6 - GPA19-01; AA19-01_651 W SUNFLOWER AVENUE

Home Browse Search

Legacy Sunflower Apartments Page 83 Mitigated Negative Declaration – March 14, 2019 The proposed apartment building is required to have mechanical ventilation systems or other means of natural ventilation as required by the Uniform Building Code. Typical construction that complies with the Uniform Building Code provides approximately 20 dBA of exterior to interior sound reduction. Based on the noise analysis some of the proposed residential units would be exposed to exterior noise levels that would require more than 20 dBA noise reduction. Therefore, upgraded window treatments would be required to achieve the City required interior noise levels. Table 6 shows the calculated exterior noise levels at each receptor site on the project along with the required exterior to interior noise level reduction and the required window sound class transmission (STC) for windows of all residential units that face Sunflower Avenue and Flower Street to meet the required interior noise level standard of 45 dBA CNEL. The City does not have exterior or interior noise standards for commercial land uses. Therefore, window upgrades to reduce interior noise levels for the proposed non-residential amenities on the site including the leasing office, mail room, fitness center, bike cafe, club room and business center/conference room, parcel room are not required. The following measure is recommended to reduce interior noise levels of the residential units that face Sunflower Avenue and Flower Street to meet Santa Ana Municipal Code section 18-313. Mitigation Measure No. 9 All residential units that face Sunflower Avenue and Flower Street shall have acoustic windows with STC ratings shown in Table 6 of the Noise Report.32 Operational Noise Impacts The operational activities associated with the proposed project have the potential to impact the nearby school, multi-family attached residential dwelling units, and single-family detached residential dwelling units. Specifically, these activities include parking lot noise and air conditioning units. Land uses surrounding the site consist of an elementary school to the north, multi-family attached and single-family detached residential dwelling units to the east, multi-family attached residential dwelling units to the south (across Sunflower Avenue), and multi-family attached residential dwelling units to the west (across Flower Street). The nearest existing sensitive receptors are the school playfields located adjacent to the north and the multi-family attached residential dwelling units located adjacent to the east. Noise associated with parking lots includes, but is not limited to idling cars/trucks, trucks diesel engines, exhaust systems, trailer coupling, air brakes, warning signal, doors closing, and starting engine noise. Noise levels associated with parking lots typically range between 44-63 dBA Leq at a distance of 100 feet. The City of Santa Ana Municipal Code Section 18-312 includes exterior noise level standards of 55 dBA during the daytime (7:00 AM to 10:00 PM) and 50 dBA during the nighttime (10:00 PM to 7:00 AM). In addition, Section 18-315 of the Municipal Code states that it is unlawful for any person to create any noise which causes the noise level at a school while it is in use to exceed the noise limits as specified in Section 18-312 prescribed for the assigned noise zone in which the school is located. The proposed project includes the development of the site with 226 multi-family attached residential dwelling units and an associated parking structure. This use is consistent with the surrounding residential uses and would not cause a substantial permanent increase in ambient noise levels or 32 Legacy Sunflower Project, Noise Impact Analysis, Gandinni, January 23, 2019. 6-105