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City of Santa Ana <br />Table 3 -15. Typical Noise Levels from Construction Activities at 50 Feet <br />Average Sound Level at 50 feet <br />Construction Activity (dBA Leq)' <br />Phase I <br />Excavation and Grading 87 <br />Final Grading, Building 86 <br />Construction, Trenching, Concrete <br />Mixing, and Asphalt Parking <br />Phase lI <br />Final Grading, Building 86 <br />Construction, Trenching, and <br />Concrete Mixing <br />1 Sound level with all pertinent equipment operating. <br />Source: U.S. Environmental Protection Agency 1971. <br />Environmental Checklist <br />Table 3 -16 shows noise levels that would occur from implementation of the project at the existing <br />sensitive receivers adjacent to the project site. The noise levels shown are calculated from the <br />acoustical center of construction. The acoustical center of construction is the idealized point from <br />which construction could occur. It takes into account the mobility of construction equipment and is <br />derived from multiplying the furthest distance construction equipment could be from a sensitive <br />receiver times the closest distance and then taking the square root of the product. <br />Table 3 -16. Noise Levels from Construction Activities at Closest Sensitive Receivers <br />Construction Activity <br />Noise Levels at <br />Receiver 15outh <br />of Project <br />(dBA Leq) <br />Noise Levels at <br />Receiver 2 East <br />of Project <br />(dBA Leq) <br />Noise Levels at <br />Receiver 3 North <br />of Project <br />(dBA Leq) <br />Noise Levels at <br />Receiver 3 West <br />of Project <br />(dBA Leq) <br />Phase I <br />Excavation and Grading <br />72 <br />73 <br />72 <br />72 <br />Fine Grading, Building <br />70 <br />71 <br />70 <br />70 <br />Construction, Trenching, <br />Concrete Mixing, and <br />Asphalt Parking <br />Phase 11 <br />Fine Grading, Building <br />70 <br />71 <br />70 <br />71 <br />Construction, Trenching, <br />and Concrete Mixing <br />As shown in Table 3 -16, the calculated loudest construction noise level would be during the <br />excavation and grading phase of Phase 1. Construction noise levels would range between 72 -- 73 <br />dBA Leq. These noise levels are higher than the typical ambient daytime noise levels measured at the <br />sensitive receivers to the north, east, and south of the project site. Noise levels of this magnitude <br />would be readily audible and would likely dominate the noise environment in the area during <br />The Academy Charter High School 3 74 June 2012 <br />Initial Study /Mitigated Negative Declaration ICF 00914.11 <br />31 B -152 <br />