(A) The provisions of this amendment shall apply to buildings or portions thereof, and to additions to existing buildings, that are constructed after the effective date of this amendment and that are located where the exterior day-night sound level exceeds 65 dB. A building that has been designed and constructed to include special sound isolation in accordance with this amendment shall not be altered. If a building is altered, it shall be proven that such alterations do not diminish the noise-isolating properties of the building.
(B) If the gross floor area of a structure or project is expanded by less than 50%, the requirements of this section apply only to the area of expansion. If the gross floor area of a structure or project is expanded by 50% or more, the requirements of this section apply to the entire structure, except for existing single family, duplex dwellings or any multifamily property used for residential purposes.
('80 Code, § 7-42) (Ord. 1857, passed 7-18-79; Am. Ord. O2002-10, passed 2-20-02)