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OURBAM 260 E. Baker St. I Suite 200 1 Costa Mesa, CA 92626 1 (949) 660-1994 C111055ROADS ,m October 9, 2019 Ms. Renee Escario RE Consulting SUBJECT: THE ADDINGTON FOCUSED NOISE ASSESSMENT MEMORANDUM Dear Ms. Renee Escario: Urban Crossroads, Inc. is pleased to provide the following Focused Noise Assessment for The Addington Project ("Project"), which is located at 2525 N. Main Street in the City of Santa Ana. The Project is proposed to consist of up to 256 dwelling units in a two to four-story residential building surrounding a parking structure with 5 above ground levels of parking and an amenity deck. This Focused Noise Assessment calculates the potential Project -related operational noise levels at nearby noise -sensitive residential receiver locations east and south of the Project. This Focused Noise Assessment is consistent with the methods and procedures used in the July 2018 Magnolia at the Park Noise Impact Analysis prepared by Urban Crossroads, Inc. (1) This Focused Noise Assessment calculates the potential operational noise levels due to the Project's stationary noise sources at seven off -site receiver locations adjacent to the Project site. Exhibit A identifies the receiver and noise source locations used to calculate the Project -related operational noise levels. The Project -related operational noise sources based on a review of the site plan include: roof -top air conditioning units, trash enclosure activity, pad -mounted transformers, parking lot vehicle movements, outdoor courtyard activity, outdoor pool/spa activity and roof -top parking activities. REFERENCE NOISE LEVELS To estimate the Project operational noise impacts, reference noise level measurements were collected from similar types of activities to represent the noise levels expected with the development of the proposed Project. The Reference Project operational noise levels are based on the noise sources provided in Table 1. It is important to note that the following projected noise levels assume the worst - case noise environment with the roof -top air conditioning units, trash enclosure activity, pad -mounted transformers, parking lot vehicle movements, outdoor courtyard activity, outdoor pool/spa activity and roof -top parking activities all operating simultaneously. In reality, the noise sources will likely vary throughout the day. OPERATIONAL NOISE The operational noise level calculations shown on Table 2 account for the distance attenuation provided due to geometric spreading, when sound from a localized stationary source (i.e., a point source) propagates uniformly outward in a spherical pattern. Hard site conditions are used in the operational noise analysis which result in noise levels that attenuate (or decrease) at a rate of 6 dBAfor each doubling of distance from a point source. 11177-09 Noise Assessment