What is laminated glass used for?
Laminated glass can be used for aesthetic reasons when you wish to add color to a façade while maintaining its transparency. However, it is primarily used for safety or structural reasons.
Laminated glass can be particularly beneficial when you need to reinforce protection from forced entry, blasts, bullet-resistance, as well as for floor-to-ceiling glazing that prevents people from falling outside. For structural reasons, it is specified for skylights, canopies, balustrades, point-supported facades, and walk-on-glass.
In urban areas, acoustic laminated glass may be specified for projects where the surrounding areas are particularly noisy. In addition to exterior applications, laminated glass can also be used on interior glazing to reduce noise from one room to another.
Laminated glass can be coated with a high-performance coating to enhance both thermal insulation or solar control providing an almost endless variety of options to suit your performance requirements.
The curtain wall method of glazing enables glass to be used safely in large, uninterrupted areas of a building, creating consistent, attractive facades. The variety of glass products available today allows architects and designers to control every aspect of aesthetics and performance, including thermal and solar control, sound and security, as well as colour, light and glare.
Laminated glass (sometimes called toughened laminated glass) comprises two or more layers of glass sandwiched together with tear-resistant plastic film interlayers (usually polyvinyl butyral (PVB) or ethylene-vinyl acetate (EVA). The aim is to create a glass composite which can absorb the energy of a person or object that strikes it, preventing penetration of the pane and potential injuries that might result from flying fragments of broken glass.
An additional benefit of laminated glass is that most ultraviolet radiation can be blocked by the PVB or EVA interlayer. Thermoset EVA layers can block up to 99.9% of UV rays.
Applications
Laminated glass can be used for safety or security reasons. It is used for architectural applications where for example, the glass could fall from a height and shatter, and also for roof, balcony and terrace balustrading, as well as for skylights. It can also be used as a decorative material due to the wide variety of interlayers available, e.g coloured, textured, meshed or patterned. It is particularly useful for windows and shopfronts in areas prone to hurricanes.
In addition to flat sheets, it can be supplied in curved sections, as may be required for car windscreens.
Manufacture
Bonding together the alternating layers of, typically annealed glass, and plastic film is usually achieved through the use of heat and pressure created by an autoclave.
Manufacture can involve using heat-strengthened glass, which, when it breaks, does so into large pieces held in the frame by the PVB inter-layer. Or it can be made from tempered glass, where the sheet may fall out of the frame but will mostly stay together due to the interlayer.
Digital printing for special effects can be created by printing on to the glass prior to laminating or printing onto the interlayer.
Configurations
Laminated glass is available in various thicknesses and configurations. A typical glass-layers configuration can comprise 2.5mm glass – 0.38mm interlayer – 2.5mm glass, resulting in ‘5.38 laminated glass’.
Thicker glass and multiple laminates giver a stronger product. Thicker configurations such as double– or triple-laminate with interlayers (int) can include the following:
Double laminate:
6mm – int – 6mm.
8mm – int – 8mm.
10mm – int – 10mm.
Triple laminate:
6mm – int – 6mm – int -6mm.
8mm – int – 8mm – int -8mm.
10mm – int – 10mm – int -10mm.
The cockpit of an aircraft such as a Boeing 747 may include a triple-laminated glass construction comprising three layers of 4mm toughened glass with 2.6mm PVB layers in between, making a total glass thickness of 17.2mm.
