R-value of Ceramic Fiberboard: A Key Indicator for High-Temperature Insulation

The R-value (thermal resistance) is an important parameter for measuring the thermal insulation performance of a material. Its calculation formula is R = thickness / thermal conductivity (λ). A higher R-value indicates better thermal insulation performance at the same thickness.

Ceramic fiberboard is a rigid refractory material made primarily from aluminosilicate fibers using a vacuum forming process. Its thermal conductivity is extremely low—only 0.03 W/(m·K) at room temperature, and only one-fifth that of clay bricks at 1000℃. This excellent characteristic makes it an ideal high-temperature insulation material.

The R-value of ceramic fiberboard is not a fixed value but varies with several factors:

Operating temperature: Thermal conductivity increases with increasing temperature. Taking a product with a density of 285 kg/m³ as an example, its thermal conductivity is approximately 0.085 W/(m·K) at 400℃, rising to 0.132 W/(m·K) at 800℃, and reaching 0.180 W/(m·K) at 1000℃.

Product Density and Processing: Due to the presence of binders and higher density, ceramic fiber boards typically have a slightly higher thermal conductivity than ceramic fiber blankets at the same temperature. Therefore, for the same thickness, the R-value is relatively low.

Board Thickness: The R-value is directly proportional to the thickness; the greater the thickness, the higher the thermal resistance.

In practical engineering applications, engineers often use thermal conductivity as the design basis, and then calculate the corresponding R-value based on the specific thickness and operating temperature. Ceramic fiber boards, with their low thermal conductivity, lightweight (density 64~500 kg/m³), and excellent thermal shock resistance, are widely used in kiln linings, high-temperature equipment insulation, and fire barriers.