Raised floor

A raised floor (also raised flooring, access floor(ing), or raised access computer floor) provides an elevated structural floor above a solid substrate (often a concrete slab) to create a hidden void for the passage of mechanical and electrical services. Raised floors are widely used in modern office buildings, and in specialized areas such as command centers, Information technology data centers and computer rooms, where there is a requirement to route mechanical services and cables, wiring, and electrical supply. Such flooring can be installed at varying heights from 2 inches (51 mm) to heights above 4 feet (1,200 mm) to suit services that may be accommodated beneath. Additional structural support and lighting are often provided when a floor is raised enough for a person to crawl or even walk beneath. A raised floor (also raised flooring, access floor(ing), or raised access computer floor) provides an elevated structural floor above a solid substrate (often a concrete slab) to create a hidden void for the passage of mechanical and electrical services. Raised floors are widely used in modern office buildings, and in specialized areas such as command centers, Information technology data centers and computer rooms, where there is a requirement to route mechanical services and cables, wiring, and electrical supply. Such flooring can be installed at varying heights from 2 inches (51 mm) to heights above 4 feet (1,200 mm) to suit services that may be accommodated beneath. Additional structural support and lighting are often provided when a floor is raised enough for a person to crawl or even walk beneath. In the U.S., underfloor air distribution is becoming a more common way to cool a building by using the void below the raised floor as a plenum chamber to distribute conditioned air, which has been done in Europe since the 1970s. In data centers, isolated air-conditioning zones are often associated with raised floors. Perforated tiles are traditionally placed beneath computer systems to direct conditioned air directly to them. In turn, the computing equipment is often designed to draw cooling air from below and exhaust into the room. An air conditioning unit then draws air from the room, cools it, and forces it beneath the raised floor, completing the cycle. Above describes what has historically been perceived as raised floor and still serves the purpose for which it was originally designed. Decades later, an alternative approach to raised floor evolved to manage underfloor cable distribution for a wider range of applications where underfloor air distribution is not utilized. In 2009 a separate category of raised floor was established by Construction Specifications Institute (CSI) and Construction Specifications Canada (CSC) to separate the similar, but very different, approaches to raised flooring.  In this case the term raised floor includes low-profile fixed height access flooring. Offices, classrooms, conference rooms, retail spaces, museums, studios, and more, have the primary need to quickly and easily accommodate changes of technology and floor plan configurations. Underfloor air distribution is not included in this approach since a plenum chamber is not created. The low-profile fixed height distinction reflects the system’s height ranges from as low as 1.6 inches (40 mm) to 2.75 inches (70 mm); and the floor panels are manufactured with integral support (not traditional pedestals & panels).  Cabling channels are directly accessible under light weight cover plates. The traditional 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. 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 with typical heights between 24 inches to 48 inches. 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 money. This bare application is used most often in office area, hallways, lobbies, museums, casinos, etc.