A modern landmark for ancient artefacts:

Exceeding energy expectations

Interior lighting uses primarily ERCO's Optec spotlights, around 1000 Dali-controlled fittings with varying beam widths and light distributions to suit individual exhibits and purposes. 'It was important to minimise the power density in the galleries with high-efficacy track lights,' says Joe Geitner, project manager of lighting consultant George Sexton Associates (GSA).

GSA not only analysed the efficiency of LED track lights available on the market before specifying the Optec luminaires, but was able to supersede the original specification because of ERCO's use of newer LED technology. 'We found several luminaires that could be upgraded in specification because ERCO had increased the performance significantly,' explains Geitner.

Optoelectronics is a core area of ERCO's expertise. To ensure high efficiency the company develops and manufactures control gear, LED modules and lens systems in-house. These high-precision lighting systems direct the light precisely on to the target area so that light is only used where it is needed. The result combines high illuminance (lux) with low connected load (watt), a decisive factor for sustainable lighting expressed in lx/W.

Powerful and precise

An example was the extensive use of the Optec 4W narrow spot with 5° beam. Although ceilings were high, this enabled powerful and precise accent lighting on exhibits with minimal energy use and no spill light. 'We required multiple beam angles,' says Geitner. 'The interchangeable lenses of the ERCO system provided additional on-site refinement during the focus and commissioning.'

The nature of the displays, largely sculptures and stonework, allowed for daylight levels that contributed to overall sustainability. Balancing light composition, colour and levels of artificial light and daylight needed careful consideration, says Geitner.

'The illumination must appear generous yet within a proscribed level and brightness and meet energy goals. Graphics and media needed to be visually accessible and easy to read. Lighting is balanced and glare-free, enhancing the visitor's experience.'

The Lapidary Wall, by Studio Adrien Gardère, exemplifies this artful equilibrium. At the heart of the museum, the wall naturally divides the public galleries from more private restoration spaces. Industrially inspired, the 10m x 76m metal rack has a lifting device that reconfigures the architectural stones on display – 760 blocks – creating a moving mosaic. This allows visitors to glimpse the work of the archaeologists and researchers through a dynamic wall of stone and light.

'The combination of daylight and artificial light to illuminate the wall makes it a bright focal point along the axis of the reception,' says Geitner. 'The angle of daylight and artificial light were carefully designed to make the inscriptions on the ancient Roman stones legible.'

'Museography and architecture are one,' says the museum's curator M’hammed Behel. 'It was so important that the lighting should accentuate and embellish both.' This also extended to the exterior lighting where ERCO's Compact surface-mounted luminaires, recessed in the roof eaves, define the building with an even, glare-free wash of light.

Supporting the vision

Throughout, the lighting supports the museum's vision and Foster + Partners' 'honest approach to materials'. LEDs are 3000K with a high CRI, 'based on the warmth and richness of the architectural stones on display,' says Geitner.

The results have met the aspirations for both sustainability and visitor experience. 'The ERCO lighting is perfect and fulfils all our expectations,' says M’hammed Behel. 'Our visitors have been so enthusiastic and we have had only congratulations about the way exhibits have been presented.'