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21-101703-Noise Report-ATTCH 7-SC2064 Redondo Beach-04-28-2021-V1 7409 Greenwood Ave N, Suite A Seattle, WA 98103 206.839.0819 P // 206.839.0824 F April 5, 2021 Denis Azarov Infinigy 2500 West Higgins Road, Suite 500 Hoffman Estates, IL 60169 Re: Acoustical Report – AT&T SC2064 Site: 29601 8th Avenue SW, Federal Way, WA 98023 Dear Denis, This report presents a noise survey performed in the immediate vicinity of the proposed AT&T telecommunications facility at 29601 8th Avenue SW in Federal Way, Washington. This noise survey 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 3, 2021. 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 45 dBA. Code Requirements The site is located within the City of Federal Way Zoning jurisdiction on property designated with an RS zoning in Residential use. All of the receiving properties are Residential. The proposed new equipment consists of equipment support cabinets and an emergency generator on a concrete pad. The cabinets are expected to run 24 hours a day. The generator will operate once a week during daytime hours for maintenance and testing purposes only. Federal Way Municipal Code Section 7.10.050 adopts by reference the maximum noise levels set forth in WAC 173-60. Under WAC 173-60-040, noise from equipment on a Class A EDNA (Residential) property is limited as follows: Class A EDNA Receiver: Noise is limited to 55 dBA during daytime hours. During nighttime, defined as the hours between 10 p.m. and 7 a.m., maximum sound levels are reduced by 10 dBA for receiving properties within Class A EDNA's. Since the support cabinets are expected to operate 24 hours a day, they must meet the 45 dBA nighttime limit. 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 AT&T SC2064 Redondo Beach Page 2 exceed 60 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 proposed equipment includes (1) Vertiv XTE 801 Series Walk-In-Cabinet (WIC). According to the manufacturer, this WIC is manufactured with a Marvair ECUA12 Air Conditioning Unit, and (1) Marvair WAC200S WAC unit. 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 Marvair ECUA12 HVAC Unit 52 dBA @ 5 ft 1 52 Marvair WAC Unit 62 dBA @ 5 ft 1 62 Total dBA (All cabinets combined) 62 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 on a concrete pad surrounded by a chain-link fence. The nearest receiving property is approximately 130 feet east of the equipment. The following table presents the predicted sound level at the nearest receiving properties: Table 2: Predicted Noise Levels: Proposed Equipment Cabinets Line Application Factor E 1 Equipment Sound Pressure Level at 5 ft (dBA), Lp1 62 2 Distance Factor (DF) Inverse-Square Law (Free Field): DF = 20*log (d1/d2) -28 (130 ft) 3 New Equipment Sound Pressure Level at Receiver, Lpr (Add lines 1 and 2) 34 As shown in Table 2, the sound pressure level from the proposed equipment is predicted to be 34 dBA at the nearest receiving property to the east, which meets the 45 dBA nighttime code limit. Noise levels at all other properties, which are further way, will be lower and within the code limits. AT&T SC2064 Redondo Beach Page 3 Emergency Equipment The proposed equipment includes one Polar Power 8220-100 20 KW diesel generator and has a sound level of 67 dBA at 23 feet in test cycle operation. The generator will be located at grade on a concrete pad surrounded by a chain-link fence. The nearest receiving property is approximately 130 feet east of the equipment. The following are the predicted sound levels at the receiving property: Table 3: Predicted Noise Levels: Proposed Emergency Generator Line Application Factor E 1 Generator Sound Pressure Level at 23 ft. (dBA), Lp1 67 2 Distance Factor (DF) Inverse-Square Law (Free Field): DF = 20log (d1/d2) -15 (130 ft) 3 New Generator Sound Pressure Level at Receiver, Lpr (Add lines 1 and 2) 52 As shown in Table 3, the sound pressure level from the proposed generator during test cycle operation is predicted to be 52 dBA at the nearest receiving property to the east, which meets the 60 dBA code limit. Noise levels at all other properties, which are further way, will be lower and within the code limits. Please contact us if you have any questions or require further information. Sincerely, SSA Acoustics, LLP Steven Hedback 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. P ersons 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.