Tempered glass

These smaller, granular chunks are less likely to cause deep penetration when forced into the surface of an object (e.g. by gravity, by wind, by falling onto them, etc.)

As a result of the increased surface stress, when broken the glass breaks into small rounded chunks as opposed to sharp jagged shards.

[citation needed] Consequently, annealed glass is fragile and breaks into irregular and sharp pieces.

"Rim-tempered" indicates that a limited area, such as the rim of the glass or plate, is tempered, and is popular in food service.

The glass is then rapidly cooled with forced air drafts while the inner portion remains free to flow for a short time.

Chemical toughening results in increased toughness compared with thermal tempering and can be applied to glass objects of complex shapes.

Polishing the edges or drilling holes in the glass is carried out before the tempering process starts.

[11] The float glass process can be used to provide low-distortion sheets with very flat and parallel surfaces as an alternative for different glazing applications.

The most common causes are:[13][14] Any breakage problem has more severe consequences where the glass is installed overhead or in public areas (such as in high-rise buildings).

A safety window film can be applied to the tempered panes of glass to protect from its falling.

François Barthélémy Alfred Royer de la Bastie (1830–1901) of Paris, France is credited with first developing a method of tempering glass[16] by quenching almost molten glass in a heated bath of oil or grease in 1874, the method patented in England on August 12, 1874, patent number 2783.

[17] The first patent on a whole process to make tempered glass was held by chemist Rudolph A. Seiden who was born in 1900 in Austria and emigrated to the United States in 1935.