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HomeMy WebLinkAbout2010-03-02-NAC-min NOISE ADVISORY COMMITTEE MINUTES 2 March 2010 Meeting A duly posted meeting of the Noise Advisory Committee (NAC), held in the Legion Room, Cary Hall, was called to order at 7:30 PM by Chairman Tony Galaitsis with members Jeanne Krieger, Martha Wood, Steve Kropper, Bob Earsy, Jack Maloney present. Present in the audience were Lexington Building Commissioner Mr. Garry Rhodes, six Shire representatives, and five Shade St. residents. The meeting had been convened at the request of Mr. Garry Rhodes, who was tasked by the Zoning Board of Appeals (ZBA) to seek procedures for addressing the noise issues related to section I of Shire’s SDUP and associated noise concerns expressed by Shade St residents. Mr. Rhodes reported that the ZBA has not taken a vote yet, and that the ZBA chairman requested assistance from NAC in the following areas: 1) Help establish the “ambient noise level” around the Shire property 2) Estimate the noise level when Raytheon occupied the site 3) Current situation and remediation under discussion regarding Building 300 4) Review whether Shire’s proposed methods for determining noise levels are reasonable Discussion by NAC members Ms. Krieger asked why a Raytheon-time noise level is relevant. Related questions were about whether the past “Raytheon noise level” referred to a) a condition with the Raytheon equipment operating, or b) a condition with the Raytheon equipment not operating (ambient). Mr. Raymond Buckley, attorney for Shire, indicated that his team knew the equipment used by Raytheon and could use a model to estimate Raytheon-time noise levels. Further discussion between NAC members established that the important and relevant quantities are the: The Equipment noise at residences with the Shire equipment ON The Ambient noise at residences with the Shire equipment OFF Consequently, any reference to the Raytheon-time noise was deemed irrelevant. Mr. Buckley agreed that this conclusion was also consistent with Shire’s position. Mr. Galaitsis asked whether anyone was concerned about daytime noise or solely about nighttime noise. Both nearby residents and Shire representatives agreed that only nighttime noise was an issue. Subsequently, Mr. Galaitsis asked what season would be used to establish the Shire Equipment noise levels (with equipment ON) and the ambient noise level (with equipment OFF). Shire proposed wintertime measurements stating that noise levels are highest when there is no foliage; citizen representatives preferred summertime measurements stating that noise levels are highest when windows are open at night. Mr. Earsy suggested a summertime measurement around 2:00 AM. Mr. Kropper asked if Equipment noise levels varied by time of day. A Shire representative suggested that HVAC operations did not vary with time of day or occupancy, but varied with environmental conditions, i.e., depending on the need for cooling versus heating. Citizen Comments Jeannie Canale, 29 Shade Street, commented that noise levels have gone up and their tones shifted since the installation of certain roof top equipment. A Shire representative responded that the installation of noise mitigation equipment is only partially completed. Michelle Ciccolo, 50 Shade Street, indicated that noise measured on Shire’s property line is less important than noise measured at residences, where it disturbs people. She suggested that some of the noise monitors proposed for Shire property line locations be placed at locations within nearby residential properties. Perhaps monitoring eight homes would be representative. Perhaps four houses would be sufficient. Mr. Galaitsis suggested that Shire representatives meet with Shade St. neighbors to select some mutually agreeable residential locations for some of the noise monitors. Both Shire representatives and residents agreed to do so. Mrs. Vicki Blier, 41 Shade St., inquired about the definition of a property line. A Shire representative opined that property line was a vertical plane from the line skyward. Shire Acoustics Consultant Comments Mike Bahtiarian, of Noise Control Engineering and consultant to Shire, briefed the NAC on a new 10-days old plan to address the noise problem. Copies of plan were distributed to members. The NAC was asked to review this plan in conjunction with the March 2, 2010 Shire HGT Ambient Sound Level Assessment Measurement Protocols (DRAFT). All proposed measurements would be conducted at ground level even though noise level may vary with height. Discussion ensued about proper design of a test to ascertain ambient noise levels including placement and count of microphones. Mr. Bahtiarian stated that the Shire team would measure octave-band and 1/3-octave-band levels at various locations with most of the Shire equipment off and some of the equipment on. He stated that another acoustics firm (Acentech from Cambridge) would model the buildings and the noise sources to calculate and subtract the active equipment noise out of the measured noise. Detailed discussion on pros and cons of plan ensued. Mr. Galaitsis and Mr. Earsy did not accept Mr. Bahtiarian’s suggestion to use L as an alternate approach to measuring EQ ambient noise. They both stated that L-90 is the appropriate metric. Mr. Galaitsis expressed concern about the Draft protocol’s modeling accuracy for ambient noise level, and suggested that the ambient noise level be actually measured with all Shire equipment shut down. Mrs. Vickie Blier inquired whether the noise level with the Shire equipment on will set a new ambient noise level, and whether a future developer could later add another 10 dBA to that level. The answer was: “No, the ambient noise level will always correspond to a condition with all present and future equipment off.” Mrs. Bleier then said that if the summer ambient noise is only 20 dBA, then the maximum allowed noise should be set relative to that. On the other hand, if the winter ambient is lower, winter may be a better time to measure the ambient. Next Step Mr. Galaitsis inquired about Shire’s schedule seeking to ensure that the NAC has adequate time to review the remaining information in time to provide comments to the ZBA. A Shire representative indicated that a revised proposal would be distributed to the NAC members before the next NAC meeting. Mr. Galaitsis requested that any new information be submitted to the NAC on Thursday before the (Tuesday) meeting to allow enough time for technical review. The NAC meeting was adjourned at 9:15 PM Minutes prepared by Steve Kropper, Acting Secretary