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Wednesday, 4 September 2013

Now there's a surprise ...

Over the last couple of days I have been reading reports of cars being damaged in the City of London, by sunlight reflected and focused on them by a new building under construction there. The building, nicknamed the "Walkie-Talkie" has fully glazed facades on all four sides. The difference between this building and other fully glazed structures in the City is that it has a concave profile to its outer walls. Those of my readers who have, in a misspent youth, played with a shaving mirror, will know that the concave reflective surface has an interesting property when one gets it to reflect sunlight onto something at just the right focal distance.

It seems that the architect has managed to achieve exactly the right focal distance between his building and the parking spaces in that section of Fenchurch Street. The result is some very expensive damage to luxury cars parked there. If the reports I've read are correct, someone in the construction team noticed this some time ago - because the developers aren't putting up a fight about it. They just pay for the damage and hope you'll not make a fuss. Now that it has reached the press of course, the City has reacted, and closed the affected parking area. The worrying part is this, no one appears to be considering the affect walking along the pavement there may have on someone should the reflected light hit their eyes, or the impact of such intense heating on the structures nearby.

We have long known that tall buildings, their services, the tarmac and concrete roads and pavements and the reflected light can cause local 'weather anomalies' around them. It is equally well known that more tarmac, more buildings and paved surfaces, cause a rise in local temperatures and, when it rains, increase the 'run-off' raising the risks of flooding. Since antiquity it has been known (Archimedes is reported to have built a weapon on the principle) that a mirror big enough and with the right curvature, can focus light to an intensity sufficient to blind and burn soldiers and - according to ancient reports - set ships on fire. As far back as the 1960s experiments showed that banks of mirrors could focus light on a 'target' - usually an arrangement of tubes filled with liquid - the produce steam and generate electricity with a turbine, so we really shouldn't be surprised that a building focusing light onto parked cars can melt the plastic trim. The surprise is that it 'only' melted it. Those 1960s experiments showed you could actually melt metals with that rig. It wasn't dubbed a "solar furnace" for nothing.

This development raises an important question for me, and perhaps it should raise it for the professions as well. The question is this: Does no one carry out an analysis of the impact of creating a structure which reflects light onto adjoining properties and surfaces? It does sometimes seem that almost everything else is considered (often in isolation and by different 'specialists' who often don't consider anyone elses reports or work), yet I have, in the past, often been astonished that some highly qualified professionals don't understand (or see) some fairly basic issues which can, and do, impact on what they propose.

Hopefully this Archimedian Mirror building will draw attention to the need to think a lot more carefully about the way so many today ignore every other discipline and focus only on their own comfort zone of knowledge. From the press I understand the designer and the developer are trying to find ways to 'mitigate' the problem. I'd suggest its a little late, this should have been identified at the design stage. Any 'mitigation' is likely to introduce some new problem somewhere else.

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