Squaring the circle: fitting square pegs into a round hole—how do you fit out radial floor plates? Bennett interior design are the first to tackle Foster's 30 St Mary Axe

Architectural Review, The, May, 2004 by Rob Gregory

At City Hall (AR August 2002), Foster and Partners justified the use of circular floor plates within a distorted spherical form, as a means of reducing solar gain. (Enclosing maximum volume within minimum envelope.) Likewise, at 30 St Mary Axe environmental priorities once again have been used to determine the building's form. A distinctive form within which spiralling light wells harness pressure differentials and daylight to improve passive ventilation and lighting performance, and external entasis reduces the building's perceived bulk and contribution to street level wind pollution. However, for commercial users, how easy is the building to occupy?

Traditionally, City dwellers have demanded big rectangular floor plates that are easily organized and subdivided in efficient open plan or cellular configurations. However, on the site of the former Baltic Exchange, this was not possible. An early strategic decision to leave residual space at the perimeter of the site, rather than in a centralized atrium configuration, in many ways dictated the building's radial organization; services and support spaces in a central core; perimeter space optimized for people to enjoy daylight, views and (when the building management system allows) fresh air; segmental light wells that rationalize each floor plate into six (almost) orthogonal office domains. Based on a 1.5m planning grid, the majority of the floors offer 16.5 m wide domains, with varying amounts of residual space being accommodated within the terraced balcony breakout spaces. Within these parameters, tp bennett's specialist interior designers, bennett interior design, were appointed to fit out floors two to 15 for owner occupiers, Swiss Re.

In response to Swiss Re's demands for simplicity, a neutral palette of materials was chosen, including thousands of cubic metres of USM's well designed Modular Furniture in muted shades of light grey and steel blue. With views clearly understood as the most valuable commodity, a strict height limit of 1100mm was enforced throughout, breached only at the balcony edges where overhanging cellular offices and terraced balcony screens are located. With slightly higher timber and glass signage screens enclosing the balcony vending points and seating areas, invisible white-noise curtains are employed to mysteriously absorb sound overspill between break-out spaces and workstations.

While space planning, finishes specification and detailing have been handled well, as you emerge from the lift lobbies, it is clear that the relationship between the convex core and the orthogonal floor plates is the inherent and principal challenge of the building. As a generic solution, bennetts chose to cloak the core with a suspended lighting halo to articulate this threshold. However, where they have been more dynamic, on floors 10 and 11, walls are used, shifted away from the line of the tangent, to create oblique tapering views; a move that brings direction and orientation to a potentially monotonous and endless gyratory space. But in fact, as Swiss Re's new building director Sara Fox says, orientation is not an issue in this building--unlike many other large-scale commercial offices. With stunning views bringing external orientation into the spaces, fit-out devices such as signage soon become obsolete as occupants get to know their skyscape context.

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The views from St Mary Axe are undeniably stunning, expansive and revealing; even on the lower floors. Early concerns that the double screen envelope would be too deep have clearly been proved wrong. Visitors are always drawn to the perimeter, pulled by a powerful centrifugal force towards windows or to peer over balcony edges. However, it is not simply stunning views that assert a gravitational pull. There is also a force that pushes you away from planet Axe's massive core. An uncomfortable and repellent force that tends to send you into orbit, away from the blind and virtually impenetrable service core (conspicuously absent from Foster's well-known section drawing.)

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It should, of course, come as no surprise that the core should be so big, containing 16 high-speed, high-capacity lifts, and all of the building's service arteries. Nevertheless, its presence still looms large as you walk around the office spaces, penetrated only occasionally when two of the three lift lobbies conjoin to provide a welcome short circuit link across the plan. Not until level 34 (the highest lettable space) does the core dissolve sufficiently to provide cross views that generate a strong east-west axis. Unfortunately, serving as the transfer floor to the spectacular skyspace restaurant suite above, it is unlikely that Swiss Re will let this space--unless, of course, the price is right. However, by occupying levels two to 15, they are offering 18 floors that provide between 1800 and 730[m.sup.2] across the three uppermost six-pack units.