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MONDO ARC

The Burj Doha, Doha, Qatar

Issue 70 Dec / Jan 2013 : Architectural : Workplace

ARCHITECT: Ateliers Jean Nouvel LIGHTING DESIGN: Yann Kersale


Nowhere is Doha’s relentless march of structural investment more apparent than along the Corniche Road, the central edge of the Qatari capital. Over the last decade the city’s skyline, in particular towards the corniche’s northern tip, has been transformed by a series of new towers whose varying shapes – the legacy of computer-calculated modeling - jostle for attention.

The Burj Doha (Doha Tower) is among the newest of these. Designed by Atelier Jean Nouvel, its architecture employs a series of innovative construction techniques to create a building both subtly traditional and strikingly modern in style. Constructed without the central support column common to most skyscrapers, the Burj is instead formed from a circumference wall of reinforced concrete dia-grid columns. Giant X-shaped pieces are linked to create the building’s tubular skeleton from which its 44 floors are suspended.

Beyond a glass wall a continuous steel latticework covers the exterior. Like the reactive metallic irises famously used on Nouvel’s Institut du Monde Arabe in Paris, the tower’s facade mimics a traditional moucharabieh screen, using it to mitigate the effects of the region’s intense sunshine. Unlike the Institut, here the latticework is static, but layered to create a visual texture and complexity. In areas most exposed to direct rays, extra, denser layers are used to cope with summer temperatures that often rise above 50ºC.

It was clear in the early planning stages that this layered façade would give the Burj a graceful dignity, but a question remained about its nighttime character. To this end, Nouvel called upon his old friend and long-time collaborator Yann Kersale to develop an appropriate lighting scheme.

Kersale conceptualised a dynamic design that would ripple between ‘gold’ and ‘silver’. His vision was to light behind the lattice cladding of the tower to give a jewel-like quality that would be highly visible to the surrounding area, those flying into the airport and those on ships in the bay. The team began investigating ways of realising Kersale’s vision.

The solution, it transpired, was to be found within the pages of mondo*arc. After spotting their advert in the magazine, a call was placed to Insta UK and a meeting arranged.

Insta UK’s Jon Estell met the client’s London-based representative to discuss options. “He explained that it was an exterior lighting project for a new tower that required a luminaire capable of withstanding temperatures of between 45-50 degree temperatures and suitable for the sea front location in the west bay of the commercial district in Doha, Qatar,” recalls Estell. “He was well versed in lighting and had specified lighting products from manufacturers all over the world. He was of the opinion that the quality associated with German engineering was needed for a project of this high profile and magnitude. He had realised that expertise in the control of light was as important as the luminaire itself. The relationship felt right from the outset.”

Each floor has a narrow expanded metal walkway between the cladding and the glass and it was here the luminaires were to be positioned, lighting an area approximately two metres wide by three metres high from a very close offset. In addition they had to be sufficiently low profile enough not to clash with the window cleaning cradle that runs on a rail and circles each floor of the building.

With an average of 82 luminaire positions proposed for each of the 44 floors as well as illumination of the tall spire at the tower’s peak, a sophisticated control system was required to operate all fixtures in concert.

Following an initial site visit in May 2010, the Insta team were invited to return with samples to test the optics and to ensure the LED colour proposed were suitable. It also allowed them to demonstrate the proposed transition from gold to silver.

As the luminaire has separate chambers, the team were able to fine-tune the beam angles to suit the space. During the mock-up, an engineer adjusted the angles and positioning of the luminaire whilst other members, located at various points around the bay, offered feedback via long-range walkie-talkies. Four of the tower’s ‘bays’ were used, spread over two floors to ensure the optimal light distribution was achieved. The tests concluded that 15 degrees in the centre chambers and 30 degrees at the extremities provided the best effect. The fittings were angled at 5 degrees to the vertical and placed right up to the glazing of the internal offices. Due to the luminaires tri-layered optic the glare is minimal to occupants in the offices.

The instalight 1050 fitting was adapted slightly for the project to allow for the transition from gold to silver. Inside the luminaire there are eight chambers each with one cool white (6000K) and two amber (590nm) high-current LEDs. The LEDs are mounted on an alucore board, which is connected to the housing to guarantee a perfect active thermal management designed for longevity. In addition to this, the PCB includes a micro controller based temperature monitoring device that transfers the actual board temperature back to the main control system in order to avoid over-heating of a fixture. This means the luminaire is self-secured against temperature damage.

A high-specific optical system with tri layered lens combination on each chamber guarantees a perfect light output. The first lens mixes the different colours of the LEDs to one single light output. The second lens adjusts the light strands parallel. The third optic defines the beam angle. All together they give the luminaire a very homogenous light output with artifact-free display of mixed colours and an excellent glare suppression, essential as the fittings were located at the base of full height glazing. Additionally the combination of the optic attachment prevents focusing of sunlight onto the LED chip common with traditional collimating lens type LED luminaires.

UNIVERS, an IP addressable control system, was used to operate the entire scheme. With initial programming carried out on a computer and downloaded to powerful master units, the system can stand alone, with different modes and scenes selected via a simple user control panel.
IP addressing allows the user to remotely access the system to update programming, check temperature TC points of the LED PCB of every luminaire on the project, and for Insta to provide remote support beyond their weeklong sign-off on the installation.

Within minutes of the switch-on in March 2012, ripples of excitement were spreading across social media, with photos, videos and comments saluting the scheme. By November the waves had reached the shores of Chicago with the Council on Tall Buildings and Urban Habitat awarding Burj Doha the honour of Best Tall Building 2012.

www.ykersale.com

 

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