SU0007300 - Laserfiche WebLink

Home Browse Search

Impact Evaluation Relative to CEQA Guidelines, Sleep Disturbance & Single Event Criteria Nighttime Asphalt Plant operations Relative to Potential Sleep Disturbance As noted previously, the focus of this analysis is on noise levels within sleeping rooms of . project-area residences. Asphalt plant noise generation at the nearest residences to the project site is predicted to average approximately 40 dB Leq, with variations of approximately +1- 5 dB depending on normal variations in atmospheric conditions. Also as noted previously, average and maximum noise levels associated with the asphalt plant operations are not appreciably different at the nearest residences located approximately 2,000+ feet from that equipment. Within the nearest residences, asphalt plant noise levels are predicted to be approximately 10 to 25 dB lower than noise levels outside the residence with windows in the open and closed positions, respectively. Given an exterior noise level of approximately 45 dB Leq or less, resulting interior levels with windows closed and open would be approximately 20 to 35 dB. As shown in Table 2, a typical background level within residences is approximately 40 dB, with a level of 30 dB equivalent to a soft whisper two feet away. Even when added to existing ambient noise levels without the asphalt plant in operation, the range noise levels predicted within the nearest residences during nighttime asphalt production is not expected to change significantly within those nearest residences. Since there is no appreciable change in noise levels predicted within the nearest residences to the Munn & Perkins asphalt plant equipment during nighttime operation of that equipment. the probability of this aspect of the project resulting in sleep disturbance is very low. Therefore, noise impacts associated with nighttime operation of the asphalt plant associated with sleep disturbance at the nearest neighbors are predicted to be less than si9flificarrf. Sleep Disturbance Impacts due to Nighttime Project-Related Truck Traffic — Bedroom Windows Closed As discussed earlier, incidents of sleep disturbance are predicted to be relatively low at interior SEL values of less than 65 dB. Given an optimized SEL value of 82 dB at 40 feet, the SEL at the nearest residential building facades located 60 feet from the centerline would be approximately 79 dB. To reduce an exterior SEL value of 79 dB outside the residence to a level of 65 dB SEL inside, a building facade noise reduction of 14 dB would be required. Typical residential construction can be expected to provide approximately 25 dB of noise reduction with windows in the closed position. Based on this degree of building facade noise reduction the interior SEL during individual truck passages at the closest residences to the roadway would be approximately 54 dB (79 — 25 = 54) when residences have their windows in the closed position. At more distant residences (i.e. beyond 60 feet from the East River Road centerline), interior SEL values would be even lower due to normal decreases in noise with increasing distance. Environmental!Noise Analysis Munn &Perkins Expanders Hours of Operations—San Joaquin County _ Page 31