A building shall be considered as separate and distinct buildings for the purpose of determining area limitations, continuity of fire walls, limitation of number of stories and type of construction where all of the following conditions are met:
- The buildings are separated with a horizontal assembly having a fire-resistance rating of not less than 3 hours.
- The building below the horizontal assembly is not greater than one story above grade plane.
- The building below the horizontal assembly is of Type IA construction.
- Shaft, stairway, ramp and escalator enclosures through the horizontal assembly shall have not less than a 2- hour fire-resistance rating with opening protectives in accordance with Section 716.5.
- The building above the horizontal assembly is not required to be of Type I construction;
- The enclosure connects fewer than four stories; and
- The enclosure opening protectives above the horizontal assembly have a fire protection rating of not less than 1 hour.
6. The building below the horizontal assembly shall be protected throughout by an approved automatic sprinkler system in accordance with Section 903.3.1.1, and shall be permitted to be any of the following occupancies:
6.1. Group S-2 parking garage used for the parking and storage of private motor vehicles;
6.2. Multiple Group A, each with an occupant load of less than 300;
6.3. Group B;
6.4. Group M;
6.5. Group R; and
6.6. Uses incidental to the operation of the building (including entry lobbies, mechanical rooms, storage areas and similar uses).