Tempered Glass

Insulite fabricates tempered glass on three state-of-the-art electric horizontal oscillating furnaces. The furnaces will temper 1/8” (3mm) to 1/2” (12mm) thick flat float glass products. These furnaces are equipped with two hearths for increased output and aspirators for tempering the new generation of post heat-treatable vacuum deposited reflective and low-e glass products available today.

The tempering furnaces heat the glass to a uniform temperature of approximately 1200 degrees Fahrenheit. Ceramic rolls convey the glass through the furnace at speeds regulated to ensure temperature uniformity and minimal optical distortions. When the glass exits from the furnace, it is rapidly cooled by a series of air nozzles. This rapid cooling puts approximately 20% of the glass surface into a state of compression, with the center core in tension. Tempered glass gains its added strength from these compressed surfaces.

Tempered Glass has approximately five times the mechanical and thermal strength of annealed glass of equal thickness. Tempered glass has a break pattern of small pieces and is less likely to cause severe injuries than annealed or heat-strengthened glass. Tempered glass cannot be cut or drilled after tempering.

Optical quality:

Bow, warp and process roll distortion may be evident. This is an inherent characteristic of the manufacturing process and is within the limits set by ASTM Standard C1048.


ASTM C 1048 Standard Specification for Heat-Treated Flat Glass.

Consumer Product Safety Commission 16 CFR 1201 Safety Standard for Architectural Glazing Materials.

ANSI Z97.1-2009 Safety Glazing Materials Used in Buildings


Safety Glass Certification Council (SGCC) www.sgcc.org

For additional information and size limitations of tempered glass contact Insulite