IBM DS8900F Introduction And Planning Manual page 98

• The raised-floor height must be at least 30.5 cm (12 in.). Clearance must be adequate to accommodate
interconnecting cables, Fibre Channel cable raceways, power distribution, and any piping that is present
under the floor. Floors with greater raised-floor heights allow for better equipment cooling.
• Fully configured, two-frame storage systems can weigh in excess of 2844 kg (6270 lbs). You must
ensure that the raised floor on which the storage system is to be installed is able to support this weight.
Contact the floor-tile manufacturer and a structural engineer to verify that the raised floor is safe to
support the concentrated loads equal to one third of the total weight of one frame. Under certain
circumstances such as relocation, it is possible that the concentrated loads can be as high as one half of
the total weight of one frame per caster. When you install two adjacent frames, it is possible that two
casters induce a total load as high as one third of the total weight of two adjacent frames.
• Depending on the type of floor tile, more supports (pedestals) might be necessary to maintain the
structural integrity of an uncut panel or to restore the integrity of a floor tile that is cut for cable entry or
air supply. Contact the floor-tile manufacturer and a structural engineer to ensure that the floor tiles
and pedestals can sustain the concentrated loads.
• Pedestals must be firmly attached to the structural (concrete) floor by using an adhesive.
• Seal raised-floor cable openings to prevent chilled air that is not used to directly cool the equipment
from escaping.
• Use noncombustible protective molding to eliminate sharp edges on all floor cutouts, to prevent
damage to cables and hoses, and to prevent casters from rolling into the floor cutout.
• Avoid the exposure of metal or highly conductive material to the walking surface when a metallic raised
floor structure is used. Such exposure is considered an electrical safety hazard.
• Concrete subfloors require treatment to prevent the release of dust.
• The use of a protective covering (such as plywood, tempered masonite, or plyron) is required to prevent
damage to floor tiles, carpeting, and tiles while equipment is being moved to or is relocated within the
installation site. When the equipment is moved, the dynamic load on the casters is greater than when
the equipment is stationary.
Nonraised floor considerations
For environments with nonraised floors, an optional overhead cabling feature is available.
Follow the special considerations and installation guidelines as described in the topics about overhead
cable management.
When you install a storage system on a non-raised floor, consider the following factors:
• The use of a protective covering (such as plywood, tempered masonite, or plyron) is required to prevent
damage to floor and carpeting while equipment is being moved to or is relocated within the installation
site.
• Concrete floors require treatment to prevent the release of dust.
Overhead cable management (top-exit bracket)
Overhead cable management (top-exit bracket) is an optional feature that includes a top-exit bracket for
managing your Fibre cables. This feature is an alternative to the standard, floor-cable exit.
Using overhead cabling provides many of the cooling and safety benefits that are provided by raised
flooring in a nonraised floor environment. Unlike raised-floor cabling, the installation planning, cable
length, and the storage-system location in relation to the cable entry point are critical to the successful
installation of the top-exit bracket.
Figure 7 on page 85 illustrates the location of the cabling for the top-exit bracket for fiber cable feature.
When you order the overhead-cable management feature, the feature includes clamping hardware and
internal cable routing brackets for rack 1 or rack 2. The following notes provide more information about
the color-coded cable routing and components in Figure 7 on page 85.
1 Customer Fibre Channel host cables. The Fibre Channel host cables, which are shown in red, are
routed from the top of the rack down to I/O enclosure host adapters.
84 IBM DS8900F: DS8900F Introduction and Planning Guide