London's St Paul's Cathedral, seat of the Bishop of London, is home to the Whispering Gallery, a thin circular balcony that runs around the inside of the iconic dome. The acoustics of the Grade I listed building give the space its name, because the area, which sits almost 100 feet above the cathedral's nave, transmits sound so accurately that visitors can whisper at one side of the dome and be heard on the other.
The gilded, heritage Tijou safety railings were recently updated and the cathedral took the opportunity to upgrade the lighting for both the railings and the Thornhill frescoes on the dome, in addition to hidden emergency lights on the floor of the gallery and exit doors. The project was undertaken by London-based CBG Light Perceptions and carried out by a team of electricians from the cathedral's Works Department. In 2023, Light Perceptions joined CBG as the Specialist Lighting team. Bruce Kirk, director of CBG Consultants and founder of Light Perceptions, discussed the project with Live Design.
Live Design: What fixtures and control did you use?
CBG: The controls are the existing Lutron system, adapted by Lutron to manage the new LED loads. The Luminaires are Iguzzini Palco floodlights with Super Spot and Medium optics and 2700K color temperature, which are independently controlled to highlight important elements. These fixtures replaced a combination of floodlights that used metal halide and halogen sources. Luminaires were chosen for their compact physical size and their ability to deliver the lumen output required with a wide variety of optics and beam control to achieve the desired effect.
LD: What aspects of the project increased its sustainability?
CBG: This was a conversion from a combination of cold cathode, metal halide and halogen light sources to an all LED solution. The energy savings are calculated to be in the region of 80%.
LD: Was the age and status of the building challenging?
CBG: St Paul’s Cathedral is one of the country’s most significant Grade I listed buildings. Accordingly, this solution was designed to reuse the fixings and wiring of the previous installation which was completed in 2004. CBG Light Perceptions has a long history of working in the UK's most important historic buildings and treats every building with the greatest respect while significantly improving its technical facilities using the most sustainable and energy-efficient systems available.
Project Personnel
St Paul’s Cathedral
- Oliver Caroe - Surveyor To The Fabric
- Martin Fletcher - Clerk of Works
- Craig Needs - Project Manager
CBG Light Perceptions
- Bruce Kirk - Director
- Justin Baby - Project Designer
About CBG Consultants
CBG Consultants are an ambitious practice of building services consultants, covering a wide range of mechanical and electrical engineering solutions specializing in sustainability, building physics and Passivhaus.
In 2023, they established a new lighting consultancy division with the acquisition of Light Perceptions Ltd, so that they could offer their clients a more comprehensive service. They specialize in maximizing the efficiency of buildings, through optimizing fabric with efficient mechanical and electrical design solutions.
Their vision is to be a leading consultancy delivering excellence in building physics and engineering for better buildings that benefit their occupants and the environment - CBG Consultants - Building Services & Building Physics.