The tempering process involves heating and cooling in a horizontal line to impart a compressive stress to the outer surfaces of the glass and an indirect tensile stress to the center of the glass. Fully tempered glass is about 5 times stronger than untreated glass and is suitable for use as safety glass as it reduces the risk of injury by shattering into dice-sized pieces when broken.

Semi-tempered glass is approximately 2 times more durable than untreated glass and is not classified as safety glass.

After tempering, the glass cannot be cut, drilled, edged or surface treated (except sandblasting).

"Tempering marks", which can only be noticed under certain viewing angles and light conditions, and distortions that occur within the tolerances of "hump" and "rotation" are inevitable and unavoidable results of heat treatment. Traces minimized by the application of a precise heat regime during the tempering process are not considered a defect in themselves. It is recommended that the marks are parallel to the ground.

Due to the microscopic Nickel Sulphide particles present in the glass paste, there is a possibility of sudden breakage in fully tempered glass. In order to reduce this risk, fully tempered glasses can be subjected to a preliminary screening by heat soak test. This test does not completely eliminate the risk of sudden breakage, but only reduces it.