Notwithstanding any other provision of this article, the board shall provide that building area for enclosed hallways in the second or higher story of any building shall be counted as two-thirds of the actual area. For purposes of this section “enclosed hallways” includes, but is not limited to, all of the following:
(a) Covered passages, arcades, shelters, porches, and planting areas.
(b) Enclosed covered areas that provide shelter between buildings that are 20 feet or more apart.
(c) Sun control devices designed and located to function in lieu of covered walks or other shelters.
(d) Mezzanines used for storage purposes.