For building footprints up to 20000 f² (1860 m²) or where multiple suction pits are required. This is the middle sized cage. It is constructed from a rolled cylinder of expanded metal decking with a sheet metal top and bottom and then hot dipped galvanized for durability. It has an 18" diameter, is 8” tall and is fitted with a welded insert ring for an easy and stable installation of the 6” exhaust pipe. This suction pit cage meets the prescriptive requirements for the current Alberta and National building code section 188.8.131.52 (1). This item may take up to 3 weeks for delivery. Ships via Canada Post Expedited.