Airport Committee Considers Residential Sound Insulation

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Thursday February 08, 2018

Acoustical windows and doors, and upgraded ventilation systems are just some of the treatments available through a Residential Sound Insulation Program for which homes within the 65 dB DNL line (decibel day-night average sound level) from the airport may be eligible.

The Residential Sound Insulation Program is one of the new land use measures being assessed through the Noise Compatibility Program update (NCP), which is part of a larger federal regulation known as the Part 150 Study program.

The Part 150 Study assesses and minimizes noise from the airport. It is a voluntary measure, but it is also the primary means by which airports can obtain financial support from the Federal Aviation Administration (FAA), including funding for noise-related projects.

The current NCP is approved for land acquisition and relocation. After the removal of upwards of 200 homes and witnessing its effects on South Burlington’s affordable housing stock, the airport is in the process of updating the NCP with land use measures beyond acquisition that better align with the community’s needs. A finalized NCP update will then be submitted to the FAA for review, and requested land measures will be implemented if the update is approved.

With the help of Jones Payne Group and HMMH, consultants hired by the airport, a Noise Compatibility Program Technical Advisory Committee is walking through the existing program details as well as educating its members and the public at-large to elicit feedback on how best to revamp its contents. The committee is comprised of stakeholders from the airport, military, affected cities and business communities; South Burlington is represented by the city manager, director of planning and zoning, and two affected residents who sat on the former Chamberlin Neighborhood Airport Planning Committee.

On January 23, the technical advisory committee reviewed the Sound Insulation Program in greater detail regarding eligibility, policy, procedures, and implementation. The program being considered helps reduce interior noise levels in a home and is an option that has sparked interest from residents.

What is the Residential Sound Insulation Program?

Eligibility

Homes that are within the 65 dB DNL noise level or higher meet the first level of eligibility. Properties that fall below this threshold are not eligible unless a lower local standard is adopted by the jurisdiction or the FAA has approved “block rounding.”

“If a jurisdiction, like the City of South Burlington, decides to adopt a lower noise contour, the 60 DNL, as noncompatible for residential use, then that would be the standard the FAA would approve for sound insulation,” Diane Carter, principal at Jones Payne Group, explained.

“The caveat is that the city would have to enforce that new land use jurisdiction and not allow any new development of residential use in that 60 DNL contour. It’s a pretty stringent standard…we typically don’t see that done. What we do see is what’s called block rounding or neighborhood equity,” she said.

In other words, if some homes in a neighborhood are eligible for the program and others in the same area are not, the airport and FAA may come to an agreement to allow the entire area (i.e. street or block) to be eligible to avoid isolation and help humanize the situation.

“We will go through that when the Noise Exposure Map (NEM) is updated with the new contour,” she said.

A Sound Insulation Program’s inception begins with the development of an Acoustical Test Plan (ATP). This includes protocol for the initial testing, an FAA review of initial testing results, special circumstances, and then a final testing phase control.

Specifically, an ATP will conduct neighborhood surveys, perform pre-construction acoustical testing, determine which structures are/are not compatible, provide a full sound insulation package design for those eligible structures, perform a pilot phase of installing the package on a sample set of eligible structures, and then conduct acoustical testing at post-construction.

The test may reveal that certain homes within the 65 dB DNL are still not eligible for the program. During pre-construction testing, homes that experience a logarithmic (energy) average interior DNL of 45 dB or higher and are constructed prior to Oct. 1, 1998, will be eligible.

To calculate the Noise Level Reduction of a home (whether a home is above, at, or below the 45 dB), a “PA-type” loudspeaker with a single generator will be placed outside of the homes, and an artificial noise will be transmitted. Measurements are taken inside and outside with the speaker on and off in all habitable rooms (garages, bathrooms, laundry rooms, and foyers are considered non-inhabitable).

FAQ: Policies and Procedures

Once an Acoustical Test Plan is approved, Burlington International Airport would then have to develop a policy and procedures manual to outline not only the purpose, goals and project planning and management of the program, but also information regarding the construction contract bid and award cycle, the construction process, eligible spaces, architectural/mechanical/electrical treatment types, and building code requirements.

Which eligible homes would receive sound insulation first?

Eligible homes in the highest noise levels receive treatment first, and then the program works out toward the program boundary. Length of residency, whether it is an owned or rented property, and contiguous blocks versus by noise level are additional criteria taken into consideration.

In response to South Burlington Superintendent David Young’s question about prioritization for Chamberlin School, which falls within the noise contour, Jones Payne Group Project Manager Sarah Degutis responded: “As part of putting the land use measures together for the NCP, we would discuss if there is a higher prioritization for other public buildings.”

How long would it take to implement?

The program’s pace is dependent on the FAA’s grant cycles and available funding. Typically, design, bid, and construction cycles last anywhere from 12-18 months depending on the size of the project. The airport would then work with the FAA’s Airport District Office to develop a capital programs work plan.

What types of treatment would homes receive?
Basic treatment examples:
• Window replacements
• Door replacements
• Additional and/or caulking replacement and weather stripping
• Central air-conditioning or ventilation system installations

For homes that need more than basic treatment:
• Addition of attic and/or wall insulation
• Addition of extra layers of wall and/or ceiling board
• Removal or treatment of through-wall A/C units
• Removal of mail slots, etc.

Typically, homes that fall in the 65-70 dB contour range with a post-construction Noise Level Reduction value of 30 dB would receive basic treatment. Homes in the 70-75 dB contour range with post-construction Noise Level Reduction value of 35 dB include the additional treatments, and anything above 75 dB with a post-construction Noise Level Reduction value of 40 dB is recommended for acquisition or heavier duty mitigation.

Implementation

Broken down into phases (50 units are typically in a phase), each phase has a process for pre-design, pre-acoustical testing, and design. Pre-design steps involve invitation letters, an application and initial survey, and homeowner outreach meeting. The design steps involve an assessment visit, design of treatments, a homeowner review and participation agreement, and developing construction documents.

In terms of the bidding process, a public bid would be issued to contractors who are insured, pass a background-check and are bonded/licensed, and the City of Burlington will award the lowest eligible bidder.

During construction, the contractor verifies the product and measurements, orders the products, and then notifies homeowners six to eight weeks prior to construction. Construction of each home takes about 30 days.
“We have our first funding on our Capital Improvement Program with the FAA to commence in 2019 for the Sound Insulation Program—if that’s going to happen or not will depend on federal funding,” said Nicolas Longo, the airport’s deputy director of aviation administration.

The Residential Sound Insulation Program is just one of several land use measures being assessed for the update. Sound barriers/buffers, sales assistance/purchase assurance, real estate disclosure, land acquisition/relocation, and avigation easement acquisition are other measures on the table.

These land use measures will be discussed in detail at the next technical advisory committee, scheduled for Tuesday, March 13, 5 p.m. at the airport. Another committee meeting is scheduled for May, and there will be a public hearing and comment period in August or September of this year.

 

SOURCE:  Miranda Jonswold, Correspondent