Welcome to the Glass Age

34 unblemished flat glass surfaces of large size. Hence the use of lozenge shaped pieces no bigger than the palm of a hand in earlier architecture and small rectangles with elegant fine glazing bars in Georgian times. At the turn of the 19 th /20 th centuries, just as automatic bottle production was beginning, so were machine methods for flat glass manufacture introduced. One example was the Fourcault method where a long refractory boat with a slot along the bottom was pressed into the hot glass surface and as the melt welled up through the slot it was taken and drawn vertically by edge gripping rollers. This gave much larger sheets. Some applications, though, required better quality surfaces than any of these methods could achieve, for example, carriage windows and mirrors. Such products required the grinding and polishing of cast sheets. This was labor intensive, so the products were expensive and only available to the rich or very rich, particularly in earlier centuries. Now though the mass production of mirrors, each reflecting a clearer personal image, has stimulated the international cosmetics trade. A major breakthrough came with the creation of the Float Glass process patented in 1952, 70 years ago. This creates one free surface and an undersurface floating in molten tin. Both are effectively distortion free. Float methods were able to give glass thicknesses from 25 mm down to one millimeter. Of course, development never ceases; the screens of mobile phones are just 0.5 mm thick and prompted the invention of yet another sheet production technology. A millennium ago, glass windows flooded our sacred buildings with light, and now we view the world and ourselves through glass —our phone screens, our mirrors and our architectural skyline. In transport, glazing allows unimpaired vision and contributes to safety and security, as well as style. Airplane cockpit windshields are chemically strengthened. Innovative designs offer thermal comfort; improve fuel efficiency by light-weighting; and integrate display features. Two-thirds of flat glass production is used in architecture, while most of the rest is for the transport industry. These applications often involve secondary processing, for example cutting, grinding and polishing. Surface treatments add considerable value by conferring characteristics such as self-cleaning, chemical resistance, light and heat transmission control for thermally efficient glazing, electrical behavior, and increased mechanical strength (Chapters 4, 6). Plant construction is capital intensive, needs appropriate expertise and has traditionally been limited to a few major players, but markets now influence the location of new facilities. After the 2008 recession, fewer than 200 factories and 400 production lines remained, but then entry barriers fell and expansion began in emerging markets such as the BRIC countries (Brazil, Russia, India and China). In the last 15 years, Russia has quadrupled its production plants to 8 while India has almost doubled to 7. Other developing markets are Asia, Africa, the Middle East and South America. Algeria, Kyrgyzstan, Malaysia, Syria, Ukraine and Vietnam have all recently built furnaces. Since 2015, China’s flat glass production capacity has grown particularly rapidly, mirroring its economic development; in 2019, capacity exceeded 60% of the global total, causing a significant surplus. China’s environmental protection and capacity replacement policies were subsequently tightened, restricting new production capacity. This required rapid industrial structural adjustment and diversification to higher-quality products. Now, China’s building and transportation industries are growing rapidly again and fundamentally changing to energy-saving, safe, and lightweight products. Green building is adding 1.6-2 billion m 2 annually to 60 billion m 2 existing floor area, 90% of which is in high-energy- consumption buildings that urgently need transformation. So the processing of energy-saving insulating glass,