Structural and Functional Properties of Architectural Glass

Abstract

There has been a significant improvement in the mechanical properties of glass sheets arising from the introduction of ‘Float Glass’ technology a few decades back. In addition, glass sheets are strengthened by tempering and ion exchange processes. Lamination is also another technique through which glasses are strengthened. All these developments have resulted in widespread use of glass in modern buildings either as facades or windows to improve the architectural design. The glasses may be either coloured (tinted) or colourless. The demand for green buildings has led to the development of low-emissivity coatings, which are multilayer thin (less than a micron thick) films in which metallic silver having the lowest emissivity of all available materials is used as the active material. Design of windows with these low-E glasses is also quite important. They may be either double or triple glazed with air gaps in between in order to enhance the insulation property. One of the internal surfaces is normally coated with low-E coating, which reflects a major part of the IR radiation. In a cold country, the heat needs to be reflected to the interior so that heating load is reduced. On the other hand, in a warm country, it has to be opposite so that the heat is to be reflected to the exterior consequently reducing the air-conditioning load.