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2020.0259.PR0008 Noise_Report_TCOMM911_Yelm_Water_Tank_08312020 SSA Acoustics, LLP 7409 Greenwood Avenue N, Suite A Seattle, WA 98103 206.839.0819 August 28, 2020 Richard Hall LDC, Inc. 20210 142nd Avenue NE Woodinville, WA 98072 Re: Acoustical Report – TCOMM911 Yelm Site: 901 Rhoton Road NW, Yelm, WA 98597 Dear Richard, This report presents a noise survey performed in the immediate vicinity of the proposed Verizon telecommunications facility 901 Rhoton Road NW in Yelm, 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 August 28, 2020. 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 52 dBA, due primarily to traffic noise on surrounding streets. Code Requirements The site is located within the City of Yelm Zoning Jurisdiction on property designated with an Industrial zoning. The receiving property to the west is Residential. 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. Yelm Municipal Code Chapter 18.70.070 adopts Washington Administrative Code 173-60 by reference. Under WAC WAC 173-60, noise from equipment on a Class C EDNA (Industrial) property is limited as follows: Class A EDNA Receiver: Noise is limited to 60 dBA during daytime hours. During nighttime hours, between the hours of 10 p.m. and 7 a.m., the maximum permissible sound level is decreased by 10 decibels. Since the support cabinets are expected to operate 24 hours a day, they must meet the 50 dBA nighttime limit. TCOMM911 Yelm Page 2 Additionally, WAC 173-60 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 The proposed equipment will be located within a Motorola MSB equipment shelter with (2) Bard W48AC 47,000 BTU HVAC units in lead/lag operating so that only one unit operates at a time. According to manufacturer data, the proposed Bard W48AC unit has a sound pressure level of 69 dBA at 5 ft. 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 HVAC units will be located on the south side of the equipment shelter which is located at grade surrounded by a chain-link fence. The nearest residential receiving property is approximately 375 feet west of the equipment. The following table presents the predicted sound level at the nearest receiving property: Table 1: Predicted Noise Levels: Proposed Equipment Cabinets Line Application Factor W 1 Sound Pressure Level at 5 ft (dBA), Lp1 69 2 Distance Factor (DF) Inverse-Square Law (Free Field): DF = 20*log (d1/d2) -38 (375 ft) 3 New Equipment Sound Pressure Level at Receiver, Lpr (Add lines 1 and 2) 31 As shown in Table 1, the sound pressure level from the proposed HVAC units is predicted to be 31 dBA at the nearest receiving property to the west, which meets the 50 dBA nighttime code limit. Noise levels are expected to meet code at all other property lines. No mitigation will be required. TCOMM911 Yelm Page 3 Emergency Equipment The proposed equipment includes one Generac SG050 50 KW generator with a level 2 sound enclosure and has a sound level of 71 dBA at 23 feet. The generator will be located at grade. The nearest residential receiving property is approximately 375 feet west of the generator. The following are the predicted sound levels at the receiving property: Table 2: Predicted Noise Levels: Proposed Emergency Generator Line Application Factor W 1 Equipment Sound Pressure Level at 23 ft. (dBA), Lp1 71 2 Distance Factor (DF) Inverse-Square Law (Free Field): DF = 20log (d1/d2) -24 (375 ft) 3 New Equipment Sound Pressure Level at Receiver, Lpr 47 As shown in Table 2, the sound pressure level from the proposed generator during test cycle operation is predicted to be 47 dBA at the nearest receiving property to the west, which meets the 65 dBA code limit. Noise levels at other receiving properties, which are further away, will be lower and within 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 re port 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 commissi oned. 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.