Laminated Glass

Overview of Laminated Glass

Laminated glass, regard as “Safety glass”, consist of two or more panes of glass with one or more layers of polyvinyl butyral (PVB) sandwiched between them and treated. The glass panes can be basic float glass or tempered or heat strengthened panel. If the glass is broken fragments tend to adhere to the PVB interlayer thereby reducing the risk of injury from falling glass and helping to resist further impact or weather damage. PVB membrane has good tenacity performance and when the laminated glass breaks due to violent force, the PVB will absorb a large amount of impact energy and disperse it rapidly. Therefore, it’s hard to break the laminated glass and the shape of the glass may be maintained even if being broken. Furthermore, personnel inside and outside the buildings will not be hurt by the glass fragment.

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Laminated Glass Process:

PVB laminated glass is manufactured by combining two or more annealed or heat treated glass sheets bonded with one or more of PVB interlayers and subjected to heat and pressure, in order to ensure perfect adhesion between the constituent elements.

The lamination process comprises the following steps:

Glass pre-processing

Cutting and grinding

Washing

Drying

Lamination

De-airing/edge sealing

Unloading

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Resin laminated glass is manufactured by pouring liquid resin into the cavity between two sheets of glass which are held together until the resin cures. Regardless, Resin Laminated glass is not considered as Safety Glass.

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Features of Laminated Glass:

Laminated glass provides durability, high-performance and multi-functional benefits and at the same time preserves the aesthetic appearance of glass. Laminated glass provides a solution to many architectural design problems and offers increased protection from the effects of disasters such as hurricane, earthquake and bomb blasts, if suitably designed.

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SAFETY

Ordinary glass windows are brittle and break into long, sharp pieces, causing serious and sometimes fatal injuries. An important feature of laminated glass is its performance under impact. That is, the internal layers of laminated glass have the capacity to absorb the energy of impact and resist penetration. Safety hazards caused due to breakages are minimized with the use of laminated glass. Although the glass may break, the glass fragments will adhere to the plastic interlayer, minimizing the risk of injury and property damage.

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SECURITY

Burglars often break windows to get to door and window handles, but laminated glass can resist the intrusion because it is virtually impossible to cut through the thick PVB layers even if the glass gets broken. Contact an expert to design suitable laminated glass for intrusion resistance.

SOUND CONTROL

Laminated glass has proven to be an excellent barrier to noise. It has a higher sound reduction index than monolithic glass of equal thickness between the frequencies of 125Hz and 4,000Hz. The shear damping performance of the PVB makes laminated glass an effective sound control product. This sound dampening is due to the low elastic property of the PVB interlayer.

UV CONTROL

While natural light plays an important role in architectural design, Ultra Violet (UV) rays in the sunlight can cause itching and fading of curtains/furniture. Laminated glass can block over 99% of the UV rays while allowing most of the visible light through.

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WEATHER AND DISASTER CONTROL

Laminated glass helps provide protection from injury and property damage caused by glass breaking because of natural disasters such as hurricane and earthquake. In areas prone to natural disasters, an expert may be contacted to design the glass combination. Similarly, it also provides protection from man-made disasters such as bomb blasts. It does so by keeping the glass intact within the glass frame.

DURABILITY

Laminated glass is exceptionally durable, maintaining its color and strength. It can be used for a variety of architectural and interior design applications such as floor glazing, stairs, balconies, balustrades, internal panelling and exterior cladding as well as for the more traditional doors and windows.

DESIGN VERSATILITY AND INSTALLATION EASE

Laminated glasses can be manufactured flat or curved. They can include annealed, toughened, heat-strengthened, wired, patterned, tinted or reflective glasses. Internal layers can be used to add color tints and for further aesthetic and privacy needs. Laminated glass is simple to install. If the glass is not heat treated, it can also be cut, drilled or notched.

LOW VISUAL DISTORTION

Distortion is caused by “roller waves” in tempered and heat-strengthened glass. This can be avoided by using laminated annealed glass. Sharp reflected images are possible with curtain walls constructed of laminated annealed glass.

Properties of Laminated Glass:

 

Properties Annealed Tempered Laminated
Alteration Possible Not possible Possible
Risk of Injury High Low Low
Impact Resistance Low High Low
Optical Distortion Low High Low
Environment Control No No Yes, protects from UV rays
Acoustic Insulation No No Yes
Heat Insulation No Yes with reflective coating Yes with reflective coating

Applications of Laminated Glass:

Laminated glass is widely used in manufacturing and automotive industries and in a variety of commercial and residential applications because of its safety, security, sound abatement and solar control characteristics.

In glass skylights, sun spaces, sloped glazing installations and curtain walls, there is always the possibility of glass breakage. This is why many building codes worldwide use laminated glass for overhead glazing.

It is used in schools, hospitals, hotels and office buildings, and wherever there are sound control requirements.

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