A platform structure typically consisting of 0.6 m 0.6 m (2 ft 2 ft) concrete-filled steel floor panels supported on pedestals 0.2 to 0.46 m (8 in. to 18 in.) above the concrete structural floor slab. Each panel can be independently removed for easy access to the underfloor plenum created below and can include openings for electrical outlets, grilles, or any other floor accessory in its thickness. In most office installations, carpet tiles are laid on top to provide a finished floor surface. Raised floor systems provide maximum flexibility and significantly lower costs associated with reconfiguring building services.

Any air supply outlet that relies on a local fan to deliver air from the plenum through the diffuser into the conditioned space of the building.

Air change effectiveness describes the ability of an air distribution system to provide ventilation (outside) air at the breathing zone (where occupants breathe). ACE is defined as the age of air that would occur throughout the space if the air were perfectly mixed, divided by the average age of air where occupants breathe.

A measure of the air exchange rate of a building, or space, that gives the time unit in hours.

A measure of the rate at which the volume of air contained within a space is replaced by supply (outside, conditioned, or recirculated) air. This is expressed in terms of air changes per hour...