Tempered glass is how many times stronger than annealed glass?

Tempered glass is how many times stronger than annealed glass?

• A. 3x
• B. 5x
• C. 7x
• D. 10x

Answer: (B)

Tempering adds strong compressive stresses to the surface of the glass, while annealed glass has no such surface compression. When a load bends the glass, those surface compressive stresses in tempered glass help resist the development of tensile cracks, delaying crack growth and greatly increasing strength. This combination typically results in about five times the bending strength of annealed glass, which is why tempered glass is chosen for safety glazing in many applications. If it breaks, tempered glass shatters into small granules rather than sharp shards, but the main strength gain comes from the surface compression that tempering creates.

Tempering adds strong compressive stresses to the surface of the glass, while annealed glass has no such surface compression. When a load bends the glass, those surface compressive stresses in tempered glass help resist the development of tensile cracks, delaying crack growth and greatly increasing strength. This combination typically results in about five times the bending strength of annealed glass, which is why tempered glass is chosen for safety glazing in many applications. If it breaks, tempered glass shatters into small granules rather than sharp shards, but the main strength gain comes from the surface compression that tempering creates.