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HomeMy WebLinkAboutRS_Noise_Study_SSA_Acoustics_180507_v1 222 Etruria Street, Ste 100, Seattle, Washington 98109 t. 206.839.0819 f. 206.839.0824 April 24, 2018 Richard Cardoza LDC, Inc. 20210 142nd Ave NE Woodinville, WA 98072 Re: Acoustical Report – Verizon SEA Garden Site: 811 N Landing Way, Renton, WA 98057 Dear Richard, The following report presents a noise study for the proposed Verizon telecommunications facility at 811 Landing Way in Renton, Washington. This noise study extends from the proposed equipment to the nearest properties. The purpose of this report is to document the existing conditions and the impacts of the acoustical changes due to the proposed equipment. This report contains data on the existing and predicted noise environments, impact criteria and an evaluation of the predicted sound levels as they relate to the criteria. Ambient Conditions Existing ambient noise levels were measured on site with a Svantek 971 sound level meter on April 24, 2018. Measurements were conducted as close to the proposed location as possible and the property lines in accordance with the State of Washington code for Maximum Environmental Noise Levels WAC 173-60-020. The average ambient noise level was 59.6 dBA, due primarily to traffic noise on Logan Avenue. Code Requirements The site is located within the City of Renton Zoning jurisdiction on property designated with a UC zoning. All of the receiving properties are zoned UC. Renton Municipal Code 8-7-4 designates UC as Class B EDNA. The proposed new equipment includes equipment support cabinets and an emergency generator. The equipment support cabinets are expected to run 24 hours a day. The generator will run once a week during daytime hours for maintenance and testing purposes only. Renton Municipal Code Chapter 8-7-2 adopts Washington Administrative Code Sections 173-60- 020, 173-60-040, 173-60-050 and 173-60-090. Under WAC 173-60-040, noise from equipment on a Class B EDNA property is limited as follows: Class B EDNA Receiver: Noise is limited to 60 dBA 24 hours a day. Verizon SEA Garden Page 2 Additionally, WAC 173-60-040 allows that during any one-hour period, the maximum permissible noise level may be exceeded by 5 dBA for a 15 minute period. Therefore, the generator must not exceed 65 dBA when running during daytime hours for maintenance testing. The generator is exempt during emergency operation. Predicted Equipment Sound Levels 24-Hour Operation Equipment The following table presents a summary of the equipment and their associated noise levels: Table 1: Equipment Noise Levels Equipment dBA (each) Quantity Combined dBA @ 5 ft Commscope RBA84 Power/ Battery Cabinet 65 dBA @ 5ft 1 65 Charles PM63912 62 dBA @ 5ft 1 62 Total dBA (All cabinets combined) 67 Methods established by ARI Standard 275-2010 and ASHRAE were used in predicting equipment noise levels to the receiving properties. Application factors such as location, height, and reflective surfaces are accounted for in the calculations. The equipment will be located at grade within an existing CMU enclosed refuse area with 8’ walls. The nearest receiving property is approximately 100 feet south of the equipment cabinets. The following table presents the predicted sound levels: Table 2: Predicted Noise Levels: Proposed Equipment Cabinets Line Application Factor S 1 Sound Pressure Level at 5 ft (dBA), Lp1 67 2 Noise Amplification – Near reflective surfaces +6 3 Noise Reduction – CMU Walls -12 4 Distance Factor (DF) Inverse-Square Law (Free Field): DF = 20*log (d1/d2) -26 (100 ft) 5 New Equipment Sound Pressure Level at Receiver, Lpr (Add lines 1 through 4) 35 As shown in Table 2, the sound pressure level from the proposed equipment is predicted to be 35 dBA at the nearest receiving property line to the south, which meets the 60 dBA code limit. Noise levels at the other properties, which are further away, will be lower and within the code limits. No further mitigation is required. Verizon SEA Garden Page 3 Emergency Equipment The proposed equipment includes one Generac SDC20 20 KW generator with a Level 1 sound enclosure and has a sound level of 65 dBA at 23 feet. The generator will be located within an existing CMU enclosed refuse area with 8’ walls. The nearest receiving property is approximately 100 feet south of the generator. The following table shows the predicted sound levels: Table 3: Predicted Noise Levels: Proposed Emergency Generator Line Application Factor S 1 Equipment Sound Pressure Level at 23 ft. (dBA), Lp1 65 2 Noise Amplification – Near reflective surfaces +6 3 Noise Reduction – CMU Walls -12 4 Distance Factor (DF) Inverse-Square Law (Free Field): DF = 20log (d1/d2) -13 (100 ft) 5 New Equipment Sound Pressure Level at Receiver, Lpr (Add lines 1 through 4) 46 As shown in Table 3, the sound pressure level from the generator is predicted to be 46 dBA at the nearest receiving property line to the south, which complies with the 65 dBA code limit during test cycle operation. Noise levels at the other properties, which are further away, will be lower and within the code limits. No further mitigation is required. Please contact us if you have any questions or require further information. Sincerely, SSA Acoustics, LLP Steven Hedback Joel Esselstrom Technician Acoustical Consultant This report has been prepared for the titled project or named part thereof and should not be used in whole or part and relied upon for any other project without the written authorization of SSA Acoustics, LLP. SSA Acoustics, LLP accepts no responsibility or liability for the consequences of this document if it is used for a purpose other than that for which it was commissioned. Persons wishing to use or rely upon this report for other purposes must seek written authority to do so from the owner of this report and/or SSA Acoustics, LLP and agree to indemnify SSA Acoustics, LLP for any and all resulting loss or damage. SSA Acoustics, LLP accepts no responsibility or liability for this document to any other party other than the person by whom it was commissioned. The findings and opinions expressed are relevant to the dates of the works and should not be relied upon to represent conditions at substantially later dates. Opinions included therein are based on information gathered during the study and from our experience. If additional information becomes available which may affect our comments, conclusions or recommendations SSA Acoustics, LLP reserves the right to review the information, reassess any new potential concerns and modify our opinions accordingly.