City Hall was designed by Foster + Partners, one of
Britain's leading architects, whose design brief was to create a building for
the GLA that would become a new landmark for the capital.
This striking rounded glass building also has many features
that make it environmentally friendly, including solar panels on the
roof.
The London.gov.uk website (visit link)
gives key facts about the building:
Height of the building: |
45m |
No. of floors: |
10 floors above the ground |
Gross floor area: |
185,000 sq ft/18,000 sq m (approx) |
Net lettable floor area: |
130,000 sq ft/12,000 sq m (approx) |
Steelwork: |
Structural frame - 2100 tons Reinforced - 1950 tons |
Concrete (core): |
13,100 sq m |
Cladding: |
7,300 sq m of triple glazed low emissivity coated clear glass,
incorporating shading devices |
Heat insulation: |
Average value= 0.7-0.8 W/m_.k |
Angle of glass front inclination: |
31 degrees |
Diameter of circular glass facade: |
45m |
Environmental strategy: |
Windows open for natural ventilation, bore hole water
cooling, heat recovery, displacement ventilation system, no chillers
required |
Energy consumption: |
Energy consumption for the GLA's environmental systems is
less than half levels in DETR good practice office guide. The radical
shape of the building minimses the surface area (approx 25 per cent less
than an equivalent rectangular building). It is self shading and the high
performance facade ensures excellent energy efficiency. |
Electrical consumption: |
Greatly reduced as a result of using cold ground water
instead of refrigeration to air condition the building. Saving use of
mains water, the water is extracted through two bore holes from the water
table beneath London and is used to cool the building and is then used for
flushing the toilets. |
Architect: |
Foster and Partners |
Construction Managers: |
MACE |
Structural, services, facade, fire, communications and
acoustics engineers: |
Arup & Partners |
Cost consultants: |
Davis Langdon & Everest and Mott Green & Wall |
Landscape architects: |
Townshends |
The same website (visit link)
contains information about the structure:
"A geometrically modified sphere
The building is 45 metres high, with 185,000 sq ft
(gross) of floor space spread over 10 floors. In conventional terms, the
building has no front or back: its shape is derived from a geometrically
modified sphere. This hybrid form is designed to minimise the surface area
exposed to direct sunlight. The building has been designed to be as green as
possible.
City Hall runs on a quarter of the energy consumed by a
typical high specification office building. This is done through ecologically
sound, passive environmental control systems and the shape and alignment of the
building. The building's design has been generated as result of thorough
scientific analysis, reducing both solar gain and heat loss via its
surface.
Minimising surface area for maximum energy
efficiency
The building's form is derived from a sphere, which has
approximately 25 per cent less surface area than a cube of the same volume. The
building leans back towards the south, where floor plates are stepped inwards
from top to bottom, providing natural shading from the most intense direct
sunlight.
The building is naturally ventilated, with windows that
can open in all office spaces. Heat generated by computers and lights is
recycled. The deep-plan floors allow for the collection of heat at the
building's core, which can then be redirected to its periphery. The combination
of all these energy saving systems means that there is no need for chillers in
the building.
Using and reusing ground water
Electrical consumption is reduced by avoiding
refrigeration and using cold ground water to air-condition the building. The
water is extracted from the water table beneath London via two bore holes and is
used to cool the building and then in toilets and for irrigation savings on
mains water."
The architect's website, Foster and Partners, (visit
link) has a brief description of the building but has some wonderful
photographs of it:
"London, UK, 1998-2002
Located on the south bank of the Thames, alongside the
new More London development, City Hall is one of the capital’s 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."