Abstract: An insulated firing chamber has oppositely disposed sidewalls with a plurality of aligned pairs of holes. A plurality of infrared lamps are disposed in the chamber. The end terminals of the lamps pass through the respective pairs of holes to the exterior of the chamber. The end terminals of the lamps are enclosed by sealed compartments so the only way for gas to escape from the compartments is through the holes in the sidewalls of the firing chamber. Nonreactive gas under pressure is introduced into the compartments to induce unidirectional gas flow through the holes into the firing chambers. The gas introduced into the compartments cools the end terminals of the lamps without danger of contaminating the environment inside the firing chamber. The compartments each have an access opening, a removable hatch that engages a gasket on the compartment around the opening to seal the opening when the hatch is in place.