Standards for space classifications

IBM® TRIRIGA® uses the standards for space classifications that are established by the International Facility Management Association (IFMA) and Building Owners and Managers Association (BOMA).

These standards are used to calculate the area measurements of buildings and spaces.
Note: IBM TRIRIGA supports the 1996 BOMA standard.
Space classification standards Description

Exterior gross

The total floor space of a building, including unusable space or excluded areas, which is measured from the outside walls.

Interior gross

The total measured area that is calculated from the inner surface of the walls, including rentable areas, interior parking, vertical penetration, and void areas.

Building rentable

The area within the interior gross that includes the usable area and a prorated portion of the common areas on the entire office floor. This area does not include vertical penetration regions, such as elevators, stairs, or mechanical risers.

Usable area

The total area that can be occupied. The usable area on a specific floor of a building depends on the corridor configurations and whether the floor has single or multiple occupants.

Assignable area

The space that is assigned for a specific purpose, for example, cafeteria.

Exterior wall

The outer wall that surrounds the total interior gross.

Interior parking

The area within the interior gross that is available for parking. This area is allotted by dividing the total rentable square footage area of a building by the total parking space.

Vertical penetration

The vertical penetration regions within the interior gross include the elevators, stairs, atrium, and the other common areas.

Core building services

The regions within the building rentable area that are dedicated to providing maintenance and core services for the building or structure.