No. 990 is an electrically heated, 500ºF (260ºC) walk-in batch oven from Grieve used for curing composite materials in vacuum bags. Workspace dimensions measure 60 x 60 x 72 in (1524 x 1524 x 1829 mm). Incoloy-sheathed tubular elements heat the unit with 40 kW (54 hp), while a 2-hp (1.5-kW) recirculating blower provides airflow to the workload. The walk-in oven features 4-in (102-mm) insulated walls throughout, aluminized steel interior and exterior, and a four-position vacuum manifold with gauge and hand valve for each position. A digital programming temperature controller, manual reset excess temperature controller with separate contactors, recirculating blower airflow switch, and power controller improve safety, and an integral five-point thermocouple jack panel is installed through the oven wall.