Information Technology Reference
In-Depth Information
FIGURE 1.6
Telecommunications room components.
exclude flammable cables (or ones that exhaust toxic gases when placed in a flame)
from any plenum spaces. A plenum is an air duct or a return air duct that is used
for forced-air circulation, such as from a heating or air conditioning (HVAC) sys-
tem. Any air space used for forced-air circulation, other than an actual room
intended for work areas, is a plenum (which means that the area above drop-in ceil-
ing tiles is plenum space if separate ducted air returns are not used). A common
arrangement is to use a plastic return-air grid in place of a ceiling tile, or to use flu-
orescent lighting fixtures with a row of vent openings along the edges, to provide
air return into the above-ceiling area and eventually back to the HVAC air handler.
All of this space is air plenum and requires special plenum-rated cables.
