Glass
It is still true that glass in architecture is more appreciated for its aesthetic value, particularly its transparency than as a dielectric material or as an information highway. Only in the past two decades or so has demand and consequently industry responded to produce new glasses which can be exploited in architecture as a truly dielectric material. By far the most important glasses for construction are the range of oxide glasses based on silica and prepared by cooling. Silica forms the network and metal oxides modify it. It is the viscous properties of glass which permits such a very wide range of compositions and hence different properties to be manufactured.
Underlying glass construction is the inescapable fact that glass construction is always dependent upon another structure – either foundations or a superstructure – which means that we must understand the scale of these structures’ short and long term dynamic behaviour. It is not a question of statics, but of dynamics, and once the scale is known and understood, it is a relatively straightforward task to design the movement interface between glass and structure, and to resolve the other issues, such as material compatability, within a desired aesthetic objective. It is at this point that our architectural practice departs from most others. We know that the only way forward to develop better results is to work closely with industry at all stages of manufacture.
Most architects are not interested in the fundamental process by which this can be achieved. Architects are concerned primarily with what products are available on the market (and accept the manufacturer’s data about their performance), how much they cost per square metre, and how best they can serve both the aesthetic and environmental standards, including safety, for their designs.
Apart from art applied to or etched into the surface of glass, the history of architecture reveals that architects have exploited it in very few ways, yet the aesthetic use of glass is virtually limitless.
Before the 16th century glass was essentially the preserve of ecclesiatical buildings – a luxury. As economic flat glass was developed it started to be used in secular buildings – to keep the rain out and let light in – but early on it was not of sufficient quality to ensure undistorted views. During the mid-late nineteenth and early twentieth century glass manufacture heralded a new dream for architects – the transparent envelope. It was the development of float glass in the mid-twentieth century which brought this dream to reality. In the past thirty years it has been the toughening of this float glass, and more recently the introduction of quality controls – heat soaking – that has permitted architects to fully realise this dream.
Twenty years ago, architects began dreaming of the “chameleon” wall. A glass wall which is dynamic. A wall which can respond at the flick of a switch to become opaque, colourful, transparent; a wall which can change its thermal performance; a wall which can capture energy and transfer this energy to other parts of the building.
Ten years ago architects, besotted with the media age, began dreaming of information walls. Decoration has for much of the twentieth century been discarded in a purge of architectural self-cleansing, best represented by the puritanical Adolf Loos in Ornament und Verbrechen. Light symbolises goodness, illumination, rationality, order, and hygiene. So, early in this century, glass became an aesthetic in its own right; its crystal transparency symbolising rational and economic thought. As twentieth century architectural aesthetes we have fastidiously abjured decoration on the grounds of virtue. To decorate glass and other materials of architecture was to be decadent and immoral, to be less than pure. The search for minimalism – as if it were the same as a monastic existence – is to fly in the face of human nature. Glass is a great survivor, and has excelled as the first choice material of architectural minimalism. Why?
This ubiquitous material’s uniqueness lies in its ability to refract and reflect light – the essential material of all architecture. Glass is phenomenal. Its lickable and durable surface can take a multitude of textured surface treatments which no other material can approach – yet continue to refract light. It can be graduated from transparency through degrees of translucency to opacity, pattern and profile rolled, macro and micro etched by machine, sand and acid etched, drilled, micro-perforated by acids, body coloured, stained, enamelled, painted, fired, and printed.
Today, the stained glass window may be thought of as an anachronism – being the product of basic glass technology when only small pieces, uneven and of irregular thickness, could be manufactured. But this misses the point. Its essential perceived qualities are the same as those of today – luminosity, translucidity and composition. The fact that we have so many more techniques does not camouflage these qualities. Now, we can compose beyond the refracted light paintings of historical narratives, stories and symbolism, with the new composite techniques to achieve higher levels of environmental performance as artistic compositions: coloured and interference laminates, processed holographic film sandwiched between glass, pixellated electroluminescence, photochromism, holograms, dichroism and switchable crystals, photovoltaics, information technology, metal deposits coatings, and in the not too distant future, biogenetic coatings and perhaps “stitched in” miniaturised lasers.
The application of these techniques seek to create responsive thermal and more intelligent glass sheaths for buildings. But, at the same time these applications can also go beyond the technical and harmonious integration of glass in buildings to seek to inspire, excite and be didactic as stained glass windows did so long ago. If we consider the dream of the information media wall, glass becomes the essential support. So far, liquid crystal technology has not been able to overcome its characteristic low-brightness and limited angle of view. Apart from miniaturised lasers, other likely developments may include miniaturised diode arrays and thin film deposits. For example, low-cost thin carbon film, combining the electrical conductance of cystalline graphite with the electron release characteristic of diamond, may enable high brightness, sharpness and wide angle view imaging to be created by the controlled illumination of phosphor coatings (cf. tv screen) with thin wall glass construction.
© Ian Ritchie 10/94
A VISION TO REDUCE CRACK PROPAGATION IN GLASS THROUGH MOLECULAR ENGINEERING
As architects and glass engineering designers for the new Leipzig International Exhibition Central Glass Hall, which will open in April 1996, I recall attending, in February 1993, a crucial meeting in Germany with the glass suppliers, processors & steel structure contractors. The purpose was to review concerns emanating from the results of a series of load & impact tests, and suspension fixing design of large laminated glass panels. With nearly 30,000m2 of glass required to create the suspended glass barrel vault, the consequences of failing to deal with both safety and the technical issues involved would be too dramatic for all concerned with the project.
On the flight home after the meeting I picked up a copy of Lufthansa’s in-flight magazine and came across an article on nano composites and research work being undertaken on “ormocers” (organically modified ceramics). This reminded me of previous articles I had read about nanotechnology and a thought crossed my mind. Would it be possible to dope glass at the molecular level to overcome the inherent inability of glass to resist crack propogation while retaining the optical properties and essential surface qualities which we associate with glass?
To develop such a new material would inevitable require research either directly with industry, or at a research institution, or collaboratively between both. In 1983, I had managed to find and bring together three industries ( two French & one Belgian ) to produce a 50% light transmitting permanent structural fabric; and in 1986, been instrumental in bringing together academia ( a physicist) with industry (Electricité de France) to successfully realise a vision of controlling the 3-D form of visible light. I remember well the initial reactions to this idea when it was discussed with the EdF.
Exploratory discussions with different glass industries of the dream of a new glass material, and the need to develop it, have so far yielded nothing. Yet one is sure that this industry should be interested, and maybe some are secretly researching it as I write. As an architect it is too often the case that one’s credentials and ideas are not those that industry will accept. The alternative is academia, and the specialist research institutes. Here, there are several involved in new materials, but collaborating with them is constrained either by budgets and existing programme commitment, or by secrecy, a quite reasonable precondition of the research contract when they are being financed by a particular industry.
Convincing people to finance new scientific/industrial ideas, is a very difficult one to crack for an architect – but it can happen.
© Ian Ritchie 1996
