18 C120-H007-05EN
CHAPTER 2 Installation Sites
2.3.2 Free-access flooring
The construction of free-access floors is reviewed with respect to the following items:
zRaised floor height
zStrength and surface material of free-access floor panels
zOpening for server-system-use
zInstallation of floor panels for a building air conditioner
Each item is described as follows:
(1) Raised floor height
Regarding the raised floor height of a free-access floor, the following factors require
consideration:
zAvailability of underfloor ventilation
zCabling height
zSafeguards against earthquakes
Table 2.2 lists suggested raised floor heights for free-access floors.
Table 2.2 Raised floor heights of free-access floors
Condition Raised floor height
Room
ventilation
Erected directly on the free-access floor
Optional earthquake-free legs that absorb the
energy of earthquakes installed to protect
against earthquakes
180 mm (7 in.) or higher
Clamped from under the free-access floor to
protect against earthquakes
250 mm (10 in.) or higher
Underfloor
ventilation
Erected directly on the free-access floor
Optional earthquake-free legs that absorb the
energy of earthquakes installed to protect
against earthquakes
300 mm (12 in.) or higher
Clamped from under the free-access floor to
protect against earthquakes
400 mm (16 in.) or higher