Electro Optical Industries, Inc. The B1500M furnace, which has an all tungsten hot zone measuring 10 x 20 in., is rated for a maximum operating temperature of 2450°C. It is designed specifically for processing ceramic parts in wet or dry hydrogen or at a vacuum level of below 1 x 10-7 torr. During hydrogen processing, the furnace features a dewpoint control system, using a heated humidifier and mass flow controllers, that can maintain dewpoints from -40°C to +60°C to within ±5°C. The dewpoint setpoint can be ramped up and down while the main hot zone temperature profile program is running.