Just how loud will it be for neighbors as the state demolishes the Casey Overpass and replaces it with a network of surface roads? The state explained the project's noise limits during a public meeting Monday night.
The limits set by MassDOT range from 75 to 90 decibels. Alex Kasprak of MassDOT explained there are two kinds of limits — one for ongoing noises like compressors and one for "impact" sounds like jackhammers. During what the DOT says will be limited nighttime work, the limits range from 62 to 80 decibels.
The limits, explained more fully below, can seem dry and technical. Forest Hills resident Rosalba Solís but them in human perspective during the question and answer period of the meeting.
"I live by the bridge," said the Hernández School teacher. "I cannot sleep with 60 decibels at night...your kids will have a very grumpy teacher. If you think I can spend three years of sleeping with 60 decibels, [you're] out of your mind."
In answer, Engineer Chris Evasius said the project will have only limited work during most people's sleeping hours.
"This is not a night job," Evasius said. "There won’t be three hours of hoe ramming at night."
Night work would be limited mostly to sections like Washington Street, where traffic considerations make daytime work untenable, planners said.
The DOT promises a two-week warning before night work is done, said Jim Kersten, the new spokesperson for the project. To get on the project's email alert list, go to this link. To report a violation, the project's hotline is 617-571-7878.
Evasius said there won't be any blasting on the project, which is expected to take more than two years. He did say some noisy night work might be required if there is an emergency.
Noise limits vary by time of day. These figures vary slightly depending on which side of the project you live on. Below are the highest limits, in decibels, in each category:
Daytime: 7 a.m. to 6 p.m.
Evening: 6 p.m. to 10 p.m.
Night: 10 p.m. to 7 a.m.
To put those in context, here's a chart of decibel levels, as provided by MassDOT:
|Space shuttle launch||160|
|Heavy diesel truck at 25 feet; power mower||90|
|Normal conversation at home||50|
The session, held at English High School, was the second construction information meeting. Fewer people turned out than the last such meeting in January. However, a similar percentage of attendees held up signs opposing the plan. Opponents would like to see a bridge rebuilt instead.