§ 158.398  ATTENUATION.
   (A)   Minimum noise attenuation requirements and standards. Where a particular structure contains different occupancy uses, the more stringent requirements shall apply, except where it is architecturally possible to achieve the appropriate noise level reduction for each different use and the uses are acoustically separated by a wall or partition with a minimum STC of 25.
   (B)   Compliance use above minimum. In any instance where noise level reduction is required by this chapter, all plans and specifications are to be certified by a recognized acoustical specialist for compliance.
   (C)   Noise reduction.
      (1)   Buildings, structures and active outdoor recreation space shall be located at the greatest distance from the noise source, taking maximum advantage of existing topographical features to minimize noise impacts, and within zoning district requirements such as required setbacks.
      (2)   Buildings and structures shall be oriented to minimize exposure to the noise source and building openings, such as windows, shall be located away from the noise source. The amount of passive outdoor recreational space where individuals would be subject to noticeable or severe levels of noise should be minimized. Landscaping materials should be used to deflect noise. Noise attenuation shall be accomplished as follows.
         (a)   All mechanical ventilation systems shall provide the minimum air circulation and fresh air supply requirements as provided in the Building Code for the proposed occupancy without the need to open any exterior doors or windows.
         (b)   The perimeter of all exterior windows and door frames shall be sealed airtight to the exterior wall construction.
         (c)   Fireplaces shall be equipped with well-fitted chimney cap devices.
         (d)   All ventilation ducts, except range hoods, connecting interior space to outdoors shall be provided with a bend such that no direct line of sight exists from exterior to interior through the vent duct.
         (e)   Doors and windows shall be constructed so they are close-fitting. Weather-stripping seals shall be incorporated to eliminate all edge gaps.
         (f)   All penetration through exterior walls by pipes, ducts, conduits and the like shall be caulked airtight to the exterior construction.
   (D)   Existing residences. Any existing residence may be added to, structurally altered or repaired without conforming to the referenced specifications provided the property owner signs a waiver indicating notification of said specifications and provided that all generally-applicable requirements of the Building Code are complied with.
(Ord. 3718, passed 6-20-2011)