20 Circulation

20 Circulation

• Definition: Non-assignable spaces required for physical access to floors or subdivisions of space within the building, whether directly bounded by partitions or not. Examples include bridges and tunnels, elevators, escalators, loading docks, lobbies, public corridors, and stairways.


Definition: A covered and walled connecting passageway for people to pass over or under the ground to gain access to another facility.

Limitations: Ground-level covered passageways, walled or not, are coded as Public Corridors (W06). Any portion of the floor area of covered and walled bridges or tunnels used exclusively for housing utility services such as gas, steam, or water lines, should not be included in a space inventory as they are considered infrastructure and should be dealt with accordingly.


Definition: The structural shaft built to accommodate one or more elevator cabs. The entire cross-sectional shaft area is to be inventoried at each floor level through which it passes.

Limitations: Individual elevator cabs are considered as fixed equipment within the shaft space; thus, their area is not added to the space inventory.


Definition: A moving passageway that carries passengers from one floor level to another, or along a level path over some distance. For a ramped escalator, the floor area taken by the entire length of each escalator at the lowest level is recorded at that floor level. The area of each floor penetrated by that escalator is inventoried on each of those floors.

Limitations: The escalator equipment itself is considered as fixed equipment and may be inventoried as a fixed asset. The overall dimensions of that equipment may be smaller than the floor area penetration inventoried for a space inventory.

Loading Dock

Definition: A covered area of a platform used to load or off-load goods or materials that are to be transported elsewhere within a reasonable amount of time such that the platform is not considered as a storage location. Only the length and width of the platform’s covered area is to be included in the inventory. If the platform is internal to the building line, that area of the platform covered by the floor immediately above is to be included in the inventory.

Limitations: Any part of the platform area not covered is excluded from the building’s gross, assignable, and nonassignable areas. Any area of a loading dock that is used for central storage of nonhazardous materials should be regarded as assignable area and coded as Central Storage (730).


Definition: A circulation area used to transition from the floor’s external entrance to internal circulation space, to pass from one corridor to another, or to move to a different level such as a lobby area outside an elevator bank. Although a Lobby may have some limited seating furniture, it is designed more for passing through (or having standing conversations) than for sitting and relaxing.

Limitations: A Lobby differs from an assignable Lounge (650) in furniture placement, use, and intent.

Public Corridor

Definition: A covered passageway or ramped area available to the general public, whether walled or not, to transport people or things from one location to another. The use of phantom walls is recommended to identify portions of passageways on the same floor level that may represent differing purposes, e.g., a main corridor versus a side corridor, or differing maintenance needs, e.g., terrazzo flooring versus carpeted flooring.

Limitations: Restricted access private circulation aisles or ramped areas used only for circulation within an organizational unit’s suite of rooms, auditoria, or other working areas should not be included. In these cases, they may fall within the service subcategories of those space use categories, or earn a separate service subcategory of “Private Circulation,” for example (see Description under 315 Office Service, p. 53).


Definition: The covered internal or external space dedicated to provide non-mechanically assisted passage from one floor level to another. In an enclosed stairway, the cross-sectional area of the stairwell is inventoried at each floor through which it passes. In an unenclosed stairway, only that area beneath the stairway structure that is not accessible or has less than a 3-foot ceiling height is included.

Limitations: In stairways that pass through floor openings larger than themselves, the open area around the stairway’s floor penetration is not counted as either gross area or usable area. In an unenclosed stairway, that area beneath the stairway structure that is accessible and has a 3-foot ceiling height or greater should be included as both gross area and usable area in the inventory.