Avaya 6424D+M User Manual page 110

If you are required to design a raised-flooring MDF, use the following guidelines.
Before designing the layout of an MDF over a raised floor, take into account the following three issues
that can affect the design:
The use of raised floor space as an air plenum. The National Electric Code (NEC) prohibits the
placement of cables that use ordinary covering materials, such as polyvinyl chloride (PVC) or
polyethylene, in the building air plenums. However, when the raised floor is used as an air plenum
the plenum typically serves only the raised-floor room, which permits the use of cables with ordinary
cover materials in that space. On the other hand, if the local codes forbid the use of ordinary
covering materials for the installation that you are planning, use ducts for such cables as the
input/output (I/O) cables (which connect the switch to the MDF).
Space availability under the floor. Is there adequate space for ducts and cables to be installed and
what is under the raised floor—for example, electrical conduits, air conditioning ducts, water pipes?
Modification of the floor tiles. Cutouts in floor tiles will have to be made to accommodate the
MDF. Discuss this with the customer. Contact the NEC regarding final requiremems for cutouts in
floor tiles. See figure 7-15, Floor Template -18 Inch Tile (L-472366), figure 7-16, Floor Template -
24 Inch Tile (L472367), and figure 7-17, Floor Template - Cabinet Lineup (L472368).
Once you have resolved the preceding issues, use the following guidelines for designing
frame installations, and the floor plan.
MDF/lDF DESIGN: DEFINITY GENERIC 2 WITH UNIVERSAL MODULES
7-25