Heat-strengthened glass Guardian

Ordinary float glass is one of the most durable building materials. The durability of float glass under normal conditions of exposure is excellent, but its thermal resistance and mechanical strength properties are limited. Where added resistance to wind load and thermal stress is required, Float Glass might need to be heat treated in order to increase its strength.

The heat-treatment process of ordinary Float Glass consists in heating the glass beyond its softening point (over 600°C) and then cooling it down rapidly. This cooling freezes the outer surfaces in their dilated mode while allowing the inner material to retract as temperature drops, thus creating compression strength on the outer layers and tension in the inner layer. Compression strengths in tempered glass are higher than in heat strengthened glass. At Guardian heat treatment is performed in horizontal furnaces, ensuring good surface properties with tight tolerances. However, the treatment process causes some optical distortion of the glass surface which is often referred to as roller-wave and warp. Such distortion is inherent to the process and can not be considered as a defect, assumed it ranges within the tolerance levels as laid down in the applicable standards.

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