Wind panel sets noise-level protocol

CAPE VINCENT — The town wind law committee created to produce a zoning amendment to deal with wind farms added a sound measurement protocol and changed setbacks from roads during its meeting Thursday afternoon.

The sound protocol came from recommendations from the acoustical engineering firm Cavanaugh Tocci Associates, Sudbury, Mass., based on a wind development zoning law written for the Association of Towns and rules for noise studies written by Cape Vincent resident Clifford P. Schneider.

The sound measurements are important because the most recent revision of the law also makes sound requirements the overriding concern on setbacks — above the standard setback distances described in the law.

"The sound requirement law trumps dimension setbacks," town engineer Kris D. Dimmick said. "We clarified that sound has priority there."

Before any wind farm is built, the town will have a background noise study done, paid for by developers. The measurements will include those for audible noise and low-frequency noise, which may be a cause of vibroacoustic disease.

The noise studies would be done with both A-weighted and C-weighted measurements. A-weighting filters out the lower frequencies while C-weighting has almost no filtering. Noise measurements generally will be done at property lines, but low-frequency noise would also be measured at structures — a change made at the urging of engineer Gregory C. Tocci.

"The low-frequency noise standard is something Greg wanted to tie to the structure," Mr. Dimmick said.

Beth A. White, president of Voters for Wind, asked if landowners participating in a wind farm could have an easement for low-frequency noise like they would for overall noise levels.

"The participating landowners should have some sort of leeway there," she said.

Mr. Dimmick said the C-weighted measurements could have an easement like the A-weighted measurements.

"I would suggest some sort of ceiling on that, too, such as the 50 decibels for the A-weighted requirement," he said.

The noise would be measured continuously for three days, then data from each hour averaged. For example, all the data from the 2-to-3 a.m. time frame would be averaged to a single-decibel measurement.

The decibel measurement from the quietest hour would be used as the baseline ambient background noise level. A wind farm could not operate at more than 6 decibels above that sound level.

After a farm is constructed, the protocol would have trained data collectors taking selective measurements during the calmest atmospheric and traffic conditions.

"The unique thing with taller turbines is that there's quite a bit of literature that shows that at 300-400 feet in the air, you get wind up there that is significant enough to generate power but no wind at ground level," Mr. Dimmick said.

During the same time frame, the law would require the operator of the wind farm to give data on the operation of the turbines near the collection site. That would allow engineers to determine if the turbines were consistently operating within the noise level requirements.

The revision also specifies the equipment that should be used for the measurements.

After reviewing available data on debris scatter from turbine failure, Mr. Dimmick recommended setbacks of 1,000 feet from participating residences and 1,200 feet from public roads. Most of the credible reports of scatter he found had debris thrown between about 980 and 1,300 feet.

The previous draft of the law had 500-foot setbacks from roads and 750-foot setbacks from houses.

Mrs. White asked for easements on those setbacks, as well.

"You more than doubled it," she said. "There are plenty of dirt roads around and plenty of seasonal roads around."

Richard Macsherry, Tibbetts Point, said, "If a school bus drives on a particular road, there is a potential issue."

Mrs. White responded, "The chances are so minuscule. I don't see why putting these restrictions on these roads is reasonable."

Mr. Dimmick said they could have some different setbacks based on whether a road was seasonal. At the next meeting, the committee will examine a list of town roads and decide on different setbacks based on seasonal road status.

The committee agreed the setback for both should be standardized at 1,000 feet.

"It just doesn't make sense to me to have the distance from the road greater than from the house," Village Trustee Robert G. Doud said.

The next meeting of the committee will be at 4 p.m. Dec. 18 at the town office.