Raised Floor - Design

Design

This type of floor consists of a gridded metal framework or substructure of adjustable-height supports (called "pedestals") that provide support for removable (liftable) floor panels, which are usually 2×2 feet or 60×60 cm in size. The height of the legs/pedestals is dictated by the volume of cables and other services provided beneath, but typically arranged for a clearance of at least six inches or 15 cm.

The panels are normally made of steel-clad particleboard or a steel panel with a cementitious internal core, although some tiles have hollow cores. Panels may be covered with a variety of flooring finishes to suit the application such as carpet tiles, high-pressure laminates, marble, stone, and antistatic finishes for use in computer rooms and laboratories. When using a panel with a cement top surface the panels are sometimes left bare and sealed or stained and sealed to create a tile appearance and save the customer some money. This bare application is used most often in office atriums, hallways, lobbies, museums, casinos, etc.

Many modern computer and equipment rooms employ an underfloor air distribution to ensure even cooling of the room with minimal wasted energy. Conditioned air is provided under the floor and dispersed upward into the room through regularly spaced diffuser tiles, blowers or through ducts directed into specific equipment. Automatic fire protection shutoffs may be required for underfloor ventilation, and additional suppression systems may be installed in case of underfloor fires.

Many office buildings are using access floor now to create more flexible and sustainable spaces. When underfloor air is designed into a building from the start of the project the building can be less expensive to build and less expensive to operate over the life of the building. Underfloor air requires less space per floor thereby reducing the overall height of the building and saving the cost of the building fascade. The blowers and air handlers required for underfloor air are much smaller and require less energy because the hot air rises naturally through the space as it comes in contact with people and equipment that warm the air and it rises to the ceiling. Additionally when buildings are designed to combine modular electrical, modular walls and access floor the space can quickly be reconfigure within the building in a few hours as compared to historical means of demolishing walls and drilling holes in the floor to route electrical. As more companies construct or renovate buildings to meet LEED (Leadership in Energy & Environmental Design) underfloor air and access floor usage will continue to grow. The USGBC (United States Green Building Council) states that approximately 25% of all new buildings are built to meet the LEED requirements today.

Because the flooring tiles are rarely removed once equipment has been installed, the space below them is seldom cleaned, and fluff and other debris settles, making working on cabling underneath the flooring a dirty job. Smoke detectors under the raised floor can be triggered by workers disturbing the dust, resulting in false alarms.