London city Hall, designed by Sir Norman Foster
City Hall houses the assembly chamber for the twenty-five elected members of the London Assembly and the offices of the mayor and staff of the Greater London Authority. Located on the south bank of the Thames, alongside the new More London development, it is one of the capitals most symbolically important new projects. Advancing themes explored earlier in the Reichstag, it expresses the transparency and accessibility of the democratic process and demonstrates the potential for a sustainable, virtually non-polluting public building.
Designed using advanced computer-modelling techniques, the building also represents a radical rethinking of architectural form. It has no front or back in conventional terms. Rather, its shape is derived from a geometrically modified sphere, a shape that achieves optimum energy performance by minimising the surface area exposed to direct sunlight. Analysis of sunlight patterns throughout the year produced a thermal map of the buildings surface, which is expressed in its cladding. A range of active and passive shading devices is also employed: to the south the building leans back so that its floor-plates step inwards to provide shading for the naturally ventilated offices; and the buildings cooling systems utilise ground water pumped up via boreholes from the water table. These energy-saving techniques mean that chillers are not needed and that for most of the year the building requires no additional heating.
The chamber faces north across the river to the Tower of London, its glass enclosure allowing Londoners to see the Assembly at work. Members of the public are also invited to share in the life of the building. At its base, opening on to a piazza is a caf overlooking the river; and from the entrance foyer, gentle ramps allow visitors to move up through the building. A flexible public space on the top floor Londons Living Room can be used for exhibitions or functions, while its riverside terrace allows visitors to enjoy unparalleled views out across the city.