Laminated glass is a sandwich made of one piece of plastic Poly Vinyl Butyral between two or more glasses. The PVB sticks with the glass, forms chemical as well as mechanical bonds. When laminated with annealed glass, the layer maintains the geometric integrity of the pane in case of breakage. Also it gives acoustic insulation as well as gives protection against damage caused due to UV radiation because it cuts almost 99% of UV radiation present in the sunlight.
Ordinary window glass is brittle, breaking into long sharp pieces which can causes serious injuries. The principal feature of Laminated safety glass is that the interlayer absorbs the energy impact and hence resists penetration. Although the glass may break, the glass fragments remain firmly bonded to the interlayer, minimizing the risk of injuries.
Burglars often try to break windows to get inside the house or a building and here the laminated glass plays an important role in resisting their intrusion. Even if the glass breaks the interlayer continues to safeguard the building until the glass is replaced.
Noise gains easiest entry to homes and buildings through windows and doors. Laminated glass proves an excellent barrier to noise, it has better Sound Transmission Loss as compared to glass of similar thickness in the frequency of 125 Hz to 4000 Hz. Also it eliminates the coincidence dip that is associated with the monolithic glass because of the viscoelastic property of the interlayer material.
SOLAR ENERGY CONTROL
While natural light is important for us too much sunlight can also mean too much heat gain inside the building.Laminated glass when used in combination with reflective glass,tinted glass or low e glass provides excellent reduction in the Solar Gains as well as reduction of sound transmission through the window.
The major cause of deterioration and fading of furnishings and pictures is the chemical reaction caused by short-wavelength UV radiation. UV absorbing additives in the interlayer in laminated glass can screen out almost all these damaging rays.
PROTECTION FROM WEATHER AND NATURAL DISASTERS
If broken, laminated glass remains in its frame, preventing interior damage while reducing flying glass protects people both indoors and outdoors. Areas subjected to heavy winds and rain such as hurricanes or cyclones, buildings often need extra protection. Flying debris carried by these winds can shatter the glass and injure people. Laminated glass can be designed to remain intact and in its frame. Buildings that are situated in areas subjected to heavy winds and rains such as hurrican and cyclones, often need extra protection.
Laminated glass is durable, it maintains its color and its strength for a very long time.
LOW VISUAL DISTORTION
Laminated Glass is usually glazed in an annealed form, avoiding the distortion caused by roller waves in the tempered and heat strengthened glass.So the facades having laminated glass have sharp reflected images and fewer distortion.
PROPERTIES OF LAMINATED GLASS
Float Glass in different thickness is basically used in the form of clear, tinted, reflective, tempered and heat strengthened glass. The PVB exhibits an extraordinary resistance in terms of UV transmission but does not reduce the visible light in the light spectrum.
• PVB thickness --0.38mm, 0.76mm, 1.14mm, 1.52mm
• PVB colors --Clear, white, gray, purple, blue, green, yellow, orange, red
• Refractive Index -- 1.48
• Visible Light Transmittance, Clear -- 89%
• Shading Coefficient, Clear -- 0.92
• UV Screening, up to 380 nm -- 99%
• Tensile Strength -- 3220 psi
• Tensile Elongation -- 205% (JIS K6771)
• Specific Gravity -- 1.07
• Specific Heat -- 0.47 Btu/lb°F
• Thermal Conductivity (K value) -- 0.12 Btu/(ft2hr°F)
• Coefficient of Thermal Expansion -- 2.6 x 10-4 in./in.°F
• Emissivity -- 0.9