Abstract: A furnace lining in which insulation fibers are formed into mats which in turn are formed into prefabricated modules each of which is installed by forcing it into interlocking engagement with a matingly configured clip that has been previously secured to an interior surface of the furnace. Each insulation module includes a tray having a bottom portion including a plurality of openings capable of interlocking engagement with projections of a complementary clip. The tray further includes projections which secure rods that pass through the ceramic fiber insulation to secure it to the tray. A preferred tool for the installation of such a furnace lining is also described and the method of installation of such a lining.