The sum of all areas on all floors of a building required for physical access to some subdivision of space, whether physically bounded by partitions or not.
Included should be, but is not limited to, public corridors, fire towers, elevators lobbies, tunnels, bridges, and each floor’s footprint of elevator shafts, escalators and stairways. Receiving areas, such as loading docks, should be treated as circulation space. Any part of a loading dock that is not covered is to be excluded from both circulation area and the gross building area. A loading dock which is also used for central storage should be regarded as assignable area and coded as central storage (730). Also included are corridors, whether walled or not, provided they are within the outside facelines of the buildings to the extent of the roof drop line.