London’s new City Hall was originally designed by Wilkinson Eyre Architects as a global sustainability showcase for Siemens – The Crystal. When it first opened in 2012, it was the first building in the world to achieve the highest possible ‘BREEAM’ and ‘LEED’ ratings for sustainable construction.
Arup was appointed by GLA to develop the Event Lighting for the new City Hall from concept design stage to Stage 3, then handover to the Contractor ISG for design execution. The lighting design intention was to create a landmark building that is highly attractive and visually impactful at night during event days. Lighting plays a key role in establishing the landmark and unique identity for the City Hall, helping to create a sense of destination and memorable experience for the local community and visitors. Light is a medium to convey message, colour light serves as a medium to celebrate national events such as New Year, Pride Day, NHS Day, Remembrance Day, Earth Day, Christmas etc.
The quality of experience is as important after dark as it is during the daylight hours. Lighting has been well integrated with the architecture, while minimising unnecessary modification to the existing architectural fabric and retaining the original architectural ‘crystal’ concept of light emanating and radiating from within.
The design challenge was to create an impactful nighttime effect through its highly glazed façade. The event feature lighting serves for both interior ambiance and at the same time functions as façade lighting visible externally. Key surfaces have been carefully identified, using the interior sloped soffit as a canvas to project colour wash light. Selected key spaces are illuminated with colour-changing RGBW LED lighting to create an internally glowing effect at night for special events. When illuminated together, a connected effect provides an overall image of the building and enhances the visual impact when viewed from up close and afar. Office lighting has deliberately been left as white light only.
Surface mounted adjustable RGBW uplighters (supplied by Architainment), have been set out at discreet positions above the roof of the committee rooms, out of sight from the Ground Floor and from street level. A technical challenge was the placement of the uplights, a combination of various luminaire optics and careful positioning was required to achieve the desired coverage and the consistent colour wash across the soffit.
Chromaticity of the LED lights can be synchronised with the LED media screen mounted at low level to achieve the optimal colour balance and effect.
Close collaboration has been carried out with luminaire supplier, Architainment, which has provided technical support from the early stage of the project and engagement with nighttime site mock up testing, together with luminaire samples which has helped define the required target luminance levels for the interior surfaces and thus the technical requirement of the luminaire products. After Stage 3, Architainment has worked closely with ISG, turning Arup’s lighting concept into reality.
