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Home My WebLink About2025-02-04-NAC-min Lexington Noise Advisory Commi?ee minutes for February 4, 2025 The commi?ee met in a remote format. Present from the commi?ee were members Barbara Katzenberg (chair), Laura Rosen, Sallye Bleiberg, Elaine Rudell, and Benjamin Lees. Mr. Pato was absent. Ms. Katzenberg called the mee?ng to order. Mr. Lees was selected as the secretary for this mee?ng. Aaron Farbo from the ﬁrm Cavanaugh Tocci in Sudbury spoke to the commi?ee about his work on construc?on mi?ga?on plans in Lexington and other towns and ci?es. He explained that Lexington’s noise bylaw addresses construc?on noise to a greater degree than most other places, which limit only the days and hours that work can be performed. The two projects he worked on in Lexington both involved signiﬁcant ledge work, which is par?cularly disrup?ve, so it makes sense that we would have a stronger bylaw. Ms. Rosen queried about the mi?ga?on measures in place for the Merriam Hill project, given that it is on a hill. Mr. Farbo said that they tried to deal with the topography by pu?ng temporary barriers as close as possible to the sources of noise, so that it wouldn’t just go over the barriers. Ms. Katzenberg asked what methods they use for measuring noise. Mr. Farbo said that for that project, they put a sound monitor at the property line, since that’s where the bylaw says it should be measured. The device measures sound con?nuously and produces several metrics at 20-minute intervals, including L (average sound energy) and L (the top 10% of the noise). For that, they go by the Boston noise eq10 ordinance, which speciﬁes how to measure construc?on noise, something few towns here do. It correlates pre?y well to what people ﬁnd annoying. You could use a shorter interval, but that risks skewing the measurements higher during brief periods of ac?vity. The Mass DEP’s rules use an L (the bo?om 10% of the noise), but L is what they think works best. 9010 Ra?ng levels are something they don’t use so much for construc?on projects but might for something like a warehouse project. There, they’re focused on con?nuous noise, so they are more forgiving for loud noises that are brief and infrequent. And they’re more restric?ve of tonal noise, like backup alarms, which are designed to be annoying. A noise bylaw could treat diﬀerent types of noise diﬀerently; Boston does not, but the Devens Enterprise Commission does. It’s diﬃcult to prove compliance with their rules on background noise, because you can’t measure the diﬀerence without shu?ng the whole facility down. They use a-weighted decibels for their measurements. In general, they do a good job of represen?ng how the ear perceives sound. There are issues with tonal noise, like a transformer, where the sound is more annoying than the numbers would suggest. When crea?ng a mi?ga?on plan, they predict noise levels by crea?ng a 3D model of the site and feeding in data about the equipment that will be used. Manufacturers provide data about some types of equipment, but for construc?on equipment they mainly rely on their own measurements, which they then store in a database for future use. If they know a project is going to involve more than 7 days of ledge work, they can collect measurements on the ﬁrst couple days. The type of rock probably has an eﬀect on the noise it produces, but that’s not something they’ve determined. For the 2 projects they’ve done in Lexington, the companies have been good to work with. Joseph Lehar, a member of the public, asked about noise from sports facili?es. Mr. Farbo has worked on several of those recently. The members then discussed the Environmental Noise booklet previously shared by Dr. Campbell, which included a sec?on on noise measurement methods. The booklet addresses ra?ng levels, which involve penal?es applied to a noise source based on how annoying a typical person is likely to ﬁnd it. Ra?ng levels are used in other countries, but don’t seem to be used in the US; but the varying limits that Mr. Farbo described from the Devens rules are probably an a?empt to achieve the same goal. Both Boston and Devens may be valuable to look at more closely. Ms. Katzenberg had previously wri?en to the city planner for Rye, New York. Rather than limi?ng the amount of noise from construc?on there, they simply limit the dura?on of projects. He recently replied that he would be willing to speak to the commi?ee about the implementa?on of their bylaw. He will be invited to a?end next month. The members agreed to meet remotely again next month and re-evaluate the mee?ng format then. Ms. Katzenberg and Ms. Bleiberg will be mee?ng with Christopher Barry at the police sta?on for another update on noise complaints. Ms. Rudell moved to adopt the minutes from January. Mr. Lees seconded. All voted in favor. Ms. Bleiberg moved to adjourn. Ms. Katzenberg seconded. All voted in favor.