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Sir Norman Foster and Partners: Exploiting the ultimate flexibility of laminated glass

Foster Director, Robin Partington (left), talking with a client

At sixty stories (300 m) high, the Commerzbank is the tallest office building in Europe. It uses a laminated glass solution for the façade facing the nearby airport to attenuate radar signals.

Sir Norman Foster has designed many of the architectural landmarks of the closing decades of the twentieth century. His firm's buildings create vast, well-lit spaces that often marry historic settings with a modern approach to architecture through, for example, glass atria and energy-efficient glass facades.

Since its inception in 1963, Sir Norman Foster and Partners, based in London and with offices worldwide, has received over 140 awards and citations for excellence and won 40 national and international competitions including the first architectural Benedictus Award, for London's Stansted Airport, in 1993. LGN spoke with long-standing Foster Director, Robin Partington, about his firm's use of laminated glass in some of its most famous projects.

LGN: What role does glass play in the work of Foster and Partners?

German regulations required that the Commerzbank tower be clad with radar-attenuating materials, solved by burying tungsten wires in the PVB interlayer of clear laminated glass.

Robin Partington: Glass plays a very important role in the work of our office. The beauty of glass is that its performance can be tailored to suit a wide range of specific requirements.

The Commerzbank atrium

The way laminated glass is used on the new headquarters building for the Commerzbank in Frankfurt is a good example. German regulations regarding the need to control radar interference caused by high rise buildings in close proximity to airports meant we had to clad the Commerzbank tower with radar-attenuating materials, similar in effect to those which clad the stealth bomber. Existing radar attenuating products comprised ceramic tiles with special insulation or a complex build-up of coated glass which was very heavily tinted, reducing light transmission.

As these solutions were inappropriate for this project, we decided to work with industry to develop new products to solve the problem. With a little lateral thinking, we developed a radar-attenuating product that uses tungsten wires buried in the PVB interlayer of clear laminated glass – an approach borrowed from the heated windscreens used in most modern vehicles. The resultant clear glass offered good daylight penetration to the offices, thus helping to reduce the energy requirements for artificial lighting.

The central atria to the tower also used laminated glass in the glazed decks which divide the building into 12-story vertical compartments. Again, daylight penetration was very important but the decks also had to satisfy safety requirements whilst forming a fire barrier. In this case, laminated glass products solved both criteria with a combination of PVB and fire gel laminates.

A landmark Foster project at the University of Cambridge Law Faculty building. The lower ground floors are lit naturally by means of a full-height, laminated glass atrium and floors of glass that are laminated for maximum structural strength.

LGN: Environmental sensitivity and energy efficiency is important to your firm's work. What role does laminated glass fill here?

RP: There is a growing worldwide demand from clients to maximize the use of daylight in buildings, not only saving energy but also improving the working environment. However, daylight is very potent and its use must be controlled to reduce heat gain, glare and other less desirable effects.

Currently, shading devices or coatings applied to glass are used as a means of control. However, in the future, greater use of the interlayer in laminated glass will offer far more opportunities for the designer as high performance interlayers have the potential to avoid some of the difficulties often associated with coated glass products. Thus, in addition to safety benefits, laminated glass would allow designers to build in more functionality, tailoring the product to suit specific needs.

LGN: How do glazing requirements vary in different parts of the world?

RP: No two projects are ever the same. The client's brief, budget and program often present differing challenges, as do the culture, politics and climate of a particular location. New buildings in London and Manchester are now taking bomb blast protection measures very seriously.

The new airport in Chep Lap Kok in Hong Kong is expected to handle 87 million passengers a year – the present capacities of Heathrow and JFK combined. All passengers will enter and leave the building through a vast entrance atrium of laminated glass, the base of which is to be used as the meeting and greeting area for arrivals, while departing passengers pass overhead on laminated glass bridges. The airport is designed for a very hostile climate including high temperatures, humidity and the occasional typhoon. Laminated glass has the potential to respond to these different influences and to offer the designer a greater flexibility.

London's Sackler Galleries demonstrate, in microcosm, how new development involving laminated glass can improve and enhance the old.

LGN: Could you give us an example where the use of laminated glass worked well in a historic setting?

RP: In 1991, Foster and Partners completed an addition to the Sackler Galleries, within Royal Academy of Arts in London. Laminated glass played an important part in the design of the glazed reception area. It was important to find an affordable, safe product to form the enclosure, which allowed daylight to flood into the space between the two original buildings.

Normal float glass incorporates iron, which gives glass its green color. But this would also affect the color of daylight inside the gallery. We could not afford optically white glass and instead found a reliable source of glass where the iron content was much lower, thus helping to solve the problem. We used laminated glass for both safety considerations and because, by incorporating a white PVB interlayer, we could control solar gain and diffuse daylight.

The sculpture shelf created within the gap between the main galleries and Burlington House.

In addition to the new Sackler Galleries, the glazed enclosure of the reception area allows new vertical circulation to be incorporated and, in the process, the garden façade of Burlington House (dating from 1666) has been revealed for the first time in over a century. The glazed reception area itself offers further exhibition space, using the parapet to exhibit sculpture from the Academy's permanent collection.

LGN: Social themes recur in your firm's work – opening up processes through the use of atria and glass. Please tell us about that.

RP: The new headquarters for Independent Television News' (ITN) London HQ is a good example, where we set out to challenge and overturn preconceived ideas about the business of gathering and disseminating news. The client wanted to open up the news gathering process – and this presented a number of architectural challenges.

The first of these was the vast basement area in which the old newspaper printing presses of the previous tenant – The Times of London – had previously been located. Some of the underground space could be used for TV studios but much was unlit and unusable.

The solution was to punch through the ground floor slab to admit light into the basement. Over this we constructed an eight-story tall, laminated glass atria. The roof was laminated glass incorporating a tinted glass layer to control solar gain. The end wall was again laminated glass but this time the interlayer comprised white PVB which allowed diffused daylight into the atria, whilst controlling the views out over the surrounding buildings.

Because you can control the thickness of the PVB interlayer far more accurately than the application of enamel onto the surface of the glass, the result is far more consistent where translucent qualities are important.

LGN: What future innovations would you like to see in architectural laminated glass?

RP: We are very interested in the potential for laminating high performance interlayers. Current developments include colored interlayers, switchable interlayers (incorporating liquid crystal technology) and photochromic interlayers that change color or transparency depending on the prevailing external conditions. There are also photovoltaic interlayers that generate electricity from sunlight, fire-suppressing interlayers with fire-rated properties, rigid interlayers which improve security performance, thin slices of stone used as interlayers for decorative effect and many more.

I believe that the challenge facing the laminated glass industry is to take full advantage of the wide range of materials that can be incorporated into a laminated construction, together with the wearing properties of glass, to protect that laminate. This offers the potential to economically develop products to suit a diverse range of client needs.