Borosilicate fire-rated glass is a low-thermal-expansion borosilicate material available in sheets up to 4500 mm × 2440 mm and thicknesses of 5 mm to 15 mm. It can be supplied as monolithic tempered panels or processed into laminated glass, coated glass, and insulating glass units (IGUs) to combine fire resistance with energy efficiency.
The base glass achieves a fire resistance rating exceeding 120 minutes. Its high softening point and low coefficient of thermal expansion provide the heat stability required in fire-rated glazing. A low-iron formulation gives a visible light transmittance (VLT) of 92 % with minimal optical distortion, maintaining transparency for egress and rescue during a fire event.
The glass is more than 8 % lighter than conventional glass of the same thickness while offering high mechanical strength. Because the raw-material system contains no nickel, the finished product is free of nickel sulphide inclusions, removing the spontaneous breakage risk associated with conventional tempered glazing.
Before tempering, the glass can be cut, ground, drilled, and coated. After tempering, it can be laminated, fabricated into IGUs, or combined with vacuum glazing and ceramic frit processes to produce composite assemblies.
Fully tempered monolithic borosilicate fire-rated glass satisfies both fire-resistance and mechanical safety requirements. Typical applications include fire-rated windows, interior fire partitions, and fire doors. It can also be installed as stand-alone curtain wall glazing or as part of coated, laminated, IGU, or ceramic frit systems.