Raised Access Floor System Product

Overview

A raised access floor replaces the idea of burying services in screed with a simple inversion: the walking surface becomes a removable lid. Steel-and-cement Floor Panels, 600 mm square, rest on a grid of adjustable Pedestals bonded to the structural slab, leaving a void from 75 mm to over a metre deep. Power, data cabling, and in many buildings the supply air itself run in that void, and any of it can be reached by lifting a 15 kg panel with a suction tool. The system dates to 1960s mainframe rooms and remains the default floor for data centers, trading floors, and control rooms, as well as offices that want churn-proof cabling.

Construction

The standard panel is a sandwich: a flat steel top sheet welded to a Bottom Pan deep-drawn with dozens of hemispherical domes, the cavity filled with lightweight cementitious Core Fill. The domes act like a waffle slab, so a 35 mm-thick panel carries a 4.5 kN concentrated load (heavy-grade panels reach 11 kN) with deflection limited to about 2.5 mm. The core also gives the floor its dead, solid footfall — an all-steel hollow panel rings; a filled one thuds. Alternatives include all-steel panels for light duty and calcium-sulphate cores favored in Europe for acoustics and fire performance. The factory-bonded Factory Covering is high-pressure laminate, conductive vinyl, or carpet tile, edged with conductive Edge Trim; in static-sensitive rooms the covering-to-ground resistance is specified between 10⁶ and 10⁹ Ω so charges bleed off people and carts without creating a shock path.

Each Pedestal is a steel tube on a 100 mm Base Plate glued to the slab with Pedestal Adhesive (plus anchors in seismic zones). A Threaded Stud screws into the tube and carries the Pedestal Head; installers sweep a rotary laser across a Laser Target and spin each head to the datum within ±1 mm, then freeze it with the Locknut. Each head seats the corners of four panels on locating lugs and a gasket. Above roughly 300 mm of height, Stringer Beams bolt between heads to form a rigid two-way grid — without them a tall pedestal field would rack sideways under braked pallet trucks — and the Stringer Gasket keeps panel joints sealed and silent.

The floor as an air system

In data centers the void doubles as a pressurized supply plenum at roughly 20–25 Pa. CRAC units blow chilled air under the floor, and it emerges exactly where racks need it through Airflow Panels: a Perforated Sheet of 25 % open area for light loads, or cast-aluminum grates at up to 56 % flowing 1,500–2,500 m³/h per tile in front of high-density racks. A Slide Damper under each tile trims flow so the cooling map follows the rack layout, and tiles are simply swapped or repositioned as the room changes.

Plenum pressure is a budget, and leaks spend it. Every cable penetration gets a Cable Grommet whose overlapping Brush Seals close around the bundle; studies of unsealed floors attribute 25 % or more of CRAC airflow to bypass leakage through unmanaged cutouts. The plenum is also a regulated space: cabling in it must be plenum-rated or in conduit, and NFPA 75 governs detection and suppression below the floor.

Field details and loads

The panel field ends at walls with site-cut Perimeter Closure strips, at open edges with Fascia Plates, and at doorways with a Ramp Unit held to a 1:12 accessible slope. Load specification follows CISCA (US) or EN 12825 (EU): concentrated load on a 25 mm square indenter, uniform load, ultimate load at a safety factor of 2, and rolling loads — the 10-pass heavy pallet and the 10,000-pass office chair — which are what actually destroy weak panels, by progressively crushing the core at the wheel line. A well-specified office floor runs Class A surfaces per ASTM E84 and supports 4.5 kN point loads; a data-center floor carrying 1,500 kg racks on casters is specified two classes up, because the worst case is not the rack in place but the rack rolling, with its whole weight on four small wheels crossing panel joints.