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Ms. Renee Escario <br />RE Consulting <br />October 9, 2019 <br />Page 3 <br />TABLE 1: REFERENCE NOISE LEVEL MEASUREMENTS <br />Noise <br />Reference Noise <br />Duration <br />Ref. <br />Source <br />Hourly <br />Level (dBA Lse) <br />Noise Source <br />Distance <br />Activity <br />@ Ref. <br />@ 50 <br />(hh:mm:ss) <br />(Feet) <br />Height <br />(Mins)7 <br />(Feet) <br />Dist. <br />Feet <br />Roof -Top Air ConditioningUnitt <br />96:00:00 <br />5' <br />5' <br />39 <br />74.4 <br />54.4 <br />Trash Enclosure Activity' <br />00:00:32 <br />5' <br />5' <br />60 <br />69.0 <br />49.0 <br />Pad -Mounted Transformer3 <br />3 <br />6' <br />5' <br />60 <br />56.0 <br />37.6 <br />Parking Lot Vehicle Movements° <br />01:00:00 <br />10, <br />5' <br />60 <br />44.0 <br />33.5 <br />Courtyard Activity' <br />00:08:00 <br />10, <br />4' <br />60 <br />73.8 <br />59.8 <br />Outdoor Pool/Spa Activity' <br />00:10:00 <br />5' <br />4' <br />60 <br />68.7 <br />48.7 <br />Roof -Top Parking° <br />00:10:00 <br />5' <br />4' <br />60 <br />1 68.7 <br />1 48.7 <br />'As measured by Urban Crossroads, Inc. on 7/27/2015 at the Santee Walmart located at 170 Town Center Parkway. <br />7 As measured by Urban Crossroads, Inc. on 5/3/2018 at a commercial and office park trash enclosure in the City of Costa Mesa. <br />' Source: NEMA TR 1-2013 Transformers, Step Voltage Regulators and Reactors, Table 2 sound level for a 500 kVA transformer. <br />4 As measured by Urban Crossroads, Inc. on 8/24/2016 in the parking lot of the Windemere Apartment community in the City of Riverside. <br />s As measured by Urban Crossroads, Inc. on Saturday night, September 21, 2019 in the City of Newport Beach. <br />`As measured by Urban Crossroads, Inc. on 7/5/2017 at the Covenant Hill Clubhouse pool in Ladera Ranch. <br />7 Anticipated duration (minutes within the hour) of noise activity during typical hourly conditions expected at the Project site based on the <br />reference noise level measurement activity. <br />The basic noise attenuation equation shown below is used to calculate the distance attenuation based <br />on a reference noise level (SPL1): <br />SPL2 = SPL1 - 20log(D2/Di) <br />Where SPL2 is the resulting noise level after attenuation, SPL1 is the source noise level, D2 is the distance <br />to the reference sound pressure level (SPL1), and D1 is the distance to the receiver location. Table 2 <br />indicates that the hourly noise levels associated with the roof -top air conditioning units, trash enclosure <br />activity, pad -mounted transformers, parking lot vehicle movements, outdoor courtyard activity, outdoor <br />pool/spa activity and roof -top parking activities are expected to range from 31.4 to 46.9 dBA Lso at the <br />sensitive off -site receiver locations. The operational noise level calculation worksheets are included in <br />Appendix A and include barrier attenuation provided by intervening structures between each noise <br />source and the receiver locations, where applicable, from the existing noise barriers and planned Project <br />buildings. <br />11177-09 Noise Assessment <br />