Toughened Safety Glass
Toughened safety glass is up to five times stronger than normal annealed (float glass) of the same thickness. Toughened glass qualifies as a Grade ‘A’ Safety Glass.
Toughened safety glass fractures into relatively small harmless particles when broken and has a greater resistance to thermal stress. Toughened glass can be subjected to temperatures ranging up to 290°C.The Heat Strengthening (Toughening) ProcessToughened glass results from the controlled heating and cooling of annealed (float) glass. Firstly, annealed glass is heated inside a furnace to a temperature in excess of 600°C. The glass is then rapidly and uniformly cooled by blasting both sides of the glass with compressed air, a process known as quenching.This ‘snap cooling’ or quenching action induces compressive stresses into the glass surface while the centre remains in tension. The cooling (or quenching) rate dictates how much stress is introduced into the sheet of glass.Most glass types can be toughened although glass of thickness less than 4mm cannot be heat strengthened. Once proccessed heat strengthened glass cannot be cut or altered.Toughened safety glass is a durable, versatile product that offers a broad range of benefits including:
- Security – being harder to break there is a lower instance of entry being gained to properties glazed with toughened glass.
- Strength – toughened safety glass is better suited to hi-rise and high wind areas.
- Heat and thermal tolerance – toughened glass can tolerate high temperatures and is well suited to glazing in bush fire rated situations.
- Thermal cracking - toughened glass is recommended where glass may at risk of thermal cracking due to stress from an uneven light / shade coefficient.
- Safety – no risk of large glass shards falling in human impact situations.