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Flat Glass for Automotive and Transports
Flat glass is an integral part of most automotive vehicles and is essential to Europe's transport industry. Flat glass is used to make windscreens, backlights, windows and sun roofs for a wide range of automobile and transport applications from cars to cruise ships and buses. At around fifteen to twenty percent of total flat glass production in volume, automotive glass is the second-largest area of application of float glass products (after the construction sector).
In addition to cars, glass is used in:
The challenges faces in these other modes of transport are very similar to those of cars, as glass needs to provide optimum visibility, whilst presenting a high level of durability, acoustic and thermal comfort as well as strength.
Glass is used for the cabin in lorries to protect the driver against bad weather conditions. For this reason, heated windscreens and water repellent coatings have been developed for side windows, providing for an improved driver vision during bad weather externalities, such as rain, ice, fog and mud.
Another important feature of the glass used in lorries is that it protects drivers against fatal accidents and is an integral part of a lorry's safety system. Laminated glass is used not only for the windscreen, but increasingly also for side windows. It is more resistant to shock and prevents the body from being ejected and the cabin from being penetrated in the case of an accident.
Glass also contributes significantly to the comfort of the cabin. Considering the size of the glazed surface of a truck, it is vital that the glass is engineered to withstand some of the solar radiation that heats up the inside of the vehicle. The glass - windscreen and sun roofs - can be tinted or applied with a thin transparent coating to absorb sun rays and to reduce UV transmission. The comfort of the cabin can also be enhanced by insulating glazing, consisting of two layers of glass separated by air or gas, thereby keeping the cold out.
Moreover, glazing can be integrated with other functions, for the benefit of the modern transport industry. By means of example, antennae can be integrated into the glass in order to manage data communication and mobile information.
The amount of glass in a bus or coach is on average ten times that of a lorry. Glass trends in bus design are also evolving, with increasing surface areas and more complex shapes of glazing. For example, the size of a windscreen on a bus sometimes exceeds five square metres. Glass technology is improving in order to maintain a high level of comfort and safety for the bus driver and passengers.
Laminated glass is used for windscreens as well as for side windows and protects against the shattering of glass in case of an accident. Laminated glass can also be equipped with invisible heating filaments in the interlayer film, which improves visibility for the driver.
Comfort is an important issue in buses, considering the large surface of the glazing. The windscreen is therefore laminated and the side windows tempered in order to reduce the temperature of the air and the components inside the bus, and to improve the efficiency of the air-conditioning. Acoustic comfort is also an important aspect, as it limits the driver's tiredness and provides for better travelling conditions for the passengers. New types of interlayers in laminated windows have therefore been developed to protect against noise more efficiently than standard films.
Glass is a significant aesthetic feature of buses and coaches. New aspects of bus and coach design include complex shapes of glazing, glass roofs, and flush glazing, which is a classical window with an opening where a sheet of glass slides on the main window.
Furthermore, glass can play an important role in decreasing the weight of buses and coaches. Some new vehicle regulations, such as those requiring low-emission engines and seat-belts, have increased the weight of vehicles. By developing side windows that are laminated from 3millimetre-sheets instead of the classical 4-mm or 5-mm sheets, the weight of a bus can be reduced by as much as 100 kg.
Glass is used in several vehicles in the off-road sector, including construction equipment cabins and agricultural machinery such as tractors and combine harvesters. Most of the cabin's glazing can be equipped with laminated glass in order to create a safe workplace, especially in the case of construction equipment and forestry machinery. Solar control glass can also be engineered especially for vehicles of low speeds, including in particular agricultural tractors that spend long hours in fields with full exposure to the sun, which is considerable and can be damaging to the health of the occupants.
Glass on boats has different applications depending on the type of boat in question. The armoured windows that are used on navy vessels are similar to the windows on military vehicles, while the glass on commercial and cruise ships is not very different from the glass used on cars. Glass on boats therefore needs to satisfy a wide range of performance criteria, especially as international standards governing marine safety become increasingly demanding. The design of glass is continuously adapting to the changing speed and design of boats. For example, high speed vessels need to be equipped with highly resistant but still very light glazing. One way of saving weight on a boat is to bond the windows directly to the structure of the boat, thus eliminating the need for a frame.
Other important specifications for marine windows include: resistance to high pressure; thermal and solar protection; defrosting and demisting; and ballistic protection. Moreover, glazing on vessels often needs to protect the on-board instrumentation from interference by electro-magnetic radiation from radars and high frequency transmitters. Acoustic protection is also a necessity for many marine windows, for example windows that are next to the flight deck on aircraft carriers. For sensitive areas of a ship, fireproof windows are often a safety requirement, for example the windows in front of the lifeboats.
Glass is used in various types of aircrafts where glass strength is of particular importance: commercial planes, regional commuter planes, helicopters and military aircrafts. Especially for cockpit windows, but also cabin windows, glass is reinforced to a very high strength by making its surfaces permanently compressed. This is achieved through one of two glass-strengthening processes: thermal tempering or chemical reinforcement. With thermal tempering, the surface compression -- and hence the reinforcement -- is limited, whereas chemical reinforcement creates a very strong glass with a high optical quality. Windshields on planes are equipped with heating systems, usually made by conductive coatings or wire-grids, in order to withstand fog and ice.
In planes, specially engineered glass also protects against the static electric charging that can occur during flights, through the means of a conductive coating that drains the static charges. Glass technology applied to aircraft also includes protection against solar radiation, electro-magnetic radar beams, and, thanks to increased durability, the particularly damaging effects of birdstrikes against the windscreen. For helicopters, special weight-reducing yet durable bird-proof glass is used.
Trains, high-speed trains, subways and other train categories use laminated glass and wired laminated glass to improve passengers' safety and comfort.
Laminated glass used for high-speed trains has extra impact-resistant strength. This specialised laminated glass is produced with transparent and elastic PVB (polyvinyl buteral) membranes sandwiched between two pieces of glass, which are laminated under high temperature and pressure. Wired laminated glass includes conductive wires or thread between the glass layers, which generate heat when given an electric charge, helping to remove fog and frost on the windshields.