Porter Outdoor Bleacher Seating Features: Seat and footboards are constructed of extruded, anodized aluminum alloy planks that are 9-1/2" wide. All planks have a non-slip, grooved-type top surface with reinforcing ribs on the underside. All plank ends are fitted with die-cut, formed aluminum caps to provide smooth end surfaces. Support frames are fabricated from heavy structural steel angles with a hot-dipped galvanized finish after final assembly, for superior corrosion resistance. Lateral "X" bracing made of 3/16" x 1" galvanized steel strips provide maximum stability. Outdoor seating meets the BOCA National Building Code Section 1003 General Means of Egress, and Section 1008 Assembly requirements.