Tempered fire-rated glass
This product starts as float glass that is heated and then rapidly cooled under controlled conditions. The source notes that subsequent physical or chemical treatment produces glass combining high mechanical strength with fire resistance and integrity. Surface quality and optical uniformity depend heavily on consistency during the heating phase.
Tempered glass
Tempered glass is pre-stressed safety glass made by heating annealed glass to softening temperature and quenching it to create surface compression. The source states that it meets CPSC 16 CFR 1201 and ANSI Z97.1 safety-glass requirements. It offers higher impact resistance, thermal-shock resistance and bending strength than annealed glass, and can be drilled, coloured or supplied in various thicknesses and sizes. It is suitable for curtain walls, windows and doors, but not for fire-compartment boundaries.
Fire-rated glass
Fire-rated glass is a specialty fabricated product designed to block flame and smoke for a defined fire-resistance rating. It is classified by whether it provides integrity only or integrity plus insulation. The source lists common types as high-strength monolithic fire-rated glass, laminated fire-rated glass, insulating fire-rated glass (IGU), grouted fire-rated glass and wired fire-rated glass. Because drilling can compromise interlayers, coatings or wire mesh, field modification is generally prohibited; the source notes a limited exception for monolithic fire-rated glass when used as a smoke baffle.
Specification boundaries
Both materials provide transparency in curtain walls and fenestration. Tempered glass can act as the substrate for certain fire-rated products, yet the two are not interchangeable. Fire-rated glass is specified for fire compartments, atrium separation, external fire-rated windows, smoke baffles, skylights and transparent floors where a fire-resistance rating is required. Its processing complexity makes it more expensive than standard tempered glass, which is not deployed where a rated fire barrier is mandated.