HomeMy WebLinkAbout2012-03-20 Planning Board Supplemental Materials (119)70 ELM North Andover, MA.doc
NOISE STUDY
TO: Andrey Tsikanovsky, Senior Project Manager
COMPANY Hudson Design Group, LLC
FROM: Callie Reis {callie.reis@noise-control.com}
Michael Bahtiarian {mikeb@noise-control.com}
DATE: February 16, 2012
SUBJECT: MetroPCS and T-Mobile Noise Evaluation UPDATE
Trinitarian Congregational Church
70 Elm Street, North Andover, 01845
INTRODUCTION
Noise Control Engineering, Inc. (NCE) was retained by the Hudson Design Group to review a
set of acoustic analyses previously performed by NCE for a combined MetroPCS and T-
Mobile personal wireless facility at 70 Elm Street in North Andover, MA. The facility is
located in the basement of the Trinitarian Congregation Church. Figure 1 shows the site,
property line, measurement locations and calculation locations.
Most noise-generating equipment is located inside the church with one item located on the
building exterior. These equipment items include:
(1) MetroPCS Modcell cabinet
(1) Galaxy power cabinet
(3) Ericsson RBS 2206 cabinets
(2) indoor battery cabinets
(1) Mitsubishi Mr. Slim air conditioning system (exterior to building)
This document summarizes the four NCE noise studies performed for this site below and
confirms that all previous assumptions and statements are still valid for the facility in 2012
with all equipment installed as designed.
NOISE LIMIT
The Town of North Andover “Zoning Bylaw”, Section 8.9 “Wireless Service Facilities”,
[1] states that “Ground-mounted equipment for wireless service facilities shall not
generate acoustic noise in excess of 50 dB at the security barrier.” The ordinance also
requires a measurement of existing noise levels, i.e., a measurement of ambient noise
Noise Control
Engineering, Inc.
799 MIDDLESEX TNPK.
BILLERICA MA 01821-3445
PHONE: 978-670-5339
FAX: 978-667-7047
E-mail: nonoise@noise-control.com
Noise Control February 16, 2012
Engineering, Inc.
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prior to the construction of the facility, and a prediction of the resulting noise levels with
the equipment installed. This prediction must be given in Ldn1. The bylaw does not place
a limit on the allowable increase over ambient noise that occurs once the facility is
operational.
REVIEW
NCE’s original analysis of the T-Mobile equipment was performed on November 17, 2008
[2]. Noise levels due to the T-Mobile equipment alone were below the 50 dB(A) limit and
NCE predicted that the measured ambient noise level of 59 dB(A) would not change once the
facility was operational. The study was amended to address “pure tone” noise per the
Massachusetts Department of Environmental Protection (MADEP) noise regulation on
December 23, 2008 [3]. Pure tones cannot be evaluated given that manufacturer supplied data
lists only overall noise levels. NCE maintains that all assumptions made in the aforementioned
reports are valid to date.
NCE performed a second analysis of the site (dated May 1, 2009) in order to predict acoustic
effects after the installation of MetroPCS equipment [4]. The approximation of noise at the
property line due to the interior equipment included evaluation of transmission loss through
the building wall as well as the typical attenuation expected as distance from the noise source
increases. Additionally, NCE calculated a combined overall sound pressure level due to both
T-Mobile and MetroPCS interior and exterior equipment.
In all directions, noise emitted from the combined T-Mobile and MetroPCS personal wireless
facility was predicted to be below the 50 dB(A) limit and the resulting ambient Ldn did not
increase above the measured 59 dB(A).
Given predicted noise levels of 23-26 dB(A) due to all operating T-Mobile and MetroPCS
equipment, NCE stated that the personal wireless facility would be inaudible at the property
line. Measurements performed on August 11, 2009 confirmed that not only had the
background noise level at the site remained the same after the equipment was installed but that
measured noise at the property line was identified as due to traffic or HVAC units on
neighboring properties [5].
CONCLUSION
The equipment for the combined T-Mobile and MetroPCS wireless facility installed at 70
Elm Street in North Andover, Massachusetts complies with the requirements of the
Zoning By-Law for the Town of North Andover. It also has no impact on Day-Night
Average Sound Levels, Ldn. NCE measurements in August 2009 have shown that no
noise impact has resulted from the operation of this equipment.
1 Day-Night Average Sound Level (DNL or Ldn) which includes 10 decibel penalty for sounds during night periods (10pm to 7am).
Noise Control February 16, 2012
Engineering, Inc.
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REFERENCES
1. Town of North Andover Massachusetts Zoning Bylaws, Section 8.9 “Wireless
Service Facilities”, Subsection 5 “Design Standards”, page 99, Revised July 10, 2006.
2. NCE Job Memo, “MetroPCS Antenna Site Noise Evaluation BOS0380C Trinitarian
Congregational Church 70 Elm Street, North Andover, 01845”, dated November 17,
2008.
3. NCE Job Memo, “MetroPCS Antenna Site Noise Evaluation BOS0380C Trinitarian
Congregational Church 70 Elm Street, North Andover, 01845”, dated December 23, 2008.
4. NCE Job Memo, “T-Mobile Antenna Site Noise Evaluation 4BZ-0023A Trinitarian
Congregational Church 70 Elm Street, North Andover, 01845”, dated May 1, 2009.
5. NCE Job Memo, “MetroPCS Antenna Site Noise Evaluation BOS0380C Trinitarian
Congregational Church 70 Elm Street, North Andover, 01845 Follow Up Noise Study”,
dated August 14, 2009.
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Engineering, Inc.
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FIGURE 1: Background noise monitoring location and noise calculation locations.