The St. Botolph Building, over 500,000 sq ft space with 14 stories high, is one of the largest office development in the City of London. Speirs + Major was appointed by Minerva plc to design the lighting scheme for the internal public area: the reception, central lift core, outer stair cores and atrium.

With speed of the essence in the business world, every element of the building was designed to aid fast and efficient circulation of people around the building. The lighting design concept aims to create a journey following the movement from the entrances to the individual office receptions, highlighting key elements to assist with way-finding, whilst emphasizing the dramatic and dynamic nature of the spaces and structures.

The main challenge of this project is the vastness of the rest of reception space after entering the revolving door. In order to avoid a dark and gloomy atmosphere, the space’s vertical surfaces were lit, resulting in a glowing outer perimeter to the whole reception and a brighter perimeter to the lower ground space to create a visual draw, with the overall impression of luminosity and brilliance.

Rather than simply wash the wall, Speirs + Major developed a cladding system of fins consisting of fully integrated lighting and a textured detail panel for the light to wash. 2,500 custom LED fittings and 8km of extrusion were used, forming not only the walls but also the balustrade system from light. Extreme efforts were made to integrate the light seamlessly and to achieve absolute visual consistency across the huge number of light fittings. The lighting designers work closely with acdc to create a series of mock-ups using 25 blades in the reception, lit from the top and the bottom.

Andrew Howis, associate director with Speirs + Major commented: “With the help of white LEDs, we identified a number of variations in the LED chips caused by the difference in their phosphor layer. This meant that, once we put a narrow lens on top, the differences were exacerbated. acdc’s unique dual binning process played a key role in ensuring these differences were overcome and complete colour consistency was guaranteed.”

Warm white downlighting is provided throughout the building which highlights the bold, dominant cool white light at the reception. However, there was a need to treat the lift cars as more personal, human spaces; these are therefore lit in contrasting warm tungsten light, which is switched off when the cars are unoccupied. On exiting the lift outside the offices, the lift lobbies and bridges are underlit to be coherent with the rest of the lift core, whilst the atrium roof structure has been uplit to ensure that the space appears light and airy regardless of the office tenants’ lighting.

Early in the design process, glazed floors were added at the central core in order to prevent the huge structure being too imposing and forming a heavy presence in the atrium. This was then uplit using a custom-designed integrated profile system; the result being a glowing, animated structure which has become the heart of the building.