Class A Fire-Rated Glass: High-Purity Fumed Silica

With the official implementation of the new national standard GB/T 15763.1-2025 for fire-rated glass, the domestic architectural fire-rated glass industry is accelerating reshuffling. Class A thermal-insulating fire-rated glass has become a mandatory selection for high-rise buildings, public buildings and data center projects. The new standard clearly divides fire-rated glass into three categories: Class A, B and C. Class A products must meet both fire resistance integrity and thermal insulation performance, with fire resistance ratings covering 1h, 1.5h, 2h and 3h, setting higher thresholds for the purity, stability and weather resistance of interlayer fire-resistant gel materials.

Nano-silicon composite fire-rated glass relies on an inorganic silica gel interlayer, which rapidly foams to form a dense ceramic thermal insulation layer in case of fire, and is currently the mainstream technical route for Class A fire-rated glass. The performance ceiling of the fire-resistant gel interlayer is largely determined by the upstream fumed silica raw material. The industry generally reports that ordinary commercial fumed silica has pain points such as difficult dispersion, sharp system viscosity rise and high heavy metal impurities, which easily cause agglomeration, micro-bubbles and high-temperature discoloration in fire-resistant gel, directly reducing the yield of finished fire-rated glass and even affecting the results of fire resistance tests.

In response to existing industry pain points, Andehu New Materials has launched the ZLPSIL-MF Series fumed nano-silica. Different from conventional fumed silica, this product is a brand-new category with ultra-high silica content independently developed by the enterprise. It is specially developed for fire-rated glass and low-viscosity industrial systems, featuring two core performances: low viscosity contribution and 47% high dispersibility. The silica content of the product reaches more than 99.999%, various heavy metals such as iron, aluminum, calcium and sodium are strictly controlled at ppm level, and trace impurities such as barium, cobalt and copper are maintained at extremely low levels.

In Class A nano-silicon fire-resistant gel formulations, this product can ensure rheological anti-settling performance without excessively increasing system viscosity, adapting to the vacuum infusion production process. It participates in the sintering of the silica matrix at high temperatures and assists in forming a dense porous thermal insulation skeleton, helping the finished glass achieve complete Class A fire resistance indicators, covering fire resistance ratings of 1 to 3 hours. In addition to fire-rated glass applications, ZLPSIL-MF is also suitable for high-end industrial formulations requiring low thickening effect such as electronic potting and optical coatings, realizing multi-scenario application of one material.

Industry insiders said that with the continuous growth of domestic fire-rated glass exports to overseas markets, specialty fumed silica featuring ultra-high purity, high dispersibility and low viscosity contribution will become an important direction for the localization substitution of upstream materials.