Pyrotherm ceramic fiber boards are rigid, high-temperature boards constructed from alumina-silica fibers and binders. This relatively lightweight board is manufactured with a uniform density. It is strong and self-supporting, and has good rigidity and modulus of rupture. These features make it well-suited for applications experiencing vibration and mechanical stress. If the material becomes wet by water, steam or oil, thermal and physical properties remain as specified upon drying.

Use of Pyrotherm ceramic fiber boards can reduce energy costs and cycling times due to their high insulating capability. This insulating feature can also protect refractory surfaces from thermal shock.

This board is very resistant to chemical attack, resisting oxidation and attack by most corrosive agents, but can be damaged if it comes in contact with hydrofluoric, phosphoric, hydrochloric and sulfuric acids, as well as concentrated alkalies.

Pyrotherm L23R is manufactured with an exterior surface lightly rigidized. If machining Pyrotherm L23R, keep in mind that machined surfaces will not retain the rigid shell.

Pyrotherm H24D is a higher density board with greater hot-strength than L20M.