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Grand Avenue Widening Project Environmental Impact Report Section 3.0 <br />noise sensitive land uses under both Alternatives 1 and 2. The results of the noise barrier <br />calculations are presented in Tables 3.6-12, 3.6-13 and 3.6-14 for the impacted residential uses <br />along the three segments of Grand Avenue <br />Noise Barrier Design <br />To be effective in reducing the noise levels, barriers must be continuous structures with no gaps <br />or gates. The walls must maintain a minimum density of 3.5 pounds per square foot. This may <br />be achieved with an earth berm, a brick wall or stud construction wall with 7/8" stucco finish, <br />3/8" plate or laminated glass, 5/8" Plexiglas or a combination of these materials. <br />Interior Noise <br />The interior noise standard for new residential construction the City of Santa Ana is 45 dB <br />CNEL. Most residential dwellings provide 20 dB of exterior -to -interior noise insulation. <br />Therefore, the property would have to be situated near the new right-of-way to exceed the <br />interior noise standard. All residential uses that could have been exposed to interior noise levels <br />in excess of the City's interior noise standard are in areas where the additional right-of-way for <br />either Alternative 1 or 2 would require a full take of the property. Therefore, no mitigation is <br />required for meeting the City's interior noise standards. <br />F: IPROJ-ENVIGrand eirWew Text - GrandWection 3 SplitlSection 3.6.doc Page 3.6-40 <br />