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874 Lewelling Blvd. <br />Noise Study <br />9 July 2018 <br />Page 5 of 8 <br /> <br /> <br /> <br />▪ Unit 1 closest to Lewelling Blvd: OITC 27 <br />▪ All other units: OITC 24 <br />Recommendations are described in the sections below based on the proposed constructions as <br />shown on drawing A100 (drawing set dated 7/6/18), which include wood frame walls, operable <br />windows, and doors. <br />Exterior Walls <br />The project proposes the following typical exterior wall assembly (Figure 2), which alone would <br />have an acoustic performance of OITC 30 or higher and would meet minimum requirements <br />for all units. <br />Figure 2 – Typical Exterior Wall Assembly <br /> <br />Windows <br />Unit 1 would require acoustically-rated window assemblies with a minimum Outdoor-Indoor <br />Transmission Class (OITC) of 27. This may be achievable with standard 1” insulated glazing as <br />this glazing alone typically provides OITC 28. Window selection for this area should be <br />confirmed with an acoustic test report (per ASTM E90 and E1332) for the entire assembly, <br />inclusive of glass, framing, hardware and seals. <br />Requirements for all other units (OITC 24) is easily achieved with standard weather sealed <br />assemblies assuming 1” insulating glazing, sound rated assemblies are not required. <br />62