Acoustics & System
Dynamics
Hoosac Wind
Sound Level Monitoring
June 2013
Prepared by
Resource Systems Group, Inc.
for
New England Wind, LLC
Resource Systems Group, Inc.
55 Railroad Row
White River Junction, VT 05001
TEL 802.295.4999 | FAX 802.295.1006
www.rsginc.com
Prepared under the direction of
Kenneth Kaliski, P.E., INCE Bd. Cert., Q.E.P. | Senior Director
RSG | www.rsginc.com
55 Railroad Row | White River Junction, VT 05001
Hoosac Wind Sound Monitoring
TABLE OF CONTENTS
1.
INTRODUCTION
1
2.
PROJECT DESCRIPTION
1
3.
INTRODUCTION TO SOUND AND TERMINOLOGY
2
4.
5.
6.
3.1
How is Sound Described?............................................................................................................ 2
3.2
How is Sound Modeled? ............................................................................................................. 4
3.3
Description of Terms ................................................................................................................... 5
3.3.1 Lmin and Lmax ................................................................................................................. 5
3.3.2 Percentile Sound Level - Ln .............................................................................................. 5
3.3.3 Equivalent Average Sound Level - Leq ............................................................................. 5
MONITORING METHODOLOGY
6
4.1
Monitoring Equipment................................................................................................................ 6
4.2
Monitoring Methodology............................................................................................................ 7
4.2.1 Attended Monitoring ....................................................................................................... 8
4.2.2 Unattended Monitoring ................................................................................................... 9
4.2.3 Other data collection ..................................................................................................... 10
MONITORING LOCATIONS
10
5.1
East Road North ........................................................................................................................ 11
5.2
East Road South ........................................................................................................................ 13
5.3
Tilda Hill North .......................................................................................................................... 14
5.4
Tilda Hill South .......................................................................................................................... 16
5.5
Moores North............................................................................................................................ 18
5.6
Moores South............................................................................................................................ 20
MONITORING RESULTS
6.1
22
Monitoring Periods ................................................................................................................... 22
6.1.1 Monitoring Period 1 – 4/3/2013 13:20 .......................................................................... 23
6.1.2 Monitoring Period 2 – 4/3/2013 22:00 .......................................................................... 26
6.1.3 Monitoring Period 3 – 4/4/2013 10:30 .......................................................................... 29
6.1.4 Monitoring Period 4 – 4/5/2013 23:43 .......................................................................... 31
6.1.5 Monitoring Period 5 – 4/8/2013 14:15 .......................................................................... 34
6.1.6 Monitoring Period 6 – 4/10/2013 13:35........................................................................ 37
6.1.7 Monitoring Period 7 – 4/11/2013 07:33........................................................................ 40
6.1.8 Monitoring Period 8 – 4/15/2013 17:00........................................................................ 42
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Hoosac Wind Sound Monitoring
6.1.9
6.1.10
6.1.11
6.1.12
6.1.13
6.2
Monitoring Period 9 – 4/17/2013 07:21........................................................................ 44
Monitoring Period 10 – 4/18/2013 02:04...................................................................... 47
Monitoring Period 11 – 4/18/2013 11:00...................................................................... 48
Monitoring Period 12 – 4/22/2013 07:00...................................................................... 50
Monitoring Period 13 – 4/22/2013 13:00...................................................................... 52
Tonality Analysis........................................................................................................................ 54
7.
COMPARISON WITH MODELING RESULTS
58
8.
DISCUSSION OF MONITORING METHODOLOGY
61
9.
SUMMARY
63
APPENDIX A: TURBINE ACTIVITY DATA
65
APPENDIX B: MONITORING LOCATION TIME HISTORIES
66
APPENDIX C: TONALITY ANALYSIS
77
LIST OF FIGURES
Figure 1: Hoosac Wind Site Map .................................................................................................................. 2
Figure 2: Common Sounds in A-weighted Decibels ...................................................................................... 3
Figure 3: Example of Descriptive Terms of Sound Measurement over Time .............................................. 6
Figure 4: Example Spectrogram from the Tilda Hill S Site on 4/10/2013 at 5:00 ...................................... 10
Figure 5: East Road North and South Monitoring Locations ..................................................................... 12
Figure 6: East Road North Monitoring Setup .............................................................................................. 13
Figure 7: East Road South Monitoring Setup ............................................................................................. 14
Figure 8: Tilda Hill North Monitoring Location .......................................................................................... 15
Figure 9: Tilda Hill North Monitoring Setup ............................................................................................... 16
Figure 10: Tilda Hill South Monitoring Location ........................................................................................ 17
Figure 11: Tilda Hill South Monitoring Setup ............................................................................................. 18
Figure 12: Moores Road Monitoring Locations ......................................................................................... 19
Figure 13: Moores North Monitoring Setup .............................................................................................. 20
Figure 14: Moores South Monitoring Setup ............................................................................................. 21
Figure 15: Sound Levels during Monitoring Period 1 – 4/3/2013 13:20 .................................................... 24
Figure 16: Sound Levels during Monitoring Period 2 – 4/3/2013 22:00 .................................................... 27
Figure 17: Sound Levels during Monitoring Period 3 – 4/4/2013 10:30 .................................................... 30
Figure 18: Sound Levels during Monitoring Period 4 – 4/5/2013 23:43 .................................................... 32
Figure 19: Sound Levels during Monitoring Period 5 – 4/8/2013 14:15 .................................................... 35
Figure 20: Sound Levels during Monitoring Period 6 – 4/10/2013 13:35 .................................................. 38
Figure 21: Sound Levels during Monitoring Period 7 – 4/11/2013 7:33 .................................................... 40
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Hoosac Wind Sound Monitoring
Figure 22: Sound Levels during Monitoring Period 8 – 4/15/2013 17:00 .................................................. 42
Figure 23: Sound Levels during Monitoring Period 9 – 4/17/2013 7:21 .................................................... 45
Figure 24: Sound Levels during Monitoring Period 10 – 4/18/2013 2:04 .................................................. 47
Figure 25: Sound Levels during Monitoring Period 11 – 4/18/2013 11:00 ................................................ 49
Figure 26: Sound Levels during Monitoring Period 12 – 4/22/2013 7:00 .................................................. 50
Figure 27: Sound Levels during Monitoring Period 13 – 4/22/2013 13:00 ................................................ 52
Figure 28: Arithmetic Average Spectrum – WT+Background for Moores North 4/4/2013 10:00 After
Startup ................................................................................................................................................ 56
Figure 29: Arithmetic Average Spectrum – WT+Background for Tilda Hill North 4/4/2013 10:00 After
Startup ................................................................................................................................................ 56
Figure 30: Arithmetic Average Spectrum – WT+Background for East Road South 4/18/2013 2:00 After
Startup ................................................................................................................................................ 57
Figure 31: Modeled sound levels compared to monitored sound levels ................................................... 60
Figure 32: East Road North - Time History Part 1 ....................................................................................... 67
Figure 33: East Road North - Time History Part 2 ....................................................................................... 67
Figure 34: East Road North - Time History Part 3 ....................................................................................... 68
Figure 35: East Road South - Time History Part 1 ....................................................................................... 68
Figure 36: East Road South - Time History Part 2 ....................................................................................... 69
Figure 37: East Road South - Time History Part 3 ....................................................................................... 69
Figure 38: Tilda Hill North - Time History Part 1 ........................................................................................ 70
Figure 39: Tilda Hill North - Time History Part 2 ........................................................................................ 70
Figure 40: Tilda Hill North - Time History Part 3 ........................................................................................ 71
Figure 41: Tilda Hill South - Time History Part 1 ........................................................................................ 72
Figure 42: Tilda Hill South - Time History Part 2 ........................................................................................ 72
Figure 43: Tilda Hill South - Time History Part 3 ........................................................................................ 73
Figure 44: Moores North - Time History Part 1.......................................................................................... 73
Figure 45: Moores North - Time History Part 2.......................................................................................... 74
Figure 46: Moores North - Time History Part 3.......................................................................................... 74
Figure 47: Moores South - Time History Part 1.......................................................................................... 75
Figure 48: Moores South - Time History Part 2.......................................................................................... 75
Figure 49: Moores South - Time History Part 3.......................................................................................... 76
LIST OF TABLES
Table 1: Decibel Addition .............................................................................................................................. 4
Table 2: Monitoring Equipment Summary................................................................................................... 7
Table 3: Curtailment Period Ideal Meteorological Parameters ................................................................... 8
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Hoosac Wind Sound Monitoring
Table 4: Monitoring Location Information................................................................................................. 11
Table 5: Curtailment Information .............................................................................................................. 22
Table 6: Sound Levels – Monitoring Period 1, Attended Method – 4/3/2013 13:20 ................................ 25
Table 7: Sound Levels – Monitoring Period 1, Unattended Method – 4/3/2013 13:20 ............................ 25
Table 8: Weather Data - Monitoring Period 1 - 4/3/2013 13:20 ............................................................... 26
Table 9: Sound Levels – Monitoring Period 2, Unattended Method – 4/3/2013 22:00 ............................ 28
Table 10: Weather Data - Monitoring Period 2 - 4/3/2013 22:00 ............................................................. 28
Table 11: Sound Levels – Monitoring Period 3, Unattended Method – 4/4/2013 10:30 .......................... 31
Table 12: Weather Data - Monitoring Period 3 - 4/4/2013 10:30 ............................................................. 31
Table 13: Sound Levels – Monitoring Period 4, Attended Method – 4/5/2013 23:43 .............................. 33
Table 14: Sound Levels – Monitoring Period 4, Unattended Method - 4/5/2013 23:43 ........................... 33
Table 15: Weather Data - Monitoring Period 4 - 4/5/2013 23:43 ............................................................. 33
Table 16: Sound Levels – Monitoring Period 5, Unattended Method – 4/8/2013 14:15 ........................... 36
Table 17: Weather Data - Monitoring Period 5 - 4/8/2013 14:15 ............................................................. 36
Table 18: Sound Levels – Monitoring Period 6, Attended Method – 4/10/2013 13:35 ............................. 39
Table 19: Sound Levels – Monitoring Period 6, Unattended Method – 4/10/2013 13:35 ........................ 39
Table 20: Weather Data – Monitoring Period 6 - 4/10/2013 13:35 .......................................................... 39
Table 21: Sound Levels – Monitoring Period 7, Unattended Method – 4/11/2013 7:33 .......................... 41
Table 22: Weather Data - Monitoring Period 7 - 4/11/2013 7:33 ............................................................. 41
Table 23: Sound Levels – Monitoring Period 8, Unattended Method – 4/15/2013 17:00 ........................ 42
Table 24: Weather Data - Monitoring Period 8 - 4/15/2013 17:00 ........................................................... 43
Table 25: Sound Levels – Monitoring Period 9, Unattended Method – 4/17/2013 7:21 .......................... 46
Table 26: Weather Data - Monitoring Period 9 – 4/17/2013 7:21 ............................................................ 46
Table 27: Sound Levels – Monitoring Period 10, Attended Method – 4/18/2013 2:04 ............................ 47
Table 28: Sound Levels – Monitoring Period 10, Unattended Method – 4/18/2013 2:04 ........................ 48
Table 29: Weather Data - Monitoring Period 10 - 4/18/2013 2:04 ........................................................... 48
Table 30: Sound Levels – Monitoring Period 11, Unattended Method – 4/18/2013 11:00 ....................... 49
Table 31: Weather Data - Monitoring Period 11 - 4/18/2013 11:00 ......................................................... 49
Table 32: Sound Levels – Monitoring Period 12, Unattended Method - 4/22/2013 7:00.......................... 50
Table 33: Weather Data - Monitoring Period 12 - 4/22/2013 7:00 ........................................................... 51
Table 34: Sound Levels – Monitoring Period 13, Attended Method – 4/22/2013 13:00 ........................... 52
Table 35: Sound Levels – Monitoring Period 13, Unattended Method - 4/22/2013 13:00........................ 53
Table 36: Weather Data - Monitoring Period 13 - 4/22/2013 13:00 ......................................................... 53
Table 37: Tonality Analysis Results ............................................................................................................ 55
Table 38: Comparison of Monitoring Results with Modeling Results using L90 minus L90 method ........ 59
Table 39: Comparison of Monitoring Results with Modeling Results using Leq minus L90 method5 ....... 59
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Hoosac Wind Sound Monitoring
Table 40:
Table 41:
Table 42:
Table 43:
Table 44:
Table 45:
Table 46:
Table 47:
Table 48:
Table 49:
Table 50:
Table 51:
Table 52:
Table 53:
Table 54:
Table 55:
Table 56:
Table 57:
Table 58:
Table 59:
Table 60:
Table 61:
Table 62:
Table 63:
Table 64:
Table 65:
Table 66:
Monitor Operational Summary .................................................................................................. 66
Tonality Analysis 4/3/2013 13:00 – MassDEP Method .............................................................. 77
Tonality Analysis 4/3/2013 13:00 – ANSI S12.9 Method ........................................................... 77
Tonality Analysis 4/3/2013 22:00 – MassDEP Method .............................................................. 78
Tonality Analysis 4/3/2013 22:00 – ANSI S12.9 Method ........................................................... 78
Tonality Analysis 4/4/2013 10:00 – MassDEP Method .............................................................. 79
Tonality Analysis 4/4/2013 10:00 – ANSI S12.9 Method ........................................................... 79
Tonality Analysis 4/5/2013 23:00 – MassDEP Method .............................................................. 80
Tonality Analysis 4/5/2013 23:00 – ANSI S12.9 Method ........................................................... 80
Tonality Analysis 4/8/2013 14:00 – MassDEP Method .............................................................. 81
Tonality Analysis 4/8/2013 14:00 – ANSI S12.9 Method ........................................................... 81
Tonality Analysis 4/10/2013 13:00 – MassDEP Method ............................................................ 82
Tonality Analysis 4/10/2013 13:00 – ANSI S12.9 Method ......................................................... 82
Tonality Analysis 4/11/2013 07:00 – MassDEP Method ............................................................ 83
Tonality Analysis 4/11/2013 07:00 – ANSI S12.9 Method ......................................................... 83
Tonality Analysis 4/15/2013 17:00 – MassDEP Method ............................................................ 84
Tonality Analysis 4/15/2013 17:00 – ANSI S12.9 Method ......................................................... 84
Tonality Analysis 4/17/2013 07:00 – MassDEP Method ............................................................ 85
Tonality Analysis 4/17/2013 07:00 – ANSI S12.9 Method ......................................................... 85
Tonality Analysis 4/18/2013 02:00 – MassDEP Method ............................................................ 86
Tonality Analysis 4/18/2013 02:00 – ANSI S12.9 Method ......................................................... 86
Tonality Analysis 4/18/2013 11:00 – MassDEP Method ............................................................ 87
Tonality Analysis 4/18/2013 11:00 – ANSI S12.9 Method ......................................................... 87
Tonality Analysis 4/22/2013 07:00 – MassDEP Method ............................................................ 88
Tonality Analysis 4/22/2013 07:00 – ANSI S12.9 Method ......................................................... 88
Tonality Analysis 4/22/2013 13:00 – MassDEP Method ............................................................ 89
Tonality Analysis 4/22/2013 13:00 – ANSI S12.9 Method ......................................................... 89
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Hoosac Wind Sound Monitoring
1.
INTRODUCTION
Hoosac Wind is a recently constructed 28.5 MW wind farm owned by New England Wind, LLC, a
subsidiary of Iberdrola Renewables, LLC. Hoosac Wind is located in Florida and Monroe,
Massachusetts, just east of North Adams. Just after operations commenced in December 2012,
complaints were received from some residents surrounding the project.
RSG was retained by New England Wind, LLC to conduct sound level monitoring at six locations
near the facility. Included in this report are:
1)
2)
3)
4)
5)
6)
2.
A description of the project,
Introduction to the science of sound,
Description of the monitoring methodology,
Description of the monitoring locations,
Monitoring results, and
Conclusions.
PROJECT DESCRIPTION
The Hoosac Wind facility is located in northwestern Massachusetts, in the Berkshire Mountains.
There are 19 1.5 MW GE 1.5 sle turbines located on two different ridges. The turbines have 63
meter (207 feet) hub heights with rotor diameters of 77 meters (253 feet).
The northwestern group of 10 turbines is located on Bakke Mountain, with all turbines having base
elevations between 845 and 902 meters (2,770 and 2,960 feet respectively). The closest public
roads to these turbines are Bliss Road, located approximately 975 meters (3,200 feet) to the east
and East Road, located approximately 1,600 meters (1 mile) to the west. The southeastern group of
nine turbines is located on Crum Hill, with turbine base elevations between 843 and 926 meters
(2,775 and 3,040 feet respectively). The closest public roads are Tilda Hill Road, located
approximately 650 meters (2,130 feet) to the west; Moores Road, located approximately 580
meters (1,900 feet) to the southeast; and Massachusetts Route 2, located approximately 1,200
meters (3,940 feet) to the south.
Project development began in 2003 through the work of enXco. New England Wind, LLC continued
with project development and construction. The project commenced operation in December 2012.
A map of the project area is shown in Figure 1.
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Hoosac Wind Sound Monitoring
Figure 1: Hoosac Wind Site Map
3.
INTRODUCTION TO SOUND AND TERMINOLOGY
3.1 How is Sound Described?
Sound is caused by variations in air pressure at a range of frequencies. Sound levels that are
detectable by human hearing are defined in the decibel (dB) scale, with 0 dB being the approximate
threshold of human hearing, and 135 dB causing pain and permanent damage to the ear. Figure 2
shows the sound levels of typical activities that generate noise.
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Hoosac Wind Sound Monitoring
Figure 2: Common Sounds in A-weighted Decibels
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Hoosac Wind Sound Monitoring
The decibel scale can be weighted to mimic the human perception of certain frequencies. The most
common of these weighting scales is the “A” weighting. It is used most frequently in environmental
noise analyses. Sound levels that are weighted by the “A” scale have units of dBA or dB(A).
3.2 How is Sound Modeled?
The decibel sound level is described on a logarithmic scale. For every 10 dB increase in sound
pressure, we perceive an approximate doubling of loudness. Small changes in sound level, below 3
dB, are generally not perceptible.
For a point source, sound level diminishes or attenuates by 6 dB for every doubling of distance due
to geometrical divergence. For example, if an idling truck is measured at 50 meters as 66 dBA, at
100 meters the level will decline to 60 dBA, and at 200 meters, 54 dBA, assuming no other
influences. From a line source, like a gas pipeline or from closely spaced point sources, like a
roadway or string of wind turbines, sound attenuates at approximately 3 dB per of doubling
distance. These “line sources” transition to an attenuation of 6 dB per doubling at a distance of
roughly a third of the length of the line source.
Other factors, such as intervening vegetation, terrain, walls, berms, buildings, and atmospheric
absorption will also further reduce the sound level reaching the listener. In each of these, higher
frequencies will attenuate faster than lower frequencies. Finally, the ground can also have an
impact on sound levels. Harder ground generally increases and softer ground generally decreases
the sound level at a receiver. Reflections off of buildings and walls can increase broadband sound
levels by as much as 3 dB.
If we add two equal sources together, the resulting sound level will be 3 dB higher. For example, if
one machine registers 76 dBA at 50 meters, two co-located machines would register 3 dB more, or
79 dBA at that distance. In a similar manner, at a distance of 50 meters, four machines, all operating
at the same place and time, would register 82 dBA and eight machines would register 85 dBA.
In adding two sound levels, 0 to 3 dB is added to the higher level as shown in Table 1. Subtracting
sound levels follow the same principles as addition.
Table 1: Decibel Addition 1
If Two Sources Differ By
0-1 dB
2-4 dB
5-9 dB
>9 dB
1
Add
3 dB
2 dB
1 dB
0 dB
𝐿𝑝 (𝑂𝑣𝑒𝑟𝑎𝑙𝑙) = 10 × log ∑𝑛𝑖=1 10
𝐿𝑝𝑖
�10
where 𝐿𝑝 (𝑂𝑣𝑒𝑟𝑎𝑙𝑙) is the overall sound pressure level from the summation of
multiple sources and 𝐿𝑝𝑖 is the individual sound pressure levels that are being summed.
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Hoosac Wind Sound Monitoring
If there are two co-located machines of equal sound power level and one is turned off, sound levels
will decrease by 3 dB. Similarly, if there are two co-located machines that differ in sound power
level by between 5 and 9 dB, and the quieter machine is turned off, the overall sound level will
decrease by 1 dB.
3.3 Description of Terms
Sound can be measured in many different ways. Perhaps the simplest way is to take an
instantaneous measurement, which gives the sound pressure level at an exact moment in time. The
level reading could be 62 dB, but a second later it could 57 dB. Sound pressure levels are constantly
changing. It is for this reason that it makes sense to describe sound levels over time.
Take as an example, the sound levels measured over time shown in Figure 3. Instantaneous
measurements are shown as a ragged grey line. The sound levels that occur over this time can be
described verbally, but it is much easier to describe the recorded levels statistically. This is done
using a variety of “levels” which are described below.
3.3.1 Lmin and Lmax
Lmin and Lmax are simply the minimum and maximum sound level, respectively, monitored over a
period of time.
3.3.2 Percentile Sound Level - Ln
Ln is the sound level exceeded n percent of the time. This type of statistical sound level, also shown
in Figure 3, gives us information about the distribution of sound levels. For example, the L10 is the
sound level that is exceeded 10 percent of the time, while the L90 is the sound level exceeded 90%
of the time. The L50 is the median and is exceeded half the time. The L90 is often described as the
“residual” level, describing a condition when most short-term contaminating sources are removed.
Massachusetts Department of Environmental Protection (MassDEP) terms the L90 the “ambient”
level, which they define as the 90th percentile level in the absence of the source of interest.
3.3.3 Equivalent Average Sound Level - Leq
One of the most common ways of describing noise levels is in terms of the continuous equivalent
sound level (Leq). The Leq is the average of the sound pressure over an entire monitoring period
and expressed as a decibel:
1
2 (𝑡)𝑑𝑡
𝑇 𝑝𝐴
𝐿𝑒𝑞𝑇 = 10 ∗ 𝑙𝑜𝑔10 � ∫𝜃
𝑇
� 2�
𝑝0
where 𝑝02 is the squared instantaneous weighted sound pressure signal, as a function of elapsed
time t, p0 is the reference pressure of 20µPa, and T is the stated time interval.
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Hoosac Wind Sound Monitoring
The monitoring period, T, can be for any amount of time. It could be one second (Leq 1-sec), one hour
(Leq(1)), or 24 hours (Leq(24)). Because Leq is a logarithmic function of the average pressure, loud
and infrequent sounds have a greater effect on the resulting Leq than quieter and more frequent
sounds. For example, in Figure 3, the L50 (median) is about 47 dB, but the Leq is 53 dB. Because it
tends to weight the higher sound levels and is representative of sound that takes place over time,
the Leq is the most commonly used descriptor in noise standards and regulations.
Figure 3: Example of Descriptive Terms of Sound Measurement over Time
4.
MONITORING METHODOLOGY
The goal of the sound monitoring at the Hoosac Wind facility was to measure sound levels when the
turbines were operating, and compare them to sound levels from when the turbines were not
operating.
As part of the methodology, sound levels were measured immediately before and/or after short
periods when the turbines were manually shut down. These shut-down periods are referred to in
the report as “curtailment” or “ambient” periods.
The monitoring protocol was developed in cooperation with and approval by MassDEP. Further
details on the monitoring methodology are shown below.
4.1 Monitoring Equipment
Sound level monitoring equipment was installed between March 26 and March 29 at six locations,
as shown in Figure 1. Two of these locations (on East Road) were intended to monitor sound
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Hoosac Wind Sound Monitoring
emissions from the Bakke Mountain turbines and the other four (on Tilda Hill and Moores Road)
were intended to monitor sound emissions from the Crum Hill turbines. MassDEP toured each
setup on April 1, prior to the first monitoring session, and approved the equipment and locations.
All meters were ANSI/IEC Type 1 sound level meters that logged A-weighted slow response sound
levels and 1/3 octave band sound levels once each second. Sound level meters were also equipped
with digital sound recorders, to assist in source identification. Each sound level meter and
microphone was calibrated at an ISO 17025 and/or ANSI Z-540-1 traceable calibration laboratory
within the past two years. In addition, each sound level meter/microphone combination was field
calibrated prior to, during, and after field measurements using either a B&K 4231 or Larson Davis
Cal200 Class 1 sound calibrator. Microphones were equipped with 7-inch ACO Pacific hydrophobic
wind screens and were mounted approximately 1.5 meters above ground level. Anemometers were
set up at four representative locations. A monitoring equipment summary is shown in Table 2.
Table 2: Monitoring Equipment Summary
Monitoring Location
East Rd N
East Rd S
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Sound Level Meter
Cesva SC 310
Larson Davis LD 824
Larson Davis LD 831
Larson Davis LD 831
Larson Davis LD 831
Larson Davis LD 824
Digital Sound Recorder
Edirol R-09HR
Edirol R-05
Edirol R-09HR
Edirol R-09HR
Edirol R-09HR
Edirol R-05
Anemometer?
Yes
Yes
Yes
No
No
Yes
4.2 Monitoring Methodology
Determining the “ambient” 2 sound levels without wind turbine sound in the vicinity of a wind
power project can be challenging. In this case, the ambient was determined by shutting down
(“curtailing”) the seven wind turbines closest to each sound level meter for 15 minutes during a
series of specific meteorological conditions. These were Turbines 3 to 10 on Bakke Mountain and
Turbines 12 to 20 on Crum Hill.
The eight ideal curtailment conditions were determined in advance in consultation with MassDEP.
These are shown in Table 3. Both day and night conditions were targeted, where night was defined
from 10 pm to 7 am. In addition, monitoring was desired during both low wind speeds near the
turbine cut-in and high wind speeds where the turbine acoustic emissions were at a maximum.
In this report, “ambient” is defined by the Massachusetts DEP noise policy: “Ambient is defined as the
background A-weighted sound level that is exceeded 90% of the time measured during equipment operating
hours. The ambient may also be established by other means with the consent of the Department”. In this case,
it represents the period during which the turbines are not operating. The ambient level is assumed to be the
L90 statistic, unless otherwise defined by the MassDEP.
2
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Hoosac Wind Sound Monitoring
Every morning, Iberdrola Renewables meteorologists would provide RSG with daily and five-day
forecasts of precipitation, hub-height wind speed, and wind direction, with a discussion of
uncertainty and other potential mitigating conditions. The MassDEP were updated daily of the
forecasts, as well. If the forecasts showed that the proper conditions were likely to be met, in
consultation with the MassDEP, an unattended or attended monitoring session would be scheduled.
In an unattended session, the appropriate turbines would be shut down for 15 minutes, while the
continuous logging sound level meters recorded the sound levels before, during, and after the
curtailment. In an attended session, RSG staff would arrive on site, and then conduct manual logging
of sound levels and observations using the installed monitoring equipment. MassDEP staff observed
two of these attended sessions, on April 4 and April 10. Both monitoring types are further described
in the next two sections of this report.
A total of 13 monitoring sessions were conducted between April 3 and April 22, 2013- six around
the Bakke Mountain turbines and seven around the Crum Hill turbines. Five were attended (three
at Crum Hill and two at Bakke Mountain) and the remainder were only unattended. In all, the
monitoring represented 70 unattended 15-minute observations of wind turbine sound and 35 15minute ambient periods during curtailments. Of these, 14 of the wind turbine monitoring periods
were also attended.
Table 3: Curtailment Period Ideal Meteorological Parameters
Parameter
Wind Direction Range
Low Wind
Wind Speeds
High Wind
Times of Day
Location
Bakke
SE to NE
3-6 m/s
9-11 m/s
Day and Night
Crum
W to NW
3-6 m/s
9-11 m/s
Day and Night
4.2.1 Attended Monitoring
During attended monitoring RSG staff observed sound levels measured by the installed sound level
meters for a period of 15-minutes either before or after a turbine curtailment period. During this
period (the Wind Turbine (WT) + Background period), A-weighted, slow-response 3 sound levels
(LAS) were written down every five seconds. Notes were also made whether wind turbine noise
was clearly discernible and whether or not there were contaminating sound sources present (such
as birds, wind-caused sound, dogs, cars, etc.). This is consistent with ANSI S12.9 Part 2, 4 which
Slow response is a meter setting that provides an exponential time constant of 1 second to the sound level
reading. In discussion of the monitoring protocol for this project, the MassDEP requested that the slow
response setting be used.
3
ANSI S12.9 Part 2, “Quantities and Procedures for Description and Measurement of Environmental Sound.
Part 2: Measurement of long-term, wide-area sound,” American National Standards Institute, 2003
4
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Hoosac Wind Sound Monitoring
states, “one must ensure that the acoustical measurements include virtually all of the sound
produced by the source under study without including significant sound from any other sources.”
During the curtailment period (the Ambient period), sound levels were observed using the same
method. This method was intended to be similar to the methodology used in sound monitoring
conducted by MassDEP at the Fairhaven Wind project.
During each of the attended monitoring periods, the sound level meters were continuously logging
sound levels every second, and the sound was also being recorded. As such, the attended sessions
could also be evaluated using the unattended methodology, discussed in the next section of this
report.
Afterwards, various acoustical parameters were evaluated for both Ambient and WT+Background
periods. This includes the following:
•
•
•
•
•
L90 – the A-weighted sound level that was exceeded 90% of the time
Leq – the equivalent average A-weighted sound level
Lmax - The WT+Background period was divided into three five minute sections. Each 5second measurement during these sections were then filtered to include only those
measurements where the wind turbines were observed to be distinct above the ambient
sound, and there were no contaminating events (such as car, dog, chainsaw, wind gusts)
other than the residual sounds (background wind or similar general background). To
obtain the Lmax, the maxima of these filtered A-weighted sound levels for each 5-minute
section were calculated.
Lmax (average)- the three 5-minute Lmax sections are arithmetically averaged
Lmax minus Ambient L90 – the Lmax (average) during the period when the turbines are
operating minus the ambient L90 when the turbines are not operating
4.2.2 Unattended Monitoring
Since sound level meters were continuously operating, they were able to capture sound levels
without staff being present. As mentioned above, several periods were monitored using this
method. The methodology for conducting and evaluating the unattended data was intended to
mimic the attended method.
For each curtailment period as well as 15 minutes before and after that period, every fifth onesecond LAS reading was extracted from the data set. For each of these five-second sound levels, the
sources of sound present in the recording were identified and noted, as well as whether wind
turbine sound was clearly discernible, during periods when they were operating. Spectrograms
were used to supplement recordings for source identification, and in the few cases where sound
recordings were not available, spectrograms were solely used. An example spectrogram is shown
in Figure 4.
After sound sources were identified, the LA90 was calculated for the ambient period and the average
of the turbine-prominent maxima from each of the 5-minute periods was calculated. Unlike the
attended method, the WT+Background data was analyzed for both 15-minute periods before and
after the curtailment period.
9
Hoosac Wind Sound Monitoring
Figure 4: Example Spectrogram from the Tilda Hill S Site on 4/10/2013 at 5:00
4.2.3 Other data collection
During the monitoring period, the Hoosac Wind facility collected both meteorological and turbine
data. These data are used in identifying the precise conditions during the each monitoring period
and for further review of conditions that affect the level of sound from the project.
The project SCADA system automatically collected turbine information, which included power
output in kW, wind speed, wind direction, and RPM.
The project operates two 60-meter meteorological towers – one on Bakke Mountain and the other
on Crum Hill. Both towers collect wind speed and wind direction. Because they are not affected by
turbulence around the turbine towers, they are considered the most representative of actual wind
speed and direction. The met tower locations are shown in Figure 1.
5.
MONITORING LOCATIONS
Six monitoring locations were chosen in the area around the wind project, as shown in Figure 1.
Locations were identified and sited in consultation with Iberdrola Renewables and MassDEP, to be
representative of past complainants. Two monitors were located west of the Bakke Hill turbines,
along East Road, two were located west of the Crum Hill turbines along Tilda Hill Road, and two
were located east/southeast of the Crum Hill Turbines along Moores Road. The GPS locations of the
monitors, along with the distance from each monitor to the closest turbine are shown in Table 4.
10
Hoosac Wind Sound Monitoring
Table 4: Monitoring Location Information
Monitor ID
East Rd N
East Rd S
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Monitor Location
818 East Road
742 East Road
Laydown Area
72 Tilda Hill Road
88 Moores Road
33 Moores Road
Coordinates
(NAD83 UTM Z18N)
X (m)
Y (m)
658,569
658,331
661,088
661,255
662,537
662,124
4,733,061
4,732,746
4,731,292
4,729,837
4,729,647
4,729,026
Closest
Turbine
T10
T10
T13
T19
T20
T20
Closest
Turbine
Distance
(m)
1,530
1,678
794
736
570
786
Closest
Turbine
Distance
(ft)
5,018
5,504
2,606
2,416
1,869
2,579
5.1 East Road North
The East Road North sound monitor was located at 818 East Road approximately 375 meters east
of East Road and approximately 590 meters east-southeast from intersection between East Road
and Henderson Road. The monitor was set up approximately 30 meters east of the landowner’s
residence in a wooded area with little undergrowth. A map showing the monitoring location is
shown in Figure 5 and a picture of the monitoring setup is shown in Figure 6.
Background sounds observed at this location include car passbys on East Road, foliage, a stream
located to the south, occasional airplane overflights, the landowner’s dogs, and biogenic sound such
as insects and birds. Wind turbine noise was infrequently discernible during the individual
monitoring periods.
As with each of the monitoring locations, snow was present on the ground at the beginning of the
monitoring period, and by the middle of April, most sites had bare ground. The exception was The
Tilda Hill North location, where snow was present at monitor pickup on April 30th.
11
Hoosac Wind Sound Monitoring
Figure 5: East Road North and South Monitoring Locations
12
Hoosac Wind Sound Monitoring
Figure 6: East Road North Monitoring Setup
5.2 East Road South
The East Road South monitor was located at 642 East Road, approximately 30 meters east of East
Road and 540 meters southeast of the intersection between East Road and Henderson Road. The
monitor was set up approximately 15 meters east of the landowner’s residence in an open area. The
monitor had an open view to turbines to the north and the remaining Bakke Mountain turbines
were visible through a single small evergreen tree to the south.
A map showing the monitoring location is shown in Figure 5 and a picture of the monitoring setup
is shown in Figure 7. Major sound sources at this location were car passbys on East Road, foliage,
occasional airplane overflights, and biogenic sounds such as insects and birds. Wind turbine noise
was sometimes discernible.
13
Hoosac Wind Sound Monitoring
Figure 7: East Road South Monitoring Setup
5.3 Tilda Hill North
The Tilda Hill North sound monitoring site was located in the laydown area that was used for wind
farm construction. The laydown area was unused and unoccupied during the monitoring period.
The sound level meter was located approximately 120 meters north-northwest of the residence at
135 Tilda Hill Road and 85 meters west of Tilda Hill Road on the edge of the clearing for the
laydown area. A map showing the monitoring location is shown in Figure 8 and a picture of the
monitoring setup is shown in Figure 9. Background sound sources identified at this location were
car passbys on Tilda Hill Road, wind through the foliage, occasional airplane overflights, and
biogenic sounds such as insects and birds. Wind turbine noise was frequently discernible at the
location.
14
Hoosac Wind Sound Monitoring
Figure 8: Tilda Hill North Monitoring Location
15
Hoosac Wind Sound Monitoring
Figure 9: Tilda Hill North Monitoring Setup
5.4 Tilda Hill South
The Tilda Hill South sound monitor was located at 72 Tilda Hill Road, approximately 70 meters east
of Tilda Hill Road, 1,050 meters north of the intersection between Tilda Hill Road and
Massachusetts Route 2, and 20 meters south of the landowner’s residence. A map showing the
monitoring location is shown in Figure 10 and a picture of the monitoring setup is shown in Figure
11. Major sound sources at this location include car passbys on Tilda Hill Road, foliage, occasional
airplane overflights, the landowner operating his wood cutting equipment, and biogenic sounds
such as insects and birds. Wind turbine noise was frequently discernible and sometimes prominent
at this location.
16
Hoosac Wind Sound Monitoring
Figure 10: Tilda Hill South Monitoring Location
17
Hoosac Wind Sound Monitoring
Figure 11: Tilda Hill South Monitoring Setup
5.5 Moores North
The Moores North sound monitor was located at 88 Moores Road, approximately 14 meters east of
Moores Road, 1,650 meters north-northeast of the intersection between Moores Road and
Massachusetts Route 2, and 13 meters northwest of the landowner’s residence. A map showing the
monitoring location is shown in Figure 12 and a picture of the monitoring setup is shown in Figure
13. Sound sources identified at this location include wind through the foliage, the landowner’s dog,
occasional airplane overflights, the landowner’s family moving throughout the yard, and biogenic
sounds such as insects and birds. Wind turbine noise was frequently discernible at this location.
18
Hoosac Wind Sound Monitoring
Figure 12: Moores Road Monitoring Locations
19
Hoosac Wind Sound Monitoring
Figure 13: Moores North Monitoring Setup
5.6 Moores South
The Moores South sound monitor was located at 88 Moores Road, approximately 170 meters
northwest of Moores Road, 950 meters north of the intersection between Moores Road and
Massachusetts Route 2, and 30 meters northwest of the landowner’s residence. A map showing the
monitoring location is shown in Figure 12 and a picture of the monitoring setup is shown in Figure
14. Major sound sources identified at this location included wind through the foliage, the
landowner’s dog, occasional airplane overflights, the landowner’s family moving throughout the
yard, and biogenic sounds such as insects and birds. Wind turbine noise was frequently discernible
at this location.
20
Hoosac Wind Sound Monitoring
Figure 14: Moores South Monitoring Setup
21
Hoosac Wind Sound Monitoring
6.
MONITORING RESULTS
6.1 Monitoring Periods
Monitoring results are summarized in this section for each monitoring time period, in the order
that they occurred. Table 5 summarizes the date and time of the curtailments, the type of
monitoring, the turbines curtailed, and the wind speed and direction as recorded at the closest
project met tower. When the Crum Hill turbines were curtailed, the monitoring data on the Tilda
Hill and Moores Road monitors were evaluated. When the Bakke Mountain turbines were curtailed,
the monitoring data on East Road was evaluated.
Following this, results are shown for each monitoring period in tabular and graphical form. Results
include the sound levels during the Ambient periods and the WT+Background periods before and
after the curtailments.
Sound level statistics include the overall Leq and L90, five-minute Lmax, Lmax average, Lmax minus
L90, average power output for the closest wind turbines and met tower meteorological data.
For the WT+Background periods, the Lmax includes only the periods where the wind turbines were
discernible without significant contaminating events above the residual sound. For the Ambient
periods, the Lmax includes all sound events.
Table 5: Curtailment Information
Curtailment
Date and Time
Turbines Curtailed
Type*
Time of Day
Met Tower
Wind Speed
and Direction
1
2
3
4
5
6
7
8
9
10
11
12
13
4/3/2013 13:20
4/3/2013 22:00
4/4/2013 10:30
4/5/2013 23:43
4/8/2013 14:15
4/10/2013 13:35
4/11/2013 07:33
4/15/2013 17:00
4/17/2013 07:21
4/18/2013 02:04
4/18/2013 11:00
4/22/2013 07:00
4/22/2013 13:00
Crum Hill (12-20)
Crum Hill (12-20)
Crum Hill (12-20)
Crum Hill (12-20)
Crum Hill (12-20)
Crum Hill (12-20)
Bakke (3-10)
Bakke (3-10)
Crum Hill (12-20)
Bakke (3-10)
Bakke (3-10)
Bakke (3-10)
Bakke (3-10)
A&U
U
U
A&U
U
A&U
U
U
U
A&U
U
U
A&U
Day
Night
Day
Night
Day
Day
Day
Day
Day
Night
Day
Night
Day
17 m/s WNW
16 m/s WNW
5 m/s WNW
9 m/s WNW
4 m/s WNW
5 m/s WNW
17 m/s ENE
5 m/s ESE
8 m/s WNW
8 m/s NNE
9 m/s SE
7 m/s E
8 m/s SEE
* A = Attended Monitoring, U = Unattended Monitoring
22
Hoosac Wind Sound Monitoring
6.1.1 Monitoring Period 1 – 4/3/2013 13:20
Monitoring Period 1 took place during the day during high-wind conditions and involved the Crum
Hill wind turbines (T12-T20) and respective monitoring locations. Figure 15 charts the sound levels
for each monitor when turbines were operating and when they were shut down. Overlain on each
chart is the 1-minute wind speed data from the Crum Hill met tower (labeled ‘met 2’ on Figure 1).
Table 6 displays the sound levels for each of the four monitoring locations for the attended method.
The Tilda Hill North and Moores South monitors were attended pre-curtailment, and the Tilda Hill
South and Moores North were attended after turbine startup.
Table 7 displays the sound levels for each of the four monitoring locations for the unattended
method.
Table 8 summarizes the meteorological and turbine data collected at the Crum Hill tower before,
during, and after the curtailments. The met data includes wind speed collected at 62 meters, wind
direction collected at 50 meters, and temperature. The turbine data includes the average singleturbine power output for the Crum Hill turbines.
23
Hoosac Wind Sound Monitoring
60
20
50
15
40
10
30
5
Sound Pressure Level (dBA)
0
20
50
15
40
10
Tilda Hill S
30
5
20
0
60
20
50
15
40
10
Moores N
30
5
20
60
0
20
50
15
40
10
Moores S
30
20
12:40:00
WT+Background
13:00:00
13:20:00
Ambient
13:40:00
WT+Background
14:00:00
14:20:00
60 m Wind Speed (m/s)
Tilda Hill N
20
60
5
0
14:40:00
Figure 15: Sound Levels during Monitoring Period 1 – 4/3/2013 13:20
24
Hoosac Wind Sound Monitoring
Table 6: Sound Levels – Monitoring Period 1, Attended Method – 4/3/2013 13:20
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax 3rd
5
minutes
Average
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
34.0
41.7
53.2
46.3
46.5
48.7
14.6
WT+Background Before Shutdown
34.9
38.8
40.0
35.6
38.6
38.1
4.0
Ambient
42.7
48.8
51.1
56.5
54.9
54.2
11.5
WT+Background After Startup
44.7
48.5
48.5
46.3
44.7
46.5
3.8
Ambient
36.6
41.2
49.2
49.1
47.1
48.5
11.9
WT+Background After Startup
42.0
43.7
46.6
46.0
46.4
46.3
9.7
Ambient
41.4
45.3
50.8
52.7
54.0
52.5
11.1
WT+Background Before Shutdown
41.9
47.0
nd
nd
nd
nd
nd
Location
Scenario
Tilda Hill N
Tilda Hill S
Moores N
Moores S
•
•
•
Lmax1, 2, and 3 represent the highest slow response five-second LAS readings reported during the first,
second, and third five-minute segments, respectively.
For WT+Background measurements, the Lmax includes only times when the wind turbines were
discernible and without significant contaminating sounds above the residual sounds.
“nd” indicates ‘not discernible’, i.e., corresponding to times when background sounds significantly masked
the wind turbines.
Table 7: Sound Levels – Monitoring Period 1, Unattended Method – 4/3/2013 13:20
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
33.9
43.1
51.5
46.6
53.3
50.5
16.6
WT+Background Before Shutdown
35.1
40.4
41.0
41.9
40.6
41.2
7.3
WT+Background After Startup
36.2
42.2
38.9
nd
39.0
39.0
5.0
Ambient
42.9
50.2
63.1
55.6
57.7
58.8
15.9
WT+Background Before Shutdown
41.4
46.2
43.4
nd.
nd
43.4
0.5
WT+Background After Startup
44.8
49.2
nd
nd
nd
nd
nd
Ambient
36.7
41.2
42.4
46.2
49.3
46.0
9.3
WT+Background Before Shutdown
40.7
43.5
42.8
44.1
42.8
43.2
6.5
WT+Background After Startup
42.0
43.9
42.8
45.2
44.0
44.0
7.3
Ambient
41.5
47.5
57.7
53.6
52.7
54.7
13.2
WT+Background Before Shutdown
42.2
48.2
41.2
nd
42.1
41.7
0.2
WT+Background After Startup
45.4
51.6
nd
nd
nd
nd
nd
Location
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Scenario
25
Hoosac Wind Sound Monitoring
Table 8: Weather Data - Monitoring Period 1 - 4/3/2013 13:20
Met Tower
62 meter
wind
speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Ambient
16.3
WT+Background Before Shutdown
14.2
WT+Background After Startup
18.2
Scenario
•
•
•
•
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
260
0
-4
257
1406
-4
257
1378
-4
The “Average Turbine Output (kW)” is the average output of the turbines that were curtailing over the
period when monitoring occurred.
The “Met Tower 60m Wind Speed (m/s)” is the average wind speed from the closest project met tower.
The “Met Tower 50m Wind Direction (degrees)” is the average wind direction from the closest project
met tower.
The “Temp (°C)” is the average temperature from the closest project met tower.
6.1.2 Monitoring Period 2 – 4/3/2013 22:00
Monitoring Period 2 took place during the night time during high-wind conditions and involved the
Crum Hill wind turbines (12-20) and respective monitor locations. Monitoring during this period
was unattended. Figure 16 charts the sound levels when the turbines were running and when they
were shut down. Table 9 displays the sound levels for each of the four monitor locations. Table 10
summarizes the meteorological data and turbine for the monitoring period.
26
Hoosac Wind Sound Monitoring
60
25
50
20
40
15
Sound Pressure Level (dBA)
10
20
60
5
25
50
20
40
15
Tilda Hill S
30
10
20
5
60
25
50
20
40
15
Moores N
30
10
20
60
5
25
50
20
40
15
Moores S
30
WT+Background
20
21:30:00
21:50:00
Ambient
22:10:00
WT+Background
22:30:00
60 m Wind Speed (m/s)
Tilda Hill N
30
10
5
22:50:00
Figure 16: Sound Levels during Monitoring Period 2 – 4/3/2013 22:00
27
Hoosac Wind Sound Monitoring
Table 9: Sound Levels – Monitoring Period 2, Unattended Method – 4/3/2013 22:00
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax
1st 5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
37.1
42.0
42.9
47.6
53.2
47.9
10.8
WT+Background Before Shutdown
39.8
44.4
nd
nd
nd
nd
nd
WT+Background After Startup
39.8
46.9
nd
nd
nd
nd
nd
Ambient
44.9
48.8
52.8
56.3
55.1
54.7
9.8
WT+Background Before Shutdown
47.4
50.9
nd
nd
nd
nd
nd
WT+Background After Startup
48.4
51.2
nd
nd
49.3
49.3
4.4
Ambient
41.6
45.5
54.1
50.2
51.0
51.8
10.2
WT+Background Before Shutdown
44.9
47.3
nd
45.7
nd
45.7
4.1
WT+Background After Startup
44.8
46.8
45.5
nd
nd
45.5
3.9
Ambient
51.7
55.1
59.4
65.4
62.9
62.6
10.9
WT+Background Before Shutdown
51.9
55.6
nd
nd
nd
nd
nd
WT+Background After Startup
52.4
55.8
nd
nd
nd
nd
nd
Location
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Scenario
nd = wind turbines not discernible
Table 10: Weather Data - Monitoring Period 2 - 4/3/2013 22:00
Met
Tower 62
meter
wind
speed
(m/s)
Met
Tower 50
meter
Wind
Direction
(degrees)
Ambient
20.2
WT+Background Before Shutdown
22.5
WT+Background After Startup
21.8
Scenario
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
275
0
-7
274
1421
-7
272
1393
-7
28
Hoosac Wind Sound Monitoring
6.1.3 Monitoring Period 3 – 4/4/2013 10:30
Monitoring Period 3 took place during the day time during low-wind conditions and involved the
Crum Hill wind turbines (12-20) and respective monitor locations. This location was monitored
using the unattended method. Figure 17 charts the sound levels when the turbines were running
and when they were shut down. Table 11 displays the sound levels for each of the four monitor
locations. Table 12 summarizes the meteorological data and turbine for the monitoring period.
Note the wind speed dropped to as low as 4 m/s during the Ambient period, as compared with an
average of over 7 m/s when the wind turbines were operating.
29
Hoosac Wind Sound Monitoring
Tilda Hill N
20
50
15
40
10
30
5
20
60
0
20
Tilda Hill S
50
15
40
10
30
5
20
0
60
Moores N
20
50
15
40
10
30
5
20
60
0
20
Moores S
50
15
40
10
30
5
WT+Background
20
10:00:00
10:20:00
Ambient
10:40:00
WT+Background
11:00:00
60 m Wind Speed (m/s)
Sound Pressure Level (dBA)
60
0
11:20:00
Figure 17: Sound Levels during Monitoring Period 3 – 4/4/2013 10:30
30
Hoosac Wind Sound Monitoring
Table 11: Sound Levels – Monitoring Period 3, Unattended Method – 4/4/2013 10:30
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax
1st 5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
21.1
26.2
34.8
33.1
33.5
33.8
12.7
WT+Background Before Shutdown
27.8
30.2
30.9
30.6
31.1
30.9
9.8
WT+Background After Startup
27.2
30.2
34.3
34.0
30.8
33.0
11.9
Ambient
26.4
36.0
49.3
42.4
47.7
46.5
20.1
WT+Background Before Shutdown
35.2
40.0
40.9
37.8
40.7
39.8
13.4
WT+Background After Startup
36.9
38.9
39.9
39.5
39.7
39.7
13.3
Ambient
33.2
35.4
44.0
39.3
39.2
40.8
7.6
WT+Background Before Shutdown
37.1
40.2
40.7
39.7
43.6
41.3
8.1
WT+Background After Startup
37.5
39.3
41.7
41.1
42.2
41.7
8.5
Ambient
28.8
34.4
36.0
47.1
42.3
41.8
13.0
WT+Background Before Shutdown
33.2
37.1
nd
nd
nd
nd
nd
WT+Background After Startup
31.4
34.8
36.3
36.4
34.9
35.9
7.0
Location
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Scenario
nd = wind turbines not discernible
Table 12: Weather Data - Monitoring Period 3 - 4/4/2013 10:30
Met Tower
62 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Ambient
5.7
WT+Background Before Shutdown
7.2
WT+Background After Startup
7.5
Scenario
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
264
0
-3
262
360
-4
271
454
-3
6.1.4 Monitoring Period 4 – 4/5/2013 23:43
Monitoring Period 4 took place during the night time during high-wind conditions and involved the
Crum Hill wind turbines (12-20) and respective monitor locations. Figure 18 charts the sound
levels when the turbines were running and when they were shut down. Table 12 displays the sound
levels for two of the four monitoring locations for the attended method, Tilda Hill N and Moores S.
There was intermittent precipitation during the Ambient period, becoming more steady at the end
of the period.
Table 13 displays the sound levels for each of the four monitoring locations for the unattended
method. In this case, we evaluated the sound levels for the unattended method after turbine startup
for the intermittent periods when the patter of precipitation could not be heard on the audio
31
Hoosac Wind Sound Monitoring
recordings. Table 15 summarizes the meteorological data and turbine for the monitoring period.
While the average wind speed difference between the Ambient and WT+Background periods is
about 1 m/s, the lowest wind speed during Ambient was about 4 m/s below the average when the
wind turbines were in operation.
Tilda Hill N
20
50
15
40
10
30
5
20
60
0
20
Tilda Hill S
50
15
40
10
30
5
20
0
60
Moores N
20
50
15
40
10
30
5
20
60
0
20
Moores S
50
15
40
10
30
5
WT+Background
20
23:20:00
23:40:00
Ambient
0:00:00
WT+Background
0:20:00
60 m Wind Speed (m/s)
Sound Pressure Level (dBA)
60
0
0:40:00
Figure 18: Sound Levels during Monitoring Period 4 – 4/5/2013 23:43
32
Hoosac Wind Sound Monitoring
Table 13: Sound Levels – Monitoring Period 4, Attended Method – 4/5/2013 23:43
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
37.3
44.1
54.3
55.3
53.0
54.2
16.9
WT+Background Before Shutdown
37.3
42.1
40.2
40.3
43.5
41.3
4.0
Ambient
34.3
40.3
49.0
49.2
49.0
49.1
14.8
WT+Background Before Shutdown
39.4
44.0
42.3
42.1
42.1
42.2
7.9
Location
Tilda Hill N
Moores S
Scenario
Table 14: Sound Levels – Monitoring Period 4, Unattended Method - 4/5/2013 23:43
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
36.8
43.7
54.7
48.9
49.7
51.1
14.3
WT+Background Before Shutdown
37.5
39.6
41.4
42.2
41.6
41.7
4.9
WT+Background After Startup
35.1
37.7
41.5
39.1
38.4
39.7
2.9
Ambient
33.2
39.5
42.4
46.9
52.9
47.4
14.2
WT+Background Before Shutdown
41.9
43.3
43.9
44.0
43.8
43.9
10.7
WT+Background After Startup
41.1
43.1
rain
43.2
42.8
43.0
9.8
Ambient
37.0
39.4
46.5
44.8
39.8
43.7
6.7
WT+Background Before Shutdown
43.8
44.8
nd
46.3
46.1
46.2
9.2
WT+Background After Startup
42.7
44.0
rain
44.9
47.8
46.4
9.3
Ambient
33.3
44.3
58.3
55.0
59.0
57.4
24.1
WT+Background Before Shutdown
39.5
44.9
42.4
41.0
43.6
42.3
9.0
WT+Background After Startup
39.3
44.6
43.2
42.8
42.0
42.7
9.4
Location
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Scenario
nd = wind turbines not discernible
Table 15: Weather Data - Monitoring Period 4 - 4/5/2013 23:43
Met Tower
62 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Ambient
11
WT+Background Before Shutdown
12
WT+Background After Startup
11
Scenario
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
294
0
-4
275
1123
-3
297
1097
-4
33
Hoosac Wind Sound Monitoring
6.1.5 Monitoring Period 5 – 4/8/2013 14:15
Monitoring Period 5 was unattended and took place during the day time during low-wind
conditions and involved the Crum Hill wind turbines (12-20) and respective monitoring locations.
The Moores South monitor did not record data due to a power failure.
Figure 19 charts the sound levels when the turbines were running and when they were shut down.
Table 16 displays the sound levels for each of the four monitoring locations. Table 17 summarizes
the meteorological data and turbine for the monitoring period.
34
Hoosac Wind Sound Monitoring
Tilda Hill N
Sound Pressure Level (dBA)
50
20
15
40
10
30
5
20
60
0
20
Tilda Hill S
50
15
40
10
30
5
20
0
60
Moores N
20
50
15
40
10
30
5
20
60
0
20
Moores S
50
15
40
10
30
5
WT+Background
20
13:50:00
14:10:00
Ambient
14:30:00
WT+Background
14:50:00
60 m Wind Speed (m/s)
60
0
15:10:00
Figure 19: Sound Levels during Monitoring Period 5 – 4/8/2013 14:15
35
Hoosac Wind Sound Monitoring
Table 16: Sound Levels – Monitoring Period 5, Unattended Method – 4/8/2013 14:15
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
19.7
23.8
31.0
32.6
29.4
31.0
11.3
WT+Background Before Shutdown
22.5
24.8
27.9
26.9
28.5
27.8
8.1
WT+Background After Startup
18.2
28.7
nd
nd
nd
nd
nd
Ambient
31.0
48.2
59.2
63.8
55.1
59.4
28.4
WT+Background Before Shutdown
33.7
55.7
nd
nd
nd
nd
nd
WT+Background After Startup
29.8
46.0
nd
nd
nd
nd
nd
Ambient
37.8
38.2
39.7
39.2
39.2
39.4
1.6
WT+Background Before Shutdown
38.3
41.1
40.7
40.1
40.6
40.5
2.7
WT+Background After Startup
38.0
39.5
nd
nd
nd
nd
nd
Ambient
pf
pf
pf
pf
pf
pf
pf
WT+Background Before Shutdown
pf
pf
pf
pf
pf
pf
pf
WT+Background After Startup
pf
pf
pf
pf
pf
pf
pf
Location
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Scenario
pf indicates no data from this monitor due to power failure
nd = wind turbines not discernible
Table 17: Weather Data - Monitoring Period 5 - 4/8/2013 14:15
Scenario
Met Tower
62 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
Ambient
3.3
299
0
9
WT+Background Before Shutdown
4.2
284
80
8
WT+Background After Startup
2.1
276
0
9
36
Hoosac Wind Sound Monitoring
6.1.6 Monitoring Period 6 – 4/10/2013 13:35
Monitoring Period 6 took place during the day time during low-wind conditions and involved the
Crum Hill wind turbines (12-20) and respective monitoring locations. Figure 20 charts the sound
levels when the turbines were running and when they were shut down. Table 18 displays the sound
levels for two of the four monitoring locations for the attended method. The Tilda Hill S and Moores
S monitors were attended pre-curtailment, However, the Tilda Hill N and Moores N were not
monitored because rain started during the ambient period. After the rain ceased wind speeds died
down to the point where the turbines stopped spinning, prohibiting completion of the attended
monitoring.
Table 19 displays the sound levels for the four monitoring locations for the unattended method.
Table 20 summarizes the meteorological and turbine data for the monitoring period.
37
Hoosac Wind Sound Monitoring
Tilda Hill N
Sound Pressure Level (dBA)
50
20
15
40
10
30
5
20
60
0
20
Tilda Hill S
50
15
40
10
30
5
20
0
60
Moores N
20
50
15
40
10
30
5
20
60
0
20
Moores S
50
15
40
10
30
5
20
13:10:00
WT+Background
13:30:00
Ambient
13:50:00
WT+Background
14:10:00
60 m Wind Speed (m/s)
60
0
14:30:00
Figure 20: Sound Levels during Monitoring Period 6 – 4/10/2013 13:35
38
Hoosac Wind Sound Monitoring
Table 18: Sound Levels – Monitoring Period 6, Attended Method – 4/10/2013 13:35
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Ambient
38.5
38.9
55.1
WT+Background Before Shutdown
38.3
38.8
nd
Ambient
27.6
35.4
WT+Background Before Shutdown
27.7
34.4
Location
Tilda Hill S
Moores S
Scenario
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
46.3
42.8
48.1
9.6
nd
nd
nd
nd
36.5
39.1
32.2
35.9
8.3
nd
nd
nd
nd
nd
nd = wind turbines not discernible
Table 19: Sound Levels – Monitoring Period 6, Unattended Method – 4/10/2013 13:35
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
24.2
26.4
37.3
27.8
27.1
30.7
6.5
WT+Background Before Shutdown
25.8
27.1
27.7
27.8
32.0
29.2
5.0
WT+Background After Startup
30.8
47.3
nd
nd
nd
nd
nd
Ambient
38.4
40.6
55.7
41.2
45.5
47.5
9.1
WT+Background Before Shutdown
38.4
43.5
nd
nd
nd
nd
nd
WT+Background After Startup
42.0
45.3
nd
nd
nd
nd
nd
Ambient
46.2
46.5
46.7
47.1
47.4
47.1
0.9
WT+Background Before Shutdown
46.2
46.4
nd
nd
nd
nd
nd
WT+Background After Startup
47.0
51.9
nd
nd
nd
nd
nd
Ambient
27.6
41.3
46.0
59.9
59.9
55.3
27.7
WT+Background Before Shutdown
27.4
31.2
nd
nd
29.0
29.0
1.4
WT+Background After Startup
30.2
35.8
36.5
35.2
nd
35.9
8.2
Location
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Scenario
nd = wind turbines not discernible
Table 20: Weather Data – Monitoring Period 6 - 4/10/2013 13:35
Met Tower
62 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Ambient
5.2
WT+Background Before Shutdown
5.6
WT+Background After Startup
6.3
Scenario
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
254
0
9
258
192
9
275
319
8
39
Hoosac Wind Sound Monitoring
6.1.7 Monitoring Period 7 – 4/11/2013 07:33
Monitoring Period 7 was unattended and took place during the day time during low wind
conditions and involved the Bakke wind turbines (3-10) and respective monitoring locations.
Figure 21 charts the sound levels when the turbines were running and when they were shut down.
Table 21 displays the sound levels for the two monitoring locations for the unattended method.
Table 22 summarizes the meteorological and turbine data for the monitoring period.
In these charts and tables representing results at East Hill Road, the meteorological data is from the
Bakke met tower, labeled ‘met 1’ in Figure 1. The turbine output data is from the seven most
southern turbines on the Bakke Mountain string, T4 through T10.
East Rd N
20
50
15
40
10
30
5
20
60
0
20
East Rd S
50
15
40
10
30
5
20
7:00:00
WT+Background
7:20:00
Ambient
7:40:00
WT+Background
8:00:00
8:20:00
60 m Wind Speed (m/s)
Sound Pressure Level (dBA)
60
0
8:40:00
Figure 21: Sound Levels during Monitoring Period 7 – 4/11/2013 7:33
40
Hoosac Wind Sound Monitoring
Table 21: Sound Levels – Monitoring Period 7, Unattended Method – 4/11/2013 7:33
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
46.8
47.2
47.5
50.2
47.2
48.3
1.5
WT+Background Before Shutdown
47.0
47.0
nd
nd
nd
nd
nd
WT+Background After Startup
46.8
46.9
nd
nd
nd
nd
nd
Ambient
36.7
48.7
68.3
45.5
62.6
58.8
22.1
WT+Background Before Shutdown
36.7
39.7
nd
nd
nd
nd
nd
WT+Background After Startup
36.9
41.5
nd
nd
nd
nd
nd
Location
East Rd N
East Rd S
Scenario
nd = wind turbines not discernible
Table 22: Weather Data - Monitoring Period 7 - 4/11/2013 7:33
Met Tower
65 meter
wind
speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Ambient
2.5
WT+Background Before Shutdown
4.4
WT+Background After Startup
3.3
Scenario
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
351
0
3
311
55
3
7
-5
2
41
Hoosac Wind Sound Monitoring
6.1.8 Monitoring Period 8 – 4/15/2013 17:00
Monitoring Period 8 took place during the day time during low-wind conditions and involved the
Bakke Hill wind turbines (3-10) and respective unattended monitoring locations. Figure 22 charts
the sound levels when the turbines were running and when they were shut down. Table 23 displays
the sound levels for the two monitoring locations for the unattended method. Table 24 summarizes
the meteorological and turbine data for the monitoring period.
20
East Rd N
50
15
40
10
30
5
20
60
0
20
East Rd S
50
15
40
10
30
5
20
16:30:00
WT+Background
Ambient
16:50:00
WT+Background
17:10:00
17:30:00
60 m Wind Speed (m/s)
Sound Pressure Level (dBA)
60
0
17:50:00
Figure 22: Sound Levels during Monitoring Period 8 – 4/15/2013 17:00
Table 23: Sound Levels – Monitoring Period 8, Unattended Method – 4/15/2013 17:00
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
40.2
40.7
41.5
41.7
42.4
41.9
1.7
WT+Background Before Shutdown
40.1
40.7
nd
nd
nd
nd
nd
WT+Background After Startup
40.6
41.6
nd
nd
nd
nd
nd
Ambient
32.7
37.6
45.2
48.8
44.4
46.1
13.4
WT+Background Before Shutdown
33.7
38.1
nd
nd
nd
nd
nd
WT+Background After Startup
32.7
38.2
nd
nd
nd
nd
nd
Location
East Rd N
East Rd S
Scenario
nd = wind turbines not discernible
42
Hoosac Wind Sound Monitoring
Table 24: Weather Data - Monitoring Period 8 - 4/15/2013 17:00
Met Tower
65 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
Ambient
5.1
131
0
9
WT+Background Before Shutdown
5.9
121
102
9
WT+Background After Startup
4.5
143
66
9
Scenario
43
Hoosac Wind Sound Monitoring
6.1.9 Monitoring Period 9 – 4/17/2013 07:21
Monitoring Period 9 took place during the day time during high-wind conditions and involved the
Crum Hill wind turbines (12-20) and respective unattended monitoring locations. The Tilda Hill
North monitor failed to collect data due to equipment failure. The monitor case shifted due to
melting snow which disconnected a cable. Figure 23 charts the sound levels when the turbines
were running and when they were shut down. At Tilda Hill S a nearby idling vehicle at the end of
the Ambient period and during WT+Background period after shutdown, raised sound levels high
enough that they are above the chart range. Table 25 displays the sound levels for each of the four
monitoring locations for the unattended method. Table 26 summarizes the meteorological and
turbine data for the monitoring period.
44
Hoosac Wind Sound Monitoring
50
Sound Pressure Level (dBA)
20
Tilda Hill N
15
40
10
30
5
20
60
0
20
Tilda Hill S
50
15
40
10
30
5
20
0
60
20
Moores N
50
15
40
10
30
5
20
60
0
20
Moores S
50
15
40
10
30
5
20
6:50:00
WT+Background
7:10:00
Ambient
7:30:00
60 m Wind Speed (m/s)
60
WT+Background
7:50:00
Figure 23: Sound Levels during Monitoring Period 9 – 4/17/2013 7:21
0
8:10:00
45
Hoosac Wind Sound Monitoring
Table 25: Sound Levels – Monitoring Period 9, Unattended Method – 4/17/2013 7:21
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax
1st 5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
ef
ef
ef
ef
ef
ef
ef
WT+Background Before Shutdown
ef
ef
ef
ef
ef
ef
ef
WT+Background After Startup
ef
ef
ef
ef
ef
ef
ef
Ambient
40.2
61.2
50.8
65.6
67.7
61.4
21.2
WT+Background Before Shutdown
43.0
45.3
45.5
47.2
46.7
46.5
6.3
WT+Background After Startup
64.4
70.3
nd
nd
nd
nd
nd
Ambient
44.5
44.8
45.2
47.0
46.6
46.3
1.8
WT+Background Before Shutdown
46.2
46.6
47.9
47.1
47.3
47.4
2.9
WT+Background After Startup
45.6
60.5
47.3
48.0
48.9
48.1
3.6
Ambient
28.8
31.4
39.4
39.1
33.7
37.4
8.6
WT+Background Before Shutdown
35.2
41.2
38.8
38.2
38.4
38.5
9.7
WT+Background After Startup
34.2
38.3
38.7
37.5
38.9
38.4
9.6
Location
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Scenario
ef = sound level monitoring equipment failure
nd = wind turbines not discernible
Table 26: Weather Data - Monitoring Period 9 – 4/17/2013 7:21
Met Tower
62 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Ambient
9.2
WT+Background Before Shutdown
9.8
WT+Background After Startup
8.9
Scenario
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
295
0
2
298
751
2
297
548
2
46
Hoosac Wind Sound Monitoring
6.1.10 Monitoring Period 10 – 4/18/2013 02:04
Monitoring Period 10 took place during the night time during high-wind conditions and involved
the Bakke Hill wind turbines (3-10) and respective monitor locations. Figure 24 charts the sound
levels when the turbines were running and when they were shut down. Table 27 displays the sound
levels for the two monitoring locations for the attended method. The East Road North monitor was
attended before and during curtailment, while the East Road South monitor was attended during
curtailment and after the turbines were restarted. Table 28 displays the sound levels the two
monitoring locations for the unattended method. Table 29 summarizes the meteorological and
turbine data for the monitoring period.
20
East Rd N
50
15
40
10
30
5
20
60
0
20
East Rd S
50
15
40
10
30
5
WT+Background
20
2:00:00
2:20:00
Ambient
2:40:00
WT+Background
3:20:00
3:00:00
Figure 24: Sound Levels during Monitoring Period 10 – 4/18/2013 2:04
60 m Wind Speed (m/s)
Sound Pressure Level (dBA)
60
0
3:40:00
Table 27: Sound Levels – Monitoring Period 10, Attended Method – 4/18/2013 2:04
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
44.2
44.5
44.9
44.8
45.0
44.9
0.7
WT+Background Before Shutdown
44.7
45.0
nd
nd
nd
nd
nd
Ambient
36.7
36.6
50.2
37.8
43.3
43.8
7.1
WT+Background After Startup
38.0
38.1
40.0
39.8
49.4
43.1
6.4
Location
East Rd N
East Rd S
Scenario
nd = wind turbines not discernible
47
Hoosac Wind Sound Monitoring
Table 28: Sound Levels – Monitoring Period 10, Unattended Method – 4/18/2013 2:04
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax
1st 5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
44.2
44.6
45.9
44.8
51.3
47.3
3.0
WT+Background Before Shutdown
44.9
45.1
nd
nd
nd
nd
nd
WT+Background After Startup
44.6
44.8
nd
nd
nd
nd
nd
Ambient
37.2
37.8
38.4
42.0
38.4
39.6
2.4
WT+Background Before Shutdown
38.1
39.8
40.4
39.9
40.2
40.2
3.0
WT+Background After Startup
37.1
38.1
42.3
38.5
39.6
40.1
2.9
Location
East Rd N
East Rd S
Scenario
nd = wind turbines not discernible
Table 29: Weather Data - Monitoring Period 10 - 4/18/2013 2:04
Met Tower
65 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
Ambient
9.6
100
0
3
WT+Background Before Shutdown
8.6
101
712
3
WT+Background After Startup
9.1
101
862
3
Scenario
6.1.11 Monitoring Period 11 – 4/18/2013 11:00
Monitoring Period 11 took place during the day time during low wind conditions and involved the
Bakke Hill wind turbines (3-10) and respective monitoring locations. Unattended monitoring took
place during this period. Figure 25 charts the sound levels when the turbines were running and
when they were shut down. Table 30 displays the sound levels for the two monitoring locations.
Table 31 summarizes the meteorological and turbine data for the monitoring period.
48
Hoosac Wind Sound Monitoring
20
East Rd N
50
15
40
10
30
5
20
60
0
20
East Rd S
50
15
40
10
30
5
20
11:00:00
WT+Background
Ambient
11:20:00
WT+Background
11:40:00
12:00:00
Figure 25: Sound Levels during Monitoring Period 11 – 4/18/2013 11:00
60 m Wind Speed (m/s)
Sound Pressure Level (dBA)
60
0
12:20:00
Table 30: Sound Levels – Monitoring Period 11, Unattended Method – 4/18/2013 11:00
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax
1st 5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
42.7
43.2
43.6
46.2
43.8
44.5
1.8
WT+Background Before Shutdown
43.2
43.6
nd
nd
nd
nd
nd
WT+Background After Startup
43.2
43.9
nd
nd
nd
nd
nd
Ambient
35.4
41.1
53.1
58.4
48.2
53.2
17.8
WT+Background Before Shutdown
37.2
39.1
39.5
40.2
39.0
39.6
4.2
WT+Background After Startup
37.3
40.4
40.2
39.7
39.6
39.8
4.4
Location
East Rd N
East Rd S
Scenario
nd = wind turbines not discernible
Table 31: Weather Data - Monitoring Period 11 - 4/18/2013 11:00
Met Tower
65 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Ambient
10.1
WT+Background Before Shutdown
9.4
WT+Background After Startup
9.7
Scenario
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
133
0
7
132
945
7
141
913
8
49
Hoosac Wind Sound Monitoring
6.1.12 Monitoring Period 12 – 4/22/2013 07:00
Monitoring Period 12 took place during the day time during high-wind conditions and involved the
Bakke Hill wind turbines (3-10) and respective monitoring locations. Unattended monitoring took
place during this period. Figure 26 charts the sound levels when the turbines were running and
when they were shut down. Table 32 displays the sound levels for the two monitoring locations.
Table 33 summarizes the meteorological and turbine data for the monitoring period.
20
East Rd N
50
15
40
10
30
5
20
60
0
20
East Rd S
50
15
40
10
30
5
20
6:30:00
WT+Background
Ambient
6:50:00
WT+Background
7:10:00
7:30:00
Figure 26: Sound Levels during Monitoring Period 12 – 4/22/2013 7:00
60 m Wind Speed (m/s)
Sound Pressure Level (dBA)
60
0
7:50:00
Table 32: Sound Levels – Monitoring Period 12, Unattended Method - 4/22/2013 7:00
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax
1st 5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
pf
pf
pf
pf
pf
pf
pf
WT+Background Before Shutdown
pf
pf
pf
pf
pf
pf
pf
WT+Background After Startup
pf
pf
pf
pf
pf
pf
pf
Ambient
33.0
37.6
49.3
44.5
40.9
44.9
11.9
WT+Background Before Shutdown
35.6
40.0
40.7
40.2
43.4
41.4
8.4
WT+Background After Startup
34.8
39.7
44.9
38.8
41.3
41.7
8.7
Location
East Rd N
East Rd S
Scenario
pf = power failure
50
Hoosac Wind Sound Monitoring
Table 33: Weather Data - Monitoring Period 12 - 4/22/2013 7:00
Met Tower
65 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Ambient
9.1
81
0
-2
WT+Background Before Shutdown
9.2
84
521
-2
WT+Background After Startup
8.8
88
469
-2
Scenario
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
51
Hoosac Wind Sound Monitoring
6.1.13 Monitoring Period 13 – 4/22/2013 13:00
Monitoring Period 13 took place during the day time during high-wind conditions and involved the
Bakke wind turbines (3-10) and respective monitoring locations. Figure 27 charts the sound levels
when the turbines were running and when they were shut down. Table 34 displays the sound levels
for the two monitoring locations for the attended method. The East Road South monitor was
attended before and during the turbine curtailment, while the East Road North was attended during
curtailment and after the turbines were restarted. Table 35 displays the sound levels for the two
monitoring locations for the unattended method. Table 36 summarizes the meteorological and
turbine data for the monitoring period.
20
East Rd N
50
15
40
10
30
5
20
60
0
20
East Rd S
50
15
40
10
30
5
WT+Background
20
12:40:00
13:00:00
Ambient
13:20:00
13:40:00
WT+Background
14:00:00
14:20:00
Figure 27: Sound Levels during Monitoring Period 13 – 4/22/2013 13:00
0
14:40:00
Table 34: Sound Levels – Monitoring Period 13, Attended Method – 4/22/2013 13:00
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
38.8
41.9
42.0
43.5
44.4
43.3
4.5
WT+Background After Startup
40.3
40.2
nd
nd
nd
nd
nd
Ambient
31.8
40.3
61.4
48.0
48.3
52.6
20.8
WT+Background Before Shutdown
36.1
38.4
40.6
40.2
38.8
39.9
8.1
Location
East Rd N
East Rd S
60 m Wind Speed (m/s)
Sound Pressure Level (dBA)
60
Scenario
nd = wind turbines not discernible
52
Hoosac Wind Sound Monitoring
Table 35: Sound Levels – Monitoring Period 13, Unattended Method - 4/22/2013 13:00
Unfiltered
Overall
L90
Unfiltered
Overall
Leq
Filtered
Lmax 1st
5
minutes
Filtered
Lmax
2nd 5
minutes
Filtered
Lmax
3rd 5
minutes
Avg
Filtered
Lmax
Lmax
minus
Ambient
L90
Ambient
38.9
43.8
63.7
43.9
45.0
50.9
12.0
WT+Background Before Shutdown
49.9
40.7
nd
nd
nd
nd
nd
WT+Background After Startup
40.4
42.4
nd
nd
nd
nd
nd
Ambient
32.5
40.1
47.5
51.4
51.5
50.1
17.6
WT+Background Before Shutdown
35.2
39.7
38.8
38.4
37.7
38.3
5.8
WT+Background After Startup
35.3
39.7
41.1
37.2
38.2
38.8
6.3
Location
East Rd N
East Rd S
Scenario
nd = wind turbines not discernible
Table 36: Weather Data - Monitoring Period 13 - 4/22/2013 13:00
Met Tower
65 meter
wind speed
(m/s)
Met Tower
50 meter
Wind
Direction
(degrees)
Ambient
10.0
WT+Background Before Shutdown
10.7
WT+Background After Startup
10.1
Scenario
Average
Turbine
Output
(kW per
turbine)
Temp
(°C)
117
0
6
117
888
5
115
887
6
53
Hoosac Wind Sound Monitoring
6.2 Tonality Analysis
Using the method described in the MassDEP policy, RSG conducted an analysis of each of the
monitoring periods for tonality. Analysis periods began with the pre-curtailment WT+Background
monitoring period and ended with the post-curtailment WT+Background monitoring period,
including only periods when the turbines were running and discernible, and there was no
significant contaminating sound above the residual sound.
The monitoring systems set up for this project logged 1/3 octave band sound levels each second
continuously. These logged values were then converted to 1/1 octave bands by logarithmically
adding the three 1/3 octave bands making up each octave band. Then, for each of the valid fivesecond measurements, each octave band was evaluated to determine whether its level exceeded
both adjacent octave bands (on the left and on the right) by more than 3 dB. This level at which the
individual band exceeds its adjacent bands is defined here as the prominence level.
The number of five-second readings that the wind turbine sound is considered tonal under the
MassDEP policy are shown in Table 37. Bird calls are excluded. Periods where tones also exist in
Ambient in the same frequencies as the wind turbine sound are noted with an asterisk. The tonal
analysis is shown in more detail in Appendix C.
Tonality was found at least once during the testing period at all monitoring locations, except East
Road North. Tones, when they existed, tended to occur in the 63 Hz or 125 Hz octave band. Figure
28 through Figure 30 show the arithmetic average spectrum over a 15-minute period after turbine
startup for Moores North and Tilda Hill North on April 4, 10:00 am, and East Rd South on April 18,
2:00 am, the three most tonal measurements.
In our professional opinion, the method described in the MassDEP policy is not effectively designed
to reflect the human perception of tonality. Analyses using full octave bands are not granular
enough to detect pure tones, and the flat 3 dB criteria used does not take into account the reduced
ability of the human ear to differentiate tones at lower frequencies. The MassDEP method was
established when monitoring equipment was not as refined as it is today, which made it difficult to
do a proper analysis of tonality. Better equipment now exist which can automatically log 1/3 octave
bands and narrowband sound levels. Improved tonality assessment methods take advantage of this
in the forms of new standards, such as ANSI S12.9 Part 3 Annex C, 5 ANSI S1.13 Annex A, 6 and IEC
American National Standards Institute, “Quantities and Procedures for Description and Measurement of
Environmental Sound. Part 3: Short-term measurements with an observer present,” ANSI/ASA S12.9 Part 3,
2008.
5
American National Standards Institute, “Measurement of Sound Pressure Levels in Air,” ANSI/ASA S1.13,
2010.
6
54
Hoosac Wind Sound Monitoring
61400-11. 7 The ANSI12.9 Part 3 standard uses 1/3 octave band sound levels and assess tonal
sound as a function of prominence above adjacent bands and the frequency of the prominent band.
The more accurate ANSI S1.13 and IEC 61400-11 methods uses narrowband data and evaluates
tonal audibility as a function of frequency and critical bandwidth.
Table 37: Tonality Analysis Results
Monitor
East Rd N
East Rd S
Bakke Turbines
Number of Filtered 5-second Samples Tonal - Wind Turbines Operating
4/11 7:00 4/15 17:00 4/18 2:00 4/18 11:00 4/22 7:00 4/22 13:00
0--0
0--0
0--0
0--0
0--0
pf
0--0
0--0
80--129
3--0
3--2
0--0
Monitor
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Crum Turbines
Number of Filtered 5-second Samples Tonal - Wind Turbines Operating
4/3 11:00 4/3 22:00 4/4 10:00 4/5 23:00 4/8 14:00 4/10 13:00 4/17 7:00
ef
0--1
0--0
18--20
1--1*
0--0
7--0
0--0
0--0
49--53
79--13
0--0
0--0
20--0
0--0
0--0
82--132
3--0
16--0*
0--0
5--3
pf
0--0
0--0
8--32
3--18*
0--13*
7--9
pf = power failure; ef = equipment failure;
xx--yy = number of 5-second tonal measurements before (xx) and after (yy) curtailment out of a potential 180
measurements;
* = Tonal sound is present in ambient
International Electrotechnical Commission, “Wind Turbines – Part 11: Acoustic measurement techniques,”
IEC 61400-11, 2012.
7
55
Hoosac Wind Sound Monitoring
Figure 28: Arithmetic Average Spectrum – WT+Background for Moores North 4/4/2013
10:00 After Startup
Figure 29: Arithmetic Average Spectrum – WT+Background for Tilda Hill North 4/4/2013
10:00 After Startup
56
Hoosac Wind Sound Monitoring
Figure 30: Arithmetic Average Spectrum – WT+Background for East Road South 4/18/2013
2:00 After Startup
As a refined analysis of tonal sound, we conducted an ANSI S12.9 Part 3 tonal analysis for all of the
monitoring periods. The first step in this method is to find prominence, that is, where one 1/3
octave band frequency rises above adjacent 1/3 octave bands. To be tonal, the prominence must be
greater than 15 dB for frequencies up to 125 Hz, 8 dB from 160 to 400 Hz, and 5 dB for higher
frequencies. This sliding scale reflects the reduced ability of the ear to differentiate tones at lower
frequencies.
In our re-evaluation using the ANSI S12.9 Part 3 definition, detailed in Appendix C, we found only
one brief period of tones likely caused by wind turbine noise. This occurred during eight fivesecond readings at Moores North on April 4. The remaining locations and periods where the
turbines emitted a tone under the MassDEP policy, were not considered tonal by the ANSI
definition due to a lack of tonal prominence.
57
Hoosac Wind Sound Monitoring
7.
COMPARISON WITH MODELING RESULTS
Sound level modeling for the project was completed by RSG using the International Standards
Organization ISO 9613-2 standard, “Acoustics – Attenuation of sound during propagation outdoors,
Part 2: General Method of Calculation.” The ISO standard states,
“This part of ISO 9613 specifies an engineering method for calculating the attenuation of
sound during propagation outdoors in order to predict the levels of environmental noise at
a distance from a variety of sources. The method predicts the equivalent continuous Aweighted sound pressure level … under meteorological conditions favorable to propagation
from sources of known sound emissions. These conditions are for downwind propagation …
or, equivalently, propagation under a well-developed moderate ground-based temperature
inversion, such as commonly occurs at night.”
The model takes into account source sound power levels, surface reflection and absorption,
atmospheric absorption, geometric divergence, meteorological conditions, walls, barriers, berms,
and terrain. The ISO standard was implemented in the Cadna A acoustical modeling software. Made
by Datakustik GmbH, Cadna A is an internationally accepted acoustical model, used by many other
noise control professionals in the United States and abroad.
Standard modeling methodology takes into account moderate nighttime inversions or moderate
downwind conditions. For this study, we modeled the sound propagation in accordance with ISO
9613-2 with spectral ground attenuation and mixed ground (G=0.5). The 2 dB K factor was added
to the manufacturer’s reported mean sound power level to reflect uncertainty.
The sound emissions provided by the manufacturer are equivalent average sound powers, with a
95% uncertainty factor, as described above. Manufacturers do not provide absolute Lmax sound
emissions. In addition, the ISO 9613-2 method is intended to calculate the equivalent average sound
pressure level and not an Lmax over time. Therefore, there is no current method available to
reliably forecast Lmax sound levels from wind turbines at a distance. As a result, in this section, we
will focus on evaluating longer term average sound levels.
Once the model is run, the next step is to determine what the appropriate monitored sound level is
at these locations. The monitored sound includes background sources that are not included in the
modeled levels. Ideally, the Leq from the WT+Background monitoring would be subtracted from
the Leq of the Ambient. However, this method cannot be used because of the significant variability
of the background sound level. Two alternative methods are therefore put forward. In the first, the
WT+Background Leq, filtered to exclude extraneous sound events, is subtracted from the Ambient
L90. This is an “apples to oranges” comparison as two different metrics are being used, and it will
most likely result in an overestimation of turbine sound levels. The second method is to subtract
WT+Background L90 from Ambient L90. In this case, the L90 is a good predictor of turbine sound,
since the turbine sound is generally constant, while the background sources tend to be very
variable.
58
Hoosac Wind Sound Monitoring
For comparison purposes, we present both methods, as shown in Table 38, Table 39, and Figure 31.
As shown levels at East Road could not be calculated as the difference between WT+Background
and Ambient L90s were consistently below 3 dB. On Tilda Hill and Moores Road, the model
accuracy was within 1 dB in both methods, with the exception of Tilda Hill North, where the model
over-predicted by 12 to 14 dB.
Table 38: Comparison of Monitoring Results with Modeling Results 8 using L90 minus L90
method
Monitoring
Location
East Road N
East Road S
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Maximum
Monitored
Turbine On
LA90
28
42
44
40
Ambient
LA90
21
33
37
33
Resulting
Maximum
Turbine Modeled
Only
Level
Difference
(dBA)
(dBA)
(dB)
36
34
27
41
-14
41
42
-1
43
43
0
38
39
-1
Table 39: Comparison of Monitoring Results with Modeling Results using Leq minus L90
method5
Monitoring
Location
East Road N
East Road S
Tilda Hill N
Tilda Hill S
Moores N
Moores S
Maximum
Monitored
Turbine On
Filtered
LAeq
30
43
43
41
Ambient
LA90
21
33
37
33
Resulting
Maximum
Turbine Modeled
Only
Level
Difference
(dBA)
(dBA)
(dB)
36
34
29
41
-12
42
42
0
42
43
-1
40
39
+1
The monitoring periods chosen for this analysis were high wind monitoring periods, with differences
between the turbine on and turbine off LA90s greater than 3 dB, and no 5-minute sub-periods where the
turbines were not discernible.
8
59
Hoosac Wind Sound Monitoring
Figure 31: Modeled sound levels compared to monitored sound levels
60
Hoosac Wind Sound Monitoring
8.
DISCUSSION OF MONITORING METHODOLOGY
One of the purposes of the study was to evaluate methods to measure both ambient sound levels
and wind turbine sound levels in order to make direct comparisons. We used both attended and
unattended sound monitoring to assess levels both immediately before a turbine shutdown, during
the shut-down, and after the turbines restarted.
We analyzed the unattended sound data during similar times as the attended data. However, they
may not have been exactly the same time, and thus there are generally small differences between
the two.
While the monitoring was overall successful in collecting data, it is worth pointing out significant
issues that we found:
•
•
It is difficult to forecast the specific meteorological conditions required. This is not so much
of an issue for unattended monitoring, since shut-downs are relatively easy. However,
attended monitoring requires advanced time to allocate staff, travel to the site, and set up.
In that time, meteorological conditions can change significantly. This is highlighted, for
example, by attended monitoring on the night of April 5, when, after the turbines were shut
down, an unexpected precipitation began. In another case on April 10, during a low-wind
condition, the turbines did not start back up after the shut-down, as wind speeds dropped
off below cut-in speed.
A benefit of the attended method is that sound monitoring equipment can be checked prior
to the measurements. While the monitors were operating at almost all of the monitoring
periods, we have sound level meter failures at three occasions during unattended
monitoring:
o
o
o
•
Period 5 at Moores South due to power failure,
Period 9 at Tilda Hill North due to movement of the sound meter during a snow melt
that disconnected the microphone preamplifier, and
Period 12 at East Road North due to power failure.
In attended monitoring, the sound level meters are checked prior to the start of the
monitoring period. These issues can be resolved through the use of data telemetry, which
allow us to check on operations remotely. However, the location has spotty cellular
coverage which makes this infeasible for most locations.
The method used for attended measurements required the observer writing down both the
sound level shown on the sound monitor and whether the wind turbines and any other
sound sources were discernable every five seconds. In practice, this is very difficult to
accomplish in the short time allocated. Inevitably, either typos are made, data is missed, the
timing is off, or the background sound sources are not clearly identified to the level that is
needed to assess a wind turbine contribution to the Lmax. Since the monitoring is done real
time, there is no way to go back and check the measurements for quality assurance. As an
example, during Monitoring Period 10, the observer marked down a 49.4 dBA level on
61
Hoosac Wind Sound Monitoring
•
•
•
•
either side of a 39.0 and 38.4 dBA level. No marking was made of any other source other
than wind turbines during that time. Since wind turbines do not characteristically increase
in level by 10 dB in five seconds, the value is clearly either a typo, or the sound was due to
some other event. In this case, because we recorded all measurements, we are able to go
back and listen to that time and confirm that the written value was a typo. However,
without that coincident unattended recording, there would be no way to quality check that
type of anomaly. In another case, in review of the unattended recordings, we found a
woodpecker which raised the sound level, which wasn’t identified earlier.
Sound source identification of wind turbines has challenges since the turbine spectrum can
be very similar to wind at lower frequencies. In attended monitoring, it can be difficult to
characterize contaminating noise events in the time allocated. This is in contrast with
unattended monitoring, where one can use several tools, including repeated listening and
spectral analysis to identify wind turbine sounds. One advantage of attended monitoring,
however, is the ability to use ones binaural hearing to identify the location of the sound to
confirm where it is coming from.
An advantage of unattended monitoring is that we are able to monitor on both sides of a
turbine shut-down. While this is theoretically possible with attended monitoring, it requires
a large amount of staff time to simultaneously monitor four or more locations.
Multiple nighttime attended monitoring periods are difficult and disruptive to staff in
comparison with unattended nighttime monitoring, which requires only the turbine
operator to turn turbines off and on again.
The background sound levels without the turbine operating are highly variable, even within
individual test periods. Of 37 testing periods, 22, or 59% had background-only Lmax to L90
differentials that were greater than 10 dB. This differential tended to increase with the
lower ambient sound levels (L90 1 minute). This is a result of the larger impact wind gusts and
other short-term events can have during low ambient sound conditions. It also makes it
more difficult to measure the true differential between background and the project.
62
Hoosac Wind Sound Monitoring
9.
SUMMARY
Sound level monitoring was carried out at the recently-constructed 28.5 MW Hoosac Wind facility,
located in northwestern Massachusetts, in response to recent complaints by some residents living
in the area.
1. A sound monitoring protocol was developed in cooperation with and approval by MassDEP.
2. Sound level monitoring was performed at six different locations. Two locations west of
Bakke Mountain (Turbines 1-10) and four locations east and west of Crum Hill (Turbines
12-20). Each microphone location was visited and approved by MassDEP staff prior to the
first monitoring session.
3. Sound levels were logged each second continuously using ANSI/IEC Type 1 sound level
meters at each location from April 3 to April 24, 2013.
4. Meteorological conditions were monitored each day and reported to RSG and MassDEP. If
forecasts indicated that conditions were within an acceptable range, a monitoring session
would be scheduled. In all, 13 monitoring sessions were conducted - seven at Crum Hill and
six at Bakke Mountain.
5. During these sessions, the seven closest turbines to each monitor were shut down for a
period of 15 minutes to measure the ambient sound level. RSG staff was present and
conducted manual attended monitoring during five of these curtailments (three at Crum Hill
and two at Bakke Hill). DEP staff observed two of these curtailments. Overall, a total of 70
15-minute monitoring periods when wind turbines were operating were evaluated.
6. The overall data capture rate during the monitoring periods was 90%. Two premature
battery failures and one equipment failure resulted in the loss of data at one station for each
of three curtailment periods. However, for each, successful monitoring at another time was
conducted under similar wind conditions.
7. Attended monitoring results showed Lmax (WT+Background) minus LA90 (Background)
differentials between not-discernible and 9.7 dB depending on location and curtailment
period. Over the same testing periods, the unattended monitoring showed differentials
between not-discernible and 10.7 dB.
8. Unattended monitoring results showed Lmax (WT+Background) minus LA90 (Background
only) differentials between not-discernible and 13.3 dB depending on location and
curtailment period. The latter higher differentials occurred when the wind speed dropped
during the ambient period. When wind turbines were operating, the average wind speed
was 7 m/s, while during the Ambient test period, winds dropped to as low as 4 m/s.
9. Many of the test periods showed high Lmax versus LA90 differentials during the Ambient
periods. In 59% of the monitoring periods, the Lmax (Background only) – L90 (Background
only) differential was greater than 10 dB. There tended to be a greater differential at lower
ambient sound levels.
10. The maximum monitored sound levels from the wind turbines, with background subtracted,
ranged from 29 dBA at Tilda Hill North to 43 dBA at Moores Road North.
63
Hoosac Wind Sound Monitoring
11. A tonality analysis, using the MassDEP octave band methodology, showed that tonal wind
turbine noise was present during some of the monitoring periods. However, more detailed
analyses using 1/3 octave bands under the ANSI S12.9 methodology showed only eight fivesecond periods of pure tones at Moores North on April 4. The remaining locations and
periods where the turbines emitted a tone under the MassDEP policy, were not considered
tonal by the ANSI S12.9 definition due to a lack of tonal prominence.
12. The maximum sound levels measured largely agreed with sound propagation modeling
results. Where they were not in agreement, the modeling results were higher than the
monitored results.
13. Both unattended monitoring and attended monitoring presented challenges. Overall, we
find the unattended monitoring best given the faster reaction time to ever-changing
meteorology, the ability to do more extensive monitoring, and better quality control.
64
Hoosac Wind Sound Monitoring
APPENDIX A: TURBINE ACTIVITY DATA
Table A 1: Turbine Activity Data by Turbine for Crum Hill Turbines
Curtailment
Period
4/3/2013
13:00
4/3/2013
22:00
4/4/2013
10:30
4/5/2013
23:43
4/8/2013
14:15
4/10/2013
13:35
4/17/2013
7:21
Turbine
Operations
Before Shutoff
After Restart
Before Shutoff
After Restart
Before Shutoff
After Restart
Before Shutoff
After Restart
Before Shutoff
After Restart
Before Shutoff
After Restart
Before Shutoff
After Restart
T12
1229
1468
1497
1323
349
495
1038
1081
48
0
161
325
911
662
T13
1122
1459
1506
1280
250
427
1109
1179
72
0
176
324
963
675
Average Turbine Output (kW)
T14
T15
T16
T17
T18
1429 1441 1423 1477 1511
1337 1321 1145 1433 1422
1512 1516 1516 1518 1524
1331 1274 1264 1292 1288
396
372
342
515
379
427
384
383
431
412
1082 1215 1360 1434 1276
969
527
717 1287 1232
65
59
84
85
108
0
0
0
0
0
197
182
215
216
193
261
227
264
399
362
883
269
448 1107 1020
580
177
346
809
531
T19
1499
1406
1524
1259
393
394
1159
1118
81
0
261
317
855
390
T20
1523
1407
1531
1242
467
409
1192
1004
178
0
215
338
720
375
Table A 2: Turbine Activity Data by Turbine for Bakke Mountain Turbines
Curtailment
Period
4/11/2013
7:33
4/15/2013
17:00
4/18/2013
2:04
4/18/2013
11:00
4/22/2013
7:00
4/22/2013
13:00
Turbine
Operations
Before Shutoff
After Restart
Before Shutoff
After Restart
Before Shutoff
After Restart
Before Shutoff
After Restart
Before Shutoff
After Restart
Before Shutoff
After Restart
T3
62
0
114
0
757
754
628
424
732
575
-2
-9
T4
59
0
158
60
621
648
793
864
805
775
1169
988
Average Turbine Output (kW)
T5
T6
T7
T8
89
62
78
70
0
0
0
0
169
124
104
94
80
116
93
69
736
798
786
799
792
888
839
829
792
846
1082 1265
846
893
980
809
798
659
473
404
578
312
354
296
1211 1202 1137 1010
1008 1001
882
958
T9
54
0
58
38
818
835
1163
998
317
290
980
967
T10
41
0
43
50
786
770
994
877
282
303
759
984
65
Hoosac Wind Sound Monitoring
APPENDIX B: MONITORING LOCATION TIME HISTORIES
The time history results for each monitor are provided in Figure 32 through Figure 43. Each figure
represents seven days’ worth of data. The equivalent sound levels (Leq) are shown in blue, the L90s
are shown in green, the wind speed at microphone height for the closest anemometer is shown in
orange, and the turbine output is shown in grey.
Table 40 shows the percentage of the test periods and percentage of the total run time from April 3
to April 24, each of the monitors were running. All operational problems are noted on the graphs
below.
Table 40: Monitor Operational Summary
Location
East Rd N
East Rd S
Tilda Hill N
Tilda Hill S
Moores N
Moores S
OVERALL
Percent Time Monitors Operating
Overall
Test Periods
90%
83%
80%
100%
50%
86%
100%
100%
95%
100%
71%
86%
90%
66
Hoosac Wind Sound Monitoring
Figure 32: East Road North - Time History Part 1
Figure 33: East Road North - Time History Part 2
67
Hoosac Wind Sound Monitoring
Figure 34: East Road North - Time History Part 3
Figure 35: East Road South - Time History Part 1
68
Hoosac Wind Sound Monitoring
Figure 36: East Road South - Time History Part 2
Figure 37: East Road South - Time History Part 3
69
Hoosac Wind Sound Monitoring
Figure 38: Tilda Hill North - Time History Part 1
Figure 39: Tilda Hill North - Time History Part 2
70
Hoosac Wind Sound Monitoring
Figure 40: Tilda Hill North - Time History Part 3
71
Hoosac Wind Sound Monitoring
Figure 41: Tilda Hill South - Time History Part 1
Figure 42: Tilda Hill South - Time History Part 2
72
Hoosac Wind Sound Monitoring
Figure 43: Tilda Hill South - Time History Part 3
Figure 44: Moores North - Time History Part 1
73
Hoosac Wind Sound Monitoring
Figure 45: Moores North - Time History Part 2
Figure 46: Moores North - Time History Part 3
74
Hoosac Wind Sound Monitoring
Figure 47: Moores South - Time History Part 1
Figure 48: Moores South - Time History Part 2
75
Hoosac Wind Sound Monitoring
Figure 49: Moores South - Time History Part 3
76
Hoosac Wind Sound Monitoring
APPENDIX C: TONALITY ANALYSIS
Table 41: Tonality Analysis 4/3/2013 13:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
500 Hz
1
0
0
3
0
1
0
0
0
2
0
0
1000 Hz
2000 Hz
4000 Hz
Moores S
250 Hz
Moores N
125 Hz
Tilda Hill S Ambient
WT+Background Before
WT+Background After
63 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
Number
of
Observ.
180
72
17
180
3
0
2
0
0
1
0
0
1
0
0
1
0
0
0
0
0
0
0
0
3
0
0
Ambient
WT+Background Before
WT+Background After
180
83
27
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Ambient
WT+Background Before
WT+Background After
180
2
4
1
0
0
0
0
0
4
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 42: Tonality Analysis 4/3/2013 13:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
10000 Hz
8000 Hz
6300 Hz
5000 Hz
4000 Hz
3150 Hz
2500 Hz
2000 Hz
1600 Hz
1250 Hz
800 Hz
1000 Hz
630 Hz
500 Hz
400 Hz
315 Hz
250 Hz
200 Hz
160 Hz
125 Hz
80 Hz
100 Hz
63 Hz
50 Hz
40 Hz
31.5 Hz
Location Scenario
Tilda Hill NAmbient
WT+Background Before
WT+Background After
0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Tilda Hill SAmbient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 17 0 1 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores N Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 1 2
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores S Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
77
Hoosac Wind Sound Monitoring
Table 43: Tonality Analysis 4/3/2013 22:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
500 Hz
0
0
0
0
0
0
0
0
0
0
0
0
1000 Hz
2000 Hz
4000 Hz
Moores S
250 Hz
Moores N
125 Hz
Tilda Hill S Ambient
WT+Background Before
WT+Background After
63 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
Number
of
Observ.
180
0
0
180
0
3
0
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Ambient
WT+Background Before
WT+Background After
180
3
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Ambient
WT+Background Before
WT+Background After
180
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 44: Tonality Analysis 4/3/2013 22:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
8000 Hz
10000 Hz
6300 Hz
5000 Hz
4000 Hz
3150 Hz
2500 Hz
2000 Hz
1600 Hz
1250 Hz
800 Hz
1000 Hz
630 Hz
500 Hz
400 Hz
315 Hz
250 Hz
200 Hz
160 Hz
125 Hz
80 Hz
100 Hz
63 Hz
50 Hz
40 Hz
31.5 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Tilda Hill S Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores N
Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores S
Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
78
Hoosac Wind Sound Monitoring
Table 45: Tonality Analysis 4/4/2013 10:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
500 Hz
0
0
0
10
18
20
0
0
0
0
0
1
1000 Hz
2000 Hz
4000 Hz
Moores S
250 Hz
Moores N
125 Hz
Tilda Hill S Ambient
WT+Background Before
WT+Background After
63 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
Number
of
Observ.
180
84
135
180
108
101
0
6
3
12
49
53
2
0
0
2
0
0
25
0
0
0
0
0
11
11
14
Ambient
WT+Background Before
WT+Background After
180
98
145
0
0
0
8
82
132
0
0
0
0
0
0
0
0
0
0
0
0
3
0
0
Ambient
WT+Background Before
WT+Background After
180
29
63
1
0
0
2
9
32
0
0
0
0
0
1
1
0
0
0
0
0
5
0
0
3
0
0
0
0
0
0
0
0
Table 46: Tonality Analysis 4/4/2013 10:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
8000 Hz
10000 Hz
6300 Hz
5000 Hz
4000 Hz
3150 Hz
2500 Hz
2000 Hz
1600 Hz
1250 Hz
800 Hz
1000 Hz
630 Hz
500 Hz
400 Hz
315 Hz
250 Hz
200 Hz
160 Hz
125 Hz
80 Hz
100 Hz
63 Hz
50 Hz
40 Hz
31.5 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
Tilda Hill S Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 1 0 1 1 0 0 0 4 0 0 0 13 0 0 0 0 14 10 1 1 0
0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 1 4 2 7 2 6 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 1 0 1 0 0
Moores N
Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 4 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3
Moores S
Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0
79
Hoosac Wind Sound Monitoring
Table 47: Tonality Analysis 4/5/2013 23:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
500 Hz
0
0
0
1
1
1
0
0
0
0
0
1
1000 Hz
2000 Hz
4000 Hz
Moores S
250 Hz
Moores N
125 Hz
Tilda Hill S Ambient
WT+Background Before
WT+Background After
63 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
Number
of
Observ.
180
111
83
180
95
21
2
1
1
1
79
13
1
1
1
1
1
1
6
1
1
1
1
1
1
1
1
Ambient
WT+Background Before
WT+Background After
180
96
38
0
0
0
0
3
0
0
0
0
0
0
0
0
0
0
3
0
0
0
0
0
Ambient
WT+Background Before
WT+Background After
180
52
62
0
0
0
6
3
19
3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
1
0
0
Table 48: Tonality Analysis 4/5/2013 23:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
8000 Hz
10000 Hz
6300 Hz
5000 Hz
4000 Hz
3150 Hz
2500 Hz
2000 Hz
1600 Hz
1250 Hz
800 Hz
1000 Hz
630 Hz
500 Hz
400 Hz
315 Hz
250 Hz
200 Hz
160 Hz
125 Hz
80 Hz
100 Hz
63 Hz
50 Hz
40 Hz
31.5 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0
Tilda Hill S Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores N
Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores S
Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
80
Hoosac Wind Sound Monitoring
Table 49: Tonality Analysis 4/8/2013 14:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
500 Hz
0
0
0
3
0
0
0
0
0
3
0
0
1000 Hz
2000 Hz
4000 Hz
Moores S
250 Hz
Moores N
125 Hz
Tilda Hill S Ambient
WT+Background Before
WT+Background After
63 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
Number
of
Observ.
180
166
0
180
0
0
7
0
0
5
0
0
3
0
0
9
0
0
9
0
0
6
0
0
28
0
0
Ambient
WT+Background Before
WT+Background After
180
119
0
0
0
0
17
16
0
1
0
0
0
1
0
0
0
0
0
0
0
0
0
0
Ambient
WT+Background Before
WT+Background After
pf
-
-
-
-
-
-
-
pf
-
-
-
-
-
-
-
pf
-
-
-
-
-
-
-
2
0
0
0
0
0
2
0
0
Table 50: Tonality Analysis 4/8/2013 14:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
8000 Hz
10000 Hz
6300 Hz
5000 Hz
4000 Hz
3150 Hz
2500 Hz
2000 Hz
1600 Hz
1250 Hz
800 Hz
1000 Hz
630 Hz
500 Hz
400 Hz
315 Hz
250 Hz
200 Hz
160 Hz
125 Hz
80 Hz
100 Hz
63 Hz
50 Hz
40 Hz
31.5 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 1 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Tilda Hill S Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 1 1 1 1 2 3 0 2 0 2 3 20 2 1 2 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores N
Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 3 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores S
Ambient
pf
WT+Background Before pf
WT+Background After
pf
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
pf = power failure
81
Hoosac Wind Sound Monitoring
Table 51: Tonality Analysis 4/10/2013 13:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
500 Hz
1
1
0
0
7
0
0
0
0
0
0
0
1000 Hz
2000 Hz
4000 Hz
Moores S
250 Hz
Moores N
125 Hz
Tilda Hill S Ambient
WT+Background Before
WT+Background After
63 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
Number
of
Observ.
180
171
0
180
0
0
21
0
0
0
0
0
0
0
0
15
0
0
2
0
0
1
0
0
10
0
0
Ambient
WT+Background Before
WT+Background After
180
0
0
0
0
0
1
0
0
0
0
0
1
0
0
2
0
0
0
0
0
0
0
0
Ambient
WT+Background Before
WT+Background After
180
4
17
7
0
0
0
0
13
0
0
0
4
0
0
1
0
0
0
0
0
23
0
0
1
0
0
0
0
0
0
0
0
Table 52: Tonality Analysis 4/10/2013 13:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
8000 Hz
10000 Hz
6300 Hz
5000 Hz
4000 Hz
3150 Hz
2500 Hz
2000 Hz
1600 Hz
1250 Hz
800 Hz
1000 Hz
630 Hz
500 Hz
400 Hz
315 Hz
250 Hz
200 Hz
160 Hz
125 Hz
80 Hz
100 Hz
63 Hz
50 Hz
40 Hz
31.5 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Tilda Hill S Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 21 0 0 1 0 2 0 0 2 3 9 3 4 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores N
Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Moores S
Ambient
WT+Background Before
WT+Background After
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
82
Hoosac Wind Sound Monitoring
Table 53: Tonality Analysis 4/11/2013 07:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
1000 Hz
2000 Hz
4000 Hz
180
0
0
500 Hz
Ambient
WT+Background Before
WT+Background After
250 Hz
East Rd S
125 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
63 Hz
Location
East Rd N
Number
of
Observ.
180
0
0
3
0
0
2
0
0
4
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 54: Tonality Analysis 4/11/2013 07:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
63 Hz
80 Hz
100 Hz
125 Hz
160 Hz
200 Hz
250 Hz
315 Hz
400 Hz
500 Hz
630 Hz
800 Hz
1000 Hz
1250 Hz
1600 Hz
2000 Hz
2500 Hz
3150 Hz
4000 Hz
5000 Hz
6300 Hz
8000 Hz
10000 Hz
Ambient
WT+Background Before
WT+Background After
50 Hz
East Rd S
40 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
31.5 Hz
Location
East Rd N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
83
Hoosac Wind Sound Monitoring
Table 55: Tonality Analysis 4/15/2013 17:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
1000 Hz
2000 Hz
4000 Hz
180
0
0
500 Hz
Ambient
WT+Background Before
WT+Background After
250 Hz
East Rd S
125 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
63 Hz
Location
East Rd N
Number
of
Observ.
180
0
0
15
0
0
12
0
0
0
0
0
0
0
0
31
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 56: Tonality Analysis 4/15/2013 17:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
63 Hz
80 Hz
100 Hz
125 Hz
160 Hz
200 Hz
250 Hz
315 Hz
400 Hz
500 Hz
630 Hz
800 Hz
1000 Hz
1250 Hz
1600 Hz
2000 Hz
2500 Hz
3150 Hz
4000 Hz
5000 Hz
6300 Hz
8000 Hz
10000 Hz
Ambient
WT+Background Before
WT+Background After
50 Hz
East Rd S
40 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
31.5 Hz
Location
East Rd N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
84
Hoosac Wind Sound Monitoring
Table 57: Tonality Analysis 4/17/2013 07:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
63 Hz
125 Hz
250 Hz
500 Hz
1000 Hz
2000 Hz
4000 Hz
Location
Scenario
Tilda Hill N Ambient
WT+Background Before
WT+Background After
Number
of
Observ.
ef
-
-
-
-
-
-
-
ef
-
-
-
-
-
-
-
ef
-
-
-
-
-
-
-
Tilda Hill S Ambient
WT+Background Before
WT+Background After
ef
108
0
4
20
0
6
0
0
1
0
0
30
0
0
0
0
0
10
1
0
1
0
0
Moores N
Ambient
WT+Background Before
WT+Background After
ef
144
110
0
0
0
0
5
3
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
Moores S
Ambient
WT+Background Before
WT+Background After
ef
45
111
1
0
0
0
7
9
0
0
0
0
0
0
0
0
0
0
0
0
51
14
10
Table 58: Tonality Analysis 4/17/2013 07:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
40 Hz
50 Hz
63 Hz
80 Hz
100 Hz
125 Hz
160 Hz
200 Hz
250 Hz
315 Hz
400 Hz
500 Hz
630 Hz
800 Hz
1000 Hz
1250 Hz
1600 Hz
2000 Hz
2500 Hz
3150 Hz
4000 Hz
5000 Hz
6300 Hz
8000 Hz
10000 Hz
31.5 Hz
Location
Scenario
Tilda Hill N Ambient
ef
WT+Background Before ef
WT+Background After
ef
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0
0
0
0
0
0
Tilda Hill S Ambient
WT+Background Before
WT+Background After
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0 24 0
0 1 0
0 0 0
1
0
0
0
0
0
0
0
0
5
1
0
Moores N
Ambient
WT+Background Before
WT+Background After
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3 10 0
0 0 0
1 0 0
Moores S
Ambient
WT+Background Before
WT+Background After
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
3
3
5
5
0
0
1
2
0
1
0
0
0
4
0
0
0
ef = equipment failure
85
Hoosac Wind Sound Monitoring
Table 59: Tonality Analysis 4/18/2013 02:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
1000 Hz
2000 Hz
4000 Hz
180
126
172
500 Hz
Ambient
WT+Background Before
WT+Background After
250 Hz
East Rd S
125 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
63 Hz
Location
East Rd N
Number
of
Observ.
180
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
80
129
0
0
0
0
102
85
0
0
0
0
0
0
0
0
0
Table 60: Tonality Analysis 4/18/2013 02:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
63 Hz
80 Hz
100 Hz
125 Hz
160 Hz
200 Hz
250 Hz
315 Hz
400 Hz
500 Hz
630 Hz
800 Hz
1000 Hz
1250 Hz
1600 Hz
2000 Hz
2500 Hz
3150 Hz
4000 Hz
5000 Hz
6300 Hz
8000 Hz
10000 Hz
Ambient
WT+Background Before
WT+Background After
50 Hz
East Rd S
40 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
31.5 Hz
Location
East Rd N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
86
Hoosac Wind Sound Monitoring
Table 61: Tonality Analysis 4/18/2013 11:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
1000 Hz
2000 Hz
4000 Hz
180
122
82
500 Hz
Ambient
WT+Background Before
WT+Background After
250 Hz
East Rd S
125 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
63 Hz
Location
East Rd N
Number
of
Observ.
180
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
0
Table 62: Tonality Analysis 4/18/2013 11:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
63 Hz
80 Hz
100 Hz
125 Hz
160 Hz
200 Hz
250 Hz
315 Hz
400 Hz
500 Hz
630 Hz
800 Hz
1000 Hz
1250 Hz
1600 Hz
2000 Hz
2500 Hz
3150 Hz
4000 Hz
5000 Hz
6300 Hz
8000 Hz
10000 Hz
Ambient
WT+Background Before
WT+Background After
50 Hz
East Rd S
40 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
31.5 Hz
Location
East Rd N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
3
1
0
0
0
0
1
0
0
0
0
87
Hoosac Wind Sound Monitoring
Table 63: Tonality Analysis 4/22/2013 07:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
500 Hz
1000 Hz
2000 Hz
4000 Hz
Ambient
WT+Background Before
WT+Background After
250 Hz
pf
125 Hz
East Rd S
Scenario
Ambient
WT+Background Before
WT+Background After
63 Hz
Location
East Rd N
Number
of
Observ.
-
-
-
-
-
-
-
pf
-
-
-
-
-
-
-
pf
-
-
-
-
-
-
-
180
136
160
0
3
1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
7
30
Table 64: Tonality Analysis 4/22/2013 07:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
80 Hz
100 Hz
125 Hz
160 Hz
200 Hz
250 Hz
315 Hz
400 Hz
500 Hz
630 Hz
800 Hz
1000 Hz
1250 Hz
1600 Hz
2000 Hz
2500 Hz
3150 Hz
4000 Hz
5000 Hz
6300 Hz
8000 Hz
10000 Hz
0
0
0
63 Hz
Ambient
WT+Background Before
WT+Background After
50 Hz
Scenario
Ambient
pf
WT+Background Before pf
WT+Background After
pf
40 Hz
East Rd S
31.5 Hz
Location
East Rd N
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
0
0
2
0
0
0
0
0
1
0
0
5
0
7
8
0
0
5
0
0
0
pf = power failure
88
Hoosac Wind Sound Monitoring
Table 65: Tonality Analysis 4/22/2013 13:00 – MassDEP Method
Number of MassDEP Tonal 5-Second Measurements
1000 Hz
2000 Hz
4000 Hz
180
122
86
500 Hz
Ambient
WT+Background Before
WT+Background After
250 Hz
East Rd S
125 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
63 Hz
Location
East Rd N
Number
of
Observ.
180
0
0
1
0
0
0
0
0
0
0
0
0
0
0
1
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
13
0
Table 66: Tonality Analysis 4/22/2013 13:00 – ANSI S12.9 Method
Number of ANSI S12.9 Part 4 Tonal 5-Second Measurements
63 Hz
80 Hz
100 Hz
125 Hz
160 Hz
200 Hz
250 Hz
315 Hz
400 Hz
500 Hz
630 Hz
800 Hz
1000 Hz
1250 Hz
1600 Hz
2000 Hz
2500 Hz
3150 Hz
4000 Hz
5000 Hz
6300 Hz
8000 Hz
10000 Hz
Ambient
WT+Background Before
WT+Background After
50 Hz
East Rd S
40 Hz
Scenario
Ambient
WT+Background Before
WT+Background After
31.5 Hz
Location
East Rd N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0 0 0
0 15 1
0 0 0
0
1
0
0
0
1
89