Noise Impact Assessment

Transcription

1 Noise Impact Assessment Green Oil Company Ltd. Botswana LSD W5M Prepared For Mr. John Q. Public, P.Eng. Green Oil Company Ltd. Prepared By Mr. James Farquharson, CET Mr. Don South, RET Ms. Turi Henderson Mr. Clifford Faszer, P.Eng. Faszer Farquharson & Associates Ltd. April 1, 2002 FFA File

2 Executive Summary In order to measure the environmental noise impact of their Botswana facility located at LSD W5M, Green Oil Company Ltd. (Green) retained Faszer Farquharson & Associates Ltd., Consultants in Acoustics and Noise Control to complete a noise impact assessment at the nearest residence to the facility. The results would be used to determine potential compliance of this facility with the Alberta Energy and Utilities Board (EUB) Noise Control Directive ID 99-8 (Directive), and to develop noise control measures for the facility if necessary. Green conducted this assessment in response to a concern from the nearest resident regarding the sound of the facility. Faszer Farquharson & Associates conducted sound pressure level measurements of the facility during a site visit on March 17, These measurements were used to determine the sound power levels for the equipment at site following accepted acoustical engineering practices for the determination of sound power levels from sound pressure levels for large machinery. The sound power levels for the individual facility items were then incorporated into ENM, an environmental noise propagation model. The ENM model was used to predict the facility sound level to the nearest residence. The modelled results were compared with the Permissible Sound Levels (PSL) of the EUB Directive in order to determine the potential for compliance with that Directive. The results of the modelling along with the PSLs of the EUB Directive are presented in the following table. Residence Predicted Facility Sound Level Green Botswana LSD W5M Predicted Sound Level (dba) EUB Daytime Permissible Sound Level (dba L eq ) EUB Nighttime Permissible Sound Level (dba L eq ) 428 metres southeast FFA File The modelling indicates that the sound level of the facility is in compliance with the daytime PSL of the EUB Directive, but not the nighttime PSL, at the residence located 428 metres southeast of the facility. Green is advised to review the Comments & Recommendations section of this report for recommended noise control measures. i

3 Contents Executive Summary... i Contents... ii Tables & Figures... iii Background & Scope... 1 Site Description & Residence Location... 1 Facility Equipment... 2 Approach... 2 Criteria... 2 Sound Pressure Level Measurements... 3 Sound Power Level Calculations... 3 Noise Model... 4 Results... 5 Discussion of Results... 6 Comments & Recommendations... 6 Conclusion... 7 Glossary... I Appendix A -- Permissible Sound Level Determination Residence 428 Metres Southeast... A-1 Appendix B -- Acoustical Specifications Acoustical Specifications... B-1 Manufacturers and Suppliers... B-4 ii

4 Tables & Figures Predicted Facility Sound Level i Figure 1 Map of Study Area 1 Table 1 Permissible Sound Levels 3 Table 2 Order Ranked Source Sound Power Levels 4 Table 3 Modelled Conditions 5 Table 4 Order Ranked Sound Pressure Levels 6 Residence 428 metres Southeast Table 5 Predicted Facility Sound Level 6 Table 6 Recommended Noise Control Measures 7 iii

5 Background & Scope Green Oil Company Ltd. (Green) wanted to determine the environmental noise impact of their Botswana facility located in LSD W5M. Green commissioned this assessment to gain a better understanding of the noise impact to the community, and in response to concerns from the nearest resident regarding the noise of the facility. The results will also be used to determine if the facility is potentially in compliance with the Permissible Sound Levels (PSL) of the Alberta Energy and Utilities Board (EUB) Noise Control Directive ID 99-8 (Directive). The assessment may also be used to develop and evaluate noise control measures for the facility if necessary. Green retained Faszer Farquharson & Associates Ltd., Consultants in Acoustics & Noise Control to complete this evaluation. Site Description & Residence Location The Green facility is located approximately 12 kilometres southwest of Somewhere, Alberta. The nearest residence is located approximately 428 metres southeast of the facility site. The terrain in the area is described as flat to rolling. The land between the facility and the residence is agricultural in use. A map of the study area indicating the location of the residence of interest in reference to the facility is presented in Figure 1. Figure 1 Study Area Map Green Botswana LSD W5M N N.T.S. FFA File

6 Facility Equipment The existing facility equipment includes a Caterpillar Model G3306 engine-driven compressor unit fitted with an Amercool cooler, with a 60 diameter fan. Both the engine and the compressor unit are housed in an insulated metal building. Approach Faszer Farquharson & Associates conducted sound pressure level measurements of the facility equipment at the site on March 17, The results of these measurements were used to calculate sound power levels for the significant noise sources associated with the facility. Data regarding the topography and vegetation of the area surrounding the facility site, along with the location of the residence with respect to the facility was noted during the site visit. Additional geographic information was obtained from commercial sources. This information was used as input parameters for an environmental noise propagation computer model to calculate the facility sound level at the residence of interest. The modelled results are presented as individual source sound levels as well as the overall combined facility sound level. The results are reviewed and compared to the PSLs of the EUB Directive to determine the potential for compliance at the nearest or most impacted residence. If required, noise control measures can then be developed for the most significant noise sources and the expected change in sound level can be predicted at the point of interest. Criteria The EUB Directive is a receiver-oriented noise regulation for energy industry facilities operating in the Province of Alberta. The EUB Directive permits specified sound levels attributable to energy industry facilities for designated receptor points including residences. In lieu of a residence within 1500 metres of a facility, the Directive indicates that a level of 40 dba L eq should not be exceeded at this distance during the nighttime period. These specified limits are the Permissible Sound Levels (PSL). The Directive requires that all proposed facilities approved after April 1988 meet these PSLs. These levels are derived from information regarding the area population density, proximity to heavily travelled transportation routes (including motor vehicle routes), rail lines, aircraft flyways and other specified adjustments. The PSL during the daytime may be adjusted to a level 10 dba above the nighttime level. The PSLs for the residence assessed are presented in Table 1. 2

7 Criteria (continued) Table 1 Permissible Sound Levels Green Botswana LSD W5M Residence Daytime Permissible Sound Level (dba L eq) Nighttime Permissible Sound Level (dba L eq) 428 metres southeast FFA File The detailed determination of the PSLs is presented in Appendix A. Sound Pressure Level Measurements Mr. Don South, RET of Faszer Farquharson & Associates conducted sound pressure level measurements of the significant noise sources associated with the compressor station equipment during a site visit on March 17, The sound pressure level measurements were conducted with a Brüel & Kjær Model 2260 Real Time Analyzer. The sound measurement system was field calibrated with a Brüel & Kjær Model 4231 calibrator upon start of the measurements and then checked at the completion. The Brüel & Kjær Model 2260 measures the 1/3 octave band sound pressure level and the overall A weighted sound level in real time. Sound Power Level Calculations Sound power levels of the significant facility noise sources were calculated from the measured sound pressure levels and manufacturers data using theoretical assessment techniques. The calculations followed accepted acoustical engineering evaluation methods for the determination of sound power levels from sound pressure levels for large machinery. The calculated sound power levels of the facility equipment are presented in Table 2, order ranked from highest to lowest overall dba sound power level. 3

8 Sound Power Level Calculations (continued) Table 2 Source Sound Power Levels Green Botswana LSD W5M Sound Power Level (db re: W) Source Description Octave Band Centre Frequency (Hz) Sum (dba) Caterpillar 3306 Engine / Amercool 60 cooler unit Open Doors East Open Doors West Engine Exhaust CoolerGround Opening Cooler Inlet Cooler Outlet Cooler Plenum Ridge Vent Muffler Shell Open Window -- East Open Window -- West Engine Air Inlet Building Skid Building FFA File The order ranked sound pressure levels at a distant point of reception may differ from the facility order ranked sound power levels. This can occur for a number of reasons including the frequency composition of each noise source, the physical height of the noise source above the ground, acoustical shielding at the site or the topography between the site and the receiver. Noise Model Faszer Farquharson & Associates employed the use of ENM, a leading environmental noise assessment software package from RTA Technology Pty. Ltd., for this assessment. The calculated source sound power levels complete with the physical information regarding the site layout and location of the nearest residence were used as input for the model. The meteorological conditions selected favour the transmission of sound from the facility site to the point of reception, thus emulating a period during which the facility may experience noise complaints. The conditions that were selected are presented in Table 3. 4

9 Noise Model (continued) Table 3 Modelled Conditions Green Botswana LSD W5M Parameter Modelled Input Temperature +25 C Wind Velocity 5.0 kph From the facility to Wind Direction the residence Relative Humidity 50% Topography Yes Terrain Category Rural Ground Type Grass Temperature Gradient ( C/100m) 0 Receiver Height Above Ground 1.5m FFA File Faszer Farquharson & Associates reviewed the model input and results during the modelling process and, where warranted, additional calculations were completed outside of the model to verify the ENM results. Results Table 4 presents the source order ranked sound pressure level results for the residence located 428 metres southeast of the facility. Table 4 Order Ranked Sound Pressure Levels Residence 428 metres Southeast Green Botswana LSD W5M Source Predicted Facility Source Sound Level Contribution (dba) Engine Exhaust 40.0 Open Doors East 40.0 Open Doors West 39.8 Cooler Outlet 32.7 Cooler Inlet 32.4 Ridge Vent 31.1 Cooler Ground Opening 30.7 Cooler Plenum 28.3 Muffler Shell 28.0 Open Window East 25.3 Open Window West 25.2 Engine Air Inlet 22.2 Building 19.5 Building Skid 16.1 Facility Sum 45.8 FFA File

10 Results (continued) Green has indicated that the operational speeds of the equipment at the site should remain constant. The facility was modelled with the building doors, windows and vents in the open position, as this may occur during warmer ambient temperatures. Discussion of Results The overall predicted facility sound level along with the PSLs of the EUB Directive for the residence assessed is presented in Table 5. Table 5 Predicted Facility Sound Level Green Botswana LSD W5M Residence Predicted Sound Level (dba) EUB Daytime Permissible Sound Level (dba L eq ) EUB Nighttime Permissible Sound Level (dba L eq ) 428 metres southeast FFA File Comparisons of the predicted to the allowable sound levels indicate that the facility is in compliance with the daytime PSL of the EUB Directive at the residence assessed, but not in compliance with the nighttime PSL of the EUB Directive at that residence. Comments & Recommendations Green has indicated that there is a concern in the community regarding the sound of the facility. In response to this concern, and in view of the results of the modelling indicating non-compliance to the PSLs of the EUB Directive, Green has requested that Faszer Farquharson & Associates prepare and evaluate a series of noise control recommendations for the facility. Implementation of these recommendations would possibly address the concerns of the nearest resident and bring the facility into compliance with the PSLs of the EUB Directive. Based on our experience in assisting clients in similar situations, Faszer Farquharson & Associates recommends the following noise control measures presented in Table 6. The recommended noise control measures are presented in a progressive list. All measures above the selected measure must be implemented in order to achieve the predicted sound level indicated at the selected measure. 6

11 Comments & Recommendations (continued) Table 6 Recommended Noise Control Measures Green Botswana LSD W5M Step Noise Control Measure Residence 1 Predicted Facility Sound Level (dba) Existing facility sound level Replace the existing engine exhaust silencer with a model that possesses higher attenuation values. Install an acoustically treated building ventilation on the Caterpillar G3306 unit that will provide adequate cooling air volumes to permit operations with building doors and other untreated ventilation openings closed. Acoustically lag or cover the building skid and cooler ground opening with gravel. Install cooler inlet and outlet silencers, making sure to enclose the cooler plenum and engine air inlet FFA File Faszer Farquharson & Associates recommends implementing measure 1 through 3. Calculations indicate that implementing the first three noise control measures would reduce the facility sound level sufficiently to meet the EUB Directive and provide an acoustical design safety factor. As discussed, Faszer Farquharson & Associates has prepared and attached the acoustical specifications for the replacement exhaust silencer, cooler inlet and outlet silencers, and for the compression building ventilation system. These specifications, as well as a listing of manufacturers and suppliers are presented in Appendix B. Conclusion The noise propagation model results indicate that the facility is in compliance with the daytime PSL of the EUB Directive, but not in compliance with the nighttime PSL of the EUB Directive at the residence assessed. The predicted sound levels indicate that implementing the recommended noise control measures as outlined in this report would result in the facility potentially complying with the EUB Directive at the nearest residence located 428 metres southeast of the facility. 7

12 Glossary

13 Glossary Ambient Sound Level A-weighted sound level Background Sound Level Calibration All noises that exist in an area and are not related to a facility covered by ID Ambient noise includes sound from other industrial noise not subject to this directive, transportation sources, animals and nature. The sound level as measured on a sound level meter using a setting that emphasizes the middle frequency components similar to the frequency response of the human ear. All noises that exist in an area including existing facilities covered by ID Background noise includes sound from other industrial noise not subject to this directive, transportation sources, animals and nature. A procedure used for the adjustment of a sound level meter using a reference source of a known sound pressure level and frequency. Calibration must take place before and after the sound level measurements. Comprehensive Level (CSL) Sound The sound level that is a composite of different airborne sounds from many sources far away from and near the point of measurement. The CSL does include industrial components and must be measured with them, but it should exclude abnormal noise events. The CSL is used to determine whether a facility is complying with ID Daytime Defined as the hours from 07:00 to 22:00. Daytime adjustment db (decibel) An adjustment that allows a 10 dba increase above the basic sound level for nighttime, as daytime sound levels are generally about 10 dba higher than nighttime values. A unit of measure of sound pressure that compresses a large range of numbers into a more meaningful scale. I

14 dba The decibel (db) sound pressure level filtered through the A filtering network to approximate human hearing response. See db and A-weighted sound level. Energy equivalent sound level (L eq ) ENM Facility Infringement L eq The L eq is a single-number average, A-weighted sound level that represents cumulative acoustical energy as measured over a specified time interval. This interval should be specified in brackets following the L eq (e.g.: L eq (9) is a nine-hour L eq ). Environmental noise prediction software created by RTA Technology Pty. Ltd. Any operation used in exploration, processing, development and transportation of energy resources. Locating a residence within the existing noise footprint (boundary) of a facility, such that the facility could be seen as not complying with ID See Energy equivalent sound level. Nighttime Defined as the hours from 22:00 to 07:00. Noise Noise Exposure Forecast (NEF) (Airport specific) Noise Impact Assessment (NIA) Generally understood as unwanted sound. The NEF contours are site specific to each airport and take into account such factors as air traffic volume, proximity to runways, flight paths and aircraft type and size. Identifies the expected sound level emanating from a facility as measured 15 m from the nearest or most impacted permanently or seasonally occupied dwelling. It also identifies what the permissible sound level is and how it was calculated. II

15 Octave 1/3 Octave Permissible Sound Level (PSL) Representative conditions Sound monitoring survey Sound level meter Sound pressure level Sound power level Spectrum Windscreen A series of electronic filters separate sound into discrete frequency bands, making it possible to know how sound energy is distributed as a function of frequency. The octave band has a centre frequency that is double the centre frequency of the octave band preceding it. The 1/3 octave band analysis provides a finer breakdown of sound distribution as a function of frequency. The maximum sound level that a facility should not exceed at a point 15m from the nearest or most impacted dwelling unit. Those conditions typical for an area and/or the nature of a complaint. Sound levels must be taken only when representative conditions exist; this may necessitate a survey of extensive duration (two or more consecutive nights). The measurement and recording of sound levels and pertinent related information over a given time period. An instrument designed and calibrated to respond to sound and to give objective, reproducible measurements of sound pressure levels. It normally has several features that enable its frequency response and averaging times to be changed. The ratio, expressed in decibels, of sound pressure to a reference pressure equal to the human threshold of hearing. The acoustic power radiated from a given sound source related to a reference power level (typically watts) expressed in decibels. A wide range or sequence of frequencies. A specialized piece of porous sponge that fits over the microphone to reduce the noise generated by the wind blowing around the microphone. III

16 Appendix A Permissible Sound Level Determination

17 Residence 428 Metres Southeast Green Botswana LSD W5M Permissible Sound Level (PSL) Determination AEUB Noise Control Directive Basic Nighttime Sound Level (BSL) Nighttime Daytime (22:00-07:00) (07:00-22:00) Dwelling Unit Density per ¼ Section of Land Proximity to Transportation* 1 8 Dwellings Dwellings >160 Dwellings Category Category Category Class A Adjustments Class Reason for Adjustment Daytime Adjustment N/A 10 Basic Sound Level Value (dba L eq ) A1 Seasonal Adjustment (1 Nov 31 Mar) +5 A2 Absence of Both Tonal and Impulse/Impact Components +5 A3 Ambient Monitoring Adjustment -10 to +10 Class Adjustment = Sum of A1, A2 and A3 (as applicable), but not to exceed a maximum of 10 dba L eq Class B Adjustments Total Class A Adjustments 0 0 Class Duration of Activity Value (dba L eq ) B1 1 day +15 B2 1 week +10 B3 < or = to 2 months +5 B4 > 2 months 0 Class B Adjustment = one only of B1, B2, B3 or B4 Class B Adjustment 0 0 PERMISSIBLE SOUND LEVEL (dba) *Proximity to Transportation Category Definitions Category 1 Category 2 Category 3 Dwelling units more than 500m from heavily travelled roads and/or rail lines and not subject to frequent aircraft flyovers. Dwelling units more than 30m but less than 500m from heavily travelled roads and/or rail lines and not subject to frequent aircraft flyovers. Dwelling units less than 30m from heavily travelled roads and/or rail lines and subject to frequent aircraft flyovers. FFA File A-1

18 Appendix B Acoustical Specifications

19 Acoustical Specifications Green Oil Company Ltd. Botswana LSD W5M Replacement Engine Exhaust Silencer Acoustical Specification A silencer for the attached described engine that meets or exceeds the following octave band centre frequency dynamic insertion loss values shall be provided by the silencer manufacturer. Octave Band Centre Frequency (Hz) Dynamic Insertion Loss (db) All specific installation requirements that pertain to the acoustical performance for the silencer shall be included in the bid. The successful silencer supplier shall guarantee the acoustical performance of the engine exhaust silencer and agree to provide a replacement should the results of a field test indicate that the silencer fails to meet the above specification. The radiated octave band sound power level of the silencer body is required to be equal to or lower than the octave band sound power levels of the exhaust outlet. B-1

20 Green Oil Company Ltd. Botswana LSD W5M Cooler Inlet and Outlet Silencer Acoustical Specification The silencer manufacturer shall provide a silencer for the cooler inlet and cooler outlet that meets or exceeds the following octave band centre frequency dynamic insertion loss values. Octave Band Centre Frequency (Hz) Dynamic Insertion Loss (db) The cooler silencer shall be constructed in such a manner that the exterior walls of the silencer meet or exceed the octave band acoustical requirement of the silencer. The cooler plenum and engine air inlet shall be enclosed. The supplier is requested to consult with the owner as to an acceptable pressure drop for the silencers. All specific installation requirements that pertain to the acoustical performance for the silencers shall be included in the bid. The successful silencer supplier shall guarantee the acoustical performance of the silencers and agree to provide a replacement(s) should the result of a field test indicate that a silencer fails to meet the above specification. B-2

21 Green Oil Company Ltd. Botswana LSD W5M Building Ventilation Silencer Acoustical Specification The silencer manufacturer shall provide silencers for the power ventilation openings of the building that meets or exceeds the following octave band centre frequency dynamic insertion loss values. Octave Band Centre Frequency (Hz) Dynamic Insertion Loss (db) This building ventilation silencer(s) shall be constructed in such a manner that the exterior walls of the silencers meet or exceed the octave band acoustical requirements of the silencer. The supplier is requested to consult with the owner as to an acceptable pressure drop for the silencer(s). The supplier is requested to discuss the overall building ventilation requirements with the owner so as to determine the required cooling air volumes that would permit unit operation with the building doors, windows and untreated openings closed. All specific installation requirements that pertain to the acoustical performance for the silencer(s) shall be included in the bid. The successful silencer supplier shall guarantee the acoustical performance of the building ventilation silencers and agree to provide a replacement(s) should the result of a field test indicate that the silencer(s) fail to meet the above specification. B-3

22 Manufacturers and Suppliers Engine Exhaust Silencers Manufacturers and Representatives Manufacturer Beaird/ Maxim Silencers 601 Benton Kelly Street Shreveport, LA Phone: (318) Fax: (318) Burgess-Manning 227 Thorn Avenue Orchard Park, NY Phone: (716) Fax: (716) Noise Solutions Inc. 310, st Street SW Calgary, Alberta T2P 3S9 Phone: (403) Fax: (403) Web: Representative RNG Controls Street NE Calgary, AB T2E 8T3 Phone: (403) Fax: (403) e- mail: Contact: Norma Ansloos Industrial Process Products Ltd. Bay F 7239 Flint Road SE Calgary, Alberta T2H 1G2 Phone: (403) Fax: (403) e- mail: sales@petromesh.com Contact: Rod Bratton Noise Solutions Inc. 310, st Street SW Calgary, Alberta T2P 3S9 Phone: (403) Fax: (403) e- mail: rod@noise-solutions.com Contact: Rod Mac Donald Silex Exhaust Silencers 7850 Tranmere Drive Mississauga, ON L5S 1L9 Phone: Fax: (905) Web: Silex Exhaust Silencers Calgary: Phone: (403) Fax: (403) e- mail: brentm@silex.com Contact: Brent McCool Universal Silencer P.O. Box 411 Stoughton, WI Phone: (608) Fax: (608) Ramtech Enterprises Ltd. 50 Glenwood Way Cochrane, AB T0L 0W3 Phone: (403) Fax: (403) Contact: Ted Thrush B-4

23 Cooler Silencers Manufacturers and Representatives Manufacturer Noise Solutions Inc. 310, st Street S.W. Calgary, Alberta T2P 3S9 Phone: (403) Fax: (403) rod@noise-solutions.com Representative Noise Solutions Inc. 310, st Street S.W. Calgary, Alberta T2P 3S9 Phone: (403) Fax: (403) rod@noise-solutions.com Contact: Rod Mac Donald Spring Air Acoustics Ltd. RR2 Balzac, Alberta T0M E0 Phone (403) Fax (403) jlorne@telusplanet.net Spring Air Acoustics Ltd. RR2 Balzac, Alberta T0M E0 Phone (403) Fax (403) jlorne@telusplanet.net Contact: Jerry Anderson B-5

24 Building Ventilation Systems Manufacturers and Representatives Manufacturer Noise Solutions Inc. 310, st Street S.W. Calgary, Alberta T2P 3S9 Phone: (403) Fax: (403) rod@noise-solutions.com Representative Noise Solutions Inc. 310, st Street S.W. Calgary, Alberta T2P 3S9 Phone: (403) Fax: (403) rod@noise-solutions.com Contact: Rod Mac Donald Spring Air Acoustics Ltd. RR2 Balzac, Alberta T0M E0 Phone (403) Fax (403) jlorne@telusplanet.net Spring Air Acoustics Ltd. RR2 Balzac, Alberta T0M E0 Phone (403) Fax (403) jlorne@telusplanet.net Contact: Jerry Anderson B-6

25 Compressor Engine Information Summary Client: File No: Facility: Unit No./ Designation: Age: Engine Manufacturer: Model No: Serial Number: Turbocharged / Normally Aspirated: Horsepower: Fixed Or Variable Speed: RPM: Exhaust System Exhaust Gas: Temperature: Mass Flow Rate: Exhaust Piping Diameter: Flange Size: Type: Muffler Configuration: 1 In: Out: Maximum Allowable Pressure Drop Across Exhaust System: Pressure Drop Imposed By Piping: Total Allowable Pressure Drop For The Muffler: - 1 Note End In/ Out Side In/ Out Side Direction In Degrees B-7