Abstract: Flooring systems including a metal raised access flooring panel (10) that is solid or is perforated by oval or oblong openings having major axes not parallel to any panel edge. The major slot axes may, for instance, be at a 45° angle to each panel edge. The slots (28) may be arranged in “clusters” of six slots, with one pair of slots above another pair and one slot to each side of, and mid-way above and below, the stacked pairs. Alternatively, the panels (10) may be perforated by circular holes arranged in a similar pattern. Adjacent panels may be interlocked with retractable pins extending from one panel (10) to another. Pedestal heads and stringers are adapted to accommodate panels of different sizes.