Pigments to Reflect the Infrared Radiation From Fire

Conventional paints transmit or absorb most of the intense infrared radiation emitted by fire, a fact that contributes to the spread of fire. Techniques used for design of coatings with high visible reflectivity are here adapted to the design of coatings that have high reflectivity in the 1 to 8 μm wavelength range important in fires. Promising materials for pigments include titanium dioxide, iron oxide, chromium oxide, and silicon, with particle diameters in the 1 to 2 μm range. Aluminum flake pigments are also effective. Pigment synthesis by the deposition of coatings on mica flakes is briefly discussed.