Architectural glass light in industrial factories. Annealed glass is glass without internal stresses caused by heat treatment, i.e., rapid cooling, or by toughening or heat strengthening. Glass becomes annealed if it is heated above a transition point then allowed to cool slowly, without being quenched. Float glass is annealed during the process of manufacture. However, most toughened glass is made from float glass that has been specially heat-treated. Annealed glass breaks into large, jagged shards that can cause serious injury and is considered a hazard in architectural applications. Building codes in many parts of the world restrict the use of annealed glass
Heated glass Heated glass Heated glass is a resistance heater created when a transparent, electrically conductive coating is applied to float glass and then subjected to an electric current. The electric current in the coating creates heat energy, which warms the glass until the glass radiates heat. The manufacturing process begins with the application of a microscopic Tin dioxide coating to a pane of float glass. This coating is transparent and conducts electricity. Then, two busbars are applied to the glass as follows: the busbars must be parallel and applied to opposing edges on the same side of the glass pane. The