The Proposed Hudson Logistics Center Sound Study Summary & Links to Hillwood's Study and Peer Review
This post highlights the sound study, peer review, and responses related to the Hudson Logistics Center proposal.
As part of the site plan review, the applicant must make adequate provisions for the elimination of undesirable and preventable elements of pollution, such as noise (§275-6H). Additionally, Hudson town code prohibits anyone from creating noise pollution (as defined by §249-2) and sets some specific limits, including (§249-4):
Continuous noise limits, depending on receptor land use and time of day
Separate impulsive (short duration) noise limits, also depending on land use and time
Restricts the amount of increase in background noise
Prohibits producing a pure tone
Restricts the times and days allowed for construction
18 May 2020
Reviewed Hudson code to determine a noise goal. Noted the different noise limits in daytime vs. nighttime and residential vs. industrial use, as well a limit on the noise increase. Set maximum noise limit equal to average noise requirement in attempt to ensure compliance.
Recommended project mitigation features include an earthen berm or sound wall as allowed by the presence of wetlands, use of certain types of tractor back-up alarms, and HVAC equipment in line with the assumptions used for modeling.
Used acoustical modelling software to predict noise levels at ear-level for nearby locations after development. Noise sources include rooftop HVAC and truck activity at select locations. Results indicate maximum noise levels at, or just above, required average levels, which the study states “meets the intent of the project goal”.
29 June 2020
Identified deficiencies with OAA sound study including:
Noise from truck travel close the residences was not included
Existing ambient noise levels were not measured to determine the expected change
Potential for a pure tone condition was not evaluated
Noise during construction was not addressed
Concluded that the applicant did not fully demonstrate there will be no negative noise impact.
13 July 2020
Described changes in the project that impact noise levels:
Buildings on lots B and C were each moved north, further from abutting residences
Updated HVAC equipment location and quantity to be more accurate
Improved earth berm with a sound wall to be placed on top in portions
Emergency generators added to each building, which sometimes contribute to noise
Responded to HMMH comments:
Argued that noise from truck travel is lower than other sources
Agreed to deploy long-term sound level monitors to measure ambient noise
Provided preliminary data based on similar facilities that a pure tone condition will not exist
Regarding construction noise, stated that project will conform to §249-4I of town code, which restricts construction to certain times
Also responded to a large number of written comments that had been sent to the Planning Board.
Benjamin Mueller, who prepared the OAA study and response, presented remotely, which can be viewed at the following link starting about 24 minutes in.
Summarized existing reports and status
Acknowledged impulsive limits in town code
Increased height of shielding (berm and wall) to address concerns at different elevations nearby
Mitigation measures continue to be refined and improved
Later during discussion, Selectman Marilyn McGrath noted multiple neighbors made complaints about the noise produced by drilling performed at Green Meadows on a weekend in June in violation of town code. Justin Pasay, a lawyer for the applicant, said that they would address that.
Questions and concerns regarding noise remain, including:
In addition to abiding by the allowed hours for construction set in §249-4I, construction noise should meet the requirements throughout §249-4, which won't have the benefit of the berm and sound wall during their creation. This noise should be estimated.
The sound study identifies Sam’s Club as an industrial use where it is clearly a business use and zoned as such, which has lower allowable noise levels.
Impulse noise limits are set in different units (dBC) than continuous (dBA), what are the expected levels in dBC, as measured according to §249-2?
Noise estimates should be done at additional elevations to predict the noise coming into bedrooms.
The sound model should include all sources simultaneously, including car and truck traffic, backup generators, and truck backup alarms, which may be louder than those assumed in the existing study.
While the noise study assumes 8 active trucks, there may be more. For example, the September Traffic Impact Study shows that from 5-6AM there are expected to be 10 tractor trailer trucks, 40 box trucks, and over 200 cars coming or going.
The noise study should not only consider expected immediate use, but also possible future use at full capacity, taking into account seasonality, growth, and the possibility of changes in tenants and ownership.
A follow-up report that incorporates the changes to the project is expected sometime in mid September, as per the schedule presented at the September 9th Planning Board meeting.