But it is not only about power. With the curtain glazing being thin, it allows developers the extra floor space that omitting the external wall creates. Also, it is quicker to assemble than the age-old plastered brick wall, though aluminium composite panels (ACPs) offer competition to curtain glazing on this front.
Some architects may also be in thrall of glass for visual (and historical) reasons alone. Along with concrete, glass was a wonder material for early 20th century modernist European architects. Design leaders such as Le Corbusier (who later designed Chandigarh) and Mies van der Rohe were trying to create a new language for European architecture that expressed the high level of industrialization Western societies had achieved. Out with the heavy, overwrought architecture of stone and brick, they said. And in with white walls, unornamented “forms” (that is, three-dimensional shapes) and industrial materials such as concrete, steel and glass.
That language was disseminated all over the world, including India. And glass went on to tighten its grip on the imagination of architects as industry developed products that mitigated its heat absorption and insulation problems. A building wrapped in glass is easier to make attractive to the popular imagination than one in which different materials have to be balanced visually.
Intelligent use
Like fire, glass works excellently if used well. The Gurgaon headquarters of Apollo Tyres, designed by Morphogenesis Architecture Studio, has “finger-like” indoor spaces alternating with enclosed open spaces, which let reflected daylight into the interiors. The reflected light is relatively glare-free and much cooler. The floor-to-ceiling glass is designed to let this light into the workspace and reduce electricity consumption to a very large degree.
Building plans can also be sensitively organized so the spaces receiving daylight through windows or curtain glazing are oriented correctly to reduce direct heat gain and let in the maximum amount of daylight.
It is also possible to provide sunscreening devices outside the glazed surface so that the hottest sun is screened off. After all, the path of the sun is fixed—and so is the angle of the building in relation to it.
To glaze or not to glaze
It all boils down to knowing why glass is being used in a building. If you want to show off, or if you are simply infatuated with glass, not only you, but the entire planet, pays a big price. Glass has a very high embodied energy—the energy that goes into making, transporting and fixing it. The embodied energy of framing materials (aluminium, for instance) is also high. Most of this energy comes from non-renewable sources.
Glass is also an expensive material, and gets more so when you choose to use double or triple glazing products, and those with various reflective coatings. The costs only mount when you consider maintenance.