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Characteristics of Automotive and Transport Glass
Europe's glazing manufacturers are constantly striving to deliver products that provide the best possible technological solutions to meet automobile manufacturers' and end-users needs from a comfort, safety and security perspective, whilst at the same time helping the industry to meet its climate commitments.
Safety and Security
Glass plays an important role in the car's ability to offer safety and security to its passengers. The automobile industry is making increasing use of laminated glass, which is a "sandwich" of two glass sheets with a thin but tough plastic layer in between. The layers are bonded to each other under controlled heat and pressure. If the glass suffers an impact, the glass layers may fragment but, depending on the force of the impact, the plastic interlayer will hold.
This is a safety advantage for the driver and passengers in case of an accident, keeping them inside the vehicle and absorbing some of the energy of the impact. Moreover, after an impact the resulting glass fragments tend to remain attached to the plastic interlayer, reducing the hazards of sharp projectiles during an accident. And the fact that windows made of laminated glass will tend to remain in their frame greatly improves the performance of the side airbags, providing the necessary support during inflation.
Laminated glass also offers a considerable security advantage making it much more difficult to break into the car (on average, it takes 10 times as long to penetrate a car window made of laminated glass than one made of toughened glass).
A different kind of passenger-safety factor is provided by UV (ultraviolet) filter glass, which blocks harmful UV rays to protect skin and eyes (as well as the materials of the car's interior). UV filter glass blocks 95% of harmful UV rays from entering the vehicle, keeping the driver and passengers safe and greatly extending the life of upholstery and fabrics.
UV filter technology can be incorporated into laminated glass for optimal safety and security.
Visibility and Visual Comfort
Good visibility conditions are key to driving safety, and visual comfort (for example, light reflections and glare) is part of visibility. The driver's field of vision is influenced by the light the windscreen allows into the cabin. Indeed, bright sunlight causes glare, rain smears the windscreen, condensation clouds the view, and ice build-up blocks out almost everything. Today's vehicle glazing technologies can deal with all of these.
Antireflective Glass
Reflections on the inside of the windscreen can be disturbing to the visual comfort and concentration of the driver. This is compounded by current design trends that lean towards lighter dashboards that are more strongly reflected in the windscreen. Anti-reflective glass, which is treated with a special coating, can reduce these reflections by up to 40% at a reflective angle of 60 degrees, and also helps reduce glare.
Hydrophobic Glass
Hydrophobic glass is coated with a polymeric layer that repels water, causing rain or other water to run off the glass without leaving droplets and also greatly improving the effectiveness of windshield wipers in completely clearing water from the windscreen. This leads to significant increases in visibility under wet conditions.
Heatable Glass
In heatable glass, invisible wires or an invisible metallic coating - in each case embedded into the interlayer of the laminated windscreen - respond to an electrical charge by raising the temperature of the glass, in cold weather speeding the removal of any condensation or ice and then of course preventing any further condensation or ice build-up.
Thermal Comfort
Today's increased use of glass in cars means that, without the right technologies, more solar energy will penetrate the interior of the car, causing high temperatures. For example, when the outside temperatures is 27°C, without anti-heat technologies, a car interior can heat up to 58°C in few minutes. Combating this solely by way of air-conditioning alone would be an environmentally unfriendly approach, leading as it would to higher fuel consumption and CO2 emissions.
In recent years, the industry has developed solar control glazing. This type of glass is specially engineered to reduce vehicle cabin by up to 7 or 8°C temperature, and reduce heat penetration in vehicles exposed to solar radiation by over 25%. In this way, a significant amount of energy is saved from powering air-conditioning units while passengers' comfort is safeguarded.
Solar control glazing
Solar control glazing has a coating that allows it to reduce the transmission of solar heat from the external environment while still permitting the optimal light transmission essential to ideal driving conditions. This type of glazing can reduce by over 25% the heat penetration in vehicles exposed to solar radiation, thus reducing the need for the use of fuel-hungry cooling systems. Dark-tinted glazing and switchable glazing also have solar control properties which can reduce the amount of solar heat entering the vehicle's cabin.
Acoustic Comfort
Acoustic laminated glass technologies have been developed to combat levels of noise penetration in vehicles, which can have an effect on people's health, causing disturbance and stress if an occupant is exposed over a prolonged period. Noise mainly comes from the sound of the car's engine, air and other environmental factors (e.g. other cars, roadworks, etc.). When using specific acoustic laminated glass, improvement of the order of 3-5dB1 can be reached, which is quite noticeable to the ear. Lower noise levels mean that the driver will become less tired, and make communication inside the vehicles more comfortable, thus contributing to overall safety.
Acoustic glazing
Acoustic glazing consists of two or more sheets of glass, bonded together with one or more acoustic interlayers. The interlayers act as a noise-dampening core, weakening the sound as it travels through the glass. Acoustic laminated glass also benefits from all the safety and security properties of standard laminated glass. Moreover, acoustic windscreens reduce the need for heavier glazing, which allows car manufacturers to reduce vehicle weight.
Style and Taste
A car is, for many people, a reflection of their desired image or style, expressing an element of who they are and what they enjoy. And the car's glass is an important visual component of this. Some people prefer the privacy of darkly tinted glass (or the "VIP image" that goes with it), others like more light and openness.
Light and aerodynamic design requires glazed surfaces of increasingly complex geometries, which can be real manufacturing challenges to ensure durability and perfect vision. Manufacturers are therefore continuously developing advanced glass shaping techniques which allow for the bending and shaping of the glass to offer car makers the freedom to achieve their design and style concepts.
According to the specific design characteristics of the brand and the expectations of clients, glass manufacturers also offer a range of different colours (e.g. green glass, dark tinted, etc.) which contribute to the car's colour harmony and make the car model unique:
Dark tinted glass keeps the interior cool by absorbing solar energy and at the same time offers privacy for passengers in the back of the car (dark tinted glass is not permitted for the driver and forward-passenger windows, nor of course for the windscreen). Dark tinted glass is available in several colours and each colour in several shades from lighter to very dark.
Switchable glazing, which responds to varying electrical conditions with correspondingly different colour properties, allows for the creation of a "customised" interior ambience. Via a simple dial, a driver or passengers can control the amount of light entering the vehicle - blocking anywhere from 4% to 40%. Heat from sunlight can be reduced by anywhere from 2 to 20%. One can select a lighter tint on cloudy days, then darken it when the sun reappears, or simply change the lighting to suit one's mood or create an appearance appropriate for the occasion.
1 Advanced Automotive Glazing Manufacturers Association (AAGMA)
