Foster and Partners has tried again on the former Baltic Exchange site in the City of London with this 179.8m curvaceous tower headquarters for reinsurance firm Swiss Re (aj 22.07.99).
The practice first caused a stir on exactly the same 0.57ha site in 1996 with proposals for a very different tower for Kvaerner/
Trafalgar House. The £400-million London Millennium Tower was almost twice as high, at 383m, and prompted outrage from the Royal Fine Art Commission and English Heritage, as well as debates about the skyline of the capital, and the need for new guidance on the issue. The proposal to push the height barrier was withdrawn amidst all the hubbub.
Now, three years on, there is still no new guidance, but the architects have opted for a smaller, less aggressive and more 'organic' form which obeys City height restrictions and sits in an existing cluster that includes the slightly taller Tower 42 (formerly the NatWest Tower). Foster's submitted a planning application last week for the £150 million building to the last ever meeting of the Royal Fine Art Commission. The commission's views on the building Foster's describes as 'radical' will be made public at the end of the week.
The scheme's glazing wraps round a diagonally-braced structure, with a new public space of around 694m2 of retail in a double-height arcade on its ground floor. The building provides 41,810m2 net of accommodation over 40 floors. At the edge of each floorplate are spiral atria, created by 'twisting' each successive floor. This allows natural ventilation - although air-conditioning is also incorporated - by using large pressure differentials generated which will draw natural air in through horizontal slots in the cladding. That cladding is of glass, with aluminium profiles and a steel frame. Every sixth floor the atria feature gardens which control and purify air movements as well as dividing the building into fire compartments. And outside, at the north eastern corner, of the site on Bury Street will be a new six-storey building for a cafe bar, offices and plant, clad in glass and stone.
Foster said that the aim of creating an 'environmentally responsible building with a natural economy of form and a detailed understanding of the urban context in which it is placed ' had been the only preconception of the practice and that it was radical 'socially, technically, architecturally and spatially.'
The project has already been likened in the press to an 'erotic gherkin' and an artillery shell. But the description of Foster's new scheme as a Cuban cigar is perhaps most appropriate, given its tapering form - and the kinds of people working nearby.