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HomeMy WebLinkAbout713013001 Environmental Noise Assessment Report i Environmental Noise Assessment Report Site No. 43323 Bogachiel 846 Dowans Creek Rd Forks, Washington EBI Project No. 6217000136 January 19, 2017 Prepared for: American Tower Corporation 10 Presidential Way Woburn, MA 01801 Prepared by: Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington EBI Consulting ii TABLE OF CONTENTS 1.0 EXECUTIVE SUMMARY .................................................................................................................... 3  2.0 BACKGROUND ................................................................................................................................ 3  3.0 REGULATORY REQUIREMENTS ........................................................................................................ 5  4.0 SITE DESCRIPTION .......................................................................................................................... 6  5.0 NOISE-GENERATING EQUIPMENT .................................................................................................. 8  6.0 MODELED POST CONSTRUCTION NOISE LEVELS .......................................................................... 9  7.0 RESULTS AND CONCLUSIONS ...................................................................................................... 10  8.0 LIMITATIONS ................................................................................................................................. 11  9.0 REVIEWER CERTIFICATION ........................................................................................................... 11  APPENDICES Appendix A Equipment Specifications Appendix B CadnA® Environmental Noise Model Results Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington 3 1.0 EXECUTIVE SUMMARY This study evaluates noise impact from the proposed emergency back-up generator and existing power cabinet on the site vicinity and evaluates the compliance for Site No. 43323 in relation to the State of Washington Administrative Code (WAC) Chapter 173-60, Maximum Environmental Noise Levels. Acoustic modeling was done to assess the potential acoustic impact at the nearest receiving property line. Based on the information collected, the existing power cabinet and proposed emergency back-up generator will operate in compliance with the noise standards, as defined in the State of Washington Administrative Code (WAC) Chapter 173-60 Maximum Environmental Noise Levels. 2.0 BACKGROUND All sounds originate from a source. The sound energy, produced by a source, creates variations in air pressure, which travel in all directions much like a wave ripples across the water. The “loudness” or intensity of a sound is a function of the sound pressure level, defined as the ratio of two pressures: the measured sound pressure from the source divided by a reference pressure (i.e. threshold of human hearing). Sound level measurements are most commonly expressed using the decibel (dB) scale. The decibel scale is logarithmic to accommodate the wide range of sound intensities to which the human ear is capable of responding. On this scale, the threshold of human hearing is equal to 0 dB, while levels above 140 dB can cause immediate hearing damage. One property of the decibel scale is that the combined sound pressure level of separate sound sources is not simply the sum of the contributing sources. For example, if the sound of one source of 70 dB is added to another source of 70 dB, the total is only 73 dB, not a doubling to 140 dB. In terms of human perception of sound, a 3 dB difference is the minimum perceptible change for broadband sounds (i.e. sounds that include all frequencies). A difference of 10 dB represents a perceived halving or doubling of loudness. Environmental sound is commonly expressed in terms of the A-weighted sound level (dBA). The A- weighting is a standard filter to make measured sound levels more nearly approximate the frequency response of the human ear. Table 1 shows the adjustments made at each octave band frequency to contour un-weighted sound levels (dB) to A-weighted sound levels (dBA). Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington 4 TABLE 1 - A-WEIGHTED OCTAVE BAND ADJUSTMENT (±dB) Octave Band Center Frequency (Hz) 32 64 125 250 500 1000 2000 4000 8000 16000 A-weighting Adjustment (±dB) -39.4 -26.2 -16.1 -8.6 -3.6 0.0 +1.2 +1.0 -1.1 -6.6 FIGURE 1 - WEIGHTED OCTAVE BAND ADJUSTMENTS (±dB) Environmental sound varies depending on environmental conditions. Some sounds are sharp impulses lasting for short periods of time, while others rise and fall over longer periods of time. There are various measures (metrics) of sound pressure designed for different purposes. The Leq, or equivalent sound level, is the steady-state sound level over a period of time that has the same acoustic energy as the fluctuating sound that was measured over the same period. The Leq is commonly referred to as the average sound level and is calculated automatically by the sound level meter using methods defined in ANSI S1.4-19831. 1 American National Standards Institute, ANSI S1-4-1983, American National Standard Specification for Sound Level Meters, 1983 Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington 5 3.0 REGULATORY REQUIREMENTS Clallam County Code, Chapter 33.49.510 (12) Noise. Clallam County stipulates that [W]ireless communication facilities shall not generate noise levels in excess of maximum standards set forth in the Washington Administrative Code, Chapter 173-60 WAC. Generators may be allowed only for emergency operation purposes. If air conditioning or other noise generating equipment is proposed, the applicant shall provide information detailing the expected noise level and any proposed abatement measures. This may require noise attenuation devices or other mitigation measures to minimize impacts.” State of Washington Administrative Code (WAC) Chapter 173-60 Maximum Environmental Noise Levels Maximum permissible environmental noise limits are set forth by the State of Washington and are referred to as Environmental Designation for Noise Abatement (EDNA). These limits are as follows: (1) No person shall cause or permit noise to intrude into the property of another person which noise exceeds the maximum permissible noise levels set forth below in this section. (2)(a) The noise limitations established are as set forth in the following table after any applicable adjustments provided for herein are applied. TABLE 2 – STATE OF WASHINGTON MAXIMUM ENVIRONMENTAL NOISE LEVELS EDNA OF NOISE SOURCE EDNA OF RECEIVING PROPERTY Class A Class B Class C CLASS A 55 dBA 57 dBA 60 dBA CLASS B 57 60 65 CLASS C 60 65 70 (b) Between the hours of 10:00 p.m. and 7:00 a.m. the noise limitations of the foregoing table shall be reduced by 10 dBA for receiving property within Class A EDNAs. (c) At any hour of the day or night the applicable noise limitations in (a) and (b) above may be exceeded for any receiving property by no more than: (i) 5 dBA for a total of 15 minutes in any one-hour period; or (ii) 10 dBA for a total of 5 minutes in any one-hour period; or (iii) 15 dBA for a total of 1.5 minutes in any one-hour period. Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington 6 4.0 SITE DESCRIPTION Site No. 43323 is located within an existing lattice tower compound on a heavily forested parcel, in Forks, Washington. According to the construction drawings, dated October 27, 2016 and aerial photographs, the nearest property line is located approximately 240 feet south of the proposed equipment. This location was selected for modeling as the nearest noise receiver. Figure 2 presents the approximate locations of the proposed generator and nearest property line. According to construction drawings and information provided by American Tower Corporation, the site and nearest property line are zoned as CF-80, Commercial Forest. The site is therefore categorized as Class C EDNA, as shown in Table 2. Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington 7 Site No. 43323 Bogachiel 846 Dowans Creek Rd Forks, Washington FIGURE 1 – SITE SCHEMATIC LEGEND Source Receiver Property Line Nearest Property  Line  Proposed Generator Existing Power Cabinet  Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington 8 5.0 NOISE-GENERATING EQUIPMENT The existing ground-mounted equipment and proposed emergency back-up generator at Site No. 43323 are designed to support wireless telecommunication antennas located on the existing tower. One Generac SD80 Emergency Back-up Generator is proposed for installation at the site, at the western portion of the existing tower compound, approximately 240 feet north of the southern property line. The generator is scheduled for week-day daytime testing only and will run for a period of no more than 15 minutes, one day per week under normal operating conditions. In order to determine worst- case operating conditions, the generator was modeled under two scenarios; normal operating conditions (daytime testing only) and emergency use (operating under a full load 24 hours a day) to determine noise impacts in the event of a loss of power. TABLE 3 – ACOUSTIC SOURCES Source Name Description  Equipment Noise  Sound Pressure  Reference  Distance  Equipment  Sound Power  dBA meters dBA  Generac SD80  (Proposed) Emergency Back‐up Generator 82.4*  7 110.1  Purcell RAC57 (Existing) Power Cabinet 66 1.524 80.65  *Maximum sound pressure level as per Generac specification sheet (Appendix A) Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington 9 6.0 MODELED POST CONSTRUCTION NOISE LEVELS The CadnaA® computer noise model was used for computing sound levels from the proposed equipment throughout the surrounding community. An industry standard, employing ISO 9613-2 methodology, CadnaA was developed to provide estimates of sound levels at distances from specific noise sources taking into account the effects of terrain features, including relative elevations of noise sources, receivers, and intervening objects (buildings, hills, trees), and ground effects due to areas of hard ground (pavement, water) and soft ground (grass, field, forest). In addition to computing sound levels at specific receiver positions, CadnaA can compute noise contours showing areas of equal and similar sound level. As input, CadnaA incorporated a geometric model of the study area, reference noise source levels. CadnaA uses a sound propagation model to project noise levels from equipment operations into the surrounding community. The three-dimensional geometric model of the study area was developed from aerial photography and digital terrain information obtained from Google Earth. Complete modeling output sheets from the CadnaA are contained in Appendix B. Table 4 summarizes the results of the acoustic modeling. Equipment-generated noise contributions at the nearest property line were calculated for Site 43323 using acoustical specifications for the existing Purcell RAC576 power cabinet and the proposed Generac SD80 emergency back-up generator. Noise specifications for proposed equipment are summarized in Table 3. TABLE 4 – POST CONSTRUCTION SOUND LEVEL RESULTS Location  Equipment Noise Impact (dBA)    Normal Operating Conditions  Equipment Noise Impact (dBA)  Emergency Use Conditions  Day Night Daytime Nighttime  Loc‐1  Nearest  Property Line  46.4 32.6 63.2 63.2  Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington 10 7.0 RESULTS AND CONCLUSIONS The equipment cabinet installation at 43323 will operate in compliance with the State of Washington Administrative Code (WAC) Chapter 173-60 Maximum Environmental Noise Levels. According to the Standard, equipment generated noise may not exceed 70 dBA at the nearest property line at any wireless telecommunication site where the acoustic source and receiver are both located on properties classified as Class C ENDA. As shown in Table 4, the combined existing and proposed equipment will generate 63.2 dBA at the nearest property line under emergency use conditions in compliance with the 70 dBA limit as outlined in the Code. Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington 11 8.0 LIMITATIONS This report was prepared for the use of American Tower Corporation. The conclusions provided by EBI are based solely on the information provided by the client. The observations in this report are valid on the date and time of the investigation. Reported noise levels contained herein are a factor of meteorological and environmental conditions present at the time of the site survey, and represent “typical” site noise levels. Measurement and calculations contained in this report should be considered accurate to within one decibel. Any additional information that becomes available concerning the site should be provided to EBI so that our conclusions may be revised and modified, if necessary. This report has been prepared in accordance with Standard Conditions for Engagement and authorized proposal, both of which are integral parts of this report and has been designed to address State of Washington Administrative Code (WAC) Chapter 173-60 Maximum Environmental Noise Levels. 9.0 REVIEWER CERTIFICATION I, Cynara Cannatella, state that: I am an employee of Envirobusiness Inc. (d/b/a EBI Consulting), which provides acoustic survey and compliance services to the wireless communications industry. I have reviewed the data collected during the site survey which is incorporated into this Site Compliance Report such that the information contained in this report is true and accurate to the best of my knowledge. Sincerely, By EBI Consulting Cynara Cannatella Senior Engineer Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington APPENDIX A EQUIPMENT SPECIFICATIONS LeftRight Front Back RADIATOR END GENERATOR END Pos 1 Pos 2 Pos 3 Pos 4 GE N E R A T O R C O N T R O L S 1 OF 1 Part No. 0184810SSD Rev. B 05/18/15 Generac Power Systems, Inc. | P.O. Box 8 | Waukesha, WI 53187 P: (262) 544-4811 © 2015 Generac Power Systems, Inc. All rights reserved. All specifications are subject to change without notice. STANDARD ENCLOSURE SD80 4.5L IVECO Notes: 1. All positions 23 ft (7M) from side faces of generator set. 2. Generator operating at full load. 3. Test conducted on a 100 foot diameter asphault surface. 4. Non-enclosed sets do not include exhaust sound during testing. Measured Sound Levels - 60 Hz 82.2 79.6 82.4 81.2 70 72 74 76 78 80 82 84 86 88 90 92 94 4321Position Number dB ( A ) @ 7 M e t e r s Actual Average Avg. 81.4 dBA Environmental Noise Assessment Report Site No. 43323 EBI Project No. 6217000136 846 Dowans Creek Rd., Forks,Washington APPENDIX B CADNAA® ENVIRONMENTAL NOISE MODEL RESULTS En v i r o n m e n t a l N o i s e A s s e s s m e n t R e p o r t S i t e N o . 4 3 3 2 3 EB I P r o j e c t N o . 6 2 1 7 0 0 0 1 3 6 8 4 6 D o w a ns C r e e k R d . , F o r k s , W a s h i n g t o n Ca d n a A ® M o d e l i n g R e s u l t s SO U R C E SO U R C E Re s u l t . P W L Coordinates (m) Na m e ID D a y ( d B A ) Ev e n i n g (d B A ) Ni g h t (d B A ) Lw / L i Ty p e Va l u e (d B A ) Fr e q u e n c y (H z ) He i g h t (m ) X Y Z Ge n e r a c S D 0 8 0 S 1 1 1 0 . 1 1 1 0 . 1 1 1 0 . 1 Lw 1 1 0 . 1 0 5 0 0 4 4 0 0 7 5 7 . 3 5 3 0 2 4 2 4 . 6 4 4 Pu r c e l l R A C 5 7 S 2 8 0 . 6 8 0 . 6 8 0 . 6 Lw 8 0 . 6 5 5 0 0 4 4 0 0 7 6 6 . 1 5 3 0 2 4 3 3 . 0 1 4 Ge n e r a c S D 0 8 0 ( t e s t i n g ) S 1 1 1 0 . 1 1 1 0 . 1 11 0 . 1 L w 1 1 0 . 1 0 5 0 0 4 4 0 0 7 5 7 . 3 5 3 0 2 4 2 4 . 6 4 4 Pu r c e l l R A C 5 7 S 2 8 0 . 6 8 0 . 6 8 0 . 6 Lw 8 0 . 6 5 5 0 0 4 4 0 0 7 6 6 . 1 5 3 0 2 4 3 3 . 0 1 4 RE C E I V E R Na m e ID D a y (d B A ) Ni g h t (d B A ) He i g h t (m ) X Y Z Ne a r e s t P r o p e r t y L i n e ( S o u t h ) R 1 6 3 . 2 6 3 . 2 4 4 0 0 7 6 2 . 8 5 3 0 2 3 6 3 . 2 7 4 Ne a r e s t P r o p e r t y L i n e ( S o u t h ) D a y t i m e Te s t i n g R 1 4 6 . 5 3 2 . 6 4 4 0 0 7 6 2 . 8 5 3 0 2 3 6 3 . 2 7 4