In smartphones, smarter buildings, huge TVs and much more, glass has become the iconic material of the 2010s.
When the famous glass entrance cube to Apple’s flagship retail centre was unveiled on New York’s Fifth Avenue in 2006, it was the perfect advertisement for a store that never closes. With walls made up of 18 glass sheets with discreet steel fixings, the nine metre square cube became an instant symbol of modernity and transparency. The marble facades of surrounding buildings seemed staid, oppressively heavy and out of date by comparison.
For Apple, whose brand image depends on being cutting edge and individualist, the glass cube was perfect. Nothing says “we’re open” like glass. A classic material of architectural modernism, it has over many decades changed the way buildings are created and perceived from outside and within.
In the past 10 years, though, it has also become the shiny face of new technology in smartphones, big-screen televisions and car infoscreens, revolutionising the way we connect, convey and absorb information.
It also plays a vital role in the creation of affordable clean energy through solar photovoltaic modules. Glass is thinner, stronger and more flexible than ever. It is more durable, transparent and UV-stable than plastics. Inbuilt technology now means it can change from clear to opaque at the flick of a switch. It can be designed to clean itself. It has become the material of our age.
Demand on the rise
Worldwide, the glass industry has been going through a massive geographic shift. Building industry demand has long underpinned the industry. In the early 2000s, three regions – North America, Western Europe and Japan – dominated demand and production. Then the global financial crisis flattened demand for new housing, and demand in those three markets collapsed.
Production cuts followed: the North American float glass industry, for instance, went from 44 working glass lines in 37 plants to 34 lines in 25 plants between 2005 and 2015, according to estimates for Glass magazine.
China, however, boomed. By 2013, according to research firm Freedonia, it had become the world’s biggest glass market. By 2018, says Freedonia, it will consume more glass than North America and Western Europe combined.
China’s surging demand and production have been driven not just by China’s building boom, but also by the two fastest-growing areas of glass demand – the soaring market in solar photovoltaic cells and the equally dynamic market for glass screens. Andreessen Horowitz analyst Benedict Evans estimates that global retail demand just for premium-priced LCD screen glass rose from around 75 million square metres in 2005 to around 350 million square metres by 2013. The rise since has been even faster.
Global demand overall for glass is expected to grow by more than 6.5 per cent a year to almost 10 billion square metres by 2018. That’s a square sheet of glass 100 kilometres on each side every year, worth more than US$100 billion. The Asia-Pacific region represents the largest market for flat glass, accounting for 52 per cent of worldwide demand in value terms in 2013.
Jon Hynd, an equities analyst with Bank of America Merrill Lynch, says demand for commercial properties is also driving growth.
“What’s really pushing glass along is demand in non-residential buildings,” he says. “Look at the new buildings in cities like Sydney – they are all floor-to-ceiling sheer glass.
“Glass also has quite a few properties it didn’t have in it 30 or 40 years ago. It’s seen, in many cases, as quite an environmentally friendly choice.”
Symbolism and sustainability
The commercial construction boom of the mid-20th century incorporated a lot of glass and a lot of air conditioning to make the buildings habitable.
“The transparency metaphor was great, but the reality was a problem,” says Matthew Blair, principal architect with Australian firm BVN, which has designed such impressive glass structures as the glazed atrium at Macquarie Group’s Sydney headquarters.
“Look at the new buildings in cities like Sydney – they are all floor-to-ceiling sheer glass.” Jon Hynd, Bank of America Merrill Lynch
“Early glass buildings performed so badly it was like being in a greenhouse. The temperature inside and outside tended to be the same. They used extraordinary amounts of energy and much of it leaked out of the windows.”
Natural light is essential to human health and wellbeing. Semi-reflective glass went some way in addressing the sustainability problem; however, transparency became compromised.
“A disconnect between the metaphor and the reality grew again, because glass was acting like a mirror,” explains Blair.
“A lot of clients would come to us saying they wanted a glass building that’s transparent so you can see in, but that’s been difficult to achieve. If you look at high-rise glass towers of the past, they have either very dark glass or it has a green or blue tint. They’re actually presenting a visage to the world that is the opposite of the intention.”
In addressing these problems, glass technology has come a long way. Protective coatings now reflect UV radiation and prevent warmth from escaping through windows in winter. They also allow glass to maintain a level of transparency.
Australian glass manufacturer Viridian, for instance, says its SmartGlass product can provide up to 39 per cent better insulation than ordinary glass.
“Just like applying insulation to your walls and roof, we can now insulate glass,” explains Lachlan Austin, general manager market strategy and growth at Viridian.
“It’s like painting one side of the glass cool.”
While protective coatings are making the material more efficient, glass is also becoming more sustainable from within.
“We’re now beginning to see solar gain dealt with on a nano level within the glass itself rather than on a physical level via sunscreens,” says BVN’s Blair. “That’s the next frontier of architectural glass.”
Thinner and stronger
Architectural glass may soon become stronger, too. Specialty glass manufacturer Corning is exploring more applications for its chemically strengthened Gorilla Glass. Introduced in 2007, the material has played a key role in the development of smartphones and tablets. As thin as 0.4mm, it is featured on 4.5 billion mobile devices and 40 major brands worldwide.
“Corning recently partnered with Ford to introduce the material to the windscreens of the new Ford GT models.”
In 2014, Corning introduced the fourth generation of Gorilla Glass and claimed it was twice as strong as any other smartphone cover glass in the market. Gorilla Glass may soon revolutionise the automotive industry, too.
Corning recently partnered with Ford to introduce the material to the windscreens of the new Ford GT models. Corning states that the lightweight glass is up to five times stronger than conventional windscreen glass.
Bend and it won’t break
While thin glass is becoming stronger, it is also becoming more flexible. The optical fibres essential for telecommunication and computer networking, for example, are made of pliable glass strands slightly thicker in diameter than human hair.
A similar thickness is now found in Corning’s Willow Glass, which is used as a substrate material on which other components, such as LCD electronics, can be set.
“It has a similar principle to glass fibre in that it’s so thin it can be bent,” explains Yi-Bing Cheng, professor of materials science and engineering at Monash University.
“Some television screens are now bendable because they’re made from flexible glass, and the latest Samsung Galaxy mobile phone has a bended edge.”
Flexible glass can now be printed roll-on-roll, just like a newspaper, and Cheng predicts it will reshape the electronics industry.
“The printing method means you’ll be able to achieve very high production rates,” he says.
There are also applications for flexible glass beyond the electronics industry. The US Government’s National Renewable Energy Laboratory is using Willow Glass to build flexible solar cells that are so strong they may eventually replace roofing shingles.
“Most solar cells can currently be roll-to-roll printed on a plastic substrate,” says Cheng. “However, plastic has disadvantages, because it’s not stable under UV light and is not scratch resistant. It can also be permeated by oxygen and water at a low rate and that causes instability over time. Glass, on the other hand, is a very good encapsulation material.”
As glass becomes stronger and thinner, its potential seems almost limitless. Developments are occurring so rapidly that even Apple rebuilt its iconic glass cube on Fifth Avenue five years after it was first constructed. Each wall of the new cube is made up of only three vast panels of low-iron glass, which enhances its transparency. The message it sends is just as impactful, if somewhat clearer.
Environmental impact of the glass industry
Conventional glass is made from three ingredients – silica sand, soda ash and limestone. Converting these materials into liquid requires heat of around 15,000 degrees Celsius. “Fundamentally, this is an energy-intensive process,” says Viridian’s Lachlan Austin.
“We’re talking about melting rock, basically. That’s a big deal.”
Viridian produces 150,000 tonnes of glass a year. Austin says its process is as energy-efficient as possible. Viridian’s Victorian plant is powered by natural gas, and it sources a very pure silica sand from the Victorian town of Lang Lang.
“That means we don’t have to mess with it too much,” he says. “We have a consistent supply, so we are not buying it on the open market. We know where our stuff comes from, we know what it’s good for and what it’s not good for and we tune our operations around that for consistency. Reliability of inputs is fundamental to make a reproducible thing like glass.”
“We’re now beginning to see solar gain dealt with on a nano level within the glass itself.” Matthew Blair, BVN
Austin also notes that Viridian’s glass saves more CO2 during its lifetime in buildings than it creates during its manufacture. “It’s one thing to talk about the embodied energy of the underlying material and it’s another thing to talk about what the material is doing for you over the life of a building,” he says.
“If it’s not completely paying itself back within about 20 to 25 years in really ordinary applications, you’re doing something wrong.”
Monash University’s Yi-Bing Cheng describes glass manufacturing as an environmentally unfriendly industry but one we have to have. “Glass is so important,” he says, “and there are many applications for which there is no alternative to it. It’s not a question of how we can get rid of the glass industry but how we can make it more environmentally friendly.”
Best in glass
Glass has an ethereal quality that allows for extraordinary architectural designs. The spectacular titanium and glass roof of China’s National Centre for the Performing Arts (known as “The Egg”) in Beijing appears to rise like a glistening island from its surrounding artificial lake.
In Bilbao, Spain, the chiselled glass facade of the Basque Health Department Headquarters now rivals the city’s emblematic Guggenheim Museum as a leading tourist attraction. Meanwhile, the twisting double-glass facade of China’s new 632-metre-high Shanghai Tower is symbolic of corporate transparency and will also significantly reduce the building’s carbon footprint by acting as a second “skin”.
“Glass does this thing with light that makes it ambiguous – it can appear solid, transparent, reflective,” says BVN principal architect Matthew Blair. “Ambiguity in architecture is
fantastic, because it drives interest.”
Blair points to The Shard in London, which was designed by Italian architectural maestro Renzo Piano.
“It’s a sculpture as much as a piece of architecture,” says Blair. “It changes, depending on the light conditions throughout the course of the day, and it becomes an object in the London skyline that’s a constant mystery.”