Reference Guide

4.10
3PAR InServ E-Class/F-Class Storage Server Physical Planning Manual
4.3.6 Additional Flooring Recommendations
Consider the following recommendations for raised floor installations:
■ The flooring should be high enough to allow under the floor routing of cables and
specified airflow to system air intakes. The recommended minimum floor clearance is
30.5 cm (12 in). An additional 3 in. (7.6 cm) should be allowed for cables and connectors. A
floor clearance of 18 in. (46 cm) is recommended for new construction.
Additional panel support may be required to restore the structural integrity of a raised
floor panel that has been cut for air opening, cable entry, and so on. Raised floors without
stringers may also require lateral support to prevent floor tile movement.
The finished floor-to-ceiling height should be a minimum of 8 ft. (2.44 m).
■ The subfloor must have adequate drainage to prevent flooding and trapping of water
beneath the raised floor. Cement should be sealed to prevent the formation of particulates.
■ To avoid an electrical hazard when using a metallic floor, no metal or conductive material
should be exposed to the walking surface.
■ Sharp edges must be eliminated on all floor cutouts where cables pass. For wood or similar
core material, all cut edges must be covered with metal or plastic clips or grommets so that
none of the core is exposed (see NFPA 75 requirements).
■ Asphalt tiles are not recommended because they produce dust that may cause equipment
malfunction.
■ Carpeting is not recommended because it produces and holds dust, and can contribute to
the buildup of electrostatic charges on people and equipment.
■ Most raised floors are composed of 24 in. (Domestic/American Standard) or 60 cm
(International/Metric) square floor tiles. The maximum panel size should not exceed 24 by
36 in. (Domestic/American Standard) or 60 by 90 cm (International/Metric). The panels
should have a flame spread rating of 15 or better when tested according to the American
Society for Testing and Materials (ASTM) Standard E 84.
■ The floor covering can contribute to a buildup of high static electrical charge. To minimize
static charge:
◆ Provide a conductive path to ground from the metallic raised floor structure through
the metallic supporting structure or separately from each tile.
◆ Ensure the maximum resistance for floor surface material is 20 gigohms, measured
between the floor surface and building ground.