January 7, Kimberly D. Bose, Secretary Federal Energy Regulatory Commission 888 First Street, N.E. Washington, D.C

Transcription

1 Gas Pipeline-Transco 2800 Post Oak Boulevard (77056) P.O. Box 1396 Houston, Texas / January 7, 2009 Kimberly D. Bose, Secretary Federal Energy Regulatory Commission 888 First Street, N.E. Washington, D.C Re: OEP/DG2E/Gas Branch 2 Transcontinental Gas Pipe Line Company, LLC Sentinel Expansion Project (Docket No. CP ) Environmental Condition 34 Pre-Construction Sound Survey at Compressor Station 200 Dear Ms. Bose: As required under Environmental Condition 34 of the Commission s Order for the above-referenced project, Transcontinental Gas Pipe Line Company, LLC (Transco) hereby submits the results of a pre-construction sound survey for Compressor Station 200. The survey was conducted on October 8 and 9, 2008 (while the station was operating at full load) with sound measurements taken at the property line and nearby noise sensitive areas (NSAs). The attached report includes drawings that show detailed information about Transco s compressor station facilities. These drawings have been removed from the public document and marked as CEII. Pursuant to Order No. 630, Critical Energy Infrastructure Information, 68 FR 9862 P 33 (2003), Transco requests that these drawings be treated as Critical Energy Infrastructure Information. Please direct any technical questions with respect to this submittal to Joseph Dean at (713) or joseph.dean@williams.com. Respectfully submitted, TRANSCONTINENTAL GAS PIPE LINE COMPANY, LLC By: Thomas F. Messick, Jr. Manager, Permits and Natural Resources cc: John Peconom, Gas Branch 2

2 TRANSCO STATION NO. 200 (TOWNSHIP OF EAST WHITELAND, PENNSYLVANIA) RESULTS OF A RECENT SOUND SURVEY PRIOR TO THE INSTALLATION OF A RECEIVER TRAP AND ASSOCIATED PIPING THAT IS RELATED TO THE SENTINEL EXPANSION PROJECT H&K Report No H&K Job No Date of Report: December 12, 2008 Prepared for: Transcontinental Gas Pipe Line Corporation A Subsidiary of Williams Gas Pipeline Company, LLC P.O. Box 1396 Houston, TX Submitted by: Paul D. Kiteck, P.E Meadowglen, Suite D Houston, Texas Applicable FERC Docket Number for Project: CP Consultants in Acoustics and Noise Control Engineering Meadowglen, Suite D, Houston, TX Phone: (281)

3 REPORT SUMMARY The following report provides the results of a recent sound survey (conducted on October 8 & 9, 2008) during full load operation of Transco Station No. 200 (abbreviated as Station in the report) prior to the installation of a receiver trap and associated piping that is related to the Sentinel Expansion Project. This sound survey was conducted in response to the United States of America Federal Energy Regulatory Commission (FERC) Order Issuing Certificate and Granting Abandonment Authority, Docket No. CP , Appendix A, Condition No. 34. The following table summarizes the measured daytime/nighttime A-wt. sound levels (i.e., L d and L n ) in the nearby community/residences during the recent 2008 sound survey with the Station operating at full capacity along with the calculated L dn based on the measured L d and L n. Station 200: Summary of Meas d Sound Data in the Community during the Recent Sound Survey Meas. Pos. Brief Description of the Sound Measurement Location Average Meas d Ld Average Meas d Ln Calc d Ldn of the Station Pos. 1 Residences at end of Cameron Ct, 1,000 ft. south of Bldg. A 48.0 dba* 49.5 dba* 55.8 dba Pos. 2 Residences at end of Kingston Circle, 450 ft. west of Bldg. A 52.2 dba 53.4 dba 59.7 dba Pos. 3 Residences at end of Elliston Court, 600 ft. SW of Bldg. A 49.2 dba 49.7 dba 56.0 dba Pos. 9 Residences north side of Station, 1,700 ft. north of Bldg. A 48.6 dba* 52.1 dba* 58.2 dba *Sound of non-station noise sources (e.g., insects, distant traffic, and distant construction activity) also contributed to the meas d A-wt. sound levels The following table summarizes the measured L d and measured L n along the Station property line adjacent to the closest residences (i.e., west and south property line of the Station) during the recent 2008 sound survey with the Station operating at full capacity along with the calculated L dn based on the measured L d and L n. Station 200: Summary of Meas d Sound Data along the West/South Property Line of the Station Meas. Pos. Brief Description of the Sound Measurement Location Average Meas d Ld Average Meas d Ln Calc d Ldn of the Station Pos. 4 NW corner of Station fenceline, along west property line of 57.7 dba 58.5 dba 64.8 dba Station (approx. 400 ft. NW of Compressor Bldg. A) Pos. 5 West property line of Station, in the adjacent power line 58.4 dba 59.0 dba 65.3 dba ROW (approx. 240 ft. west of Compressor Bldg. A) Pos. 6 West property line/fenceline of Station (approx. 500 ft. SSW 57.4 dba 57.2 dba 63.6 dba of Compressor Bldg. A) Pos. 7 SW corner of Station fenceline, along south property line of Station (approx. 1,000 ft. south of Compressor Bldg. A) 50.9 dba* 50.7 dba* 57.1 dba *Sound of non-station noise sources (e.g., insects, distant traffic, and distant construction activity) also contributed to the meas d A-wt. sound levels -Page i-

4 TABLE OF CONTENTS Page 1.0 INTRODUCTION SOUND LEVEL CRITERIA DESCRIPTION OF THE SITE/FACILITY MEASUREMENT LOCATIONS AND METHODOLOGY Sound Measurement Locations Data Acquisition and Sound Measurement Equipment STATION OPERATING CONDITIONS DURING SOUND SURVEY MEASUREMENT RESULTS AND FINAL COMMENT APPENDIX: DRAWING/FIGURES, SUMMARY OF SOUND SURVEY DATA, AND SUMMARY OF ACOUSTICAL TERMINOLOGY Figure 1: Area Layout and Reported Sound Measurement Positions in nearby Community... 8 Figure 2: Drawing showing Sound Measurement Positions around the Station Property... 9 Table A: Summary of Meas d Sound Data during Recent 2008 Sound Survey Table B: Meteorological Conditions during the Recent 2008 Sound Survey Table C: Meas d Daytime Levels and Unweighted O.B. SPLs during Oct. 8 Tests Table D: Meas d Nighttime Levels and Unweighted O.B. SPLs during Oct. 8 Tests Table E: Meas d Daytime Levels and Unweighted O.B. SPLs during Oct. 9 Tests SUMMARY OF TYPICAL METRICS AND ACOUSTICAL TERMINOLOGY Page ii-

5 1.0 INTRODUCTION In this report, (H&K) provides the results of a recent sound survey (i.e., conducted October 8 & 9, 2008) during full load operation of Transco Station No. 200 prior to the installation of a receiver trap and associated piping that is related to the Sentinel Expansion Project. Station No. 200 (abbreviated as Station in the report) is a natural gas compressor station located in the Township of East Whiteland, Pennsylvania. This sound survey was conducted in response to the United States of America Federal Energy Regulatory Commission (FERC) Order Issuing Certificate and Granting Abandonment Authority, Docket No. CP , Appendix A, Condition No. 34. For the reader s information, a summary of acoustical terminology and technical information in this report and a list of typical metrics used to measure and regulate environmental noise are provided at the end of this report (Appendix, pp ). 2.0 SOUND LEVEL CRITERIA The Office of Energy Projects (OPC) of the FERC require that after the planned Station modifications, the noise of the Station at full capacity (i.e., full load operation of all authorized units) does not exceed the previously existing noise levels at nearby noise-sensitive areas (NSAs), such as residences, schools and hospitals, if the existing Station sound contribution is equal to or greater than a day-night average sound level (i.e., L dn ) of 55 dba. If both the daytime A-weighted ( A-wt. ) equivalent sound level (i.e., L d ) and nighttime A-wt. equivalent sound level (i.e., L n ) are measured and/or estimated, then the L dn is calculated using the following formula: L dn = 10log L /10 9 d ( L 10) n + / DESCRIPTION OF SITE/FACILITY Figure 1 (Appendix, p. 8) provides an area layout around the Station showing the location of nearby residences and residential areas along with the chosen sound measurement positions in the nearby community/residences surrounding the Station. The closest residences include singlefamily houses and townhomes located in the Malvern Hunt Subdivision, located along the West Side of the Station. There are also residences on the North Side of the Station, near the intersection of Old Valley Road and North Bacton Hill Road. The closest residences (i.e., area of the Malvern Hunt Subdivision) are approximately 450 feet from Compressor Building A at the Station (i.e., townhomes at the end of Kingston Circle). Other nearby residences in the Malvern Hunt Subdivision are approximately 600 to 1,000 feet from Compressor Building A (i.e., residences on Elliston Court and Cameron Court). -Page 1-

6 Figure 2 (Appendix, p. 9) shows a layout of the buildings/equipment associated with the Station along with the location of the sound measurement positions around the Station property line and on the Station property. The Station is equipped with thirteen (13) engine-driven reciprocating compressor units, and the total authorized Station capacity is 30,860 horsepower (HP). The following Table 1 provides a brief description of the Station compressor units: Unit Nos. Manufacturer & Model No./Type Type of Driver Type of Compressor Transco HP Limit FERC Auth. HP In-Service Date #1 #6 Clark BA-8 Gas Engine Integral Reciprocating 2,050 HP 1,760 HP Apr, 1951 #7 & #8 Clark TLA-6 Gas Engine Integral Reciprocating 2,100 HP 2,000 HP Dec, 1957 #9 Clark TLA-6 Gas Engine Integral Reciprocating 2,100 HP 2,000 HP Oct, 1961 #10 Clark TCV-10 Gas Engine Integral Reciprocating 3,400 HP 3,400 HP Dec, 1962 #11 Clark TCV-10 Gas Engine Integral Reciprocating 3,400 HP 3,400 HP Dec, 1968 #12 Clark TCV-16 Gas Engine Integral Reciprocating 5,500 HP 5,500 HP Apr, 1970 #13 Clark TLA-6 Gas Engine Integral Reciprocating 2,100 HP 2,000 HP Mar, Units Totals: 33,000 HP 30,860 HP Table 1: Brief Description of the Gas Compressor Units at Transco Station 200 Units #1 #9 and Unit #13 are located inside Compressor Building A. Units #10, #11 and #12 are located in Compressor Building B. The Station does not operate all 13 units because of the authorized operating capacity of the Station, and consequently, 12 units is the maximum number of compressor units that operate simultaneously. 4.0 MEASUREMENT METHODOLOGY/LOCATIONS AND OPERATING CONDITIONS 4.1 Sound Measurement Locations During the recent 2008 sound survey, ten (10) locations were chosen to measure the sound level in the surrounding residential areas and around the Station property during Station operation. The following is a description of the reported sound measurement positions: Pos. 1: Residences at end of Cameron Court, between houses at 31 and 36 Cameron Court, in the Malvern Hunt Subdivision. This sound measurement position and associated homes are approximately 1,000 feet south of Compressor Building A; Pos. 2: Residences at end of Kingston Circle, between townhomes at 11 and 18 Kingston Circle, in the Malvern Hunt Subdivision. These homes are approximately 450 feet west of Compressor Building A and are considered the closest residences to the Station; Pos. 3: Residences at end of Elliston Court, between townhomes at 12 and 14 Elliston Court, in the Malvern Hunt Subdivision. This sound measurement position and nearby townhomes are approximately 600 feet SW of Compressor Building A; -Page 2-

7 Pos. 9: At the corner of Old Valley Road and North Bacton Hill Road, near residences located approximately 1,700 feet north of Compressor Building A. Residences at this location were the closest NSA prior to the development of the Malvern Hunt Subdivision; Pos. 4: NW corner of the Station fenceline (i.e., along the west property line of the Station), approximately 400 feet NW of Compressor Building A; Pos. 5: West Side of the Station (i.e., west property line of the Station), in the power line right-ofway (ROW) and approximately 240 feet west of Compressor Building A; Pos. 6: Along the west Station fenceline (i.e., along the west property line of the Station), approximately 500 feet SSW of Compressor Building A; Pos. 7: SW corner of the Station fenceline (i.e., along the south property line of the Station), approximately 1,000 feet south of Compressor Building A; Pos. 8: In driveway leading to Radio Tower, approximately 100 feet from the Office Building; Pos. 10: On the sidewalk in front of the Office Building, approximately 300 feet south of Compressor Building B. 4.2 Data Acquisition and Sound Measurement Equipment During the recent 2008 sound survey, at the sound measurement locations in the community (i.e., surrounding residences), the L eq and the L 90 & L 10 (i.e., L percent A-wt. levels that are exceeded for 90 and 10 percent of the time, respectively) were measured at five (5) feet above ground. Also, during the recent 2008 sound survey, the unweighted octave-band (O.B.) sound pressure levels (SPLs) [i.e., L eq, L 90 and L 10 SPLs] were measured in the community. Typically, several sample periods of the environmental sound level were measured at each sound measurement position in the community. At each sound measurement location on the Station property (i.e., Pos. 4, 5, 6, 7, 8 & 10), only A-wt. sound levels (i.e., L eq ) and unweighted O.B. SPL measurements were measured. The sound measurements at the nearby NSAs attempted to exclude "extraneous sound" such as intermittent vehicles passing immediately by the sound measurement location. The acoustical measurement system consisted of a Larson-Davis (LD) Model 2900 Real Time Analyzer/SLM (a Type I SLM per ANSI Standard S1.4 & S1.11) with a 1/2-in. LD condenser microphone covered by a windscreen, and the analyzer/slm was calibrated with a LD Model CA250 microphone calibrator that was calibrated within one (1) year of the test dates. -Page 3-

8 5.0 STATION OPERATING CONDITIONS DURING SOUND SURVEY Paul Kiteck of H&K performed this recent sound survey around the Station and in the nearby community areas during the daytime/nighttime of October 8, 2008 and during the daytime of October 9, During these recent sound tests on October 8 & 9, the wind was blowing primarily from the southwest and west, which is a wind condition that would result in less Station noise propagating toward the Malvern Hunt Subdivision (RE: discussion of factors that influence outdoor sound propagation in the Appendix, p. 16). During these recent sound survey tests with Station equipment operating, twelve (12) units were operated (i.e., all units except Unit #2), and as a result, the Station was operated at approximately full load conditions. The following Table 2 provides a summary of the operating conditions of the Station units that occurred during this recent 2008 sound survey in which the Station operating at approximately full load/capacity. Unit No. Transco HP Limit %Torque Actual BHP During Survey Engine Speed Flow (MMscfd) Load Step #1 1,800 HP 101% 2061 HP 300 rpm #2 1,800 HP 0% 0 HP 0 rpm 0 0 #3 1,800 HP 101% 2067 HP 300 rpm #4 1,800 HP 101% 2058 HP 300 rpm #5 1,800 HP 101% 2064 HP 300 rpm #6 1,800 HP 100% 2042 HP 300 rpm #7 2,100 HP 93% 1952 HP 300 rpm #8 2,100 HP 93% 1955 HP 300 rpm #9 2,100 HP 94% 1964 HP 299 rpm #10 3,400 HP 99% 3348 HP 300 rpm #11 3,400 HP 99% 3374 HP 300 rpm #12 5,500 HP 100% 5478 HP 299 rpm #13 2,100 HP 94% 1964 HP 299 rpm Table 2: Summary of Station Operating Conditions during Sound Tests on Oct. 8 9 ( 08) The results of Table 2 indicate that the actual horsepower (HP) capacity of the Station during the recent sound survey was 30,116 HP, which is approximately the full load horsepower capacity of the Station (i.e., 30,860 HP). In addition, total Station flow was approximately 1570 MMscfd, MLA & MLB suction pressures were approximately 494 psig, MLA discharge pressure was 642 psig and MLB discharge pressure was 700 psig. -Page 4-

9 6.0 MEASUREMENT RESULTS AND FINAL COMMENT Table A (Appendix, p. 10) summarizes the measured A-wt. sound levels (i.e., daytime & nighttime L eq, L 90 and L 10 ) at the sound measurement locations in the community (i.e., surrounding residences) during the 2008 sound survey along with the arithmetic average of the measured L d and measured L n since more than one test sample was taken during the sound survey tests. In addition, the calculated L dn are provided in Table A, as calculated from the measured L d (i.e., arithmetic average of L d measured on Oct. 8 & 9) and the measured L n. Meteorological conditions during the respective sound survey test periods are summarized in Table B (Appendix, p. 10). Table C (Appendix, p. 11) shows the measured daytime A-wt. sound levels (i.e., L d, L 90 and/or L 10 ) and unweighted O.B. SPLs (i.e., L d, L 90 and/or L 10 SPLs) at all of the sound measurement positions during the daytime (i.e., afternoon) sound tests on Oct. 8 ( 08). Table D (Appendix, p. 12) shows the measured nighttime A-wt. sound levels (i.e., L n, L 90 and/or L 10 ) and unweighted O.B. SPLs (i.e., L n, L 90 and/or L 10 SPLs) at all of the sound measurement positions during the nighttime sound tests on Oct. 8 ( 08). Table E (Appendix, p. 13) shows the measured daytime A-wt. sound levels (i.e., L d, L 90 and/or L 10 ) and unweighted O.B. SPLs (i.e., L d, L 90 and/or L 10 SPLs) at all of the sound measurement positions during the daytime (i.e., morning) sound tests on Oct. 9 ( 08). The following Table 3 summarizes the average of the measured L d and L n during the recent 2008 sound survey at the sound measurement positions in the community (i.e., Pos. 1, 2, 3 & 9) along with the calculated L dn based on the measured L d and L n. Meas. Pos. Brief Description of the Sound Measurement Location Average Meas d Ld Average Meas d Ln Calc d Ldn of the Station* Pos. 1 Residences at end of Cameron Ct, 1,000 ft. south of Bldg. A 48.0 dba 49.5 dba 55.8 dba* Pos. 2 Residences at end of Kingston Circle, 450 ft. west of Bldg. A 52.2 dba 53.4 dba 59.7 dba* Pos. 3 Residences at end of Elliston Court, 600 ft. SW of Bldg. A 49.2 dba 49.7 dba 56.0 dba* Pos. 9 Residences north side of Station, 1,700 ft. north of Bldg. A 48.6 dba 52.1 dba 58.2 dba* Table 3: Summary of Meas d Sound Levels (i.e., Ld & Ln) in the Community during Full Load Operation of the Station along with the Calc d Ldn (i.e., *based on the Meas d Ld & Ln). At Meas. Pos. 2 and Meas. Pos. 3 (i.e., Malvern Hunt Subdivision) during the recent 2008 sound survey, the Station noise was the dominant noise contributor since these sound measurement positions are relatively close to the Station. At Meas. Pos. 1 (i.e., end of Cameron Court) and Meas. Pos. 9 (i.e., Old Valley Rd. & North Bacton Hill Rd.) during the recent 2008 sound survey, the noise of the Station was a significant noise contributor although the noise of distant vehicle traffic and the sound of insects also contributed to the measured A-wt. sound levels. Other -Page 5-

10 audible sound sources during the sound survey in the community not associated with the Station equipment (i.e., non-station sound sources ) included occasional noise of high-altitude aircraft and distant construction activity (i.e., occurred during the daytime sound tests). The following Table 4 summarizes the measured L d (i.e., arithmetic average of L d measured on Oct. 8 & 9) and the measured L n (i.e., as measured during the evening of Oct. 8) along the Station property line adjacent to the closest residences (i.e., west and south property line of the Station) during the recent 2008 sound survey with the Station operating at full capacity along with the calculated L dn based on the measured L d and L n. Meas. Pos. Pos. 4 Pos. 5 Pos. 6 Pos. 7 Brief Description of the Sound Measurement Location NW corner of Station fenceline, along west property line of Station (approx. 400 ft. NW of Compressor Bldg. A) West property line of Station, in the adjacent power line ROW (approx. 240 ft. west of Compressor Bldg. A) West property line/fenceline of Station (approx. 500 ft. SSW of Compressor Bldg. A) SW corner of Station fenceline, along south property line of Station (approx. 1,000 ft. south of Compressor Bldg. A) Meas d Meas d Calc d Ldn of Ld Ln the Station 57.7 dba 58.5 dba 64.8 dba 58.4 dba 59.0 dba 65.3 dba 57.4 dba 57.2 dba 63.6 dba 50.9 dba 50.7 dba 57.1 dba Table 4: Summary of Meas d Sound Levels (i.e., Ld & Ln) along West/South property line of Station during Full Load Operation of the Station along with the Calc d Ldn. For these sound tests along the Station property line (i.e., Meas. Pos. 4, 5, 6 & 7), the noise of the Station was the most dominant noise source since these sound measurement positions are relatively close to the Station equipment. The measured sound level at Meas. Pos. 7 also included the sound of non-station noise sources, such as the sound of insects, noise of distant vehicle traffic and the noise of distant construction activity (daytime, only). As a final comment, it is our opinion that the reported measured sound data adequately quantifies the existing sound levels around the Station for the meteorological conditions that occurred during this recent 2008 sound survey. If the wind was blowing was blowing from a different direction (e.g., northeast and/or east), the noise contribution of the Station in the Malvern Hunt Subdivision could be higher than measured during this recent 2008 sound survey since the direction of wind can influence the sound propagation of a sound source to a receiver. file: Transco\Station 200 Sentinel Project Modifications\Report Pre-Constr 2008 Sound Survey at Station 200 submitted version to FERC.doc -Page 6-

11 APPENDIX STATION DRAWINGS AND FIGURES SUMMARY OF THE MEASURED AND REPORTED SOUND LEVEL DATA DURING THE RECENT 2008 SOUND SURVEY SUMMARY OF TYPICAL METRICS AND ACOUSTICAL TERMINOLOGY -Page 7-

12 OLD VALLEY RD. POS.9 N 1700' GRANVILLEWAY TRANSCO STATION 200 MAIN PIPELINE R.O.W. 8/10/12 KINGSTON CIRCLE 7/9/11 14/16/18 POS.2 ELLISTON CT. 450' 600' 14/16/18 BLDG. A BLDG. B STATION PROPERTY LINE N. BACTON HILL RD. POS.3 AVONDALE CIRCLE 1000' MALVERN HUNT SUBDIVISION MALVERN HUNTWAY PIPELINE R.O.W POS SELF STORAGE 1 3 APPROXIMATE SCALE IN FEET SWEDESFORD ROAD CAMERON CT LEGEND - MEASUREMENT POSITION - HOUSE OR MULTI-FAMILY DWELLING - BUILDING (COMMERCIAL PROPERTY) Figure 1: Transco Station 200: Area Layout showing the Location of Nearby Residences and Location of the Chosen Sound Measurement Positions in the Community. -Page 8-

13 Information Removed for Treatment as Critical Energy Infrastructure Information Figure 2: Transco Station 200: Drawing showing the Station Buildings and Location of the Reported Sound Measurement Positions around the Station Property/Fenceline.

14 Measured A-Weighted (A-Wt.) Sound Levels (dba) Ldn via Meas. D-time N-time D-time N-time D-time N-time Avg. of Position Leq (Ld) Leq (Ln) L90 L90 L10 L10 Ld & Ln Notes/Observations during Tests Pos. 1: Residences at Daytime: Low-freq. noise of station, distant traffic, end of Cameron Ct., Note (1) insects/birds & distant contruction noise south of area. 1000' from Bldg. A 46.2 Nighttime: Station noise audible & significant, distant 47.9 vehicle traffic, insects (2 khz O.B.), wind-related noise. Pos. 2: Residences at Daytime: Mostly station noise at this location, some end of Kingston Cir., Note (1) insects/birds, at times, distant traffic & aircraft audible. 450' from Bldg. A 51.7 Nighttime: Mostly station noise (dominant/constant), 51.5 distant vehicle traffic and insects. Pos. 3: Residences at Daytime: Mostly station noise at this location, some end of Elliston Ct., Note (1) insects/birds, distant traffic & construction noise. 600' from Bldg. A 47.4 Nighttime: Mostly station noise (dominant/constant), 46.1 distant vehicle traffic, insects, at times, distant aircraft. Pos. 9: Residences, Daytime: Station noise audible & significant, insects corner of Old Valley Note (1) contributed to A-wt. level, distant vehicle traffic & wind. & N. Bacton Hill Rd Nighttime: Station noise audible & significant, insects 46.3 contributed to A-wt. level (2 khz & 4 khz O.B.). Table A: Transco Station No. 200: Summary of the Daytime Sound Levels and Nighttime Sound Levels as Meas'd on October 8 & 9 (2008) with Station at Full Load/Capacity along with the Calc'd Ldn, as Calculated from the Meas'd Ld and Meas'd Ln. Note (1): Ldn calc'd by adding 6.4 db to meas'd Ld if nighttime sound levels (Ln) not measured. If both the Ld and Ln are measured and/or estimated, Ldn is calculated using the following formula: L dn = 10log L /10 9 d ( L + 10) / 10 n Measurement Set Temp. R.H. Wind Wind Peak Position Date/Time of Testing ( F) (%) Direction Speed Wind Sky Conditions Pos :00 PM - 5:00 PM (10/8/08) Wind from the Mostly cloudy, initially, then Daytime (Afternoon) SW/SSW mph mph became mostly clear Pos :00 PM - 10:00 PM (10/8/08) Wind from Overcast (mostly cloudy) Nighttime (Before Midniight) the South mph mph Pos :00 AM - 11:00 AM (10/9/08) Wind from the Mostly cloudy Daytime (Morning) West/WSW mph mph Table B: Transco Station No. 200: Meteorological Conditions During the Daytime and/or Nightime Sound Measurements around the Station on October 8 & 9, Page 10-

15 Measurement Set Type of Sound Pressure Level (SPL) in db per Octave-Band (O.B.) Frequency (in Hz) A-Wt. Position Time Metric Level Pos. 1: Residences at 2:00 PM Leq end of Cameron Ct., 2:00 PM L ' from Bldg. A 2:00 PM L :15 PM Leq Pos. 2: Residences at 2:30 PM Leq end of Kingston Cir., 2:30 PM L ' from Bldg. A 2:30 PM L :40 PM Leq Pos. 3: Residences at 3:05 PM Leq end of Elliston Ct., 3:05 PM L ' from Bldg. A 3:05 PM L :15 PM Leq Pos. 9: Residences, 3:30 PM Leq corner of Old Valley 3:30 PM L & N. Bacton Hill Rd. 3:30 PM L :45 PM Leq Pos. 4: NW corner of 4:02 PM Leq Station fenceline; 4:03 PM Leq ' from Bldg. A Avg. SPL Leq Pos. 5: West Side of 4:05 PM Leq Station propety line; 4:08 PM Leq ' from Bldg. A Avg. SPL Leq Pos. 6: West Side of 4:15 PM Leq Station fenceline, 4:18 PM Leq ' SSW of Bldg. A Avg. SPL Leq Pos. 7: SW corner of 4:20 PM Leq Station fenceline; 4:25 PM Leq ' south of Bldg. A Avg. SPL Leq Pos. 8: On access road 4:35 PM Leq to Radio Tower; 100' 4:40 PM Leq from Office Bldg. Avg. SPL Leq Pos. 10: On sidewalk 4:50 PM Leq in front of Office Bldg. 5:00 PM Leq ' S. of Bldg. B Avg. SPL Leq Table C: Transco Station No. 200: Meas'd Daytime Ambient A-Wt. Sound Levels and Unweighted O.B. SPLs as Meas'd on October 8 (2008) during Full Load Operation of the Station/Units. -Page 11-

16 Measurement Set Type of Sound Pressure Level (SPL) in db per Octave-Band (O.B.) Frequency (in Hz) A-Wt. Position Time Metric Level Pos. 1: Residences at 9:50 PM Leq end of Cameron Ct., 9:50 PM L ' from Bldg. A 9:50 PM L :00 PM Leq Pos. 2: Residences at 9:00 PM Leq end of Kingston Cir., 9:00 PM L ' from Bldg. A 9:00 PM L :10 PM Leq Pos. 3: Residences at 9:18 PM Leq end of Elliston Ct., 9:18 PM L ' from Bldg. A 9:18 PM L :30 PM Leq Pos. 9: Residences, 8:45 PM Leq corner of Old Valley 8:45 PM L & N. Bacton Hill Rd. 8:45 PM L :50 PM Leq Pos. 4: NW corner of 8:00 PM Leq Station fenceline; 8:02 PM Leq ' from Bldg. A Avg. SPL Leq Pos. 5: West Side of 8:05 PM Leq Station propety line; 8:07 PM Leq ' from Bldg. A Avg. SPL Leq Pos. 6: West Side of 8:12 PM Leq Station fenceline, 8:15 PM Leq ' SSW of Bldg. A Avg. SPL Leq Pos. 7: SW corner of 8:18 PM Leq Station fenceline; 8:20 PM Leq ' south of Bldg. A Avg. SPL Leq Pos. 8: On access road 8:25 PM Leq to Radio Tower; 100' 8:28 PM Leq from Office Bldg. Avg. SPL Leq Pos. 10: On sidewalk 8:30 PM Leq in front of Office Bldg. 8:32 PM Leq ' S. of Bldg. B Avg. SPL Leq Table D: Transco Station No. 200: Meas'd Nighttime Ambient A-Wt. Sound Levels and Unweighted O.B. SPLs as Meas'd on October 8 (2008) during Full Load Operation of the Station/Units. -Page 12-

17 Measurement Set Type of Sound Pressure Level (SPL) in db per Octave-Band (O.B.) Frequency (in Hz) A-Wt. Position Time Metric Level Pos. 1: Residences at 10:30 AM Leq end of Cameron Ct., 10:30 AM L ' from Bldg. A 10:30 AM L :45 AM Leq Pos. 2: Residences at 9:20 AM Leq end of Kingston Cir., 9:20 AM L ' from Bldg. A 9:20 AM L :30 AM Leq Pos. 3: Residences at 9:40 AM Leq end of Elliston Ct., 9:40 AM L ' from Bldg. A 9:40 AM L :00 AM Leq Pos. 9: Residences, 9:00 AM Leq corner of Old Valley 9:00 AM L & N. Bacton Hill Rd. 9:00 AM L :10 AM Leq Pos. 4: NW corner of 8:10 AM Leq Station fenceline; 8:12 AM Leq ' from Bldg. A Avg. SPL Leq Pos. 5: West Side of 8:15 AM Leq Station propety line; 8:17 AM Leq ' from Bldg. A Avg. SPL Leq Pos. 6: West Side of 8:20 AM Leq Station fenceline, 8:22 AM Leq ' SSW of Bldg. A Avg. SPL Leq Pos. 7: SW corner of 8:25 AM Leq Station fenceline; 8:28 AM Leq ' south of Bldg. A Avg. SPL Leq Pos. 8: On access road 8:30 AM Leq to Radio Tower; 100' 8:32 AM Leq from Office Bldg. Avg. SPL Leq Pos. 10: On sidewalk 8:35 AM Leq in front of Office Bldg. 8:38 AM Leq ' S. of Bldg. B Avg. SPL Leq Table E: Transco Station No. 200: Meas'd Daytime Ambient A-Wt. Sound Levels and Unweighted O.B. SPLs as Meas'd on October 9 (2008) during Full Load Operation of the Station/Units. -Page 13-

18 SUMMARY OF TYPICAL METRICS FOR REGULATING ENVIRONMENTAL NOISE AND ACOUSTICAL TERMINOLOGY IN 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-weighted ( 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 that shows a graphical representation of the A-wt. filter response per frequency (in Hz) Hz 63 Hz 125 Hz 250 Hz 500 Hz 1,000 Hz 2,000 Hz 4,000 Hz 8,000 Hz 16,000 Hz db db db -8.6 db -3.2 db 0 db +1.2 db +1.0 db -1.1 db -6.6 db RELATIVE RESPONSE, 10 db 0-10 C B, C A -20 B A ,000 FREQUENCY, Hz -Page 14-

19 (3) Human Perception of Change in Sound Level A 3 db change of sound level is barely perceivable by the human ear 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 (4) Sound Pressure Level (L p 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 [i.e., 20 micropascals (20 µpa) or microbar]. (5) Octave Band Sound Pressure Level (SPL): Sound is typically measured in frequency ranges (e.g., high-pitched sound, low-pitched sound) that provides more meaningful sound data regarding the 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, two noise sources can have the same dba rating and yet sound completely different. For example, a high-pitched sound concentrated at a frequency of 2000 Hz could have the same dba rating as a much louder low-frequency sound concentrated at 50 Hz. (6) Daytime Sound Level (L d ) & Nighttime Sound Level (L n ): L d 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 n 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.). (7) Equivalent Sound Level (L eq ): The equivalent sound level (L eq ) 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 L eq 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 L eq has been used broadly to relate individual and community reaction to aircraft and other environmental noises. (8) Day-Night Average Sound Level (L dn ): The L dn is an energy average of the measured daytime L eq (L d ) and the measured nighttime L eq (L n ) plus 10 db. The 10-dB adjustment to the L n is intended to compensate for nighttime sensitivity. As such, the L dn 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, an L dn is approximately 6.4 db above the measured L eq. Consequently, an L dn of 55 dba corresponds to a L eq of 48.6 dba. If both the L d and L n are measured, then the L dn is calculated using the following formula: L dn = 10log L /10 9 d ( L 10) n + / 10 -Page 15-

20 (9) Background or Ambient Noise: The total noise produced by all other sources associated with a given environment in the vicinity of a specific source of interest, and includes any Residual Noise. (10) 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. (11) Sound Power Level (L w 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 watt is conventionally used. (12) Broadband Noise: Noise comprised of a wide frequency range and not characterized by any tonal components. (13) 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. (14) Airborne Sound: Sound transmitted through air as a medium rather than through a liquid or solid. (15) Groundborne Vibration: A condition in which sound waves generated by a noise source, which is in contact with the ground, are transmitted to and through the ground. (16) Factors that Influence Outdoor Sound Propagation The direction of wind can influence the sound propagation of a sound source to a receiver. For example, wind blowing from a natural gas compressor facility in the direction of the receiver can increase the received sound level contributed by the facility by 2 to 3 db at distances of 1,000 to 2,000 feet. In addition, atmospheric temperature inversions that can occur at night (i.e., a result of colder air near the ground) can increase the received sound level by 2 to 3 db at distances of 1,000 to 2,000 feet. Consequently, the sound contribution at the noise complainant s house could increase by 4 to 6 db due to favorable atmospheric conditions (e.g., wind from the station toward the house and/or temperature inversion). Regarding the acoustical effect of vegetation, many rows of trees have some value as an acoustical barrier. However, the sound attenuation from dense plantings more than 100 feet deep will be limited by the flanking of sound energy over the top of the canopy of trees. If dense plantings consist mostly of deciduous vegetation, there may be somewhat less sound attenuation due to trees during months when the leaves have fallen although the effect of wind direction and temperature inversion are considered the most significant factors that influence outdoor propagation of sound. -Page 16-

21 (17) Relevant Standards, associated Standards Institute(s) and References American National Standards Institute (ANSI) S1.4: Specification for SLM: Type I SLM: Sound level meters (SLM) that meet this specification have a tolerance of +/- 0.5 db from 22.4 to 11,200 Hz. Type II SLM: Sound level meters that meet this specification have a tolerance of +/- 0.5 db from 63 to 2,000 Hz and +/- 1.0 db from 22.4 to 11,200 Hz. ANSI S (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 E : 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 17-

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