Case study: 30 St Mary Axe
Ceilings, partitions and raised floors in Swiss Re’s new headquarters
Swiss Re’s new headquarters is being constructed in the iconic 30 St Mary Axe, designed by Foster and Partners. Bennett Interior Design faced the challenge of providing a rectilinear and economical ceiling grid within a circular building. Each floor plate is subdivided by six triangular lightwells that create fixed areas of rectilinear space between.
The requirements of the ceilings are many, including visual appearance, acoustic quality, accessibility and durability. Overall, the ceiling should provide a clean, crisp surface with good sound absorption properties while allowing easy access to the services above.
A feature ring ceiling constructed from GRG (‘The Halo’) circles the core. The intention of this feature is to define the circulation, provide a junction between the square grid of the accessible ceilings and circular core, and light the core wall. Access to services emanating from the core at high level is via the adjacent accessible ceiling. The halo level is set 250mm below that of the accessible ceiling so that it appears to float and also masks unsightly tile cuts.
The ceiling has been set out in such a way as to align with the building grid to allow sensible partition locations and minimal cut tiles.
Plasterboard margins are used in certain locations to interface with the base build at the light wells and the curved perimeter. We selected a 750 x 750mm, perforated metal tile on a concealed grid with integral acoustic pads.
Studies showed that this size of tile is most suited to accepting the varying core-to-perimeter dimensions while minimising the number of tiles and working well with the building grid. A revolutionary new ‘ultra micro-perforation’ by SAS International Ceiling Systems has been chosen to avoid the greyness in appearance of the more standard micro-perforated ceiling tiles.
The perforation pattern is 0.7mm diameter holes at 5mm centres, giving only 1.5 per cent open area with no plain margin. The tiles are clip-in, hinge-down and polyester powder coated (RAL 9010, 20 per cent gloss), with acoustic backing panels supported on a concealed grid.
At six locations corresponding to the light wells, additional floating feature ceilings lead from the circulation circle out along the balcony edges. These frame the view through to the light wells and act as a visual separation from the office. To enhance this further they are finished in a feature colour that is complementary to the basebuild elements.
Due to the unique shape of the floor plates at 30 St Mary Axe, and the importance of the external view, studies were undertaken to determine the optimum lighting type and configuration. It was found that circular light fittings presented the most consistent external appearance while maintaining excellent lighting levels within the office space. The fittings are spaced on a 1.5m grid, giving the best spread of light and flexibility for reconfiguring office locations. At all times a lighting level of 400 lux will be maintained at desk level across the office and open-plan zones.
PRODUCT DATA SAS International Ceiling Systems. 750 x 750mm ultra micro-perforated ceiling system (pattern 0.7mm diameter holes at 5mm centres giving 1.5 per cent open area with no plain margin). Clip-in, hinge-down polyester powder coated ceiling tiles (RAL 9010, 20 per cent gloss) with acoustic backing pads supported on a concealed grid.