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HomeMy WebLinkAboutNoise Study 001281004 AZ Office CA Office 4960 S. Gilbert Rd, Suite 1-461 1197 Los Angeles Ave, Suite C-256 Chandler, AZ 85249 Simi Valley, CA 93065 p. (602) 774-1950 p. (805) 426-4477 www.mdacoustics.com | www.ebiconsulting.com MD Acoustics, LLC | EBI Consulting, Inc. 1 JN: 04602236_Letter Report.docx EBI JN: 6222001691 April 11, 2022 Crafton Communications, Inc. 107 Frankfurt Circle Birmingham, AL 35221 C/O EBI Consulting Subject: TMobile – Port Townsend 83041 – Noise Review Letter – Port Townsend, WA MD Acoustics, LLC (MD) has completed a noise review letter for TMobile – Port Townsend 83041 project located at 1760 Kala Point Dr. RV Lot, in Port Townsend, WA 98368 The site plan utilized for the project is located in Exhibit A (page 3 of this report). The project assessed the future diesel generator noise level projections to the nearest sensitive receptors and compared to the City’s applicable noise limits as outlined in the City’s Municipal Code. The project proposes to install a Generac SD080 4.5L 80KW Diesel Generator with a Level 2 acoustical enclosure. A glossary of acoustical terms is located in Appendix A. 1.0 Acoustics Requirements The project is located in the jurisdiction of the City of Port Townsend, WA which is located in Jefferson County. Both the City of Port Townsend’s municipal code and the County of Jefferson County code will be referenced for noise limits regarding telecommunication equipment. Jefferson County’s Code JCC 18.42.090 (1) (g) outlines guidelines for noise generated by wireless services and is as follows: (g) Noise generated by a wireless facility shall not exceed the maximum environmental noise levels set forth in Chapter 173-60 WAC as it is now in effect or hereafter amended. Chapter 173-60 of the WAC specifies a maximum noise level of 55 dBA daytime (7AM – 10PM) and 45 dBA nighttime (10pm – 7AM) Therefore, the project may not exceed the most strict residential noise level of 45 dBA. 2.0 Study Method and Procedure MD performed one (1) 10-minute measurement on 3/24/2022 as shown in Appendix C. Based on the baseline noise readings performed at the site, the ambient noise level measured 68 dBA at the existing equipment. MD used this noise measurement and extrapolated it to the nearest property lines. Noise levels at the property lines from the existing equipment range 10 to 29 dBA. See Exhibit B. The future equipment noise level was modeled using SoundPlan 3D (SP) acoustic modeling software. SP is capable of evaluating stationary noise sources (e.g. point sources such as exhaust from generators) at various receptor locations. SP’s software utilizes algorithms (based on inverse square law and reference equipment noise level data) to calculate the noise projections. The software allows the user to input specific noise sources, spectral content, sound barriers, building placement, topography and TMobile – Port Townsend 83041 Noise Review Letter Port Townsend, WA MD Acoustics, LLC | EBI Consulting, Inc. 2 JN: 04602236_Letter Report.docx EBI JN: 6222001691 noise. The model assumes the implementation of a Generac SD080 80kW 5.4L generator with a level 2 enclosure and a reference noise level of 71.7 dBA measured at 7 meters. Appendix D provides the model’s inputs and outputs 3.0 Findings A total of Three (3) receptors were modeled to accurately evaluate the future operational noise levels. A receptor is denoted by a yellow dot. The dot represents either a property line, a sensitive receptor such as an outdoor sensitive area/building facade or a calibration point (point where sound pressure levels are confirmed to match manufacturer’s noise data). Receptors 1-3 represent the projected noise level at the nearest sensitive receptors. Table 1 presents the measured ambient noise level, the project’s projected noise level, and the combined project plus ambient noise level condition. It should be noted that the baseline noise level will only change under a power loss (emergency) situation or during routine maintenance. Table 1: Worst-Case Predicted Emergency Operational Noise Level at Nearest property Receptor1 Existing Ambient Noise Level (dBA, Leq)2 Project Noise Level (dBA, Lmax) Total Combined Noise Level (dBA, Lmax(h)) 1 10 48 48 2 26 51 51 3 29 54 54 Notes: 1. R1 is the eastern Property line, R2 is the southern Property line, R3 is the western Property line 2. The measured ambient Leq MD calculated the noise level projection to the nearest property lines. The projected noise levels to the nearest property lines will range from 48 dBA to 54 dBA which exceeds the the most strict nighttime noise standard of 45 dBA. Exhibit C provides the future noise level projections based on the proposed project design (page 4 of this report). The projected noise level ranges from 48 to 54 dBA which exceeds the nighttime noise limit of 45 dBA. In order to meet the 45 dBA nighttime noise limit the generator will need a custom sound enclosure made by Commercial Acoustics or equivalent that will give a 9 dB reduction. In order for the project to meet the Washington Administrative Code of 45 dBA nighttime noise limit the project will need to use a custom acoustical enclosure to reduce the noise level or a smaller generator. TMobile – Port Townsend 83041 Noise Review Letter Port Townsend, WA MD Acoustics, LLC | EBI Consulting, Inc. 3 JN: 04602236_Letter Report.docx EBI JN: 6222001691 4.0 Conclusion MD is pleased to provide this noise review for this project. The project will comply with the County’s applicable noise allowable limits based on the proposed design. If you have any questions regarding this letter, please call our office at (602) 774-1950. Sincerely, MD Acoustics, LLC Robert Pearson Acoustical Consultant TMobile – Port Townsend 83041 Noise Review Letter Port Townsend, WA MD Acoustics, LLC | EBI Consulting, Inc. 4 JN: 04602236_Letter Report.docx EBI JN: 6222001691 Exhibit A Site Plan TMobile – Port Townsend 83041 Noise Review Letter Port Townsend, WA MD Acoustics, LLC | EBI Consulting, Inc. 5 JN: 04602236_Letter Report.docx EBI JN: 6222001691 Exhibit B Existing Ambient Noise Level TMobile – Port Townsend 83041 Noise Review Letter Port Townsend, WA MD Acoustics, LLC | EBI Consulting, Inc. 6 JN: 04602236_Letter Report.docx EBI JN: 6222001691 Exhibit C Future Operational Noise Level MD Acoustics, LLC | EBI Consulting, Inc. JN: 04602236_Letter Report.docx Appendix A Glossary of Acoustical Terms MD Acoustics, LLC | EBI Consulting, Inc. JN: 04602236_Letter Report.docx Glossary of Terms A-Weighted Sound Level: The sound pressure level in decibels as measured on a sound level meter using the A-weighted filter network. The A-weighting filter de-emphasizes the very low and very high frequency components of the sound in a manner similar to the response of the human ear. A numerical method of rating human judgment of loudness. Ambient or Background Noise Level: The composite of noise from all sources, near and far. In this context, the ambient noise level constitutes the normal or existing level of environmental noise at a given location. Decibel (dB): A unit for measuring the amplitude of a sound, equal to 20 times the logarithm to the base 10 of the ratio of the pressure of the sound measured to the reference pressure, which is 20 micro-pascals. dB(A): A-weighted sound level (see definition above). Equivalent Sound Level (LEQ): The sound level corresponding to a steady noise level over a given sample period with the same amount of acoustic energy as the actual time varying noise level. The energy average noise level during the sample period. Field Sound Transmission Class (FSTC): The field sound transmission class (FSTC) rating is used for in situ wall and floor/ceiling sound isolation performance assessment. The standard requires the measurement of sound transmission loss and includes required procedure to show that the FSTC rating, as it has been determined by the test procedure, was not influenced by flanking of sound around the partition intended to be tested. Sound transmission class and FSTC ratings are intended by standard to be equivalent; however, practical experience indicates that FSTC ratings tend to be up to five ratings points less than laboratory-measured STC ratings. Day-Night Level (LDN or DNL): LDN is the average noise level over a 24-hour period. The noise between the hours of 10PM to 7AM is artificially increased by 10 dB. This noise is weighted to take into account the decrease in community background noise of 10 dB during this period. Noise: Any unwanted sound or sound which is undesirable because it interferes with speech and hearing, or is intense enough to damage hearing, or is otherwise annoying. The State Noise Control Act defines noise as "...excessive undesirable sound...". Noise Isolation Class (NIC): The noise isolation class (NIC) rating is similar to STC and FSTC. However, the standard STC rating contour is applied to the one-third octave band noise reduction measured in a field situation, rather than the transmission losses measured in the field. No correction to the measured noise reduction data is made to account for partition size, receiving room absorption, or sound flanking. Like the STC and FSTC ratings, the field measured NIC rating of a noise reduction spectrum is equal to the value of the contour crossing at 500 Hz. In the absences of sound flanking, the NIC is generally within five points of the laboratory STC rating for typical building partition constructions. The NIC rating is used to assess the sound isolation performance of in situ partition construction, especially complicated ones that involve MD Acoustics, LLC | EBI Consulting, Inc. JN: 04602236_Letter Report.docx multiple sound transmission paths that are not suited for laboratory testing. The NIC rating is often used in lieu of STC and FSTC. Normalized Noise Isolation Class (NNIC): The normalized noise isolation class (NNIC) is the same as the NIC rating except the receiving room absorption is normalized to correspond to a 0.5-s reverberation time. Sound Level (Noise Level): The weighted sound pressure level obtained by use of a sound level meter having a standard frequency-filter for attenuating part of the sound spectrum. Sound Level Meter: An instrument, including a microphone, an amplifier, an output meter, and frequency weighting networks for the measurement and determination of noise and sound levels. Sound Transmission Class (STC): To quantify STC, a Transmission Loss (TL) measurement is performed in a laboratory over a range of 16 third-octave bands between 125 – 4,000 Hertz (Hz). The average human voice creates sound within the 125 – 4,000 Hz 1/3rd octave bands. STC is a single-number rating given to a particular material or assembly. The STC rating measures the ability of a material or an assembly to resist airborne sound transfer over the specified frequencies (see ASTM International Classification E413 and E90). In general, a higher STC rating corresponds with a greater reduction of noise transmitting through a partition. STC is highly dependent on the construction of the partition. The STC of a partition can be increased by: adding mass, increasing or adding air space, adding absorptive materials within the assembly. The STC rating does not assess low frequency sound transfer (e.g. sounds less than 125 Hz). Special consideration must be given to spaces where the noise transfer concern has lower frequencies than speech, such as mechanical equipment and or/or music. The STC rating is a lab test that does not take into consideration weak points, penetrations, or flanking paths. Even with a high STC rating, any penetration, air-gap, or “flanking path can seriously degrade the isolation quality of a wall. Flanking paths are the means for sound to transfer from one space to another other than through the wall. Sound can flank over, under, or around a wall. Sound can also travel through common ductwork, plumbing or corridors. Noise will travel between spaces at the weakest points. Typically, there is no reason to spend money or effort to improve the walls until all weak points are controlled first. MD Acoustics, LLC | EBI Consulting, Inc. JN: 04602236_Letter Report.docx Appendix B Washington Administrative Code WAC 173-60-040 Maximum permissible environmental noise levels. (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. 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 limi- tations of the foregoing table shall be reduced by 10 dBA for receiv- ing property within Class A EDNAs. (c) At any hour of the day or night the applicable noise limita- tions 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. [Order 74-32, § 173-60-040, filed 4/22/75, effective 9/1/75.] Certified on 10/25/2019 WAC 173-60-040 Page 1 MD Acoustics, LLC | EBI Consulting, Inc. JN: 04602236_Letter Report.docx Appendix C Field Measurement Data www.mdacoustics.com AZ Office 4960 S. Gilbert Rd, Ste 1-461 Chandler, AZ 85249 CA Office 1197 E Los Angeles Ave, C-256 Simi Valley, CA 93065 Project:T-Mobile Kala Point Site Observations: Site Address/Location:1760 KALA POINT DR Date:3/24/2022 Field Tech/Engineer:Roma Stro General Location: Sound Meter:NTi Audio SN:A2A-07095-E0 Site Topo: Settings:A-weighted, slow, 1-sec, 10-minute interval Ground Type: Meteorological Con.:70 degrees F, 2 to 5 mph wind, eastern direction Site ID:ST-1 2-Minute Continuous Noise Measurement Datasheet 1 -meter is approx 40' from nearest property line Clear sky, measurement was performed within 6-feet of existing cell tower. Ambient noise consisted of noise from the cooling units, wildlife, and some storage unit activity. Measurement was taken within 40 feet from the north PL Noise Source(s) w/ Distance: Flat Hard site conditions, reflective Figure 1: Monitoring Locations 1 10Min_Field Sheet Template_Awtg ST1.xlsx www.mdacoustics.com AZ Office 4960 S. Gilbert Rd, Ste 1-461 Chandler, AZ 85249 CA Office 1197 E Los Angeles Ave, C-256 Simi Valley, CA 93065 Project:T-Mobile Kala Point Site Address/Location:1760 KALA POINT DR Site ID:ST-1 Location Start Stop Leq Lmax Lmin L2 L8 L50 L90 L95 1 12:51 PM 1:01 PM 67.9 75.8 59.3 74 68.7 67.9 65.3 64.7 Figure 1: ST-1 Photo Figure 2: ST-1 Photo 10-Minute Continuous Noise Measurement Datasheet - Cont. Table 1: 10-Min Baseline Noise Measurement Summary 10Min_Field Sheet Template_Awtg ST1.xlsx MD Acoustics, LLC | EBI Consulting, Inc. JN: 04602236_Letter Report.docx Appendix D Soundplan Input/Output Tmobile 1760 Kala Point Contribution spectra - Situation 1 - Per Plan - SP Source Time slice Sum dB(A) 63Hz dB(A) 125Hz dB(A) 250Hz dB(A) 500Hz dB(A) 1kHz dB(A) 2kHz dB(A) 4kHz dB(A) 8kHz dB(A) Receiver 1 Fl G dB(A) Leq 47.8 dB(A) Generac SD80 4.5L L2A Enclosure Leq 47.8 44.5 37.9 36.7 35.9 38.8 34.9 37.8 12.1 Receiver 2 Fl G dB(A) Leq 54.0 dB(A) Generac SD80 4.5L L2A Enclosure Leq 54.0 50.4 43.9 43.7 42.5 44.9 41.2 44.7 21.4 Receiver 3 Fl G dB(A) Leq 50.7 dB(A) Generac SD80 4.5L L2A Enclosure Leq 50.7 47.2 40.7 40.2 39.1 41.6 37.8 41.3 17.6 SoundPLAN 8.2 MD Acoustics LLC 4960 S. Gilbert Rd Chandler, AZ 85249 Phone: 602 774 1950 1 Tmobile 1760 Kala Point Contribution level - Situation 1 - Per Plan - SP 9 Source Source type Leq dB(A) A dB Receiver 1 Fl G dB(A) Leq 47.8 dB(A) Generac SD80 4.5L L2A Enclosure Point 47.8 0.0 Receiver 2 Fl G dB(A) Leq 54.0 dB(A) Generac SD80 4.5L L2A Enclosure Point 54.0 0.0 Receiver 3 Fl G dB(A) Leq 50.7 dB(A) Generac SD80 4.5L L2A Enclosure Point 50.7 0.0 SoundPLAN 8.2 MD Acoustics LLC 4960 S. Gilbert Rd Chandler, AZ 85249 Phone: 602 774 1950 1 Tmobile 1760 Kala Point 3rd octave spectra of the sources in dB(A) - Situation 1 - Per Plan - SP 4 Name l or A m,m² Li dB(A) R'w dB L'w dB(A) Lw dB(A) 50Hz dB(A) 63Hz dB(A) 80Hz dB(A) 100Hz dB(A) 125Hz dB(A) 160Hz dB(A) 200Hz dB(A) 250Hz dB(A) 315Hz dB(A) 400Hz dB(A) 500Hz dB(A) 630Hz dB(A) 800Hz dB(A) 1kHz dB(A) 1.25kHz dB(A) 1.6kHz dB(A) 2kHz dB(A) 2.5kHz dB(A) 3.15kHz dB(A) 4kHz dB(A) 5kHz dB(A) 6.3kHz dB(A) 8kHz dB(A) 10kHz dB(A) Generac SD80 4.5L L2A Enclosure 91.7 91.7 80 80.3 80.3 76.3 76.3 76.3 81.3 81.3 81.3 78.3 78.3 78.3 77.3 77.3 77.3 73.3 73.3 73.3 78.3 78.3 78.3 60.3 60.3 60.3 SoundPLAN 8.2 MD Acoustics LLC 4960 S. Gilbert Rd Chandler, AZ 85249 Phone: 602 774 1950 1 MD Acoustics, LLC | EBI Consulting, Inc. JN: 04602236_Letter Report.docx Appendix E Manufacturers Cut Sheet LeftRight Front Back RADIATOR END GENERATOR END Pos 1 Pos 2 Pos 3 Pos 4 GENERATOR CONTROLS1 OF 1 Part No. 0184830SSD 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. LEVEL 2 ACOUSTIC 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 70.4 74.2 71.271.0 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 4321Position NumberdB (A) @ 7 MetersActual Average Avg. 71.7 dBA LeftRight Front Back RADIATOR END GENERATOR END Pos 1 Pos 2 Pos 3 Pos 4 EMMISION DATA1 OF 1 Part No. 0184800SSDRev. B 05/18/15Generac Power Systems, Inc. | P.O. Box 8 | Waukesha, WI 53187P: (262) 544-4811 © 2015 Generac Power Systems, Inc. All rights reserved. All specifications are subject to change without notice. NON-ENCLOSED (OPEN SET) 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 87.086.0 87.787.4 74 76 78 80 82 84 86 88 90 92 94 96 98 100 4321Position NumberdB (A) @ 7 MetersActual Average Avg. 87.0 dBA