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BMC L Pad Noise Impact
Assessment Report
April 24, 2017
Prepared for:
Ursa Operating Company
792 Buckhorn Dr
Rifle, Colorado 81650
Prepared by:
Behrens and Associates, Inc.
13806 Inglewood Avenue
Hawthorne California 90250
Justin Puggioni
Acoustical Technical Director
Jason Peetz
Engineering Manager
IlliMilr—
Corporate Office: Hawthorne, California
Carson, California - Aledo, Texas — Napa California — Longmont, Colorado — McDonald, Pennsylvania
Phone 800-679-8633 — Fax 310-331-1538
www.environmental-noise-control.com - www.drillingnoisecontrol.com
Behrens and Associates, Inc.
Environmental Noise Control
1. Introduction
The purpose of this study is to assess the noise impact of the drilling and fracing operations at the BMC L Pad
located approximately 900 feet south of N Battlement Pkwy and 400 feet west of Spencer Pkwy in Garfield County,
Colorado (Figure 1-1). Drilling and fracing noise levels have been assessed in terms of the COGCC Noise
Standards. To assess the noise impact, a noise model representing the drilling and fracing operations was
constructed and compared to the allowable noise levels.
The following is provided in this report:
• The Colorado Oil and Gas Conservation Commission (COGCC) Noise Standards
• The results of noise modeling representing the drilling and fracing operations
• Recommendations for noise mitigation measures to decrease noise emissions of the drilling and fracing
operations.
----N,Bot Hem cnt-Pkwyw.
Figure 1-1 BMC L Pad Location
Introduction
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2. Noise Fundamentals
Sound is most commonly experienced by people as pressure waves passing through air. These rapid fluctuations in
air pressure are processed by the human auditory system to produce the sensation of sound. The rate at which sound
pressure changes occur is called the frequency. Frequency is usually measured as the number of oscillations per
second or Hertz (Hz). Frequencies that can be heard by a healthy human ear range from approximately 20 Hz to
20,000 Hz. Toward the lower end of this range are low-pitched sounds, including those that might be described as a
"rumble" or "boom". At the higher end of the range are high-pitched sounds that might be described as a "screech"
or "hiss".
Environmental noise generally derives, in part, from a combination of distant noise sources. Such sources may
include common experiences such as distant traffic, wind in trees, and distant industrial or farming activities. These
distant sources create a low-level "background noise" in which no particular individual source is identifiable.
Background noise is often relatively constant from moment to moment, but varies slowly from hour to hour as
natural forces change or as human activity follows its daily cycle.
Superimposed on this low-level, slowly varying background noise is a succession of identifiable noisy events of
relatively brief duration. These events may include the passing of single -vehicles, aircraft flyovers, screeching of
brakes, and other short-term events. The presence of these short-term events causes the noise level to fluctuate.
Detailed acoustical definitions are provided in the Appendix A.
COMMON OUTDOOR NOISE LEVEL
SOUND LEVELS dB (A)
110
8-747-200 Takeoff at 2 mi.
Gas Lawn Mower at 3 ft.
Diesel Truck at 150 ft.
DC -9-30 Takeoff at 2 mi.
Noisy Urban Daytime
B-757 Takeoff at 2 mi.
Commercial Area
----Quiet Urban Daytime
Quiet Urban Nighttime
Quiet Suburban Nighttime
Quiet Rural Nighttime
COMMON INDOOR
SOUND LEVELS
Rock Sand
100 Inside Subway Train
(New York)
90 Food Blender at 3 ft.
80
70
Normal Speech
60 at 3 ft_
50
Garbage Disposal at 3 ft.
Shouting at 3 ft.
Vacuum Cleaner
at 10 ft.
Large Business Office
Dishwasher Next Room
Small Theatre, Large
Conference Room •
(Background)
Library
Bedroom at Night--
Concert
ight--Concert Hall (Background)
II ftlf
Broadcast & Recording
Studio
Threshold of Hearing
1
Figure 2-1 Typical Indoor and Outdoor Sound Levels
Noise Fundamentals
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Environmental Noise Control
3. Noise Standards
Iv
3.1 Colorado Oil and Gas Conservation Commission (COGCC)
The analysis was developed to evaluate drilling and fracing noise levels at adjacent occupied structures and verify
compliance of drilling operations with the Colorado Oil and Gas Conservation Commission (COGCC) Section 802
"Noise Abatement" requirements. The COGCC Code lists exterior noise limits for stationary noise sources. The
noise limits are provided in Table 1.
Table 3-1 COGCC Sec. 802(b) Noise Abatement Requirements "Exterior Noise Level Limits"
Zone
7:00 am to next 7:00 pm
7:00 pm to next 7:00 am
Residential/Agricultural/Rural
55 dBA
50 dBA
Commercial
60 dBA
55 dBA
Light Industrial
70 dBA
65 dBA
Industrial
80 dBA
75 dBA
Section 802.b of the standard states:
The type of land use of the surrounding area shall be determined by the Director in consultation with the Local
Government Designee taking into consideration any applicable zoning or other local land use designation. In the
hours between 7:00 a.m. and the next 7:00 p.m. the noise levels permitted above may be increased ten (10) dB(A)
for a period not to exceed fifteen (15) minutes in any one (1) hour period. The allowable noise level for periodic,
impulsive or shrill noises is reduced by five (5) dB (A) from the levels shown.
(1) Except as required pursuant to Rule 604.c.(2)A., operations involving pipeline or gas facility
installation or maintenance, the use of a drilling rig, completion rig, workover rig, or stimulation is
subject to the maximum permissible noise levels for industrial zones.
Section 802C.(1) of the standard states:
Sound levels shall be measured at a distance of three hundred and fifty (350) feet from noise source. At the request
of the complainant, the sound level shall also be measured at a point beyond three hundred fifty (350) feet that the
complainant believes is more representative of the noise impact. If an oil and gas well site, production facility, or
gas facility is installed closer than three hundred and fifty (350) feet from an existing occupied structure, sound
levels shall be measured at a point twenty-five feet from the structure toward the noise source. Noise levels from
oil and gas facilities located on surface property owned, leased, or otherwise controlled by the operator shall be
measured at the three hundred and fifty (350) feet or at the property line, whichever is greater.
Noise Standards
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3.2 Colorado Oil and Gas Conservation Commission Setback Rules
Section 604.c.(2)
A. Noise.
Operations involving pipeline or gas facility installation or maintenance, or the use of a drilling rig, are
subject to the maximum permissible noise levels for Light Industrial Zones, as measured at the nearest
Building Unit. Short-term increases shall be allowable as described in 802.c. Stimulation or re -stimulation
operations and Production Facilities are governed by Rule 802.
Noise Standards
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4. BMC L Pad Noise Modeling
The noise modeling was completed with use of three-dimensional computer noise modeling software. All models in
this report were developed with SoundPLAN 7.4 software using the ISO 9613-2 standard. Noise levels are
predicted based on the locations, noise levels and frequency spectra of the noise sources, and the geometry and
reflective properties of the local terrain, buildings and barriers. To ensure a conservative assessment and
compliance with ISO 9613-2 standards, light to moderate winds are assumed to be blowing from the source to
receptor.
The drilling rig scheduled to be utilized at the site is Capstar #123. The sound level data used for the drilling rig in
the noise model are based on previous measurements of a similar drilling rig in operation. The rig is oriented with
the V -door facing southeast and the generators placed on the northwest side of the pad. The sound level data for the
fracing equipment are based on previous measurements of Halliburton pump trucks. Twelve hydraulic fracturing
pump trucks operating simultaneously have been included in the model.
Noise levels have been assessed for two locations adjacent to the site and are consistent with the requirements of
the COGCC standards. Receiver 1 represents a residence and has been placed at the property line which is greater
than 350 feet from the nearest noise source. Receiver 2 represents a childcare facility and has been placed 350 feet
from the edge of the pad. The locations of the receiver points are shown in Figure 4-1.
Figure 4-1 Receiver Locations
BMC L Pad Noise Modeling
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4.1 Unmitigated Noise Modeling Results
The results of the unmitigated drilling and fracing noise modeling are presented in Table 4-1. The locations in the
table correspond to the locations identified in Figure 4-1. The predicted noise levels represent only the contribution
of the project operations and do not include ambient noise or noise from other facilities. Actual field sound level
measurements may vary from the modeled noise levels due to other noise sources such as traffic, other facilities,
other human activity, or environmental factors.
Table 4-1 A -weighted Unmitigated Noise Modeling Results
Drilling Fracing
dBA dBA
Receiver
1 39.2 56.2
2 53.1 69.3
COGCC Noise Limit 70.0 Day / 65.0 Night 80.0 Day / 75.0 Night
All receivers comply with the A -weighted COGCC noise limits for drilling and fracing. The results of the noise
modeling are also shown as noise contour maps. Figure 4-2 shows the unmitigated drilling noise contour map in the
A -weighted scale and Figure 4-3 shows the unmitigated fracing noise contour map in the A -weighted scale.
BMC L Pad Noise Modeling
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Environmental Noise Control
Figure 4-2 Unmitigated Drilling Noise Contour Map (dBA)
Noise Level, dBA
= 30.0
=35.0
= 40.0
= 45.0
= 50.0
= 55.0
= 60.0
= 65.0
= 70.0
= 75.0
= 80.0
= 85.0
= 90.0
4
0 200 400 600
feet
BMC L Pad Noise Modeling
Behrens and Associates, Inc.
Environmental Noise Control
Figure 4-3 Unmitigated Fracing Noise Contour Map (dBA)
Noise Level, dBA
30.0
= 35.0
= 40.0
= 45.0
= 50.0
= 55.0
= 60.0
= 65.0
= 70.0
= 75.0
= 80.0
= 85.0
= 90.0
0 200 400 600
feet
BMC L Pad Noise Modeling
Behrens and Associates, Inc.
Environmental Noise Control
4.2 Mitigation Layout
Noise mitigation has been included in the modeling to reduce noise levels below the unmitigated scenarios. The
noise mitigation included in the modeling is described below:
• 1,040 -foot -long, 40 -foot -high STC -32 acoustical wall along the perimeter of the pad.
The layout for the mitigation scenario is shown in Figure 4-4.
Total 1,040 ft -long, 40 -ft -
high STC 32 acoustical wall
Figure 4-4 Mitigation Layout
BMC L Pad Noise Modeling
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Environmental Noise Control
4.3 Mitigated Noise Modeling Results
The results of the mitigated noise modeling are presented in Table 4-2. The locations in the table correspond to the
locations identified in Figure 4-1. The predicted noise levels represent only the contribution of the project
operations and do not include ambient noise or noise from other facilities. Actual field sound level measurements
may vary from the modeled noise levels due to other noise sources such as traffic, other facilities, other human
activity, or environmental factors.
Table 4-2 A -weighted Drilling and Fracing Noise Modeling Results
Drilling Fracing
Unmitigated Mitigated Unmitigated Mitigated
Receiver dBA dBA dBA dBA
1 39.2 32.7 56.2 51.6
2 53.1 43.6 69.3 58.9
COGCC Noise Limit
70.0 Day / 65.0 Night 80.0 Day / 75.0 Night
With the inclusion of the recommended mitigation, the predicted noise levels comply with the A -weighted COGCC
noise limits at all receivers for the drilling and fracing operations.
The results of the noise modeling are also shown as noise contour maps. Figure 4-5 shows the mitigated drilling
noise contour map in the A -weighted scale and Figure 4-6 shows the mitigated fracing noise contour map in the A -
weighted scale.
BMC L Pad Noise Modeling
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eaPre eek.Dt
Receiver 1
32.7 dBA
Figure 4-5 Mitigated Drilling Noise Contour Map (dBA)
Noise Level, dBA
= 30.0
= 35.0
= 40.0
= 45.0
= 50.0
= 55.0
= 60.0
= 65.0
= 70.0
= 75.0
= 80.0
= 85.0
= 90.0
0 200 400 600
feet
BMC L Pad Noise Modeling
Behrens and Associates, Inc.
Environmental Noise Control
Figure 4-6 Mitigated Fracing Noise Contour Map (dBA)
Noise Level, dBA
= 30.0
= 35.0
= 40.0
= 45.0
= 50.0
= 55.0
= 60.0
= 65.0
= 70.0
= 75.0
i=
= 80.0
= 85.0
90.0
4
0 200 400 600
feet
BMC L Pad Noise Modeling
Behrens and Associates, Inc.
Environmental Noise Control
5. Conclusion
A noise model of drilling and fracing operations was constructed for the BMC L Pad in Garfield County, Colorado.
The unmitigated and mitigated drilling and fracing noise models demonstrate that the planned operations will
comply with the A -weighted noise limits at all receivers.
Conclusion
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Appendix A - Glossary of Acoustical Terms
Appendix A - Glossary of Acoustical Terms
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Ambient Noise
The all-encompassing noise associated with a given environment at a specified time, usually a composite of sound
from many sources both near and far.
Average Sound Level
See Equivalent -Continuous Sound Level.
A -Weighted Sound Level, dB(A)
The sound level obtained by use of A -weighting. Weighting systems were developed to measure sound ina way that
more closely mimics the ear's natural sensitivity relative to frequency so that the instrument is less sensitive to
noise at frequencies where the human ear is less sensitive and more sensitive at frequencies where the human ear is
more sensitive.
Community Noise Equivalent Level (CNEL)
A 24-hour A -weighted average sound level which takes into account the fact that a given level of noise may be
more or less tolerable depending on when it occurs. The CNEL measure of noise exposure weights average hourly
noise levels by 5 dB for the evening hours (between 7:00 pm and 10:00 pm), and 10 dB between 10:00 pm and 7:00
am, then combines the results with the daytime levels to produce the final CNEL value. It is measured in decibels,
dB.
Day -Night Average Sound Level (Ldn)
A measure of noise exposure level that is similar to CNEL except that there is no weighting applied to the evening
hours of 7:00 pm to 10:00 pm. It is measured in decibels, dB.
Daytime Average Sound Level
The time -averaged A -weighted sound level measured between the hours of 7:00 am to 7:00 pm. It is measured in
decibels, dB.
Decay Rate
The time taken for the sound pressure level at a given frequency to decrease in a room. It is measured in decibels
per second, dB/s.
Decibel (dB)
The basic unit of measurement for sound level.
Direct Sound
Sound that reaches a given location in a direct line from the source without any reflections.
Divergence
The spreading of sound waves from a source in a free field, resulting in a reduction in sound pressure level with
increasing distance from the source.
Energy Basis
This refers to the procedure of summing or averaging sound pressure levels on the basis of their squared pressures.
This method involves the conversion of decibels to pressures, then performing the necessary arithmetic
calculations, and finally changing the pressure back to decibels.
Appendix A - Glossary of Acoustical Terms
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Equivalent -Continuous Sound Level (Leq)
The average sound level measured over a specified time period. It is a single -number measure of time -varying noise
over a specified time period. It is the level of a steady sound that, in a stated time period and at a stated location, has
the same A -Weighted sound energy as the time -varying sound. For example, a person who experiences an Leq of
60 dB(A) for a period of 10 minutes standing next to a busy street is exposed to the same amount of sound energy
as if he had experienced a constant noise level of 60 dB(A) for 10 minutes rather than the time -varying traffic noise
level. It is measured in decibels, dB.
Fast Response
A setting on the sound level meter that determines how sound levels are averaged over time. A fast sound level is
always more strongly influenced by recent sounds, and less influenced by sounds occurring in the distant past, than
the corresponding slow sound level. For the same non -steady sound, the maximum fast sound level is generally
greater than the corresponding maximum slow sound level. Fast response is typically used to measure impact sound
levels.
Field Impact Insulation Class (FIIC)
A single number rating similar to the impact insulation class except that the impact sound pressure levels are
measured in the field.
Field Sound Transmission Class (FSTC)
A single number rating similar to sound transmission class except that the transmission loss values used to derive
this class are measured in the field.
Flanking Sound Transmission
The transmission of sound from a room in which a source is located to an adjacent receiving room by paths other
than through the common partition. Also, the diffraction of noise around the ends of a barrier.
Frequency
The number of oscillations per second of a sound wave.
Hourly Average Sound Level (HNL)
The equivalent -continuous sound level, Leq, over a 1 -hour time period.
Impact Insulation Class (IIC)
A single number rating used to compare the effectiveness of floor/ceiling assemblies in providing reduction of
impact -generated sound such as the sound of a person's walking across the upstairs floor.
Impact Noise
The noise that results when two objects collide.
Impulse Noise
Noise of a transient nature due to the sudden impulse of pressure like that created by a gunshot or balloon bursting.
Insertion Loss
The decrease in sound level measured at the location of the receiver when an element (e.g., a noise barrier) is
inserted in the transmission path between the sound source and the receiver.
Appendix A - Glossary of Acoustical Terms
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Inverse Square Law
A rule by which the sound intensity varies inversely with the square of the distance from the source. This results in
a 6dB decrease in sound pressure level for each doubling of distance from the source.
Masking
The process by which the threshold of hearing for one sound is raised by the presence of another sound.
Maximum Sound Level (Lmax)
The greatest sound level measured on a sound level meter during a designated time interval or event.
NC Curves (Noise Criterion Curves)
A system for rating the noisiness of an occupied indoor space. An actual octave -band spectrum is compared with a
set of standard NC curves to determine the NC level of the space.
Noise Isolation Class (NIC)
A single number rating derived from the measured values of noise reduction between two enclosed spaces that are
connected by one or more partitions. Unlike STC or NNIC, this rating is not adjusted or normalized to a measured
or standard reverberation time.
Noise Reduction
The difference in sound pressure level between any two points.
Noise Reduction Coefficient (NRC)
A single number rating of the sound absorption properties of a material. It is the average of the sound absorption
coefficients at 250, 500, 1000, and 2000 Hz, rounded to the nearest multiple of 0.05.
Normalized Noise Isolation Class (NNIC)
A single number rating similar to the noise isolation class except that the measured noise reduction values are
normalized to a reverberation time of 0.5 seconds.
Octave
The frequency interval between two sounds whose frequency ratio is 2. For example, the frequency interval
between 500 Hz and 1,000 Hz is one octave.
Octave -Band Sound Level
For an octave frequency band, the sound pressure level of the sound contained within that band.
One -Third Octave
The frequency interval between two sounds whose frequency ratio is 21\(1/3). For example, the frequency interval
between 200 Hz and 250 Hz is one-third octave.
One -Third -Octave -Band Sound Level
For a one -third -octave frequency band, the sound pressure level of the sound contained within that band.
Outdoor -Indoor Transmission Class (OITC)
A single number rating used to compare the sound insulation properties of building facade elements. This rating is
designed to correlate with subjective impressions of the ability of facade elements to reduce the overall loudness of
ground and air transportation noise.
Appendix A - Glossary of Acoustical Terms
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Peak Sound Level (Lpk)
The maximum instantaneous sound level during a stated time period or event.
Pink Noise
Noise that has approximately equal intensities at each octave or one -third -octave band.
Point Source
A source that radiates sound as if from a single point.
RC Curves (Room Criterion Curves)
A system for rating the noisiness of an occupied indoor space. An actual octave -band spectrum is compared with a
set of standard RC curves to determine the RC level of the space.
Real -Time Analyzer (RTA)
An instrument for the determination of a sound spectrum.
Receiver
A person (or persons) or equipment which is affected by noise.
Reflected Sound
Sound that persists in an enclosed space as a result of repeated reflections or scattering. It does not include sound
that travels directly from the source without reflections.
Reverberation
The persistence of a sound in an enclosed or partially enclosed space after the source of the sound has stopped, due
to the repeated reflection of the sound waves.
Room Absorption
The total absorption within a room due to all objects, surfaces and air absorption within the room. It is measured in
Sabins or metric Sabins.
Slow Response
A setting on the sound level meter that determines how measured sound levels are averaged over time. A slow
sound level is more influenced by sounds occurring in the distant past that the corresponding fast sound level.
Sound
A physical disturbance in a medium (e.g., air) that is capable of being detected by the human ear.
Sound Absorption Coefficient
A measure of the sound -absorptive property of a material.
Sound Insulation
The capacity of a structure or element to prevent sound from reaching a receiver room either by absorption or
reflection.
Sound Level Meter (SLM)
An instrument used for the measurement of sound level, with a standard frequency -weighting and standard
exponentially weighted time averaging.
Appendix A - Glossary of Acoustical Terms
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Sound Power Level
A physical measure of the amount of power a sound source radiates into the surrounding air. It is measured in
decibels.
Sound Pressure Level
A physical measure of the magnitude of a sound. It is related to the sound's energy. The terms sound pressure level
and sound level are often used interchangeably.
Sound Transmission Class (STC)
A single number rating used to compare the sound insulation properties of walls, floors, ceilings, windows, or
doors. This rating is designed to correlate with subjective impressions of the ability of building elements to reduce
the overall loudness of speech, radio, television, and similar noise sources in offices and buildings.
Source Room
A room that contains a noise source or sources.
Spectrum
The spectrum of a sound wave is a description of its resolution into components, each of different frequency and
usually different amplitude.
Tapping Machine
A device used in rating different floor constructions against impacts. It produces a series of impacts on the floor
under test, 10 times per second.
Tone
A sound with a distinct pitch.
Transmission Loss (TL)
A property of a material or structure describing its ability to reduce the transmission of sound at a particular
frequency from one space to another. The higher the TL value the more effective the material or structure is in
reducing sound between two spaces. It is measured in decibels.
White Noise
Noise that has approximately equal intensities at all frequencies.
Windscreen
A porous covering for a microphone, designed to reduce the noise generated by the passage of wind over the
microphone.
X -Percentile -Exceeded Sound Level
The A -Weighted sound level equaled or exceeded by a fluctuating sound level x percent of a stated time period.
E.g., the letter symbol L10 represents the sound level which exceeded for more than 30 minutes in an hour, L25 is
the sound level exceeded for more than 15 minutes in an hour, L8 is the sound level exceeded for more than 5
minutes in an hour, and L2 is the sound level exceeded for more than 1 minute in an hour.
Appendix A - Glossary of Acoustical Terms
20
From: Justin Puggioni [mailto:jpuggioni@baenc.com]
Sent: Thursday, July 6, 2017 11:47 AM
To: Dwayne Knudson <dknudson@ursaresources.com>
Cc: Jennifer Lind <jlind@ursaresources.com>; Cari Mascioli <CMascioli@ursaresources.com>; Tom Carter
<tcarter@baenc.com>; Jason Peetz <jpeetz@baenc.com>; Andrew Truitt <atruitt@baenc.com>
Subject: RE: Phase II NTC Items - Sound Study
Dwayne,
In terms of the explanation you require, as stated in the Noise Modeling section of the report, "The noise modeling was
completed with use of three-dimensional computer noise modeling software. All models in this report were developed
with SoundPLAN 7.4 software using the ISO 9613-2 standard. Noise levels are predicted based on the locations, noise
levels and frequency spectra of the noise sources, and the geometry and reflective properties of the local terrain,
buildings and barriers. To ensure a conservative assessment and compliance with ISO 9613-2 standards, light to
moderate winds are assumed to be blowing from the source to receptor." The noise contour maps were developed
using the same software and calculation method.
Based on the distance propagation equation, moving the BMC L Pad 100 ft to the north would result in less than 1 dB
difference in comparison with the modeled noise levels at Receptor A and Receptor B. This sound level difference would
be difficult to measure in the field and generally considered not perceptible.
For the noise modeling of the BMC A Pad production, I anticipate we won't have file data for this type of equipment.
Therefore, I will require noise measurements at 10, 25 and 50 ft north, south, east and west of the injection well pumps
while in operation. Each measurement should include octave or 1/3 octave band frequency data. If you're able to
provide this then please let me know. We will be putting a proposal together for this additional noise modeling shortly.
Thank you,
Justin Puggioni
Acoustical Technical Director
Behrens and Associates • Environmental Noise Control
13806 Inglewood Avenue 1 Hawthorne, California 1 90250
Office 310 679 8633 • Direct 424 456 7055 • Fax 310 331 1538
www.environmental-noise-control.com 1 www.drillingnoisecontrol.com
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