Glass Expert discusses Why Tempered Glass Is Safety Glass

Tempered glass is safety glass because it breaks into small cubes. The edges of these cubes are still sharp. They are not "rounded". From a glass expert point of view, the safety aspect comes strictly from the small size, which is a function of the temper stress. If these pieces are interlocked, they can behave in a manner similar to a larger piece broken from an annealed piece of glass.