Do you know the reason behind the characteristic ‘spider web’ cracking pattern when the impact is not enough to completely pierce the glass windows of automobiles. The answer is that safety glasses are used in automobiles.
Types of safety glass: There are two categories of safety glasses.
• Laminated glass
• Tempered glass
Laminated glass: It is made by sandwiching a thin layer of PVB (polyvinyl butyric) between two or more panes of glass. As compared to a monolithic glass panel of identical thickness this structure is superior in terms of risk of injury by shards, impact resistance. Adhesion of PVB to glass provides safety. The plastic film holds the glass in place when the glass breaks reducing the risk of injury from falling glass. It has a great sound proofing effect due to PVB interlayer. It filters the UV rays by 97-98%.
Tempered glass: Tempering includes heating the glass up to very high temperature about 700ºC. It is then quickly cooled. As the temperature increases viscosity decreases. As cooling starts viscosity raises turning glass semi elastic. The result is a tough, durable glass with better resistance to thermal & mechanical shocks.
Uses of Safety Glass: Laminated safety glass is used in cutting boards, thermometers, automobiles, railways, marine vessels, aircrafts, defense, household construction
applications and other industrial applications. Tempered safety glass is used in doors of oven, computer monitors, shelves of refrigerator and LCDs. It can also be used in side lights, shower and tub enclosure, interior partitions, storm doors, patio-door assemblies, escalator and stairway balustrades.It is used as a glazing product in windows and spandrel areas.Special building applications include sloped glazing, racquetball courts, skylights and solar panels.
