown Daily Times

27 February 2009

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