HomeMy WebLinkAbout1.18 Noise assessment studyCHEVRON PICEANCE BASIN NATURAL
GAS DEVELOPMENT PROJECT
(GARFIELD COUNTY, COLORADO)
RESULTS OF A PRELIMINARY ACOUSTICAL ASSESSMENT OF
THE PROJECT WHICH INCLUDES A CENTRAL PRODUCTION
FACILITY AND SEVERAL NATURAL GAS WELL SITES
H &K Report No. 2205
H &K Job No. 4004
Date of Report: March 13, 2008
Prepared for:
Environmental Resources Management (ERM)
6455 S Yosemite St. Ste. 900
Greenwood Village, Colorado 80111 -4954
Project Applicant: Chevron North America Exploration and Production
Submitted by:
Paul D. Kiteck, P.P. (primary author)
Hoover & Keith Inc.
11391 Meadowglen, Suite D
Houston, Texas 77082
Hoover & Keith Inc.
Consultants in Acoustics and Noise Control Engineering
11391 Meadowglen, Suite D, Houston, TX 77082
Phone: (281) 496 -9876
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
REPORT SUMMARY
Hoover & Keith Inc.
H&K Job No. 4004
H &K Report No. 2205 (03113108)
This report includes the results of a preliminary acoustical assessment of the Chevron Piceance
Basin Natural Gas Development Project to be located primarily in Garfield County, Colorado,
which includes a Central Production Facility (i.e., a natural gas gathering /transmission compressor
station) along with booster compressors and several well sites that will include well drilling activities.
The primary purpose of the acoustical assessment is estimate the sound attributable to project
facilities that could generate noise, such as the Central Production Facility (CPF), compare the
results of the acoustical assessment to applicable sound criteria and assess the potential noise
impact of the project facilities. In addition, a limited amount of ambient sound tests were conducted
at the project site, and based on the measured ambient sound data, the ambient sound levels for the
area surrounding the project are 25 dBA to 35 dBA (typical ambient A -wt. sound level of 30 dBA).
At a distance of 1 mile south of the facility (in the area of the canyon, along Clear Creek Road), the
estimated sound contribution of the CPF during operation is 35 dBA. Consequently, at the closest
occupied residences to the CPF (i.e., homes at the intersection of Clear Creek Road & CR -204,
approx. 6 miles south of the CPF), the noise attributable to the CPF should be significantly lower
than the typical ambient sound level (e.g., 30 dBA), and therefore, the noise of the CPF should not
be audible at the closest residences to the CPF.
The estimated sound contribution of the CPF during operation at the closest "non- Chevron" property
of potential noise concern (i.e., Colorado Nature Ranch; closest property line located approx. 4,000
feet west of the CPF) is 26 dBA, which is equal to or lower than the ambient sound level for this
area. Consequently, the "potential noise increase" of the ambient noise level at the closest non -
Chevron property (i.e., Colorado Nature Ranch) during full load operation of the CPF should be less
than 3 dB. As a result, the noise of the CPF may be slightly perceivable /audible at areas of the
Colorado Nature Ranch that are closest to the CPF but the noise of the CPF should have minimum
noise impact.
In regard to the Colorado Oil and Gas Conservation Committee (COGCC) Rules and Regulations,
the results of the acoustical assessment indicates that the noise attributable to the project facilities
(e.g., noise generated by the CPF and other noise - generating facilities) should be well below the
maximum permissible levels specified in the COGCC Rules and Regulations for this type of facility.
For reference, it is anticipated that any other facilities associated with the project, such as the
operation of booster compressors in the project area and/or well drilling operations on well pads, will
generate lower sound levels than the CPF during full load operation.
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ERM -- Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
TABLE OF CONTENTS
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
Page
1.0 INTRODUCTION 1
2.0 BRIEF DESCRIPTION OF THE SITE AND FACILITIES 1
3.0 SOUND CRITERIA, TYPICAL METRICS AND TERMINOLOGY 2
4.0 MEASUREMENT RESULTS, OBSERVATIONS AND METHODOLOGY 3
4.1 Measurement Equipment and Data Acquisition 3
4.2 Summary of the Measured Ambient Sound Levels and Observations 3
5.0 ACOUSTICAL ANALYSIS (CPF) 4
6.0 SUMMARY OF NOISE CONTROLS AND /OR EQUIPMENT NOISE LEVELS 6
6.1 Building Enclosing the Engines /Compressors 6
6.2 JW Cooler for Each Gas Compressor Unit 6
6.3 Turbine and Generator for the Gen -Set 6
6.4 Exhaust of the Gen -Set Turbine 6
6.5 Engine Exhaust and Engine Air Intake 6
7.0 SUMMARY AND FINAL COMMENT 7
APPENDIX: FIGURES, SOUND DATA, RESULTS OF ANALYSIS, DESCRIPTION OF ANALYSIS
METHODOLOGY, SOURCE OF SOUND DATA, COGCC REGULATIONS, TERMINOLOGY......... 8 -23
Figure 1: "Overview" of Project Area, Areas of Interest & Sound Measurement Positions ...9
Figure 2: "Closer" View of Area around CPF and Sound Measurement Positions 10
Figure 3: Conceptual Layout of Buildings and Equipment for the CPF 11
Description of the Analysis Methodology and Source of Data 12 -13
Table A: Est'd Sound Contribution of the CPF during Operation at 1/2 Mile 14
Table B: Est'd Sound Contribution of the CPF during Operation at 1 Mile.. 15
Table C: Est'd Sound Contribution of the CPF at the Colorado Nature Ranch 15
COGCC Noise Requirements (800 Series of the Rules and Regulations) 16 -17
Summary of Metrics for Regulating Environmental Noise and Acoustical Terminology 19-22
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ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
1.0 INTRODUCTION
Hoover & Kelth Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13108)
in this report, we include the results of a preliminary acoustical assessment of the Chevron
Piceance Basin Natural Gas Development Project to be located primarily in Garfield County,
Colorado. In addition, a limited amount of ambient sound tests were conducted at the project site
and a summary of the ambient sound tests are included. The primary purpose of the acoustical
assessment is estimate the sound attributable to project facilities that could generate noise,
compare the results of the acoustical assessment to applicable sound criteria and assess the
potential noise impact of the project facilities.
2.0 BRIEF DESCRIPTION OF THE SITE AND FACILITES
Figure 1 (Appendix, p. 9) shows an 'overview" of the project area showing the general location
of project facilities, location of the ambient sound measurement positions and other areas of
interest. Figure 2 (Appendix, p. 10) shows a "closer view' of the primary project facilities (e.g.,
CPF and nearby well sites) and location of ambient sound measurement positions around the
area of the CPF.
The project is located primarily in Garfield County, Colorado, in the area of the Piceance Basin
(CO), approximately 16 miles NNW of DeBeque (CO). The land around the project is mostly
rough terrain /mountains with activities related to the gas exploration /transmission in the area, and
property for the project/area that is owned by Chevron is relatively large. In summary, the project
includes a Central Production Facility (CPF), which is a natural gas gathering /transmission
compressor station, booster compressors and several well sites that will include well drilling
activities.
The closest residences and other potentially noise- sensitive areas (e.g., Cowboy Chapel) not
located on Chevron property are approximately 6 miles south the CPF (i.e., near the intersection
of Clear Creek Rd. with CR -204). There are also a couple houses on the Chevron property
located along Clear Creek Road. The closest non- Chevron property of potential noise concern is
the area of the Colorado Nature Ranch, for which its closest property line is approximately 4,000
feet west of the CPF.
Figure 3 (Appendix, p. 11) shows the current preliminary layout of buildings /equipment for the
CPF. A total of four (4) engine- driven compressor units will be initially employed at the CPF for
natural gas gathering /transmission. Each compressor unit will consist of a Caterpillar (CAT)
Model G3520 engine driving a "high- speed" reciprocating gas compressor. The engines and
compressors for gas compressor units will be enclosed in an insulated metal building (i.e.,
Compressor Building). The following describes auxiliary equipment and other notable equipment
at the CPF:
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13108)
➢ Outdoor engine jacket -water (JW) air - cooled heat exchanger (i.e., JW cooler) for each main
gas compressor, each JW cooler is designed a vertical fan that are direct- driven by the
engine (Le., via belts /sheaves), and the JW cooler will also function as a gas aftercooler;
➢ Exhaust engine system designed with an exhaust muffler system;
➢ Engine air intakes, which include an air filter /cleaner system;
➢ Aboveground gas piping and piping system components (e.g., inlet separators, fuel gas
scrubber, intermediate separator) along with other miscellaneous equipment.
➢ One (1) Solar turbine- driven generator and the turbine /generator for the gen -set to be
installed inside a skid - mounted Solar acoustical enclosure.
➢ Turbine exhaust for each gen -set will include an exhaust muffler.
There also will be a need to utilize booster compressor units (i.e., "smaller" engine - driven
compressor units) at or near some of the planned well sites. We understand that these booster
compressor units will each be designed with a skid- mounted acoustical enclosure covering the
engine - compressor for each package, and each package will include an outdoor engine JW /utility
cooler designed with a vertical fan that is direct- driven by the engine (i.e., via belts /sheaves).
3.0 SOUND CRITERIA, TYPICAL METRICS AND TERMINOLOGY
The Colorado Oil and Gas Conservation Committee ( COGCC) regulate the oil and gas drilling
and production industry in the State of Colorado and the mission of the COGCC is to promote the
responsible development of Colorado's oil and gas natural resources. The COGCC has the
responsibility for regulating noise from natural gas facilities in Colorado, and Series 800 (Le.,
"Aesthetic and Noise Control Regulations"; Section 801 and Section 802) of the COGCC Rules
and Regulations address noise requirements (i.e., maximum allowable noise levels) for natural
gas facilities in the State of Colorado. The complete noise regulations given in the COGCC
Rules and Regulations are provided toward the end of the report (Appendix, pp. 16-17). The
following summarizes our interpretation of the noise requirements of the COGCC Rules and
Regulations as it applies to this project and the noise generated during operation of the CPF and
other project facilities (e.g., booster compressors or well drilling activities):
➢ In remote locations, where there is no reasonably proximate occupied structure or designated
outside activity area, similar to the area surrounding the site of the CPF or booster
compressor(s) for this project, the Tight industrial standard may be applicable. Consequently,
to comply with the COGCC noise regulations, it is assumed that the noise radiated at the
Chevron property line should not exceed a nighttime level of 65 dBA (i.e., between 7:00 PM
to the next 7:00 AM), and at the property line of any residential -zoned area (e.g., closest
residences), the noise generated by the CPF or booster compressors should not exceed a
nighttime sound level of 50 dBA (i.e., between 7:00 PM to the next 7:00 AM).
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
In addition, if the intruding noise (e.g., noise of CPF during operation) causes less than a 3 dB
increase in the overall ambient noise at nearby NSAs (Le., defined as "potential noise increase "),
the noise should be barely audible /perceivable by the human ear and should have minimum
noise impact on the acoustical environment. If the intruding noise causes an increase in the
overall ambient noise of between 4 dB and 9 dB, the intruding noise may be audible by the
human ear but should still have minimum noise impact on the acoustical environment.
For the reader's information, a summary of applicable acoustical terminology in this report and
typical metrics used to measure and regulate environmental noise is provided at the end of the
report (Appendix, pp. 19 — 22).
4.0 MEASUREMENT RESULTS, OBSERVATIONS AND METHODOLOGY
4.1 Measurement Equipment and Data Acquisition
A limited amount of ambient sound measurements at the project site were performed by Paul
Kiteck of H &K during our site visit in the daytime January 29, 2008. At each sound measurement
position, the equivalent A -wt. sound level (i.e., Leq) and unweighted octave -band (O.B.) sound
pressure levels (i.e., SPLs) were measured at 5 feet above ground. Sound measurements
attempted to exclude "extraneous sound" such as cars or trucks passing immediately by the
sound measurement location or other intermittent sources not typical of the ambient noise
environment. The sound measurement system consisted of a Larson -Davis (LD) Model 2900
Real Time Analyzer /Sound Level Meter (a Type I SLM per ANSI Standard S1.4 & S1.11) and a
112 -in. condenser microphone with windscreen (analyzer /SLM calibrated with a LD Model CA250-
0493 microphone calibrator that was calibrated within 1 year of the service date).
4.2 Summary of the Measured Ambient Sound Levels and Observations
The following Table 1 summarizes the measured /reported ambient daytime A -wt. sound levels
(i.e., Leq) and some the sound measurement positions were taken relatively close to existing well
drilling activities. Note that the ambient daytime Leq (i.e., also referred to as Ld) assumed to be
similar to or equal to the ambient nighttime A -wt. sound levels (i.e., Ln).
Meas.
Pos.
Description of Sound Measurement Location
Range of Meas'd
Daytime A -Wt. Sound
Levels (i.e., Ld)
Pos. 1
Area of a house on Chevron Property, located along Clear Creek Road.
26 to 35 dBA
Pos. 2
Area near the location of the CPF, along Toms Creek Road
28 to 32 dBA
Pos. 3
Along Clear Creek Rd, 600 feet east of well drilling operations at Well 598-35-AV
46 to 48 dBA*
Pos. 4
Approximately 250 feet south of well drilling operations at Well 598 -26 -AV
60 to 61 dBA*
Pos. 5
Approximately 300 feet south of well drilling operations at Well 598 -35 -AV
58 to 59 dBA*
Table 1: Summary of the Meas'd Daytime A -Wt. Sound Levels at Areas of Interest for he Project
*Noise of the well drilling operations (i.e., drilling rig at the well site) was the dominate noise source.
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
During the site visit on Jan. 29 ('08), the meteorological conditions were as follows: Temperature
of 23 — 27 deg. F., mostly clear sky and there was a light wind primarily from the north. During
the daytime sound tests at the ambient sound measurement positions not located near well
drilling activities (i.e., Pos. 1 & Pos. 2), the audible noise sources that contributed to the ambient
noise included distant construction equipment, the sound of birds, the sound of wind blowing in
the trees /grass and at times, the noise of distant aircraft. We believe that the measured ambient
sound data at Meas. Pos. 1 and Meas. Pos. 2 represents the typically daytime and nighttime A-
wt. sound levels for the area during times of relatively low wind conditions. At measurement
positions located relatively close to well drilling activities (i.e., Pos. 3, Pos. 4 & Pos. 5), the noise
of the well drilling operations (Le., drilling rig) was the dominant noise source.
In summary, based on the measured sound data at the site, the typical ambient sound levels for
the area surrounding the project are 25 dBA to 35 dBA, with a typical ambient A -wt. sound level
of 30 dBA. Consequently, if the resulting /predicted sound level contribution due to the operation
of project facilities is equal to or less than the typical ambient level (e.g., 30 dBA); the noise of
the CPF and other project facilities will probably not be audible.
5.0 ACOUSTICAL ANALYSIS (CPF)
The noise associated with the CPF during full load operation is considered the primary facility for
the project that could generate significant noise. in addition, the noise of booster compressors
during operation and well drilling activities could generate noise, but it is anticipated that other
project facilities, such as booster compressors and well drilling activities, will generate lower
sound levels than the noise associated with the CPF during operation. The estimated sound
contribution of the CPF assumes the operation of 3 gas compressor units and 2 gen -sets. The
acoustical analysis of the CPF considers the noise produced by all continuous - operating
equipment that typically would operate at the facility. The following stationary noise sources
associated with the CPF were considered significant:
➢ Noise generated by the engines /compressors that penetrates the Compressor Building;
➢ Noise of the engine exhaust of each gas compressor unit;
➢ Noise radiated from aboveground gas piping and associated components;
➢ Noise of the outdoor JW cooler for each gas compressor unit;
➢ Noise associated with the turbine exhaust of each gen -set (includes an exhaust muffler);
➢ Noise of the turbine /generator that radiates from the generator skid- mounted enclosure.
For this acoustical analysis, we estimated the sound contribution of the CPF at different distances
(e.g., noise contribution at 1/2 mile and 1 mile south of the CPF, along the canyon, from the site)
and at the closest area to the CPF of potential noise concern (i.e., Colorado Nature Ranch). A
detailed description of the methodology for the acoustical analysis and the source of sound data
for the CPF acoustical assessment are provided in the Appendix (pp. 12 -13).
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
Table A (Appendix, p. 14) shows the spreadsheet calculation of the estimated A -wt. sound level
and unweighted O.B. SPLs at the a distance of approximately 1/2 mile south of the CPF (along the
canyon) as contributed by the CPF noise sources based on standard day conditions (i.e., no
wind, 60 deg. F., 70% R.H.) along with the estimated total noise of the CPF (i.e., noise of the
CPF plus the typical ambient noise). The analysis includes the effect of anticipated noise control
measures for the facility equipment.
Table B (Appendix, p. 15) is the spreadsheet calculation of the estimated A -wt. sound level and
unweighted O.B. SPLs generated by the CPF at the distance of approximately 1 mile south of the
CPF (along the canyon) as extrapolated from the estimated sound contribution at 1/2 mile (Le.,
results in Table A).
Table C (Appendix, p. 15) is the spreadsheet calculation of the estimated A -wt. sound level and
unweighted O.B. SPLs generated by the CPF at the closest property line of the Colorado Nature
Ranch (i.e., approximately 4,000 feet west of the CPF) as extrapolated from the estimated sound
contribution at 1/2 mile (i.e., results in Table A), noting that the Colorado Nature Ranch is
considered the closest non - Chevron area of potential noise concern.
The following Table 2 summarizes the calculated /estimated A -wk. sound levels of the CPF
assuming operation of 3 CAT engine- driven reciprocating compressor units and other
continuous - operating equipment at the CPF.
Facility Operating Condition and Description of the Location
Est'd A -Wt. Sound
Level Contribution
of the CPF
Est'd sound contribution of CPF during operation at 1,4 mile from site center (along canyon)
43 dBA
Est'd sound contribution of the CPF during operation at 1 mile from site center (along canyon)
35 dBA
Est'd sound contribution of CPF at CO Nature Ranch (closest property line 4,000' west of CPF)
26 dBA
Table 2: Est'd A -Wt. Sound Level of the CPF at Several Distances and at the Closest Area to the CPF of
Potential Noise Concern (i.e., Colorado Nature Ranch).
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
6.0 SUMMARY OF NOISE CONTROL AND /OR EQUIPMENT NOISE LEVELS FOR PROJECT
The following section provides a summary of anticipated noise control measures and equipment
noise levels associated with the CPF equipment along with other assumptions or
recommendations that may affect the noise generated by the CPF during operation.
6.1 Building Enclosing the Engines /Compressors
Noise control measures will be applied to the building (Compressor Building) enclosing the
engines and compressors rather than to the equipment themselves. The following describes
specific requirements and other items related to the building components.
> The walls /roof will be constructed with an exterior metal skin, and it is recommended as a
minimum, employ 24 —gauge metal. Building interior surfaces will be covered with insulation,
and it is recommended as a minimum, 6 -inch thick "high- density" mineral wool (6.0 -8.0 pcf
uniform density), covered with a perforated liner.
6.2 JW Cooler for Each Gas Compressor Unit
Based on sound tests by H &K of the JW cooler for the gas compressor unit, the A -wt. sound
level is approximately 72 -74 dBA at a distance of 50 feet.
6.3 Turbine and Generator for the Gen -Set
The turbine and associated generator for each gen -set will be installed in a Solar acoustical skid -
mounted enclosure, typically designed to achieve an A -wt. sound level of approximately 85 dBA
at 3 feet from the enclosure during operation of the gen -set,
6.4 Exhaust of the Gen -Set Turbine
The muffler for the turbine exhaust associated with the gen -set will be a Solar Model AX -5530
dissipative -type muffler with an overall length of 228 inches (i.e., 19 feet, from ground to stack
exhaust flange) and diameter of 72 inches (i.e., 6 feet).
6.5 Engine Air Intake and Engine Exhaust
The engine exhaust for each gas compressor unit will include a "residential- grade" muffler, and
the engine air intake(s) for each gas compressor unit with include a "standard" air filter.
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
7.0 SUMMARY AND FINAL COMMENT
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
At a distance of 1 mile south of the facility (in the area of the canyon, along Clear Creek Road),
the estimated sound contribution of the CPF during operation is 35 dBA. Consequently, at the
closest occupied residences to the CPF (Le., homes at the intersection of Clear Creek Road &
CR -204, approx. 6 miles south of the CPF), the noise attributable to the CPF should be
significantly lower than the typical ambient sound level (e.g., 30 dBA), and therefore, the noise of
the CPF should not be audible at the closest residences.
The estimated sound contribution of the CPF during operation at the closest "non- Chevron"
property of potential noise concern (Le., Colorado Nature Ranch; closest property line located
approx. 4,000 feet west of the CPF) is 26 dBA, which is equal to or lower than the ambient sound
level for this area. Consequently, the "potential noise increase" of the ambient noise level at the
closest non - Chevron property (i.e., Colorado Nature Ranch) during operation of the CPF should
be less than 3 dB. As a result, the noise of the CPF may be slightly perceivable at areas of the
Colorado Nature Ranch that are closest to the CPF but the noise of the CPF should have
minimum noise impact.
For reference, it is anticipated that any other facilities associated with the project, such as the
operation of booster compressors in the project area and/or well drilling operations on well pads,
will generate lower sound levels than the CPF during full load operation.
In regard to the COGCC Rules and Regulations, the results of the acoustical assessment
indicates that the noise attributable to the project facilities (e.g., noise generated by the CPF and
other noise - generating facilities) should be well below the maximum permissible levels specified
in the COGCC Rules and Regulations for this type of facility.
As a final comment, to insure that the project facilities generate minimum noise impact, H &K will
provide review the noise - related equipment submittals and other design features (e.g.,
Compressor Building design) during the detailed design phase for the project.
File. Pro WordfRMSChevran Piceance PrajecFRepod - Noise Assessment for Chevron Piceance Development Projecl.dec
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
APPENDIX
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
➢ FIGURE 1: OVERVIEW LAYOUT AROUND THE
PROJECT SITE, AREAS OF INTEREST
AND SOUND MEASUREMENT POSITIONS
➢ FIGURE 2: CLOSER AREA LAYOUT AROUND THE
PROJECT SITE /CPF AND AMBIENT
SOUND MEASUREMENT POSITIONS
➢ FIGURE 3: CONCEPTUAL LAYOUT OF BUILDINGS &
EQUIPMENT FOR THE CPF
➢ ANALYSIS METHODOLOGY (NOISE ATTRIBUTABLE TO
THE CPF) AND THE SOURCE OF SOUND DATA
➢ ACOUSTICAL ANALYSIS (CFP)
➢ COLORADO OIL & GAS CONSERVATION COMMISSION
(COGCC) NOISE REGULATIONS (800 SERIES OF THE
RULES AND REGULATIONS)
➢ SUMMARY OF TYPICAL METRICS FOR REGULATING
ENVIRONMENT NOISE AND ACOUSTICAL
TERMINOLOGY
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
WELL SITE
598.26 WITH
BOASTER -1 AREA OF
COMPRESSOR - BOOSTER
PARCEL ■ COMPRESSOR
POS. 3 -) �t BOUNDARY
WELL SITE
598 -25- V
L 7
WELL SITE
159835 WITH
BOOSTER
I COMPRESSOR
CLEAR
CREEK RD.
(CR -211)
POS. 2
WELL SITE
598 -25-BV
WELL SITE
598 -25 -CV
TOM CREEK RD.
BOUNDARY WITH
COLORADO
NATURE
RANCH
COLORADO NATURE
RANCH BOUNDARY
APPROX. 4,000'
FROM CPF
LEG END
- NON - RESIDENTIAL BUILDING
- HOUSE OR MOBILE HOME
NSA- NOISE SENSITIVE AREA
- MEASUREMENT POSITION
- WELL SITE
APPROXIMATE SCALE IN FEET
0 2700 5400 10800
CENTRAL
PRODUCTION
FACILITY ICPF)
WELL SITE
36-1
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
SHINER
RIDGE
HINER GATE
(TEMPORARY
OFFICE)
SHINER
RIDGE - -P..-
HOUSE ON
CHEVRON
PROPERTY
CLEAR
- CREEK RO.
(CR -211)
CLEAR
CREEK
SHINER
RIDGE
HOUSE ON
CHEVRON
PROPERTY
I POS.1
SHINER
RIDGE —I.-
ROAN
CREEK RD.
(CR -204)
COWBOY C
OTHER - .—. CHAPEL 5
HOMES ��-�•
ROAN - 1 \t ROAN
CREEK d CREEK RO.
(CR -204)
CLEAR
CREEK
CLEAR
CREEK RD.
(CR -211)
CLOSEST
RESIDENCES
NOT ON
CHEVRON
PROPERTY
CLEAR
CREEK
TREES
Figure 1: Chevron Piceance Development Project: "Overview" Layout Showing the Project
Facilities, Other Areas of Interest and Ambient Sound Measurement Positions.
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ERM -- Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
POS. 4 (250' FROM
WELL DRILLING RIG --
DURING OPERATION)
WELL SITE
598 -26 WITH
BOOSTER
COMPRESSOR!
---_, PARCEL
BOUNDARY
WELL SITE
598 -35 WITH _
BOOSTER 1 \
COMPRESSOR
POS.3 1
Hoover & Kelth Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13108)
WELL SITE !
598- 25 -AV
AREA OF
BOOSTER
COMPRESSOR
WELL SITE _Y
598 -25 -BV
CLEAR
CREEK RD.
(CR -211)
POS. 5 (300' FROM � ~`
WELL DRILLING RIG
WELL SITE
598 -25 -CV �� \
TOM CREEK /-1
RD,
DURING OPERATION)
BOUNDARY WITH
COLORADO
NATURE
RANCH
7
POS. 2
L -`, \
COLORADO NATURE ��1
RANCH BOUNDARY
APPROX. 4,080' L
FROM CPF JJ j
SHINER
RIDGE ■
LEGEND
o - NON - RESIDENTIAL BUILDING
- HOUSE OR MOBILE HOME
NSA- NOISE SENSITIVE AREA
- MEASUREMENT POSITION
} - WELL SITE
APPROXIMATE SCALE IN FEET
0 1100 2200
4400
Figure 2: Chevron Piceance Development Project: "Closer" Area View of Project Facilities and
Area(s) of Interest and Sound Measurement Positions in the Area of the CPF.
-Page 10-
CENTRAL
PRODUCTION
FACILITY (CPF)
WELL SITE
36-1
ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
WAREHOUSE
BUILDING
ELECTRICAL ELECTRICAL COMMUNICATIONS
s BUILDING SUSTATFON BUILDING
'I
EE DE
GENIES. L
CONTROL
BUILDING
1NSTR
Al R
SKID D
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
TRUE
NORTH
TOM CREEK RD.
El
❑
TURBINE - DRIVEN
GEN-SET
1 L
CLEAR
CREEK RD.
(CR -211)
LIQUID
SEPARATOR
GAS
SEPARATOR
GLYCOL GAS FILTER
TOWER / SEPARATOR
PUMPS
COND.
LOADING
\KID
000J
0 0 0 0 DIKE
7
VRU f 1I
/1
FUEL GAS
j SKID
PIPE RACK
FLARE SCRUBBER
PUMP SKID
PIPE RACK
COMPRESSOR
BUILDING WITH
ENGINE DRIVEN
COMPRESSOR UNITS
GLYCOL
REBOILER / SURGE
SKID
FENCELINE
CENTRAL APPROXIMATE SCALE IN FEET
PRODUCTION
FACILITY (CPF) 1 0 35 70
Figure 3: Chevron Piceance Development Project: Conceptual Layout of the Buildings and
Equipment at the Central Production Facility (CPF).
-Page 11-
y
140
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
ANALYSIS METHODOLOGY (NOISE ATTRIBUTABLE TO CPF)
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
In general, the predicted sound level contributed by the CPF equipment was calculated as a function of
frequency from estimated unweighted octave -band (0.B.) sound power levels (PWLs) for each significant
sound source. The following summarizes the acoustical analysis procedure for the Station:
➢ Initially, unweighted O.B. PWL values of the significant noise sources were determined from
equipment manufacturer's sound data and/or actual sound level measurements performed by H &K at
similar type of equipment/components expected for this gas compressor facility.
➢ Then, expected noise reduction (NR) or attenuation in dB per O.B. frequency due to any noise control
measures, hemispherical sound propagation (discussed in more detail below*) and atmospheric
sound absorption (discussed in more detail below * *) were subtracted from the unweighted octave -
band PWLs to obtain the unweighted 0.B. SPLs of each noise source. Since sound shielding by
buildings can influence the sound level contributed at the NSAs, we also included the sound shielding
due to buildings, if appropriate. The sound attenuation effect due to foliage or land contour was not
considered in the analysis although there probably will be some attenuation due to foliage /trees.
➢ Finally, the resulting estimated unweighted O.B. SPLs for all noise sources associated with the
Station (with noise control and other sound attenuation effects) were logarithmically summed, and the
total 0.B. SPLs for all noise sources were corrected for A- weighting to provide the estimated overall
A -wt. sound level contributed by the Station at the closest NSA. The predicted sound contribution of
the Station at the closest NSA was utilized to estimate the Station noise contribution at the other
nearby NSAs that are more distant that the closest NSA.
*Attenuation due to hemispherical sound propagation: Sound propagates outwards in all directions (Le.,
length, width, height) from a point source, and the sound energy of a noise source decreases with
increasing distance from the source. In the case of hemispherical sound propagation, the source is
located on a flat continuous plane/surface (e.g., ground), and the sound radiates hemispherically (i.e.,
outward, over and above the surface) from the sound source. The following equation is the theoretical
decrease of sound energy when determining the resulting SPL values of a noise source at a specific
distance Cr) of a receiver from the estimated PWL values:
Decrease in SPL ( "hemispherical propagation ") from a noise source = 20 *Iog(r) — 2.3 dB
where "r" is distance of the receiver from the noise source.
* *Attenuation due to air absorption: Air absorbs sound energy, and the amount of absorption
( "attenuation ") is dependent on the temperature and relative humidity (R.H.) of air and frequency of
sound. For example, the attenuation due to air absorption for 1000 Hz O.B. SPL is approximately 1.5 dB
per 1,000 feet for standard day conditions (i.e., no wind, 60 deg. F. and 70% R.H.).
-Page 12-
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
SOURCE OF SOUND DATA (CPF)
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
The following describes the source of sound data used for estimating the source sound levels and /or the
source PWLs for the CPF (e.g., engines /compressors and other equipment/components associated with
the compressor installation).
(1)
Estimated PWL values of equipment inside the building (i.e., engines, compressors and other
equipment inside the building) was calculated from sound data measured by H &K on a similar
type of compressor installation.
(2) Exhaust PWL values were calculated from field sound data measured by H &K on a similar type of
engines to be utilized at this facility. The DIL values for the exhaust muffler are generally lower
than the recommended values in order that the analysis incorporates a "margin of safety."
(3)
Noise radiated from aboveground piping is primarily a result the noise generated by the gas
compressors. Consequently, measurement of both near field and far field sound data on gas
piping is presumed to be an accurate method of quantifying the noise associated with the piping,
and estimated PWL values for piping in the analysis were determined from near field and far field
sound data by H &K on a similar type of compressor to that of the proposed compressor unit.
(4) The estimated PWL values for coolers (e.g., JW /aux cooler and gas cooler) were designated to
meet the design noise goal and the estimated PWL values for the cooler utilized in the acoustical
analysis assumes some noise associated with piping associated with the coolers. The noise
level for the cooler used in the acoustical analysis is generally higher than the sound level
requirement in order that the noise design analysis incorporates an acoustical "margin of safety."
In addition, there can be other noise associated with the cooler that is not directly related to the
operation of the cooler fans.
(5) The estimated PWL values for the engine air intake were calculated from measured sound data
in the field tests by H &I< on similar engine that will be employed.
-Page 13-
ERM -- Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
Source No.
& Dist (Ft)
Noise Sources and Other Conditions/Factors
associated with Acoustical Analysis
PWL or SPL in dB Per Octave-Band Center Frequency (Hz)
2600
2600
2600
PWL of Engines /Compressors inside Bldg. (4 Units)
Attenuation of the Building
NR of any Additional Noise Mitigation Measures
Misc. Atten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
31.51 63 1 125 1 250 1 500 1 1000 j 2000 j 4000 8000
112
-6
0
0
-66
0
40
115
-10
0
0
-66
0
39
120
-16
0
0
-66
-1
37
118
-20
0
0
-66
-1
31
118
-22
0
0
-66
-2
28
116
-25
0
0
-66
-4
21
118
-30
0
0
-66
-8
14
118
-32
0
0
-66
-20
0
115
-32
0
0
-66
-36
0
A -Wt.
Level
124
29
2)
2600
2600
2600
3)
2600
2600
2600
4)
2600
2600
2600
PWL of Unsilenced Engine Exhaust (1 Unit)
PWL of Unsilenced Exhaust for 4 Units ( +6 dB)
Atten. of Noise Control (Exhaust Muffler)
NR of any Additional Noise Mitigation Measures
Misc. Atten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
PWL ofJW /Utiiity Cooler for 1 Unit
PWL of All 4 JWAJtility Coolers ( +6 dB)
120
126
-16
0
0
-66
0
44
125
131
Atten. of Noise Control
NR of any Additional Noise Mitigation Measures
Misc. Atten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
PWL of Unsilenced Turbine Exhaust of Gen Set (1 Uni
Atten. of Noise Control (Exhaust Muffler)
Misc. Atten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
110
116
-22
0
0
-66
0
43
112
118
132
138
-30
0
0
-66
-1
41
108
114
126
132
-35
0
0
-66
-1
30
105
111
124
130
-38
0
0
-66
-2
24
102
108
126
132
-38
0
0
-66
-4
24
98
104
126
132
-35
0
0
-66
-8
23
95
101
114
120
-25
0
0
-66
-20
9
92
98
100
106
-20
0
0
-66
-36
0
88
94
131
137
31
104
110
0
0
0
-66
0
50
120
-2
0
-66
0
52
0
0
0
-66
0
52
123
-5
0
-66
0
52
0
0
0
-66
-1
47
120
-12
0
-66
-1
41
0
0
0
-66
-1
44
123
-22
0
-66
-2
33
0
0
0
-66
-2
40
127
-30
0
-66
-2
29
0
0
0
-66
-4
34
119
-30
0
-66
-4
19
0
0
-66
-8
27
112
-28
0
-66
-8
10
0
0
0
-66
-20
12
104
-25
0
-66
-20
0
0
0
0
-66
-36
0
96
-20
0
-66
-36
0
41
126
32
5)
2600
2600
2600
PWL of Outdoor Gas Piping for All Compressor Units
NR of Noise Control
Misc. Atten. (e.g., Shielding by Compr. Bldg.)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
105
0
0
-66
0
39
104
0
0
-66
0
38
102
0
0
-66
35
100
0
0
-66
-1
33
98
0
0
-66
-2
30
95
0
0
-66
-4
25
92
0
0
-66
-8
18
90
0
0
-66
-20
4
88
0
0
-66
-36
0
101
6)
2600
2600
2600
PWL of Turbine-Driven Gen Set (1 Unit)
NR of any Additional Noise Mitigation Measures
Misc. Atten. (e.g., Shielding by Compr. Bldg.)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
104
0
0
-66
0
38
2600
2600
2600
PWL of Pumps, VRUs, Coolers, Glycol Regen. Skid
NR of any Additional Noise Mitigation Measures
Misc. Alten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
105
0
0
-66
0
39
97
0
0
-66
0
31
102
0
0
-66
0
36
98
0
0
-66
_1
31
98
0
0
-66
-1
31
97
0
0
-66
-1
30
95
0
0
-66
-1
28
100
0
0
-66
-2
32
92
0
0
-66
-2
24
96
0
0
-66
-4
26
90
0
0
-66
-4
20
96
0
0
-66
-8
22
88
0
0
-66
-8
14
92
0
0
-66
-20
6
86
0
0
-66
-20
0
85
0
0
-66
-36
0
85
0
0
-66
-36
0
31
102
32
96
26
Est'd Total Sound Contribution of CPF at 1/2 mile south of Site f 55 f 55 150 145 I 42 1 36 130 115 1 0 1 43.1
Typical Ambient Sound Level at this Location 1 30.0
Est'd Sound Level of CPF plus Ambient Level (dBA)
43.3
'Est'd Potential Increase {dB)
13.3
Table A: Chevron Piceance Central Production Facility (CPF): Est'd Sound Contribution of the CPF at Approx.
1/2 Mile south of the Site (in the Area of Canyon) assuming Operation of Four (4) Compressor Units
(i.e., CAT Model 63520 Engine - Driven CompressorUnits) and One (1) Solar Gen Set.
NOTE: DIL, NR & PWL values on this spreadsheet analysis should not be used as the specified values.
Refer to the "Noise Control & Sound Requirements" in the report or other company specifications.
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13108)
Source No.
& Dist (Ft)
Noise Sources and Other Conditions/Factors
associated with Acoustical Analysis
SPL in dB Per Octave -Band Center Frequency (Hz)
A -Wt.
Level
31.5
63
125
250
500
1000
2000
4000
8000
4000
4000
Esfd SPLs of Station at 2600 Ft. (RE: Table A)
55
55
50
45
42
36
30
15
0
43.1
5280
Hemisph Radiation [201og(5280/2600) = 6 d6]
-6.0
-6.0
-61)
-6.0
-6.0
-6.0
-6.0
-6.0
-6.0
5280
Atm. Absorption (70% R.H., 60 deg F)
0
0
-1
-1
-2
-4
-8
-20
-37
Est'd Total Sound Contribution of CPF at 1 mile south of Site
49
49
43
38 134 1
26
16
0
0 1 35.1
Typical Ambient Sound Level at this Location
30.0
Est'd Sound Level of CPF plus Ambient Level (d BA)
36.3
IEst'd Potential Increase (dB)
6.3
Table B: Chevron Piceance Central Production Facility (CPF): Est'd Sound Contribution of the CPF at Approx.
1 Mile south of the Site (in the Area of Canyon) assuming Operation of Four (4) Compressor Units
(Le., CAT Model G3520 Engine - Driven Compressor Units) and One (1) Solar Gen Set.
Source No.
& Dist (Ft)
Noise Sources and Other Conditions/Factors
associated with Acoustical Analysis
SPL in dB Per Octave -Band Center Frequency (Hz)
A -Wt.
Level
31.5
63
125
250
500
1000
2000
4000
8000
4000
4000
Esrd SPLs of Station at 2600 Ft. (RE: Table A)
Attenuation due to Shiner Ridge
Hemisph Radiation [201 og(4500/2600) = 3.7 dB]
Atm. Absorption (70 %R.H., 60 deg F)
55
-6
-3.7
0
55
-8
-3.7
0
50
-10
-3.7
0
45
-12
-3.7
-1
42
-14
-3.7
-1
36
-15
-3.7
-2
30
-18
-3.7
-4
15
-20
-3.7
-11
0
-20
-3.7
-19
43.1
Est'd Total Sound Contribution of the Station at NSA #3
45
43 ] 36
29
23 115
4
0
0
26.0
Typical Ambient Sound Level at this Location
f 30.0
Est'd Sound Level of Station pfus Ambient Ln (dBA)
31.5
IEst'd
Potential Increase (dB)
1.5
Table C; Chevron Piceance Central Production Facility (CPF): Est'd Sound Contribution of the CPF at Approx.
4,000 Ft. West of Site (CO Nature Ranch, West of Shiner Ridge) assuming Operation of Four(4)
Compressor Units (i.e., CAT Model G3520 Engine - Driven Compressor Units) and One (1) Solar Gen Set.
ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H&K Job No, 4004
H &K Report No. 2205 (03/13/08)
COLORADO OIL & GAS CONSERVATION COMMISSION (COGCC) NOISE
REQUIREMENTS (800 SERIES OF THE RULES AND REGULATIONS)
The COGCC regulates the oil and gas drilling and production industry in the State of Colorado and the
mission of the COGCC is to promote the responsible development of Colorado's oil and gas natural
resources. This "responsible development" balances efficient exploration and production of oil and gas
with the prevention of waste, protection of mineral owner's rights, and protection of public health, safety
and welfare and the environment. In Colorado, the COGCC has the responsibility for regulating noise
from oil and gas facilities.
AESTHETIC AND NOISE CONTROL REGULATIONS
(Rules related to Noise Regulations and Noise Abatement as of November 30, 2006)
801. INTRODUCTION
The rules and regulations in this section are promulgated to control aesthetics and noise impacts
during the drilling, completion and operation of oil and gas wells and production facilities. Any Colorado
county, home rule or statutory city, town, territorial charter city or city and county may, by application to
the Commission, seek a determination that the rules and regulations in this section, or any individual rule
or regulation, shall not apply to oil and gas activities occurring within the boundaries, or any part thereof,
of any Colorado county, home rule or statutory city, town, territorial charter city or city and county, such
determination to be based upon a showing by any Colorado county, home rule or statutory city, town,
territorial charter city or city and county that, because of conditions existing therein, the enforcement of
these rules and regulations is not necessary within the boundaries of any Colorado county, home rule or
statutory city, town, territorial charter city or city and county for the protection of public health, safety and
welfare.
802. NOISE ABATEMENT
a. The goal of this rule is to identify noise sources related to oil and gas operations that
impact surrounding landowners and to implement cost- effective and technically- feasible mitigation
measures to bring oil and gas facilities into compliance with the allowable noise levels identified in
subsection c. Operators should be aware that noise control is most effectively addressed at the siting and
design phase, especially with respect to centralized compression and other downstream "gas facilities"
(see definition in the 100 Series of these rules),
b. Oil and gas operations at any well site, production facility or gas facility, shall comply with
the following maximum permissible noise levels. 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. The type of land use of the surrounding area shall
be determined by the Commission in consultation with the local governmental designee taking into
consideration any applicable zoning or other local land use designation.
c. In the hours between 7:00 a.m. and the next 7:00 p.m. the noise levels permitted below
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.
-Page 16-
ERM -- Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
ZONE 7:00 am to next 7:00 pm 7:00 pm to next 7:00 am
(Daytime) (Nighttime)
Residential /Agricultural /Rural 55 db(A) 50 db(A)
Commercial 60 db(A) 55 db(A)
Light industrial 70 db(A) 65 db(A)
Industrial 80 db(A) 75 db(A)
in remote locations, where there is no reasonably proximate occupied structure or
designated outside activity area the light industrial standard may be applicable.
Pursuant to Commission inspection or upon receiving a complaint from a nearby property owner
or local governmental designee regarding noise related to oil and gas operations, the Commission shall
conduct an onsite investigation and take sound measurements as prescribed herein.
The following provide guidance for the measurement of sound levels and assignment of points of
compliance for all and gas operations:
(1) Sound levels shall be measured at a distance of three hundred and fifty (350) feet from the
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 fifty (350) feet from an existing occupied structure, sound levels shall be
measured at a point twenty -five (25) feet from the structure towards 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 three hundred and fifty (350) feet or at the
property line, whichever is greater.
In situations where measurement of noise levels at three hundred and fifty (350) feet is
impractical or unrepresentative due to topography, the measurement may be taken at a lesser
distance and extrapolated to a 350 -foot equivalent using the following formula:
db(A) @DISTANCE 2 = db(A) @DISTANCE 1 — 20 x Iog10(distance 2 /distance 1)
(2) Sound level meters shall be equipped with wind screens, and readings taken when the wind
velocity at the time and place of measurement is not more than five (5) miles per hour.
(3) Sound level measurements shall be taken four (4) feet above ground level.
(4) Sound levels shall be determined by averaging minute -by- minute measurements made over a
minimum fifteen (15) minute sample duration if practicable. The sample shall be taken under
conditions that are representative of the noise experienced by the complainant (e.g., at night,
morning, evening, or during special weather conditions).
(5) In all sound level measurements, the existing ambient noise level from all other sources in the
encompassing environment at the time and place of such sound level measurement shall be
considered to determine the contribution to the sound level by the oil and gas operation(s).
-Page 17-
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
d. in situations where the complaint or Commission onsite inspection indicates that low
frequency noise is a component of the problem, the Commission shall obtain a sound level measurement
twenty -five (25) feet from the exterior wall of the residence or occupied structure nearest to the noise
source, using a noise meter calibrated to the db(C) scale. If this reading exceeds 65 db(C), the
Commission shall require the operator to obtain a low frequency noise impact analysis by a qualified
sound expert, including identification of any reasonable control measures available to mitigate such low
frequency noise impact. Such study shall be provided to the Commission for consideration and possible
action.
e. Exhaust from all engines, motors, coolers and other mechanized equipment shall be
vented in a direction away from all occupied buildings.
f. All facilities within four hundred (400) feet of occupied buifdings with engines or motors
which are not electrically operated shall be equipped with quiet design mufflers or equivalent. All mufflers
shall be properly installed and maintained in proper working order.
➢ For reference the following is a summary of the COGCC noise requirements as it applies to the CPF,
per H &K interpretation:
In remote locations, where there is no reasonably proximate occupied structure or designated outside
activity area, similar to the area surrounding the site of the CPF or booster compressor(s) for this
project, the light industrial standard may be applicable. Consequently, to comply with the COGCC
noise regulations, it is assumed that the noise radiated at the Chevron property line should not
exceed a nighttime level of 65 dBA (i.e., between 7:00 PM to the next 7:00 AM), and at the property
line of any residential -zoned area (e.g., closest residences), the noise generated by the CPF or
booster compressors should not exceed a nighttime sound level of 50 dBA (i.e., between 7:00 PM to
the next 7:00 AM).
-Page 18-
ERM r Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
SUMMARY OF TYPICAL METRICS FOR REGULATING ENVIRONMENTAL NOISE
AND ACOUSTICAL TERMINOLOGY RELATED TO THE REPORT
(1) Decibel (dB): A unit for expressing the relative power level difference between acoustical or
electrical signals. It is ten times the common logarithm of the ratio of two related quantities that
are proportional to power. When adding dB or dBA values, the values must be added
logarithmically. For example, the logarithmic addition of 35 dB plus 35 dB is 38 dB.
(2) A- Weighted Sound Level (dBA): The A -wt. sound level is a single - figure sound rating, expressed
in decibels (Re 20 µPa), which correlates to the human perception of the loudness of sound. The
dBA level is commonly used to measure industrial and environmental noise since it is easy to
measure and provides a reasonable indication of the human annoyance value of the noise. The
dBA measurement is not a good descriptor of a noise consisting of strong low- frequency
components or for a noise with tonal components. The A- weighted curve approximates the
response of the average ear at sound levels of 20 to 50 decibels. The following are the relative
response of A- weighted filter per octave band frequency, and a graph /curve is provided below
that shows a graphical representation of the A -wt. filter response per frequency (in Hz).
31.5
Hz
63
Hz
125
Hz
250
Hz
500
Hz
1,000
Hz
2,000
Hz
4,000
Hz
8,000
Hz
16,000
Hz
-39.4 dB
-26.2 dB
-16.1 dB
-8.6 dB
-3.2 dB
0 dB
+1.2 dB
+1.0 dB
-1.1 dB
-6.6 dB
RELATIVE RESPONSE,
1 dB
10
0
-10
-20
- 30
- 40
-50
16 31.5 63 125 250 500 1000 2000 4000 8000 16,000
FREQUENCY, Hz
-Page 19-
_}
• ,.
B, C
B
/
■
A
16 31.5 63 125 250 500 1000 2000 4000 8000 16,000
FREQUENCY, Hz
-Page 19-
ERM -- Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
(3)
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
C- Weighted Sound Level (dBC): The C-wt. sound level is a single - figure sound rating, expressed
in decibels (Re 20 µPa), which correlates to the human perception of the loudness of sound in
excess of 85 decibels. The dBC level is commonly used to measure industrial and environmental
noise since it is easy to measure and provides a reasonable indication of the overall sound. The
difference between C and A- weighted sound levels provides and indication of the amount of
lower frequency sound energy. The following are the relative response of C- weighted filter per
octave band frequency, and a graph/curve is provided that shows a graphical representation of
the C -wt. filter response per frequency (in Hz), and the graph /curve above in Definition (2) shows
a graphical representation of the C -wt. filter response per frequency (in Hz).
31.5
Hz
63
Hz
125
Hz
250
Hz
500
Hz
1,000
Hz
2,000
Hz
4,000
Hz
8,000
Hz
16,000
Hz
-3.2 dB
-1.O dB
-0.2 dB
0 dB
O dB
O dB
-0.2 dB
-0.8 dB
,
-3.O dB
-8.5 dB
(4) Background or Ambient Noise: The total noise produced by all other sources of a given
environment in the vicinity of a specific source of interest, and includes any Residual Noise.
(5)
Human Perception of Change in Sound Level
D A 3 dB change of sound level is barely perceivable by the human ear
D A 5 or 6 dB change of sound level is noticeable
D if sound level increases by 10 dB, it appears as if the sound intensity has doubled.
(6) Sound Pressure Level (Lp or SPL): Ten times the common logarithm to the base 10 of the ratio of
the mean square sound pressure to the square of a reference pressure. Therefore, the sound
pressure level is equal to 20 times the common logarithm of the ratio of the sound pressure to a
reference pressure (20 micropascals or 0.0002 microbar).
(7)
(8)
Octave Band Sound Pressure Level (SPL): Sound is typically measured in frequency ranges
(e.g., high - pitched sound, low - pitched sound, etc.) that provides more meaningful sound data
regarding the sound character of the noise. When measuring two noise sources for comparison,
it is better to measure the spectrum of each noise, such as in octave band SPL frequency
ranges. Then, the relative loudness of two sounds can be compared frequency range by
frequency range. As an illustration, 2 noise sources can have the same dBA rating and yet
sound completely different. For example, a high- pitched sound at a frequency of 2000 Hz could
have the same dBA rating as a much louder low - frequency sound at 50 Hz.
Daytime Sound Level (Ld) & Nighttime Sound Level (Ln): Ld is the equivalent A- weighted sound
level, in decibels, for a 15 hour time period, between 07:00 to 22:00 Hours (7:00 a.m. to 10:00
p.m.). L„ is the equivalent A- weighted sound level, in decibels, for a 9 hour time period, between
22:00 to 07:00 Hours (10:00 p.m. to 7 :00 a.m.).
-Page 20-
ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
(9)
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No, 2205 (03113108)
Equivalent Sound Level (Leq): The equivalent sound level (Leq) can be considered an average
sound level measured during a period of time, including any fluctuating sound levels during that
period. In this report, the Leq is equal to the level of a steady (in time) A- weighted sound level that
would be equivalent to the sampled A- weighted sound level on an energy basis for a specified
measurement interval. The concept of the measuring Leq has been used broadly to relate
individual and community reaction to aircraft and other environmental noises.
(10) Day -Night Average Sound Level (Ldn): The Ldn is an energy average of the measured daytime Leq
(Ld) and the measured nighttime Leq (Ln) plus 10 dB. The 10 -dB adjustment to the Ln is intended
to compensate for nighttime sensitivity. As such, the Ldn is not a true measure of the sound level
but represents a skewed average that correlates generally with past sound surveys which
attempted to relate environmental sound levels with physiological reaction and physiological
effects. For a steady sound source that operates continuously over a 24 -hour period and
controls the environmental sound level, a Ldn is approximately 6.4 dB above the measured Leg.
Consequently, a Ldn of 55 dBA corresponds to an Leg of 48.6 dBA. If both the La and Ln are
measured, then the Ldn is calculated using the following formula:
15 9
Ldn = 101ogio 24 IOL,no +— 24 10 ^ +10)/10
(11) L- Percent Sound Levels: The L percent levels (e.g., L5o, L90 & L70) refer to the A- weighted sound
levels that are exceeded for 90, 50 and 10 percent of the time, respectively, during a sound
measurement period. For example, the 50- percentile exceeded sound level is designated to as
L50 and is sometimes described as the median sound level. The range between the L10 and L90
values usually provides a good indication of the variability of the sound levels during the period of
measurement.
(12) Sound Level Meter (SLM): An instrument used to measure sound pressure level, sound level,
octave -band SPL, or peak sound pressure level, separately or in any combinations thereof. The
measured weighted SPL (i.e., A -Wt. Sound Level or dBA) is obtained by the use of a SLM having
a standard frequency- filter for attenuating part of the sound spectrum.
(13) Sound Power Level (Lw or PWL): Ten times the common logarithm of the ratio of the total
acoustic power radiated by a sound source to a reference power. A reference power of a
picowatt or 10 -12 watt is conventionally used.
(14) Tone: A tone is a sound sensation- having pitch, which is a listener's perception of the
frequency (for example, the higher the frequency, the higher the pitch). For a measured
sound spectrum, a tone is represented as a "peak" in the spectrum curve. Noise that
contains significant tones is considered a tonal type of noise.
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03113108)
(15) Relevant Standards, associated Standards Institute(s) and References
American National Standards Institute (ANSI): ANSI is the national coordinator of voluntary
standards development and the clearinghouse in the U.S.A. for information on national and
international standards.
American National Standards Institute (ANSI) S1.4: Specification for SLM:
Type 1 SLM:
Type II SLM:
Sound level meters (SLM) that meet this specification have a tolerance
of +1- 0.5 dB from 22.4 to 11,200 Hz.
Sound level meters that meet this specification have a tolerance of +/-
0.5 dB from 63 to 2,000 Hz and +1- 1.0 dB from 22.4 to 11,200 Hz.
ANSI 51.11 -1971 (R- 1976): Specifications for Octave, Half- Octave and Third - Octave Filter Sets.
Includes a method to convert SPLs in the "old octave bands" to SPLs in the new octave bands ".
ASTM Standard E1014 -84: Standard Guide for the Measurement of Outdoor A- Weighted Sound
Level. This guide covers the measurement of A- weighted sound levels outdoors at specified
locations or along particular site boundaries, using a general- purpose sound level meter.
End of Report
-Page 22-
CHEVRON PICEANCE BASIN NATURAL
GAS DEVELOPMENT PROJECT
(GARFIELD COUNTY, COLORADO)
RESULTS OF A PRELIMINARY ACOUSTICAL ASSESSMENT OF
THE PROJECT WHICH INCLUDES A CENTRAL PRODUCTION
FACILITY AND SEVERAL NATURAL GAS WELL SITES
H &K Report No. 2205
H &K Job No. 4004
Date of Report: March 13, 2008
Prepared for:
Environmental Resources Management (ERM)
6455 S Yosemite St. Ste. 900
Greenwood Village, Colorado 80111 -4954
Project Applicant: Chevron North America Exploration and Production
Submitted by:
Paul D. Kiteck, P.E. (primary author)
Hoover & Keith Inc.
11391 Meadowglen, Suite D
Houston, Texas 77082
Hoover & Keith Inc.
Consultants in Acoustics and Noise Control Engineering
11391 Meadowgien, Suite D, Houston, TX 77082
Phone: (281) 496 -9876
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
REPORT SUMMARY
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13108)
This report includes the results of a preliminary acoustical assessment of the Chevron Piceance
Basin Natural Gas Development Project to be located primarily in Garfield County, Colorado,
which includes a Central Production Facility (i.e., a natural gas gathering /transmission compressor
station) along with booster compressors and several well sites that will include well drilling activities.
The primary purpose of the acoustical assessment is estimate the sound attributable to project
facilities that could generate noise, such as the Central Production Facility (CPF), compare the
results of the acoustical assessment to applicable sound criteria and assess the potential noise
impact of the project facilities. In addition, a limited amount of ambient sound tests were conducted
at the project site, and based on the measured ambient sound data, the ambient sound levels for the
area surrounding the project are 25 dBA to 35 dBA (typical ambient A -wt. sound level of 30 dBA).
At a distance of 1 mile south of the facility (In the area of the canyon, along Clear Creek Road), the
estimated sound contribution of the CPF during operation is 35 dBA. Consequently, at the closest
occupied residences to the CPF (i.e., homes at the intersection of Clear Creek Road & CR -204,
approx. 6 miles south of the CPF), the noise attributable to the CPF should be significantly lower
than the typical ambient sound level (e.g., 30 dBA), and therefore, the noise of the CPF should not
be audible at the closest residences to the CPF.
The estimated sound contribution of the CPF during operation at the closest "non- Chevron" property
of potential noise concern (Le., Colorado Nature Ranch; closest property line located approx. 4,000
feet west of the CPF) is 26 dBA, which is equal to or lower than the ambient sound level for this
area. Consequently, the "potential noise increase" of the ambient noise level at the closest non -
Chevron property (i.e., Colorado Nature Ranch) during full load operation of the CPF should be less
than 3 dB. As a result, the noise of the CPF may be slightly perceivable /audible at areas of the
Colorado Nature Ranch that are closest to the CPF but the noise of the CPF should have minimum
noise impact.
In regard to the Colorado Oil and Gas Conservation Committee (COGCC) Rules and Regulations,
the results of the acoustical assessment indicates that the noise attributable to the project facilities
(e.g., noise generated by the CPF and other noise - generating facilities) should be well below the
maximum permissible levels specified in the COGCC Rules and Regulations for this type of facility.
For reference, it is anticipated that any other facilities associated with the project, such as the
operation of booster compressors in the project area and/or well drilling operations on well pads, will
generate lower sound levels than the CPF during full load operation.
-Page i-
ERM -- Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
TABLE OF CONTENTS
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
Page
1.0 INTRODUCTION 1
2.0 BRIEF DESCRIPTION OF THE SITE AND FACILITIES 1
3.0 SOUND CRITERIA, TYPICAL METRICS AND TERMINOLOGY 2
4.0 MEASUREMENT RESULTS, OBSERVATIONS AND METHODOLOGY 3
4.1 Measurement Equipment and Data Acquisition 3
4.2 Summary of the Measured Ambient Sound Levels and Observations 3
5.0 ACOUSTICAL ANALYSIS (CPF) 4
6.0 SUMMARY OF NOISE CONTROLS AND /OR EQUIPMENT NOISE LEVELS 6
6.1 Building Enclosing the Engines /Compressors 6
6.2 JW Cooler for Each Gas Compressor Unit 6
6.3 Turbine and Generator for the Gen -Set 6
6.4 Exhaust of the Gen -Set Turbine 6
6.5 Engine Exhaust and Engine Air Intake 6
7.0 SUMMARY AND FINAL COMMENT 7
APPENDIX: FIGURES, SOUND DATA, RESULTS OF ANALYSIS, DESCRIPTION OF ANALYSIS
METHODOLOGY, SOURCE OF SOUND DATA, COGCC REGULATIONS, TERMINOLOGY......... 8 -23
Figure 1: "Overview" of Project Area, Areas of Interest & Sound Measurement Positions ... 9
Figure 2: "Closer" View of Area around CPF and Sound Measurement Positions 10
Figure 3: Conceptual Layout of Buildings and Equipment for the CPF 11
Description of the Analysis Methodology and Source of Data 12 -13
Table A: Est'd Sound Contribution of the CPF during Operation at' /2 Mile 14
Table B: Est'd Sound Contribution of the CPF during Operation at 1 Mile 15
Table C: Est'd Sound Contribution of the CPF at the Colorado Nature Ranch 15
COGCC Noise Requirements (800 Series of the Rules and Regulations) 16 -17
Summary of Metrics for Regulating Environmental Noise and Acoustical Terminology 19 -22
-Page ii-
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
1.0 INTRODUCTION
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
In this report, we include the results of a preliminary acoustical assessment of the Chevron
Piceance Basin Natural Gas Development Project to be located primarily in Garfield County,
Colorado. In addition, a limited amount of ambient sound tests were conducted at the project site
and a summary of the ambient sound tests are included. The primary purpose of the acoustical
assessment is estimate the sound attributable to project facilities that could generate noise,
compare the results of the acoustical assessment to applicable sound criteria and assess the
potential noise impact of the project facilities.
2.0 BRIEF DESCRIPTION OF THE SITE AND FACILITES
Figure 1 (Appendix, p. 9) shows an "overview" of the project area showing the general location
of project facilities, location of the ambient sound measurement positions and other areas of
interest. Figure 2 (Appendix, p. 10) shows a "closer view" of the primary project facilities (e.g.,
CPF and nearby well sites) and location of ambient sound measurement positions around the
area of the CPF.
The project is located primarily in Garfield County, Colorado, in the area of the Piceance Basin
(CO), approximately 16 miles NNW of DeBeque (CO). The and around the project is mostly
rough terrain /mountains with activities related to the gas exploration /transmission in the area, and
property for the project/area that is owned by Chevron is relatively large. In summary, the project
includes a Central Production Facility (CPF), which is a natural gas gathering /transmission
compressor station, booster compressors and several well sites that will include well drilling
activities.
The closest residences and other potentially noise - sensitive areas (e.g., Cowboy Chapel) not
located on Chevron property are approximately 6 miles south the CPF (i.e., near the intersection
of Clear Creek Rd. with CR -204). There are also a couple houses on the Chevron property
located along Clear Creek Road. The closest non - Chevron property of potential noise concern is
the area of the Colorado Nature Ranch, for which its closest property line is approximately 4,000
feet west of the CPF.
Figure 3 (Appendix, p. 11) shows the current preliminary layout of buildings /equipment for the
CPF. A total of four (4) engine- driven compressor units will be initially employed at the CPF for
natural gas gathering /transmission. Each compressor unit will consist of a Caterpillar (CAT)
Model G3520 engine driving a "high- speed" reciprocating gas compressor. The engines and
compressors for gas compressor units will be enclosed in an insulated metal building (i.e.,
Compressor Building). The following describes auxiliary equipment and other notable equipment
at the CPF:
-Page 1-
ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Kelth Inc.
H &K Job No. 4004
H &K Report No. 2205 (03113108)
➢ Outdoor engine jacket -water (JW) air - cooled heat exchanger (Le., JW cooler) for each main
gas compressor, each JW cooler is designed a vertical fan that are direct - driven by the
engine (i.e., via belts /sheaves), and the JW cooler will also function as a gas aftercooler;
➢ Exhaust engine system designed with an exhaust muffler system;
➢ Engine air intakes, which include an air filter /cleaner system;
Aboveground gas piping and piping system components (e.g., inlet separators, fuel gas
scrubber, intermediate separator) along with other miscellaneous equipment.
➢ One (1) Solar turbine - driven generator and the turbine /generator for the gen -set to be
installed inside a skid - mounted Solar acoustical enclosure.
➢ Turbine exhaust for each gen -set will include an exhaust muffler.
There also will be a need to utilize booster compressor units (i.e., "smaller" engine- driven
compressor units) at or near some of the planned well sites. We understand that these booster
compressor units will each be designed with a skid - mounted acoustical enclosure covering the
engine- compressor for each package, and each package will include an outdoor engine JW /utility
cooler designed with a vertical fan that is direct - driven by the engine (i.e., via belts /sheaves).
3.0 SOUND CRITERIA, TYPICAL METRICS AND TERMINOLOGY
The Colorado 011 and Gas Conservation Committee (COGCC) regulate the oil and gas drilling
and production industry in the State of Colorado and the mission of the COGCC is to promote the
responsible development of Colorado's oil and gas natural resources. The COGCC has the
responsibility for regulating noise from natural gas facilities in Colorado, and Series 800 (Le.,
"Aesthetic and Noise Control Regulations"; Section 801 and Section 802) of the COGCC Rules
and Regulations address noise requirements (Le., maximum allowable noise levels) for natural
gas facilities in the State of Colorado. The complete noise regulations given in the COGCC
Rules and Regulations are provided toward the end of the report (Appendix, pp. 16 -17). The
following summarizes our interpretation of the noise requirements of the COGCC Rules and
Regulations as it applies to this project and the noise generated during operation of the CPF and
other project facilities (e.g., booster compressors or well drilling activities):
In remote locations, where there is no reasonably proximate occupied structure or designated
outside activity area, similar to the area surrounding the site of the CPF or booster
compressor(s) for this project, the light industrial standard may be applicable. Consequently,
to comply with the COGCC noise regulations, it is assumed that the noise radiated at the
Chevron property line should not exceed a nighttime level of 65 dBA (i.e., between 7:00 PM
to the next 7:00 AM), and at the property line of any residential -zoned area (e.g., closest
residences), the noise generated by the CPF or booster compressors should not exceed a
nighttime sound level of 50 dBA (i.e., between 7:00 PM to the next 7:00 AM).
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
In addition, if the intruding noise (e.g., noise of CPF during operation) causes less than a 3 dB
increase in the overall ambient noise at nearby NSAs (i.e., defined as "potential noise increase "),
the noise should be barely audible /perceivable by the human ear and should have minimum
noise impact on the acoustical environment. If the intruding noise causes an increase In the
overall ambient noise of between 4 dB and 9 dB, the intruding noise may be audible by the
human ear but should still have minimum noise impact on the acoustical environment.
For the reader's information, a summary of applicable acoustical terminology in this report and
typical metrics used to measure and regulate environmental noise is provided at the end of the
report (Appendix, pp. 19 -- 22).
4.0 MEASUREMENT RESULTS, OBSERVATIONS AND METHODOLOGY
4.1 Measurement Equipment and Data Acquisition
A limited amount of ambient sound measurements at the project site were performed by Paul
Kiteck of H &K during our site visit in the daytime January 29, 2008, At each sound measurement
position, the equivalentA -wt. sound level (i.e., Leq) and unweighted octave -band (O.B.) sound
pressure levels (i.e., SPLs) were measured at 5 feet above ground. Sound measurements
attempted to exclude "extraneous sound" such as cars or trucks passing immediately by the
sound measurement location or other intermittent sources not typical of the ambient noise
environment. The sound measurement system consisted of a Larson -Davis (LD) Model 2900
Real Time Analyzer /Sound Level Meter (a Type I SLM per ANSI Standard S1.4 & S1.11) and a
1 /2 -in. condenser microphone with windscreen (analyzer /SLM calibrated with a LD Model CA250-
0493 microphone calibrator that was calibrated within 1 year of the service date).
4.2 Summary of the Measured Ambient Sound Levels and Observations
The following Table 1 summarizes the measured /reported ambient daytime A -wt. sound levels
(Le., Leq) and some the sound measurement positions were taken relatively close to existing well
drilling activities. Note that the ambient daytime Leq (i.e., also referred to as Ld) assumed to be
similar to or equal to the ambient nighttime A -wt. sound levels (i.e., Ln).
Meas.
Pos.
Description of Sound Measurement Location
Range of Meas'd
Daytime A -WI. Sound
Levels (i.e., Ld)
Pos. 1
Area of a house on Chevron Property, located along Clear Creek Road.
26 to 35 dBA
Pos. 2
Area near the location of the CPF, along Toms Creek Road
28 to 32 dBA
Pos. 3
Along Clear Creek Rd, 600 feet east of well drilling operations at Well 598 -35 -AV
46 to 48 dBA*
Pos. 4
Approximately 250 feet south of well drilling operations at Well 598 -26 -AV
60 to 61 dBA*
Pos. 5
Approximately 300 feet south of well drilling operations at Well 598 -35 -AV
58 to 59 dBA*
Table 1: Summary of the Meas'd Daytime A -Wt. Sound Levels at Areas of Interest for the Project
*Noise of the well drilling operations (i.e., drilling rig at the well site) was the dominate noise source.
-Page 3-
ERM -- Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
During the site visit on Jan. 29 ('08), the meteorological conditions were as follows: Temperature
of 23 -- 27 deg. F., mostly clear sky and there was a light wind primarily from the north. During
the daytime sound tests at the ambient sound measurement positions not located near well
drilling activities (i.e., Pos. 1 & Pos. 2), the audible noise sources that contributed to the ambient
noise included distant construction equipment, the sound of birds, the sound of wind blowing in
the trees /grass and at times, the noise of distant aircraft. We believe that the measured ambient
sound data at Meas. Pos. 1 and Meas. Pos. 2 represents the typically daytime and nighttime A-
wt. sound levels for the area during times of relatively low wind conditions. At measurement
positions located relatively close to well drilling activities (i.e., Pos. 3, Pos. 4 & Pos. 5), the noise
of the well drilling operations (i.e., drilling rig) was the dominant noise source.
In summary, based on the measured sound data at the site, the typical ambient sound levels for
the area surrounding the project are 25 dBA to 35 dBA, with a typical ambient A -wt. sound level
of 30 dBA. Consequently, if the resulting /predicted sound level contribution due to the operation
of project facilities is equal to or less than the typical ambient level (e.g., 30 dBA); the noise of
the CPF and other project facilities will probably not be audible.
5.0 ACOUSTICAL ANALYSIS (CPF)
The noise associated with the CPF during full load operation is considered the primary facility for
the project that could generate significant noise. In addition, the noise of booster compressors
during operation and well drilling activities could generate noise, but it is anticipated that other
project facilities, such as booster compressors and well drilling activities, will generate lower
sound levels than the noise associated with the CPF during operation. The estimated sound
contribution of the CPF assumes the operation of 3 gas compressor units and 2 gen -sets. The
acoustical analysis of the CPF considers the noise produced by all continuous - operating
equipment that typically would operate at the facility. The following stationary noise sources
associated with the CPF were considered significant:
> Noise generated by the engines /compressors that penetrates the Compressor Building;
➢ Noise of the engine exhaust of each gas compressor unit;
> Noise radiated from aboveground gas piping and associated components;
> Noise of the outdoor JW cooler for each gas compressor unit;
• Noise associated with the turbine exhaust of each gen -set (includes an exhaust muffler);
> Noise of the turbine /generator that radiates from the generator skid - mounted enclosure.
For this acoustical analysis, we estimated the sound contribution of the CPF at different distances
(e.g., noise contribution at % mile and 1 mile south of the CPF, along the canyon, from the site)
and at the closest area to the CPF of potential noise concern (i.e., Colorado Nature Ranch). A
detailed description of the methodology for the acoustical analysis and the source of sound data
for the CPF acoustical assessment are provided in the Appendix (pp. 12 -13).
ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
Table A (Appendix, p. 14) shows the spreadsheet calculation of the estimated A -wt. sound level
and unweighted O.B. SPLs at the a distance of approximately % mile south of the CPF (along the
canyon) as contributed by the CPF noise sources based on standard day conditions (i.e., no
wind, 60 deg. F., 70% R.H.) along with the estimated total noise of the CPF (Le., noise of the
CPF plus the typical ambient noise). The analysis includes the effect of anticipated noise control
measures for the facility equipment.
Table B (Appendix, p. 15) is the spreadsheet calculation of the estimated A -wt. sound level and
unweighted O.B. SPLs generated by the CPF at the distance of approximately 1 mile south of the
CPF (along the canyon) as extrapolated from the estimated sound contribution at 1/2 mile (i.e.,
results in Table A).
Table C (Appendix, p. 15) is the spreadsheet calculation of the estimated A -wt. sound level and
unweighted O.B. SPLs generated by the CPF at the closest property line of the Colorado Nature
Ranch (i.e., approximately 4,000 feet west of the CPF) as extrapolated from the estimated sound
contribution at 1/2 mile (Le., results in Table A), noting that the Colorado Nature Ranch is
considered the closest non - Chevron area of potential noise concern.
The following Table 2 summarizes the calculated /estimated A -wt. sound levels of the CPF
assuming operation of 3 CAT engine- driven reciprocating compressor units and other
continuous - operating equipment at the CPF.
Facility Operating Condition and Description of the Location
Est'd A -Wt. Sound
Level Contribution
of the CPF
Est'd sound contribution of CPF during operation at ' /Z mile from site center (along canyon)
43 dBA
Est'd sound contribution of the CPF during operation at 1 mile from site center (along canyon)
35 dBA
Est'd sound contribution of CPF at CO Nature Ranch (closest property line 4,000' west of CPF)
26 dBA
Table 2: Est'd A -Wt. Sound Level of the CPF at Several Distances and at the Closest Area to the CPF of
Potential Noise Concern (i.e., Colorado Nature Ranch).
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc,
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
6.0 SUMMARY OF NOISE CONTROL AND /OR EQUIPMENT NOISE LEVELS FOR PROJECT
The following section provides a summary of anticipated noise control measures and equipment
noise levels associated with the CPF equipment along with other assumptions or
recommendations that may affect the noise generated by the CPF during operation.
6.1 Building Enclosing the Engines /Compressors
Noise control measures will be applied to the building (Compressor Building) enclosing the
engines and compressors rather than to the equipment themselves. The following describes
specific requirements and other items related to the building components.
D The walls /roof will be constructed with an exterior metal skin, and it is recommended as a
minimum, employ 24 —gauge metal. Building interior surfaces will be covered with insulation,
and it is recommended as a minimum, 6 -inch thick "high- density" mineral wool (6.0 -8.0 pcf
uniform density), covered with a perforated liner.
6.2 JW Cooler for Each Gas Compressor Unit
Based on sound tests by H &K of the JW cooler for the gas compressor unit, the A -wt. sound
level is approximately 72 -74 d13A at a distance of 50 feet,
6.3 Turbine and Generator for the Gen -Set
The turbine and associated generator for each gen -set will be installed in a Solar acoustical skid -
mounted enclosure, typically designed to achieve an A -wt. sound level of approximately 85 dBA
at 3 feet from the enclosure during operation of the gen -set.
6.4 Exhaust of the Gen -Set Turbine
The muffler for the turbine exhaust associated with the gen -set will be a Solar Model AX -5530
dissipative -type muffler with an overall length of 228 inches (i.e., 19 feet, from ground to stack
exhaust flange) and diameter of 72 inches (i.e., 6 feet).
6.5 Engine Air Intake and Engine Exhaust
The engine exhaust for each gas compressor unit will include a "residential- grade" muffler, and
the engine air intake(s) for each gas compressor unit with include a "standard" air filter.
-Page 6-
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
7.0 SUMMARY AND FINAL COMMENT
Hoover & Keith inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13108)
At a distance of 1 mile south of the facility (in the area of the canyon, along Clear Creek Road),
the estimated sound contribution of the CPF during operation is 35 dBA. Consequently, at the
closest occupied residences to the CPF (Le., homes at the intersection of Clear Creek Road &
CR -204, approx. 6 miles south of the CPF), the noise attributable to the CPF should be
significantly lower than the typical ambient sound level (e.g., 30 d8A), and therefore, the noise of
the CPF should not be audible at the closest residences.
The estimated sound contribution of the CPF during operation at the closest "non - Chevron"
property of potential noise concern (i.e., Colorado Nature Ranch; closest property line located
approx. 4,000 feet west of the CPF) is 26 dBA, which is equal to or lower than the ambient sound
level for this area. Consequently, the "potential noise increase" of the ambient noise level at the
closest non - Chevron property (i.e., Colorado Nature Ranch) during operation of the CPF should
be less than 3 dB. As a result, the noise of the CPF may be slightly perceivable at areas of the
Colorado Nature Ranch that are closest to the CPF but the noise of the CPF should have
minimum noise impact.
For reference, it is anticipated that any other facilities associated with the project, such as the
operation of booster compressors in the project area and/or well drilling operations on well pads,
will generate lower sound levels than the CPF during full load operation.
In regard to the COGCC Rules and Regulations, the results of the acoustical assessment
indicates that the noise attributable to the project facilities (e.g., noise generated by the CPF and
other noise - generating facilities) should be well below the maximum permissible levels specified
in the COGCC Rules and Regulations for this type of facility.
As a final comment, to insure that the project facilities generate minimum noise impact, H &K will
provide review the noise - related equipment submittals and other design features (e.g.,
Compressor Building design) during the detailed design phase for the project.
File: ProgWordhERMlC ievron Piceance ProjecOReport - Noise Assessment for Chevron Piceancce Development FrojecLtloc
-Page 7-
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
APPENDIX
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
> FIGURE 1: OVERVIEW LAYOUT AROUND THE
PROJECT SITE, AREAS OF INTEREST
AND SOUND MEASUREMENT POSITIONS
> FIGURE 2: CLOSER AREA LAYOUT AROUND THE
PROJECT SITE /CPF AND AMBIENT
SOUND MEASUREMENT POSITIONS
> FIGURE 3: CONCEPTUAL LAYOUT OF BUILDINGS &
EQUIPMENT FOR THE CPF
> ANALYSIS METHODOLOGY (NOISE ATTRIBUTABLE TO
THE CPF) AND THE SOURCE OF SOUND DATA
> ACOUSTICAL ANALYSIS (CFP)
• COLORADO OIL & GAS CONSERVATION COMMISSION
(COGCC) NOISE REGULATIONS (800 SERIES OF THE
RULES AND REGULATIONS)
> SUMMARY OF TYPICAL METRICS FOR REGULATING
ENVIRONMENT NOISE AND ACOUSTICAL
TERMINOLOGY
-Page 8-
ERM -- Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
WELL ShTE
598 -26 WITH
BOOSTER -. -AREA OF
\ /COMPRESSOR BOOSTER
''.. PARCEL COMPRESSOR
P08. 3 ti_) ` 1 BOUNDARY WELL SITE J,
CLEAR 598-25 -BV
7 CREEK RD, WELL SITE
WELL SITE \ \ \` � (CR -211) 598-25 -CV
598-35 WITH ] L� 1 .TOM CREEK D.
[COMPRESSOR
P05.2 �`
OMPRESSOR - 1___..., _,� L < CENTRAL
PRODUCTION
BOUNDARY WITH % %\ 'i'� �� FACILITY (CPF)
WELL SITE
598-25- V
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
COLORADO
NATURE -- -r
RANCH L
COLORADO NATURE
RANCH BOUNDARY
APPROX. 4.000'
FROM CPF
LEGEND
o - NON - RESIDENTIAL BUILDING
- HOUSE OR MOBILE HOME
NSA- NOISE SENSITIVE AREA
- MEASUREMENT POSITION
- WELL SITE
APPROXIMATE SCALE IN FEET
0 2700 5400 10800
WELL SITE
36 -1
SHINER
RIDGE
.1
SHINER
RIDGE
HOUSE ON
CHEVRON
PROPERTY CLEAR
-. CREEK RD.
(CR -211)
HLNER GATE
(TEMPORARY
OFFICE)
CLEAR
CREEK
SHINER
RIDGE
POS.1 ( \t
1�
SHINER
RIDGE "I.`
ROAN
CREEK RO.
(CR -204)
OTHER
HOMES
ROAN Apr-
CREEK
COWBOY
CHAPEL
HOUSE ON
CHEVRON
PROPERTY
CLEAR
CREEK
CLEAR
-- CREEK RD.
(CR -211)
CLOSEST
RESIDENCES
NOT ON
CHEVRON
PROPERTY
ROAN
CREEK RD.
(CR -204)
CLEAR
CREEK
� -TREES
Figure 1: Chevron Piceance Development Project: "Overview" Layout Showing the Project
Facilities, Other Areas of Interest and Ambient Sound Measurement Positions.
-Page 9-
ERM -- Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
l
POS. 4 (250' FROM
WELL DRILLING RIG --72-- -
K
DURING OPERATION)
WELL SITE
598 -26 WITH
BOOSTER I
COMPRESSOR/
PARCEL
BOUNDARY
WELL SITE
598 -35 WITH
BOOSTER
COMPRESSOR
CLEAR
CREEK RD.
\� (OR-21/)
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
WELL SITE
598-25-AV - - - -�
AREA OF
BOOSTER -`
COMPRESSOR
WELL SITE
598 -25 -BV
POS. 5 (300' FROM
WELL DRILLING RIG
DURING OPERATION)
BOUNDARY WITH
COLORADO
NATURE
RANCH
POS. 3
WELL SITE
598 -25-CV
TOM CREEK
RD.
CJ 1I
CENTRAL
PRODUCTION
FACILITY (CPF)
COLORADO NATURE
RANCH BOUNDARY
APPROX. 000'
FROM CPF
LEGEND
- NON- RESIDENTIAL BUILDING
w - HOUSE OR MOBILE HOME
NSA- NOISE SENSITIVE AREA
- MEASUREMENT POSITION
- WELL SITE
APPROXIMATE SCALE IN FEET
0 1100 2200
4400
SHINER �[
RIDGE
Figure 2: Chevron Piceance Development Project: "Closer" Area View of Project Facilities and
Area(s) of Interest and Sound Measurement Positions in the Area of the CPF.
-Page 10-
WELL SITE
36-1
`N
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
I
WAREHOUSE V.77_1
BUILDING j [El
!
I I
ELECTRICAL
BUILDING
11,7
ELECTRICAL COMMUNICATIONS
SUSTATION BUILDING
Hoover & Keith Inc.
H&K Job No. 4004
H&K Report No. 2205 (03/13108)
TRUE
NORTH
1
0
TOM CREEK RD.
1,0
;1H
DIESEL
!a GEN.
INSTR.
I AIR HI
SKID LO
CONTROL
BUILDING
LIQUID
SEPARATOR
-
TURBINE-DRIVEN
GEN-SET
GAS
SEPARATOR
1 PUMPS
00 0
0 0 0 0
DIKE
COND.
LOADING "'
\ SKID VRU 11
GLYCOL GAS FILTER
TOWER SEPARATOR
1 --] FUEL GAS
L _ ! L i SKID
PIPE RACK
CLEAR
CREEK RD.
(CR-211)
CENTRAL
PRODUCTION
FACILITY (CPF)
, FLARE SCRUBBER
PUMP SKID
PIPE RACK
COMPRESSOR
BUILDING WITH
ENGINE DRIVEN
COMPRESSOR UNITS
GLYCOL
REBOILER / SURGE
SKID
FENCELINE
APPROXIMATE SCALE IN FEET
0 35 70
Figure 3: Chevron Piceance Development Project: Conceptual Layout of the Buildings and
Equipment at the Central Production Facility (CPF).
-Page 11-
140
ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
ANALYSIS METHODOLOGY (NOISE ATTRIBUTABLE TO CPF)
Hoover & Keith Inc.
H&K Job No. 4004
H &K Report No. 2205 (03113108)
In general, the predicted sound level contributed by the CPF equipment was calculated as a function of
frequency from estimated unweighted octave -band (O.B.) sound power levels (PWLs) for each significant
sound source. The following summarizes the acoustical analysis procedure for the Station:
➢ Initially, unweighted O.B. PWL values of the significant noise sources were determined from
equipment manufacturer's sound data and/or actual sound level measurements performed by H &K at
similar type of equipment/components expected for this gas compressor facility.
➢ Then, expected noise reduction (NR) or attenuation in dB per O.B. frequency due to any noise control
measures, hemispherical sound propagation (discussed in more detail below *) and atmospheric
sound absorption (discussed in more detail below * *) were subtracted from the unweighted octave -
band PWLs to obtain the unweighted O.B. SPLs of each noise source. Since sound shielding by
buildings can influence the sound level contributed at the NSAs, we also included the sound shielding
due to buildings, if appropriate. The sound attenuation effect due to foliage or land contour was not
considered in the analysis although there probably will be some attenuation due to foliage /trees.
➢ Finally, the resulting estimated unweighted O.B. SPLs for all noise sources associated with the
Station (with noise control and other sound attenuation effects) were logarithmically summed, and the
total O.B. SPLs for all noise sources were corrected for A- weighting to provide the estimated overall
A -wt. sound level contributed by the Station at the closest NSA. The predicted sound contribution of
the Station at the closest NSA was utilized to estimate the Station noise contribution at the other
nearby NSAs that are more distant that the closest NSA.
*Attenuation due to hemispherical sound propagation: Sound propagates outwards in all directions (i.e.,
length, width, height) from a point source, and the sound energy of a noise source decreases with
increasing distance from the source. In the case of hemispherical sound propagation, the source is
located on a flat continuous plane /surface (e.g., ground), and the sound radiates hemisphericaliy (i.e.,
outward, over and above the surface) from the sound source. The following equation is the theoretical
decrease of sound energy when determining the resulting SPL values of a noise source at a specific
distance ( "r ") of a receiver from the estimated PWL values:
Decrease in SPL ( "hemispherical propagation ") from a noise source = 20 *Iog(r) - 2.3 dB
where "r" is distance of the receiver from the noise source.
* *Attenuation due to air absorption: Air absorbs sound energy, and the amount of absorption
( "attenuation ") is dependent on the temperature and relative humidity (R.H.) of air and frequency of
sound. For example, the attenuation due to air absorption for 1000 Hz O.B. SPL is approximately 1.5 dB
per 1,000 feet for standard day conditions (i.e., no wind, 60 deg. F. and 70% R.H.).
ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
SOURCE OF SOUND DATA (CPF)
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
The following describes the source of sound data used for estimating the source sound levels and/or the
source PWLs for the CPF (e.g., engines /compressors and other equipment/components associated with
the compressor installation).
(1)
Estimated PWL values of equipment inside the building (i.e., engines, compressors and other
equipment inside the building) was calculated from sound data measured by H &K on a similar
type of compressor installation.
(2) Exhaust PWL values were calculated from field sound data measured by H &K on a similar type of
engines to be utilized at this facility. The DIL values for the exhaust muffler are generally lower
than the recommended values in order that the analysis incorporates a "margin of safety."
(3)
Noise radiated from aboveground piping is primarily a result the noise generated by the gas
compressors. Consequently, measurement of both near field and far field sound data on gas
piping is presumed to be an accurate method of quantifying the noise associated with the piping,
and estimated PWL values for piping in the analysis were determined from near field and far field
sound data by H &K on a similar type of compressor to that of the proposed compressor unit.
(4) The estimated PWL values for coolers (e.g., JW /aux cooler and gas cooler) were designated to
meet the design noise goal and the estimated PWL values for the cooler utilized in the acoustical
analysis assumes some noise associated with piping associated with the coolers. The noise
level for the cooler used in the acoustical analysis is generally higher than the sound level
requirement in order that the noise design analysis incorporates an acoustical "margin of safety."
In addition, there can be other noise associated with the cooler that is not directly related to the
operation of the cooler fans.
(5)
The estimated PWL values for the engine air intake were calculated from measured sound data
in the field tests by H &K on similar engine that will be employed.
-Page 13-
ERM — Chevron Piceance Basin Natural as Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03113/08)
Source No.
& Dist (Ft)
Noise Sources and Other Conditions/Factors
associated with Acoustical Analysis
1)
2600
2600
2600
'PWL of Engines/Compressors inside Bldg. (4 Units)
Attenuation of the Building
NR of any Additional Noise Mitigation Measures
Misc. Atten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
PWL or SPL in dB Per Octave -Band Center Frequency (Hz)
31.5 1 63 1 125 1 250 l 500 11000 2000 1 40001 8000
112
-6
0
0
-66
0
40
115
-10
0
0
-66
0
39
120
-16
0.
0
-66
-1
37
118
-20
0
0
-66
-1
31
118
-22
0
0
-66
-2
28
116
-25
0
0
-66
-4
21
118
-30
0
0
-66
-8
14
118
-32
0
0
-66
-20
0
115
-32
0
0
-66
-36
0
A -Wt.
Level
124
29
2)
2600
2600
2600
PWL of Unsilenced Engine Exhaust (1 Unit)
PWL of Unsilenced Exhaust for 4 Units ( +6 dB)
120
126
125
131
132
138
126
132
124
130
Atten. of Noise Control (Exhaust Muffler)
NR of any Additional Noise Mitigation Measures
Misc. Atten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.M., 60 deg F)
Source Sound Level Contribution
-16
0
0
-66
0
44
-22
0
0
-66
0
43
3)
2600
2600
2600
PWL of JWIUtility Cooler for 1 Unit
PWL of All 4 JWAJtiiity Coolers ( +6 dB)
Atten. of Noise Control
NR of any Additional Noise Mitigation Measures
Misc. Atten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
110
116
0
0
0
-66
0
50
112
118
0
0
0
-66
0
52
-30
0
0
-66
-1
41
108
114
0
0
0
-66
-1
47
-35
0
0
-66
-1
30
-38
0
0
-66
-2
24
126
132
-38
0
0
-66
-4
24
126
132
114
120
100
106
131
137
105
111
0
0
0
-66
-1
44
102
108
0
0
0
-66
-2
40
98
104
-35
0
0
-66
-8
23 t
95
101
-25
0
0
-66
-20
9
-20
0
0
-66
-36
0
31
92
98
0
0
0
-66
-4
34
0
0
0
-66
-8
27
0
0
0
-66
-20
12
88
94
0
0
0
-66
-36
0
104
110
41
4)
2600
2600
2600
5)
PWL of Unsilenced Turbine Exhaust of Gen Set (1 Uni
Atten. of Noise Control (Exhaust Muffler)
Misc. Atten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
PWL of Outdoor Gas Piping for All Compressor Units
NR of Noise Control
Misc. Atten. (e.g., Shielding by Corner. Bldg.)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
PWL of Turbine- Driven Gen Set (1 Unit)
NR of any Additional Noise Mitigation Measures
Misc. Atten. (e.g., Shielding by Compr. Bldg.)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
120
-2
0
-66
0
52
123
-5
0
-66
0
52
120
-12
0
-66
-1
41
123
-22
0
-66
-2
33
127
-30
0
-66
-2
29
119
-30
0
-66
-4
19
112
-28
0
-86
-8
10
104
-25
0
-66
-20
0
96
-20
0
-66
-36
0
126
32
2600
2600
2600
6)
2600
2600
2600
7)
105
0
0
-66
0
39
104
0
0
-66
0
38
104
0
0
-66
0
38
97
0
0
-66
0
31
102
0
0
-66
-1
35
98
0
0
-66
-1
31
100
0
0
-66
-1
33
97
0
0
-66
-1
30
2600
2600
2600
PWL of Pumps, VRUs, Coolers, Glycol Regen. Skid
NR of any Additional Noise Mitigation Measures
Misc. Atten. (e.g., Shielding or Land Contour)
Hemispherical Radiation
Atm. Absorption (70% R.H., 60 deg F)
Source Sound Level Contribution
105
0
0
-66
0
39
102
0
0
-66
0
36
98
0
0
-66
-1
31
95
0
0
-66
-1
28
98
0
0
-66
-2
30
100
0
0
-66
-2
32
92
0
0
-66
-2
24
95
0
0
-66
-4
25
96
0
0
-66
-4
26
92
0
0
-66
-8
18
96
0
0
-66
-8
22
90
0
0
-66
-20
4
92
0
0
-66
-20
88
0
0
-66
-36
0
85
0
0
-66
-36
0
101
31
102
32
90
0
0
-66
-4
20
88
0
0
-66
-8
14
86
0
0
-66
-20
0
85
0
0
-66
-36
0
96
26
L st d Total Sound Contribution of CPF at 112 mile south of Site 55 l 55 1 50 J 45 1 42 36 1 30 1 15 1 0 43.1
Typical Ambient Sound Level at this Location
30.0
Est'd Sound Level of CPF plus Ambient Level (dBA)
lEst'd Potential Increase (dB)
43.3
13.3
Table A: Chevron Piceance Central Production Facility (CPF): Est'd Sound Contribution of the CPF at Approx.
1/2 Mile south of the Site (in the Area of Canyon) assuming Operation of Four(4) Compressor Units
(i.e., CAT Model G3520 Engine - Driven Compressor Units) and One (1) Solar Gen Set.
NOTE; DIL, NR & PWL values on this spreadsheet analysis should not be used as the specified values.
Refer to the "Noise Control & Sound Requirements" in the report or other company specifications.
ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
Source No.
& Dist (Ft)
Noise Sources and Other Conditions/Factors
associated with Acoustical Analysis
SPL in dB Per Octave -Band Center Frequency (Hz)
A -Wt.
Level
31.5
63
125
250
500
1000
2000
4000
8000
4000
4000
Esfd SPLs of Station at 2600 Ft. {RE: Table A)
55
55
50
45
42
36
30
15
0
43.1
5280
Hemisph Radiation [201og(5280/2600) = 6dB]
-6.0
-6.0
-6.0
-6.0
-6.0
-6.0
-6.0
-6.0
-6.0
5280
Atm. Absorption (70 %R.H., 60 deg F)
0
0
-1
-1
-2
-4
-8
-20
-37
Est'd Total Sound Contribution of CPF at 1 mile south of Site
49
49
43
38
34
26
16
0
0 1
35.1
Typical Ambient Sound Level at this Location
30.0
Est'd Sound Level of CPF plus Ambient Level (d BA)
36.3
1Est'd Potential Increase (dB)
6.3
Table B: Chevron Piceance Central Production Facility (CPF): Est'd Sound Contribution of the CPF at Approx.
1 Mile south of the Site (in the Area of Canyon) assuming Operation of Four (4) Compressor Units
(i.e., CAT Model G3520 Engine - Driven Compressor Units) and One (1) Solar Gen Set.
Source No.
& Dist (Ft)
Noise Sources and Other Conditions/Factors
associated with Acoustical Analysis
SPL in dB Per Octave -Band Center Frequency (Hz)
A -Wt.
Level
31.5
63
125
250
500
1000
2000
4000
8000
4000
4000
Esfd SPLs of Station at 2600 Ft. (RE: Table A)
Attenuation due to Shiner Ridge
Hemisph Radiation [20`1og(4500/2600) = 3.7 dB]
Atm. Absorption (70 % R.H., 60 deg F)
55
-6
-3.7
0
55
-8
-3.7
0
50
-10
-3.7
0
45
-12
-3.7
-1
42
-14
-3.7
-1
36
-15
-3.7
-2
30
-18
-3.7
-4
15
-20
-3.7
-11
0
-20
-3.7
-19
43.1
Este) Total Sound Contribution of the Station at NSA #3
45
43
36
29
23 1
15 1_
4
0
0
26.0
Typical Ambient Sound Level at this Location
30.0
Est'd Sound Level of Station plus Ambient Ln (dBA)
31.5
IEst'd
Potential Increase (dB}
1.5
Table C: Chevron Piceance Central Production Facility (CPF): Est'd Sound Contribution of the CPF atApprox.
4,000 Ft. West of Site (CO Nature Ranch, West of Shiner Ridge) assuming Operation of Four(4)
Compressor Units (i.e., CAT Model G3520 Engine - Driven Compressor Units) and One (1) Solar Gen Set.
ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
COLORADO OIL & GAS CONSERVATION COMMISSION (COGCC) NOISE
REQUIREMENTS (800 SERIES OF THE RULES AND REGULATIONS)
The COGCC regulates the oil and gas drilling and production industry in the State of Colorado and the
mission of the COGCC is to promote the responsible development of Colorado's oil and gas natural
resources. This "responsible development" balances efficient exploration and production of oil and gas
with the prevention of waste, protection of mineral owner's rights, and protection of public health, safety
and welfare and the environment. In Colorado, the COGCC has the responsibility for regulating noise
from oil and gas facilities.
AESTHETIC AND NOISE CONTROL REGULATIONS
(Rules related to Noise Regulations and Noise Abatement as of November 30, 2006)
801. INTRODUCTION
The rules and regulations in this section are promulgated to control aesthetics and noise impacts
during the drilling, completion and operation of oil and gas wells and production facilities. Any Colorado
county, home rule or statutory city, town, territorial charter city or city and county may, by application to
the Commission, seek a determination that the rules and regulations in this section, or any individual rule
or regulation, shall not apply to oil and gas activities occurring within the boundaries, or any part thereof,
of any Colorado county, home rule or statutory city, town, territorial charter city or city and county, such
determination to be based upon a showing by any Colorado county, home rule or statutory city, town,
territorial charter city or city and county that, because of conditions existing therein, the enforcement of
these rules and regulations is not necessary within the boundaries of any Colorado county, home rule or
statutory city, town, territorial charter city or city and county for the protection of public health, safety and
welfare.
802. NOISE ABATEMENT
a. The goal of this rule is to identify noise sources related to oil and gas operations that
impact surrounding landowners and to implement cost - effective and technically- feasible mitigation
measures to bring oil and gas facilities into compliance with the allowable noise levels identified in
subsection c. Operators should be aware that noise control is most effectively addressed at the siting and
design phase, especially with respect to centralized compression and other downstream "gas facilities"
(see definition in the 100 Series of these rules).
b. Oil and gas operations at any well site, production facility or gas facility, shall comply with
the following maximum permissible noise levels. 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. The type of land use of the surrounding area shall
be determined by the Commission in consultation with the local governmental designee taking into
consideration any applicable zoning or other local land use designation.
c. In the hours between 7:00 a.m. and the next 7:00 p.m. the noise levels permitted below
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.
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No, 4004
H &K Report No. 2205 (03/13/08)
ZONE 7:00 am to next 7:00 pm 7:00 pm to next 7:00 am
(Daytime) (Nighttime)
Residential /Agricultural /Rural 55 db(A) 50 db(A)
Commercial 60 db(A) 55 db(A)
Light industrial 70 db(A) 65 db(A)
Industrial 80 db(A) 75 db(A)
In remote locations, where there is no reasonably proximate occupied structure or
designated outside activity area, the Tight industrial standard may be applicable.
Pursuant to Commission inspection or upon receiving a complaint from a nearby property owner
or local governmental designee regarding noise related to oil and gas operations, the Commission shall
conduct an onsite investigation and take sound measurements as prescribed herein.
The following provide guidance for the measurement of sound levels and assignment of points of
compliance for oil and gas operations:
(1) Sound levels shall be measured at a distance of three hundred and fifty (350) feet from the
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 fifty (350) feet from an existing occupied structure, sound levels shall be
measured at a point twenty -five (25) feet from the structure towards 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 three hundred and fifty (350) feet or at the
property line, whichever is greater.
In situations where measurement of noise levels at three hundred and fifty (350) feet is
impractical or unrepresentative due to topography, the measurement may be taken at a lesser
distance and extrapolated to a 350 -foot equivalent using the following formula:
db(A) @DISTANCE 2 = db(A) @DISTANCE 1 — 20 x log10(distance 2 /distance 1)
(2) Sound level meters shall be equipped with wind screens, and readings taken when the wind
velocity at the time and place of measurement is not more than five (5) miles per hour.
(3) Sound level measurements shall be taken four (4) feet above ground level.
(4) Sound levels shall be determined by averaging minute -by- minute measurements made over a
minimum fifteen (15) minute sample duration if practicable. The sample shall be taken under
conditions that are representative of the noise experienced by the complainant (e.g., at night,
morning, evening, or during special weather conditions).
(5) In all sound level measurements, the existing ambient noise level from all other sources in the
encompassing environment at the time and place of such sound level measurement shall be
considered to determine the contribution to the sound level by the oil and gas operation(s).
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Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03113108)
d. In situations where the complaint or Commission onsite inspection indicates that low
frequency noise is a component of the problem, the Commission shall obtain a sound level measurement
twenty -five (25) feet from the exterior wall of the residence or occupied structure nearest to the noise
source, using a noise meter calibrated to the db(C) scale. If this reading exceeds 65 db(C), the
Commission shalt require the operator to obtain a low frequency noise impact analysis by a qualified
sound expert, including identification of any reasonable control measures available to mitigate such low
frequency noise impact. Such study shall be provided to the Commission for consideration and possible
action.
e. Exhaust from all engines, motors, coolers and other mechanized equipment shall be
vented in a direction away from all occupied buildings.
f. All facilities within four hundred (400) feet of occupied buildings with engines or motors
which are not electrically operated shall be equipped with quiet design mufflers or equivalent. All mufflers
shall be properly installed and maintained in proper working order.
For reference the following is a summary of the COGCC noise requirements as it applies to the CPF,
per H &K interpretation:
In remote locations, where there is no reasonably proximate occupied structure or designated outside
activity area, similar to the area surrounding the site of the CPF or booster compressor(s) for this
project, the light industrial standard may be applicable. Consequently, to comply with the COGCC
noise regulations, it is assumed that the noise radiated at the Chevron property line should not
exceed a nighttime level of 65 dBA (i.e., between 7:00 PM to the next 7:00 AM), and at the property
line of any residential -zoned area (e.g., closest residences), the noise generated by the CPF or
booster compressors should not exceed a nighttime sound level of 50 dBA (i.e., between 7:00 PM to
the next 7:00 AM).
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ERM — Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
SUMMARY OF TYPICAL METRICS FOR REGULATING ENVIRONMENTAL NOISE
AND ACOUSTICAL TERMINOLOGY RELATED TO THE REPORT
(1) Decibel (dB): A unit for expressing the relative power level difference between acoustical or
electrical signals. It is ten times the common logarithm of the ratio of two related quantities that
are proportional to power. When adding dB or dBA values, the values must be added
logarithmically. For example, the logarithmic addition of 35 dB plus 35 dB is 38 dB.
(2) A- Weighted Sound Level (dBA): The A -wt. sound level is a single- figure sound rating, expressed
in decibels (Re 20 ).tPa), which correlates to the human perception of the loudness of sound. The
dBA level is commonly used to measure industrial and environmental noise since it is easy to
measure and provides a reasonable indication of the human annoyance value of the noise. The
dBA measurement is not a good descriptor of a noise consisting of strong low - frequency
components or for a noise with tonal components. The A- weighted curve approximates the
response of the average ear at sound levels of 20 to 50 decibels. The following are the relative
response of A- weighted filter per octave band frequency, and a graph /curve is provided below
that shows a graphical representation of the A -wt. filter response per frequency (in Hz).
31.5
Hz
63
Hz
125
_ Hz
250
Hz
500
Hz
1,000
Hz
2,000
Hz
4,000
Hz
8,000
Hz
16,000
Hz
-39.4 dB
-26.2 dB
-16.1 dB
-8.6 dB
-3.2 dB
0 dB
+1.2 dB
+1.0 dB
-1.1 dB
-6.6 dB
RELATIVE RESPONSE,
dB
10
0
- 10
-20
-30
- 40
-50
16 31.5 63 125 250 500 1000 2000 4000 8000 16,000
FREQUENCY, Hz
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',
13, C
.
B .•
/
A
16 31.5 63 125 250 500 1000 2000 4000 8000 16,000
FREQUENCY, Hz
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ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
(3)
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
C- Weighted Sound Level (dBC): The C -wt. sound level is a single - figure sound rating, expressed
in decibels (Re 20 µPa), which correlates to the human perception of the loudness of sound in
excess of 85 decibels. The dBC level is commonly used to measure industrial and environmental
noise since it is easy to measure and provides a reasonable indication of the overall sound. The
difference between C and A- weighted sound levels provides and indication of the amount of
lower frequency sound energy. The following are the relative response of C- weighted filter per
octave band frequency, and a graph /curve is provided that shows a graphical representation of
the C -wt. filter response per frequency (in Hz), and the graph /curve above in Definition (2) shows
a graphical representation of the C -wt. filter response per frequency (in Hz).
31.5
Hz
63
Hz
125
Hz
250
Hz
500
Hz
1,000
Hz
2,000
Hz
4,000
Hz
8,000
Hz
16,000
Hz
-3.2 dB
-1.0 dB
-0.2 dB
0 dB
0 dB
0 dB
-0.2 dB
-0.8 dB
-3.0 dB
-8.5 dB
(4) Background or Ambient Noise: The total noise produced by all other sources of a given
environment in the vicinity of a specific source of interest, and includes any Residual Noise.
(5)
Human Perception of Change in Sound Level
➢ A 3 dB change of sound level is barely perceivable by the human ear
D. A 5 or 6 dB change of sound level is noticeable
➢ If sound level increases by 10 dB, it appears as if the sound intensity has doubled.
(6) Sound Pressure Level (LP or SPL): Ten times the common logarithm to the base 10 of the ratio of
the mean square sound pressure to the square of a reference pressure. Therefore, the sound
pressure level is equal to 20 times the common logarithm of the ratio of the sound pressure to a
reference pressure (20 micropascals or 0.0002 microbar).
(7)
(8)
Octave Band Sound Pressure Level (SPL): Sound is typically measured in frequency ranges
(e.g., high - pitched sound, low- pitched sound, etc.) that provides more meaningful sound data
regarding the sound character of the noise. When measuring two noise sources for comparison,
it is better to measure the spectrum of each noise, such as in octave band SPL frequency
ranges. Then, the relative loudness of two sounds can be compared frequency range by
frequency range. As an illustration, 2 noise sources can have the same dBA rating and yet
sound completely different. For example, a high- pitched sound at a frequency of 2000 Hz could
have the same dBA rating as a much louder low- frequency sound at 50 Hz.
Daytime Sound Level (Ld) & Nighttime Sound Level (L„): Ld is the equivalent A- weighted sound
level, in decibels, for a 15 hour time period, between 07:00 to 22:00 Hours (7:00 a.m. to 10:00
p.m.). L is the equivalent A- weighted sound level, in decibels, for a 9 hour time period, between
22 :00 to 07:00 Hours (10:00 p.m. to 7:00 a.m.).
ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
(9)
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
Equivalent Sound Level (Le): The equivalent sound level (Leq) can be considered an average
sound level measured during a period of time, including any fluctuating sound levels during that
period. In this report, the Leq is equal to the level of a steady (in time) A- weighted sound level that
would be equivalent to the sampled A- weighted sound level on an energy basis for a specified
measurement interval. The concept of the measuring Leq has been used broadly to relate
individual and community reaction to aircraft and other environmental noises.
(10) Day -Night Average Sound Level (Ldn): The Ldn is an energy average of the measured daytime Leq
(Ld) and the measured nighttime Lea (Ln) plus 10 dB. The 10 -dB adjustment to the Ln is intended
to compensate for nighttime sensitivity. As such, the Ldn is not a true measure of the sound level
but represents a skewed average that correlates generally with past sound surveys which
attempted to relate environmental sound levels with physiological reaction and physiological
effects. For a steady sound source that operates continuously over a 24 -hour period and
controls the environmental sound level, a Ldn is approximately 6.4 dB above the measured Leq.
Consequently, a Ldn of 55 dBA corresponds to an Leq of 48.6 dBA. If both the Ld and Lr, are
measured, then the Ldn is calculated using the following formula:
Ldn = 101oPio(2410La io + 410(L +io)noJ
(11) L- Percent Sound Levels: The L percent levels (e.g., L50, L90 & L10) refer to the A- weighted sound
levels that are exceeded for 90, 50 and 10 percent of the time, respectively, during a sound
measurement period. For example, the 50- percentile exceeded sound level is designated to as
L50 and is sometimes described as the median sound level. The range between the L10 and L90
values usually provides a good indication of the variability of the sound levels during the period of
measurement.
(12) Sound Level Meter (SLM): An instrument used to measure sound pressure level, sound level,
octave -band SPL, or peak sound pressure level, separately or in any combinations thereof. The
measured weighted SPL (i.e., A -Wt. Sound Level or dBA) is obtained by the use of a SLM having
a standard frequency - filter for attenuating part of the sound spectrum.
(13) Sound Power Level (Lw or PWL): Ten times the common logarithm of the ratio of the total
acoustic power radiated by a sound source to a reference power. A reference power of a
picowatt or 10 -72 watt is conventionally used.
(14) Tone: A tone is a sound sensation - having pitch, which is a listener's perception of the
frequency (for example, the higher the frequency, the higher the pitch). For a measured
sound spectrum, a tone is represented as a "peak" in the spectrum curve. Noise that
contains significant tones is considered a tonal type of noise.
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ERM - Chevron Piceance Basin Natural Gas Development Project
Results of a Preliminary Acoustical Assessment for the Project
Hoover & Keith Inc.
H &K Job No. 4004
H &K Report No. 2205 (03/13/08)
(15) Relevant Standards, associated Standards Institute(s) and References
American National Standards Institute (ANSI): ANSI is the national coordinator of voluntary
standards development and the clearinghouse in the U.S.A. for information on national and
international standards.
American National Standards Institute (ANSI) S1.4: Specification for SLM:
Type 1 SLM: Sound level meters (SLM) that meet this specification have a tolerance
of +1- 0.5 dB from 22.4 to 11,200 Hz.
Type II SLM: Sound level meters that meet this specification have a tolerance of *1-
0.5 dB from 63 to 2,000 Hz and +1- 1.0 dB from 22.4 to 11,200 Hz.
ANSI 51.11 -1971 (R- 1976): Specifications for Octave, Half- Octave and Third - Octave Filter Sets.
Includes a method to convert SPLs in the "old octave bands" to SPLs in the "new octave bands ".
ASTM Standard E1014 -84: Standard Guide for the Measurement of Outdoor A- Weighted Sound
Level. This guide covers the measurement of A- weighted sound levels outdoors at specified
locations or along particular site boundaries, using a general - purpose sound level meter.
End of Report
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