Workspace dimensions of No. 864 measure 6.5 by 35 by 1.5?, and 1,650,000 BTU are installed in a modulating natural gas burner to heat the oven chamber. A 24,500-cfm, 20-hp recirculating blower provides vertical downward airflow to the workload. The oven has a 5" open-belt loading zone; 35" insulated heat zone with recirculated airflow; and 1" open-belt unloading zone. Other features include 4" insulated walls, aluminized steel interior and exterior, and side access doors to inspect the load and service the heating chamber.