Lloyd's of London
By early 1980 the detailed configuration of the building had emerged. The scheme was approved in May the following year, by which time the demolition work to the 1928 building was substantially complete. The basic ‘doughnut’ arrangement remained and the building emerged as a forceful and highly individual presence in the urban landscape.
The building is comprised of a series of concentric galleries overlooking a central atrium, with each gallery capable of being used as part of the underwriting room, or as office space. The Room is housed on the lower four levels and all vertical movement within The Room is by a central escalator system, providing easy and open access to the first four levels. Below the Room, adjacent to Leadenhall Market, is a semi-public area housing Lloyd’s restaurant and coffee house, a wine bar, library, meeting rooms and reception. A slightly sunken, partially covered pedestrian area of intimate scale encircles the building, while a new small-scale passageway, the Green Yard, leads through the conserved Lloyd’s gateway to Leadenhall Market.
The structure was originally conceived as steel, however during the design development the fire authorities were opposed to this approach. Despite fears that a concrete frame would be overly bulky, the design team resolved to use the restriction as a learning opportunity and undertook a study tour of concrete buildings in the USA as part of their research. Steel, however is widely employed in the cladding of the building, particularly in the service towers.
The third material that characterises the external appearance of the building is glass, triple glazing incorporating rolled glass is used to achieve a sparkling quality that contrasts with the soft sheen of the stainless steel.
The essence of the Lloyd's servicing system is the use of the atrium form, concrete structure and triple-glazed cladding as active elements. Conditioned air is distributed through a sub-floor plenum into the offices, while stale air is extracted from above through the luminaires. The extracted air is passed to the perimeter of the building and forced through the triple-layered glazing, ensuring an almost zero heat loss from the offices during winter and reducing heat gain during summer. Heat from the return air is collected in the basement sprinkler tanks and re-used. The internal concrete soffit and slabs are heat sinks, absorbing heat during occupation and being cooled off overnight using naturally chilled night air. This allows cooling to follow a 24-ghour cycle and reduces the peak cooling requirement. Air handling equipment is located at basement level and in four service tower plantrooms.
The new development contributes positively to the dense medieval street environment that characterises the City of London, reinforcing the pattern implicit in the street layout.
In defining a strategy and not a building, a legible system was developed that broadly allocated zones, defined movement and levels so that areas could change in an orderly basis without disrupting the business. The highly articulated service towers around the perimeter lend an immediate sense of order and hierarchy to the building’s appearance.
The ground level acts as a public space, encouraging workers and tourists into the building, where a coffee house and wine bar contribute to the life of the surrounding streets.
The design greatly increases the quality of the internal working environment, with access to natural light and ventilation from the perimeter. The all-glass facade contributes dynamically to the energy efficiency of the building, using the triple glazing as a return air plenum.
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