The larger opening provides an easily accessible means for equipment to be installed or removed from a building. Equipment access roof hatches are available in steel, aluminum and stainless steel construction and in one standard single leaf size [Type F, 48” x 48” (1219mm x 1219mm)]. Special single leaf sizes (Type SS) are available and are recommended for widths up to 5’0” (1524mm). For larger openings, specify double leaf construction (Type D). For best operation, specify aluminum construction for single leaf hatches over 3’0” (914mm) wide and double leaf hatches over 7’0” (2134mm) in width.