For all buildings, the definition of floor area in Section 12-10 (DEFINITIONS) shall be modified in accordance with the provisions of this Section.
 

1. Flood control devices
   
   In all districts, for every linear foot of protection by temporary flood control devices and associated fixtures, including emergency egress systems that are assembled prior to a storm and removed thereafter, up to 15 square feet of floor space used for the storage of such devices may be excluded from the definition of floor area, provided that in no event shall such exempted floor space exceed 1,000 square feet.
2. Buildings containing non-residential uses
   
   In Commercial and Manufacturing Districts, where the permitted commercial or manufacturing floor area ratio does not exceed 1.0, up to 500 square feet of floor space may be excluded from the definition of floor area, provided that:
   1. the building is used exclusively for non-residential uses; and
   2. such floor space is located at or above the flood-resistant construction elevation.