For years, office lighting design guides have encouraged us to light desks and screens, rather than tasks and people.
Now that’s all changing.
When engineering consultancy Cundall moved to its new office in the centre of Birmingham, the company took the opportunity to design a lighting scheme that focuses on people, and uses a tiny 4W of energy per square metre.
Cundall took over a 650m2 floor of the 25-year-old building. Andrew Bissell, director of the firm’s lighting practice CundallLight4, took the lead on the project, supported by senior lighting designer Luke Artingstall. The team worked with Peter Grant Architects and Overbury Contractors.
When the Cundall team decided it was time to get rid of the old non-dimmable 600 x 600 ceiling fittings with their 40W PL lamps, they realised that they might as well remove the whole ceiling and design the lighting from a blank canvas.
Bissell says: ‘Initially we programmed the lighting for the desks furthest from the windows at 700 lx with all the other desks at 400 lx on task areas. Following feedback from staff we dropped this to 600 lx and 300 lx. To complement the task lighting we also illuminated the acoustic panels above each desk. We achieved an average of 160 lx on the acoustic panel which is just over 50 per cent on the task plane illuminance.’
The office uses a combination of LED and fluorescent sources. Fluorescent fittings from Fagerhult were found to be most efficient for direct/indirect suspended lighting while LED downlights, spotlights and directional pendants from Concord and ACDC. For the table and freestanding lamps, Cundall eschewed the fancy design houses, and got them from Ikea.
Clean and co-ordinated
‘What is very evident as you walk around the space and work within the space is the level of co-ordination of the different services. With all of the services on display, a lot of time was spent ensuring the ductwork, acoustic panels, lighting, fire alarms and so on, support the overall aesthetic rather than detract from it.’
While the services are very visible, the design feels coordinated and consistent. Off-white paint is used above the implied soffit line to separate the office space and the service zone. Functional elements such as ducts were specified in silver to set them apart, while the acoustic panels and recessed lights are white, to create a ‘clean’ soffit.
In the reception area, the lighting focuses on the reception desk and the Cundall logo behind it. Elsewhere, a large wall with images of some of Cundall’s projects is illuminated to an average of 200 lx.
The total connected load for the lighting in the office is just over 6W/m2. To put that in context, another recently refurbished floor in the same building uses 11W/m2. And controls mean that the load in use at any time is even lower, ranging from below 4W/m2 to just under 5W/m2, depending on the season. Bissell says it’s the lowest operating load he’s seen for office lighting, and it’s one way that Cundall is fulfilling its pledge, as part of the One Planet Living initiative, to use only its fair share of the earth’s resources.
The lighting design has won multiple awards, and the refurbishment won a gold Ska rating for sustainability from the Royal Institution of Chartered Surveyors.
It also gets the thumbs up from the most important people: the people who work in it. In staff surveys, the Birmingham office came out top of Cundall’s 20 offices on many measures, beating industry averages.
Cundall is looking to introduce similar low-carbon, ‘people-centric’ solutions in the rest of its offices.