Access Floor

Published February 2000

A raised-floor system used in computer installations and open-plan offices to provide under-floor space for wire distribution and, in some applications, distribution of conditioned air; it allows outlets to be located anywhere in the room. The system consists of metal or concrete panels supported at each corner by adjustable pedestals that rest on the structural slab. Floor coverings must be carpet tiles, laminated tiles or some other material that can be removed in sections. Panels are situated 4 to 18 inches above the structural floor, are usually 2' x 2' and are removable to allow access to the underlying power, telephone and coaxial cables. Activations are through pedestal service fittings or through panel holes and boxes attached to the panels' undersides. Power cables are distributed under the access floor through conduit or manufactured wiring systems. In access floors that are used for air return, data and phone cables are encased in conduits or raceways; in non-environmental applications (or when plenum cable is used), cables lie on the floor.