Chamberlin Sound Tests Complete

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Thursday January 01, 1970

The effects of airport noise, the subsequent demolition of 200 homes in the Chamberlin neighborhood and efforts to mitigate sound have long been topics of great interest and concern in South Burlington. More recently, the focus has been on the effects of aircraft noise at Chamberlin Elementary School, located in the heart of this changing neighborhood. In order to understand the current situation and prepare for the future, the district contracted for a baseline survey of existing conditions to be conducted at the school. The results were presented to the school board June 6.

Chamberlin School is situated a half mile from the Burlington International Airport and near the Vermont Air National Guard base, which often contributes to what has been identified as “the Chamberlin Pause” or “educational pause,”—necessary pauses during lessons which occur when an aircraft is flying overhead. As part of its master planning and visioning process, the district is carefully considering current needs and next steps for the building, which may include sound insulation or consolidation.

Superintendent David Young has had frequent correspondence with airport officials regarding use of FAA funding for noise mitigation at the school. Nicolas Longo, the airport’s deputy director of aviation administration, confirmed that they are working on a federal grant application that encourages studying the eligibility and implementation of sound insulation at the school. On a separate occasion, the airport received FAA approval earlier this spring for new Noise Exposure Maps (NEMs) using projected F-35 data.

However, grant approval for the school is uncertain, and with the F-35 arrival slated for fall of 2019, the school district contracted with an independent environmental consulting firm, ATC, in late 2017 to help measure the noise decibel levels inside and outside the school under current conditions. This includes the existing F-16s and other aircraft operations; F-35 data projections were not included.

ATC has experience performing noise monitoring for commercial, industrial, educational, and governmental issues. Project Principal Thomas Broido, Robert Montgomery, and Devin Porter of ATC conducted the study and reported their findings to the board.

However, Longo has confirmed that the airport would not be able to use independent survey results in the work being done with the FAA Part 150 Study.

The Process
Data was collected by ATC on April 10, 11 and 19 at three locations: inside a classroom with the windows open during the day and closed at night (for safety precautions), inside a different classroom with the windows closed during the day and night, and outside on the school playground.

Noise levels were measured throughout the day (approximately 7:00 a.m. – 10:00 p.m.), the school day (approximately 8:00 a.m. – 4:00 p.m.) and at night (approximately 10:00 p.m.– 7:00 p.m.).

ATC used Casella CEL-633C sound level meters which were placed on stands about four to six feet above the ground or floor to collect environmental noise levels continuously throughout the day, school day, and night, using the A-weighting scale (dBA).

The survey also included personal noise exposure monitoring of five employees. One teacher was monitored in the classroom with open windows during work hours, two teachers were monitored in the classroom with closed windows, and two employees (recess monitor/School’s Out attendant) were monitored in the playground and cafeteria.

Data Comparison and Results
ATC compared its findings against data in the United States Air Force F-35 Operational Basing Final Environmental Impact Statement (FEIS) presented in 2013, the Vermont Occupational Safety and Health Administration (VOSHA) regulations concerning hearing conservation, as well as the 1992 FICON report (Federal Interagency Committee on Noise).

The purpose of the ATC study was to apply actual numbers to previous reports which were based on computer modeled data.

In short, the results were similar to data in the FEIS, below thresholds in VOSHA, and exceeded thresholds from the FICON report. Based on this, ATC made the following conclusions:

• Calculated DNLs (Day Night Level) for all locations during all sampling events were below the 70 dBA baseline level presented in the Air Force’s Final Environmental Impact Statement. The maximum calculated DNL sampling from ATC was 63.7 dBA on April 19 in the classroom with the windows open.

• Calculated DNLs for all locations during all sampling events exceeded both the indoor (45 dB) and outdoor (55 dB) FICON thresholds. ATC’s findings on the playground ranged from 61.1-62.0 dB.

• Measured eight-hour equivalent noise levels for all locations during all sampling events were below the 74 dBA baseline level presented in the FEIS.

• Observed aircraft noise events in excess of 75 dBA were higher than the baseline level presented in the FEIS. The FEIS calculated five speech interferences with the windows closed, whereas ATC’s data ranged from 22-37 interferences.

• Observed aircraft noise events in excess of 65 dBA were similar to the baseline level in the FEIS. The FEIS calculated 25 speech interference events with the windows open. ATC’s data was similar, ranging from 21-25.

• Measured employee noise exposures were below the applicable (mandatory) VOSHA Permissible Exposure Limit and Action Level.

“For us, this has been a noise issue. It’s been around for a solid 20 years or more, and this is our first step [in addressing it].” Young said. “There does seem to be a high level of comparability to the EIS Study.”

“The FEIS said the school was in the 70-74 DNL contour with a predicted number of 70, and we’re very close to that,” Broido confirmed. “They didn’t measure at the school but they used other measurements to model what would be at the school, and it looks like that was accurate.”

When asked if there were any concerns with what the data revealed, Broido explained that “these results did not surprise us. Nothing jumped out.”

“I think a lot of people in the community would be interested to know what were the causes of the spikes,” suggested board member Alex McHenry. “Were they fire trucks? Aircraft taking off? If we determine it’s an airplane, what kind of airplane? If those sorts of details were easily forthcoming, I think that would be information people would be interested in.”

“Just because these noise levels are below a certain level does not mean education at Chamberlin is not being impacted,” he added. “If you have something called a Chamberlin Pause, that’s a problem right there.”

For purposes of determining a baseline, Chair Elizabeth Fitzgerald expressed that the survey has completed its job.

“The findings and conclusions—along with questions that we’ll have, to get access to data—has met our goal,” she said. “I’m encouraged that, for the most part, the modeling and the actual testing are fairly in line. It looks like there are a couple of areas that, relative to certain incident levels at certain decibels, seems to be the fundamental issue. We need to respond to the noise mitigation efforts as well.”

Board member Martin LaLonde added: “In addition to establishing a baseline, we did want to see if there were any significant red flags right now that would lead us to having to do something—whatever is going to happen down the road. From this report, I can’t tell that there is; nothing seems to leap out.”

He continued: “There are obviously some things that we need to find out—a little more information to work into the mitigation efforts…. We’ll have to plan that out through the [master planning and visioning] subcommittee process.”

The Master Planning and Visioning subcommittee—which is comprised of Young, Business Manager John Aubin, former Business Manager John Stewart, and board members LaLonde, Steve Wisloski and Bridget Burkhardt—looks at enrollment, demographics, the first phase of an architectural analysis of middle and high schools, and school climate conditions; it also assesses safety and security at each facility.

With the Chamberlin School sound testing completed, Young plans to roll out recommendations and discuss the details of a more comprehensive rubric in preparation for the June 20 board meeting.

To view the complete ATC survey, visit the South Burlington School District website, click the “Our District,” and the “Master Planning and Visioning” tabs, and select the “2018 update.”

 

SOURCE: Miranda Jonswold , Correspondent