Question 17Steam Plants - 1st Asst/Chief

The correct answer is D) Firebrick. Firebrick is the appropriate refractory material for use in areas directly exposed to the highest heat in a furnace. Firebrick is a specialized type of brick designed to withstand extremely high temperatures without deterioration. It is composed of clay and other heat-resistant minerals, making it suitable for use in the hottest parts of a furnace where temperatures can reach over 2,000°F. The other options, such as insulating block, baffle mix, and insulating brick, are not suitable for direct exposure to the highest heat levels in a furnace. These materials are better suited for less intense heat zones or for insulation purposes, but they lack the thermal resistance and durability of firebrick.