The Grieve Corp.
No. 908 is a natural gas-heated box furnace with a maximum operating temperature of 2000 F (1095 C). Workspace dimensions are 48 in. W x 48 in. D x 48 in. H (1,220 x 1,220 x 1,220 mm). The furnace features 7 in. (180 mm) thick walls, comprising 5 in. (130 mm) of 2300 F (1260 C) firebrick and 2 in. (50 mm) of 1700 F (930 C) ceramic fiber insulation, plus a 7 in. thick floor made from 4.5 in. (115 mm) of 2300 F (1260 C) firebrick and 2.5 in. (65 mm) of 1900 F (1040 C) block insulation. A firebrick plate hearth supported by firebrick piers is provided, as well as an air-operated vertical lift door and an automatic door switch to drive the burners to a low fire whenever the door is opened.