The Potential Synergy between Noise
Mitigation and Weatherization for the Green
Line Extension
Prepared by Ian Adelman, Meg Howard, and Doug Piatt
The Potential Synergy between Noise Mitigation and Weatherization for the
Green Line Extension
Prepared by Ian Adelman, Meg Howard, and Doug Piatt
Executive Summary
The Green Line Extension through Somerville will create noise impacts to many
residential and institutional buildings along the corridor. MassDOT has proposed
initial plans for a noise mitigation project intended to adequately mitigate the noise
impacts in accordance with the Federal Transit Administration guidelines.
This report shows that many of the affected residences are in Environmental Justice
areas as defined by Massachusetts. We also show that many of the residences were
constructed before 1900 and therefore likely to be very energy inefficient. In
addition to impacting these areas with increased noise, there is concern the Green
Line Extension may result in the displacement of many of the low-income residents
that the project intended to serve.
We looked closely at the proposed noise mitigation measures for the Green Line
Extension, various other noise mitigation projects, and spoke with noise mitigation
experts at Jones Payne Group. Our research enabled us to better understand the
synergy between noise mitigation and weatherization. Many of the treatments are
identical; many noise treatments provide energy benefits; and, many weatherization
treatments provide noise benefits. We also reviewed the FTA’s guidelines for noise
mitigation and various noise mitigation projects and proposals in Massachusetts to
understand the precedent set for MBTA and MassDOT transit projects.
Massachusetts’ interpretation and implementation of a noise mitigation project is to
spend at least two percent of hard construction costs, up to $5,000 per residence
per decibel of mitigation (up to $30,000 per residence) and to allow noise mitigation
funds to be spent on mitigations that do not provide noise reductions.
The noise mitigation plan for the Green Line Extension has not been formalized, but
from what has been drafted it does not appear to be following this precedent. In
addition to being equitable, MassDOT should maintain its standard for noise
mitigation plans for the Green Line Extension because it can be used to combat
displacement of low income and racial minority residents. A plan that recognizes the
sound insulation and weatherization synergy and provides maximum energy
benefits for residences will decrease living costs and improve quality of life while
providing adequate noise mitigation. A plan that is substandard and ignores energy
benefits will be inequitable and will exacerbate displacement.
Introduction
The extension of the Green Line through Somerville will cause noise impacts to
many buildings along the corridor. The Final Environmental Impact Report
identified 164 homes and businesses that will receive noise mitigation measures as
part of the cost of the Green Line Extension. For many of the homes and businesses
along the route, noise mitigation will be in the form of a noise barrier. In addition to
or in place of the noise barriers several buildings will receive sound insulation
treatments. Many of the impacted buildings were built at the turn of the century, are
likely to be energy inefficient and are located in environmental justice areas.
The noise barriers will be a crucial step to ensuring that outdoor space, like this
garden below, remains useable.
Sound insulation treatments have the potential benefit of providing weatherization
improvements to the affected areas, especially if sound treatments are done with
weatherization taken into consideration. This will save energy and reduce utility
bills for these residents while still providing adequate noise mitigation. This report
provides maps of the existing housing and environmental justice conditions overlaid
by the impacted buildings. It compares weatherization and sound insulation
measures, outlines available weatherization funding and reviews other noise
mitigation projects.
From this review and analysis we conclude that a noise mitigation project for the
Green Line Extension informed by the synergy between sound insulation and
weatherization will prevent displacement by reducing energy costs and providing
adequate noise mitigation. Where as, a noise mitigation project that ignores the
synergy will disproportionately impact low income and minority residents and
increase displacement.
Proposed Noise Impacts and Mitigation for the Green Line Extension
The Green Line will be a new source of noise impacts along the corridor. The project
will cause additional noise impacts by relocating the commuter rail tracks in some
places by up to 18 feet (FEIR, 7-13). Future noise levels along the west side of the
tracks are projected to generally increase by one to two decibels. In some locations,
however, the noise increases will be higher (five decibels at the Alston Street near
Cross Street) (FEIR, 7-14).
Any increase in noise levels along the tracks may be considered as moderate or
severe impacts because of the already high noise levels. MassDOT and MBTA
estimate that the extension would expose 121 residential buildings to moderate
noise levels and 43 residential buildings to severe noise levels. In addition to the
residential buildings, Tufts Science and Technology Center, Outside the Line Artist’s
Studio and Bacon Hall at Tufts University will be impacted by moderate noise levels
and Walnut Street Center will be impacted with severe noise levels (FEIR, 7-14).
(See the included maps for details on location and level of impact)
MasDOT proposes to “mitigate for both moderate and severe noise impacts
wherever feasible and wherever noise levels are above 65 dBA” (FEIR, 8-8). “Noise
mitigation including noise barriers and potential sound insulation treatments would
be feasible, reasonable and effective in mitigation of all potential noise impact due to
the Propose Project” (FEIR, 7-15). MassDOT determined noise barriers would not be
feasible or effective mitigation at the following locations: Brickbottom Lofts,
Apartment complex on Pearl Street, Visiting Nurses Association, Tufts Science and
Technology Center, Outside the Lines Art Studio, Tufts Bacon Hall and Walnut Street
Center in Union Square (FEIR, 8-10). Sound insulation treatments to these buildings
will be necessary. According the FEIR, MassDOT considers sound insulation, “costeffective if it can improve the noise reduction of the building by five decibels or
more” (FEIR, 7-15).
Existing Conditions
Our group developed a series of maps to show the proposed Green Line corridor
through Somerville. These maps highlight the houses that the Final Environmental
Impact Report calls out for severe noise impact (red) or moderate noise impact
(orange). The parcel for each of these houses is color coded based on the year built.
This shows that many of the houses along the Green Line corridor were built before
1900. These houses most likely have minimal insulation, making them particularly
vulnerable to noise pollution and cold weather.
The maps also highlight the 2000 Massachusetts Environmental Justice areas. The
state uses census data to define environmental justice areas by income, race,
percent foreign born and percent English speaking. For more information about the
definition of environmental justice communities in Massachusetts see:
http://www.mass.gov/mgis/cen2000_ej.htm
Finally, the maps also show the proposed station locations and the proposed
locations of noise barriers.
These maps are followed by a series of pictures of the current housing stock.
Residences use backyards for gardening and decks.
Older housing stock—with many homes built before 1900--may especially
benefit from weatherization.
Historic properties require special attention.
“Construct noise barriers with materials and colors compatible with adjacent
historic properties. Provide noise mitigation (sound insulation) for sensitive
historic structures that cannot be protected using noise
barriers.” -FEIR
No noise barrier proposed for this location.
No noise barrier proposed for this location.
Standard Noise Mitigation Measures
In addition to reducing the noise that the trains make, MassDOT has two basic
means to reduce noise impacts for buildings along the corridor: noise barriers and
building sound insulation. The table below details the proposed measures for the
Green Line Extension. Most sound insulation treatments for transit projects are only
concerned with the side of the building facing the tracks.
Noise Mitigation Measures
Sound insulation treatments
Noise barriers
Description
 Adding an extra layer of glazing to
windows
 Sealing any holes in exterior
surfaces that act as sound leaks
 Providing forced ventilation and
air conditioning so that windows
do not need to be opened
 Noise barriers would range from
six to 12 feet tall and
 Barriers would block the view of
the right-of-way from adjacent
homes.
Source: FEIR Executive Summary Page 27
Standard Weatherization Measures
Many of the homes adjacent to the Green Line Extension right of way were built
around the turn of the last century (see maps in the previous section) and therefore
have old windows and doors and little insulation.
Weatherization Measure
Windows and doors
Insulation
Description
 Replace old, poor quality
windows with well insulating
new ones
 Outside doors are replaced with
better insulating doors and
resealed
 Storm doors and windows can be
installed for added insulation
 Reseal old doors and windows


Insulation, cont.

Insulation injected into exterior
walls to increase the R-Value
Foundations can be better
insulated on the outside with
high-density foam board panels
Attic access hatches replaced with


Air sealing



higher R-Value ones, or resealed
Ventilation ducts are wrapped in
insulation
Floors above basements are
insulated to improve heat
efficiency in the rooms above
Air sealing of any spaces that leak
air in or out of the building
As a part of painting or siding
process, sealants and caulking are
used to seal exterior gaps
Expanding foam is used to seal
opening where pipes penetrate
floors and walls
The synergy is obvious
Comparing the two tables, there is an obvious overlap between weatherization and
noise insulation measures. Combining noise mitigation and weatherization into one
cost efficient program should work well for the Green Line Extension Project. When
we met with Jones and Payne to discuss the idea, they indicated that combining the
two is a growing practice that they are starting to suggest to clients. One of the most
common measures they use to insulate for both noise and weather is to replace
windows.
New windows that work well are double or triple pane, with one of the panes having
a two-layer laminate of glass that further reduces noise penetration as well as
beneficial weatherizing qualities. Having good storm windows installed also makes
a big difference in reducing sound and temperature transfer.
The main difference between noise mitigation and weatherization is whether or not
the whole house or “building envelope” is treated. A noise mitigation program
would replace only windows in “line of sight” of the direction the train noise is
coming from and maybe a couple others in a room so as to make all the windows
match. Weatherization programs usually replace all the windows at one time so they
all match and the whole building becomes better insulated.
The difference between these two approaches comes down to the amount of funding
available and possibly getting the building owner involved in special financing
incentives that enable the purchase of the windows not included in the noise
mitigation.
Potential Cost for Noise Mitigation
The MBTA considers it reasonable to allocate at least two percent of hard
construction costs toward noise and vibration mitigation (see section on precedents
for details). Assuming hard construction costs to be $763 million (80 percent of total
costs), the MBTA should have allocated at least $15,264,000 for noise and vibration
mitigation. The FEIR currently estimates $2.7 million will be spent for noise barriers
(FEIR, 8-9), but says, “costs for sound insulation and noise barriers to be determined
in the next phase.” An additional $9.4 million is allocated for vibration mitigation.
Currently, the total allocation for noise and vibration mitigation would be
approximately $12.1 million or approximately $3.164 million below our estimate of
two percent of hard construction costs.
A sound insulation program that follows the precedent set by the MBTA’s agreement
with the Town of Scituate concerning the Greenbush Line (see section on
precedents for details) would provide an average of $30,000 for severely impacted
residences, $18,269 for moderately impacted residences and $7,000 for low impact
residences. For the Green Line Extension this would add up to a total of $3,500,549
(121 moderately impacted residences and 43 severely impacted residences). If
MassDOT provided estimates for the number of low impact residences this figure
could be much higher.
Sources of Funding for Weatherization in Somerville
Weatherization has become a priority in Somerville’s effort to become more energy
efficient. Some funding may be available for weatherization efforts, especially for
low-income areas, this funding could be used to supplement any additional
measures beyond what is necessary for noise mitigation. Funding sources include:
 The Menotomy Weatherization Assistance Program. Households earning
below 60% of the AMI are eligible for this funding, which serves around
thirty Somerville residences a year for an average of $1,437.33 per unit.
 State and utility incentives
 The Housing Rehabilitation Program: Offers qualified households zero
percent loans for up to $25,000. Household earning below 80% AMI are
eligible for this program.
 The Office of Sustainability & Environment. This city department is currently
developing a program to support home energy retrofits.
Current Procedure for Mass Save Weatherization
 Make an appointment for an energy audit.
 A representative stops by and changes light bulbs to compact fluorescents
and gives out a programmable thermostat at no charge. Gives out brochures
on the types of programs that are supported. Sets up an appointment for an
insulation audit to be done.
 Representative for the insulation audit comes over and does tests to
determine how well insulated the exterior walls and ceilings are. Rep.
explains how much insulation is inside the exterior walls and if there is a
need to further insulate them.
 A blower-door air seal test is done that measures the air leaks in and out of
the building. This test uses air and or vacuum pressure to test for leaks.
 A written quote is mailed to the house explaining how much additional
insulation will cost and how much of the cost will be covered by government
programs. The methods of injecting insulation into existing walls are also
reviewed.
 The NSTAR rebate covers $2000 worth of insulating work, the quote received
for a two family house in Somerville was for $8900
Review of case studies and precedents
A review of recent noise mitigation projects, mitigation agreements, an MBTA
environmental consequences report and Federal guidelines establish a precedent
for future noise mitigation projects in Massachusetts. The examples and guidelines
suggest that funding for residential sound insulation programs should be used to
provide energy benefits in addition to adequate sound insulation at the discretion of
the residences.
The Federal Transit Administration’s “Transit Noise and Vibration Impact
Assessment” manual provides guidance for appropriate mitigation measures.
It suggests that severe noise impacts should be avoided when possible, but when
unavoidable severe noise impact mitigation will be incorporated into the project
(FTA, p 3-11). Moderate noise impacts should be mitigated when reasonable (FTA, p
3-11) and in coordination with community input (FTA, 3-12). The document does
not define reasonable cost thresholds but does offer guidance. The median cost
threshold for sound barriers is $24,000 per residence. The FTA considers $25,000 to
$30,000 per benefitted residence to be a reasonable cost (FTA, p 3-13). The manual
also provides guidance concerning effective building insulation treatments. These
include caulking and sealing gaps, installing new doors and windows that meet
acoustical standards, sealing vents and ventilation openings and relocating them to
a side of the building away from the noise source (FTA, p 6-43).
There is no published and publicly available MBTA and MassDOT interpretation of
the FTA guidance manual. However, the Blue Line noise mitigation project, the noise
mitigation agreement between the MBTA and the Town of Scituate and the
“Environmental Consequences Report: Noise” for the South Coast Rail project
establish standard practices in Massachusetts and should be applied to the Green
Line Extension.
The MBTA went beyond standard sound insulation treatments for noise mitigation
for the Blue Line. They extended treatments to the whole building envelope,
including supplemental wall and ceiling work and upgrades to through wall air
conditioners (Jones Payne, 2001). The above average treatments were intended to
match noise mitigation measures for properties that were receiving noise mitigation
through a MassPort program.
The “Environmental Consequences Technical Report: Noise” for the South Coast Rail
recommended allocating, “two percent of the hard construction costs of a project for
avoidance or mitigation of noise and vibration impacts. If this sum proves
insufficient to complete the NMP, then additional funds will be requested so that the
entire NMP can be implemented” (EOT, p 6-2). It also stated that Measures will be
considered cost-effective by EOT if the total cost of the wall or other measures is
less than $30,000 per dwelling unit and the wall is found to be effective in reducing
noise levels below the impact threshold (EOT, p 6-3). Cost-effectiveness limit for
building noise mitigation will be $5,000 per dwelling unit per decibel of noise
impact projected above the Severe Noise Impact Level (not to exceed $30,000 total)
(EOT, p 6-3). The owners of properties that are affected by noise above the Severe
Noise Impact Level, and who may be eligible for building noise mitigation will be
consulted during the design phase, and will be allowed to identify preferred building
noise mitigation measures from a list of potential measures (EOT, 6-3,4). Potential
measures list will include measures, such as window replacement or sound
insulation in the house. Homeowners may elect, singly or in concert with others, to
install measure that may not reduce exterior noise levels, or may not be fully
effective in reducing interior noise levels, such as air conditioning (EOT, p 6-4).
The mitigation agreement between the MBTA and the Town of Scituate for noise
impacts caused by the Greenbush Line provides a clear precedent for the MBTA’s
noise mitigation process. The owners of noise impacted properties where sound
insulation mitigation was proposed were permitted the option of using all or a
portion of their allocated sound insulation funds for sound insulation treatments to
the residence or other expenses (MBTA and Scituate, p 6). The MBTA agreed to
spend $755,000 to provide sound insulation to 59 residences for an average cost of
$12,796 per residence. However, only two of those residences were severely
impacted and MBTA spent $30,000 on mitigation for each. 31 residences were low
impact and received an average of $7,000 and 26 were medium impact and received
an average of $18,269. MBTA used a formula of providing $5,000 for sound
insulation mitigation per household per dB of mitigation, even for low impact
residences (MBTA and Scituate, Attachment 4).
Lessons from Precedents
Residents should play a role in determining what noise mitigation measures are
desired. The MBTA has a precedent for spending $5,000 per dB of noise reduction
per residence, up to $30,000 for severely impacted residences. It is appropriate to
spend noise mitigation funds on treatments that do not provide noise benefits if that
is the desire of the residences. Contrary to the FEIR for the Green Line Extension, it
was considered cost-effective to pay for treatments that resulted in less than five
decibels of noise reduction.
Our Recommendations
MassDOT has recognized the need for noise mitigation, but has not yet created a
mitigation plan. This is the opportune time for CCP to intervene and present
MassDOT with a plan supported by the community that addresses energy benefits in
addition to noise impacts.
CCP needs to ensure that MassDOT and the MBTA develop the Green Line Extension
through Somerville with the same standards they used in other communities. CCP
should recognize that following the precedent from the Greenbush Line, the South
Coast Rail and the Blue Line is an opportunity to prevent displacement and improve
the quality of life for environmental justice communities along the corridor.
The sound insulation industry recognizes the synergy with and support for
weatherization. Unfortunately there is no definitive published research yet that
outlines the correlation. However, there is forthcoming research. A pilot study is
being conducted in the area around the Forth Lauderdale-Hollywood International
Airport. The “Early Action Volunteer Residential Sound Insulation Pilot Program” is
an attempt to evaluate the energy benefits of sound insulation treatments. Their
study will conclude in less than a year from now.
Additionally, the Federal Aviation Administration, which funds numerous
residential sound insulation projects when airports expand, is developing new noise
mitigation guidelines. Jones Payne Group is working with the FAA to make sure the
new guidelines incorporate the connection between sound insulation and
weatherization. When these guidelines are complete, we recommend they be
applied to transit projects as well.
Jones Payne Group is conducting research as well. They are looking at the change in
energy use before and after a building is insulated for noise. Their study is in the
preliminary stage, but will provide crucial data for quantifying the connection. We
recommend CCP contact Jones Payne Group for the study details and as a potential
resource for developing a “community noise mitigation plan.”
CCP should coordinate stakeholders to be involved in the development of a
“community noise insulation plan” to best leverage mitigation funds. Residents
living along the corridor can also be consulted for anecdotal data. We spoke with
one family that upgraded their insulation and noticed a significant improvement in
both noise reduction and energy use. There are likely numerous other residents
with similar experiences that should be considered resources.
In addition to homeowners and renters, rental property owners should be
considered important stakeholders. Many of the impacted residential buildings are
likely to be rentals. Landlords should recognize that a well-designed noise
mitigation plan is an opportunity to improve their properties and the stability of
their renters.
CCP should recommend a noise mitigation plan that creates a pilot program to test
the synergies between noise mitigation and weatherization. In the pilot program, as
well as, the first step in sound insulation for every treated house, a blower door test
and energy audit should be conducted.
Instead of just replacing window inserts or providing another layer of glazing,
windows and doors in their entirety should be replaced, sealed and gasketted. Line
of sight treatments should be extended to the entire house. MassSave funding, as
well as, Somerville’s own energy efficiency retrofit program should be combined
with the noise mitigation funds to provide the most comprehensive weatherization
treatments.
References and additional resources
Executive Offices of Transportation and Public Works (EOT). (2009) “Environmental
Consequences Technical Report: Noise.” Prepared by Vanasse Hangen
Brustlin, Inc. Boston, MA. Available at:
http://southcoastrail.eot.state.ma.us/downloads/EC_Noise%20Report%20w
ith%20Figures.pdf
Federal Transit Administration (FTA). (2006) “Transit Noise and Vibration Impact
Assessment.” Available at:
http://www.fta.dot.gov/documents/FTA_Noise_and_Vibration_Manual.pdf
Fort Lauderdale-Hollywood International Airport. (2010) “Early Action Voluntary
Residential Sound Insulation Pilot Program.” Available at:
http://www.fllsoundinsulation.com/index.html
Jones Payne Group. (2001) Blue Line Residential Sound Insulation Program 19962001. Available at:
http://www.jonespayne.com/projects/pdf/nm_rail_mbta.pdf
MBTA and Town of Scituate. (2002) “Mitigation agreement concerning the
Greenbush Line Project in the Town of Scituate.” Available at:
http://www.town.scituate.ma.us/documents/mbtafinal.pdf