TABLE OF CONTENTS The modularity of all components of raised floor systems can be an advantage in space planning, particularly over large open plan areas. Consider the compatibility of anticipated building plan geometries with the dimensions of the floor grid established by the raised floor system.
Raised floor panel dimensions: 24 in. (610 mm) square
Underfloor plenum pedestal spacing: same as floor panels, e.g., 24 in. (610 mm)
In new construction, underfloor air distribution has the potential to achieve a reduction in floor-to-floor heights compared to projects with ceiling-based air distribution. This is accomplished by reducing the overall height of service plenums and/or by changing from standard steel beam construction to a concrete (flat slab) structural approach. A single large overhead plenum to accommodate large supply ducts and other building services can be replaced with a smaller ceiling plenum for air return and piping for sprinklers combined with a lower-height underfloor plenum for unducted air flow and other building services [Kight 1992]. Floor-to-floor heights for overhead systems using steel beam construction can also be reduced by using beam penetrations for ducts and other building services. In this comparison, if steel beam construction is used in both designs, floor-to-floor heights should be equal or lower for UFAD buildings. Significantly reduced vertical height requirements can be achieved using concrete flat slab construction, which is usually more expensive than steel beam construction but is preferred for underfloor systems due to thermal storage benefits. In the example...
