Consultant David Jesson opens a window on the wonderfully versatile material of glass.
Are you a glass half full or half empty kind of person? (The scientist says the glass is twice as big as it needs to be, the engineer that it has a factor of safety of 2).
Glass has been in use for thousands of years; its use by humans predates that of bronze and iron, although our ancestors initially made use of naturally occurring glasses to make tools, ornaments and utensils. Over time, we grew adept at manufacturing intricate, delicate creations, rather than simply making a cutting edge with a piece of obsidian. The Romans even had a glass-making process which led to the dispersion of gold as nanoparticles within the silica, so that the glass changed colour depending upon the incidence of the light.
It took a bit longer for glass to be used architecturally though, and initially the use was limited. Glossing over a thousand years of secretive guilds, stained glass for cathedrals, and the development of optics, large scale glass structures were generally associated with the rich and powerful until the end of the nineteenth century and the rise of the skyscraper. Even then, it wasn’t until the development of float glass in the 1950s that it became possible to build with seriously large sections.
Architects are well known for their desire to ‘make a statement’. This includes making staircases with glass treads and/or side panels, for example. I’m not sure that I’d want one in my house, but mainly because I can imagine how difficult it is to keep clean. We tend to think of glass as fragile, especially when a favourite drinking vessel smashes on a tiled floor. But equally, we know that glass can be tough and durable – think about that chip in your car windscreen that a well-known repair service will be along to repair any moment. The biggest headache for architects is therefore likely to be determining the impact of wind-loading on glass façades.
Glass is wonderful versatile, with some fascinating properties, making it an excellent material for construction – and we haven’t even got onto the subject of glass fibre for composites...