14 ATTACHMENT 04 - Laserfiche WebLink

TABLE 3 Summary of Short-Term Noise Measurements T e ' Short-Term Noise 7esei � t,joisLIVIeasurement-Locatibri Le,` I..me Lmn- L L"i o L so j;'; L ST 1: Northeastern corner of the project site, —85 feet from the entrance of the proposed 61 72 47 70 64 58 52 59 carwash (11/25/2013, 2:50-3:00 p.m.) ST-2: Southwestern corner of the project site, —100 feet from the exit of the proposed 61 71 49 68 64 59 54 58 carwash (11/25/2013, 3:10-3:20 p.m.) FUTURE PREDICTED NOISE ENVIRONMENT For the proposed project, the existing convenience store and attached automotive service shop would be demolished. The proposed 7-Eleven store will be constructed in its place. Along with the store, a proposed carwash would be constructed adjacent to the store on the east side. Based on the orientation of the proposed carwash, vehicles would enter from the northern side of the property, adjacent to West Las Positas Boulevard. Noise-sensitive receptors to the north and northeast of the project site would be exposed to noise propagating from the carwash entrance. However, there is a proposed addition to the store, located on the north side of the building that would acoustically shield noise-sensitive receptors located to the northwest and west of the property site from noise emanating from the carwash entrance. The proposed carwash would be approximately 40 feet in length, and the vehicles would exit on the southeastern corner of the property. No doors are included in the building plans for the carwash, and no shielding from the noise at the exit is included in the plans. Figure 1 shows the proposed project superimposed onto the existing project site. A speaker box located at the entrance of the carwash would create minimal noise, which would be directed towards the driver's window of the car to be washed. The proposed carwash design does not include a conveyor belt. So, the main source of operational noise would come from water pump and spray noise during the wash cycle inside the carwash building and the blowers and vacuum used during the drying process after the washing cycle is complete. The blowers and vacuums would be located at the exit of the carwash. Since the pumps are located in the building interior and the water spray noise would occur in the wash tunnel and be largely shielded from any noise-sensitive receptors in the vicinity, the noise that could have the greatest impact on noise-sensitive receptors in the area would be the blower and vacuum systems. An AeroDry Systems, LLC, dryer system is proposed for use at the carwash. This system consists of two blowers with single motors and a third blower with two motors. A summary of the blower sound level measurements conducted by D.L. Adams Associates in 2002 was provided for this analysis. Results of that study showed overall A-weighted levels to be approximately 82.5 dBA at 5 feet and 79.4 dBA at 20 feet from the exit end of the tunnel. Based on previous car wash studies, levels at various distances can be extrapolated from this information; Table 4 presents the approximate noise levels for the AeroDry System at various distances from the blower. To reduce noise levels, AeroDry has also suggested their quiet dryer systems, which includes four 60-horsepower towers of the dryer installed inside the bay. Installing variable frequency drives (VFDs) would allow for decreased fan rotation, which would reduce noise levels by Page 11