Engineering, lighting technology and workmanship at the highest level

Chandeliers for Swiss National Bank SNB

Depending on the shape of the interior, the lighting situation and the furnishings, the chandeliers for the conference rooms each feature an individual geometry in a modular design, giving off both indirect and direct light.

Initial Situation

The main Swiss National Bank building at Bundesplatz in Bern has been renovated numerous times since it first opened in 1912. As part of the complete renovation of the SNB premises, the meeting rooms as well as entrance- and corridor lights were redesigned in line with technical and operational optimisations.

The aim of the renovation was an architectural and structural upgrading of the object, taking into account aspects of historic preservation and in recognition of its special cultural value.

In this context, the illumination concept and luminaires were designed by vogt partner and developed together with Aebi & Vincent Architekten. BURRI won the invitation to tender and was tasked with implementing this challenging assignment – from technical development and electrical engineering, all the way to installation.

Two different basic typologies of luminaires were developed in the course of the project. Chandeliers for the conference rooms as well as corridor- and entrance luminaires.

Chandeliers

Depending on the shape of the interior, the lighting situation and the furnishings, the chandeliers for the conference rooms each feature an individual geometry in a modular design, giving off both indirect and direct light. Alongside the electronics and lighting engineering, the implementation of the design specifications of the chandeliers (up to 4.5m metres in width, few suspension points) was particularly challenging. The cleaning and maintenance concept was incorporated already in the development phase.

The basic structure of the large ellipses was milled from a tension-free aluminium block and gloss nickel-plated. This allowed the milled dual-arch segments to be screwed together to form high-precision, dimensionally stable rings. The over 500 structured glass components were inserted from above through slots. The light bar, which was likewise milled and fitted with custom-made LED prints, with different lenses illuminating upwards and downwards, was inserted between the upper and lower rings.

A further and particular challenge was the luminaire for the legendary “Salon bleu”. This consists of two differently sized ring structures with eight suspension points, all of which is arranged to match the historic ceiling stucco. A total of 388 upwardly-emitting LEDs and 208 downwards-emitting LEDs were installed, each with different special lenses and 876 structured glass components.

The entire value chain was implemented in Switzerland, from the design to the engineering, all the way to construction, industrial production and traditional art of glass blowing.

Making of

Competencies deployed in development: 
Development and construction
Design and prototyping

Development

BURRI developed these luminaires over several phases in close cooperation with architects and lighting designers as well as a broad network of partners in the areas of lighting technology, electrical engineering, CNC milling, glass craftsmanship and electroplating. The use of different prototypes enabled BURRI to fully assess the lighting engineering, design and statics and perfect these up to production maturity. All control units and circuit boards with varying curvatures were developed in-house by BURRI.

For the chandeliers, a particular challenge lay in the development of a high-precision, torsion-resistant but nevertheless extremely slim frame structure. In addition, hundreds of small glass parts had to be inserted with millimetre precision.

From a technical perspective, the delicate and ornamental ceiling attachment, which neatly matches the cherished ceiling stucco, was a further difficult nut to crack. The luminaire suspension in the ‘Salon Bleu’ is therefore limited to just eight suspension points, which are precisely integrated into the existing stucco ensembles.

Prototype

BURRI tested various glass components with different surfaces and structures for both function and aesthetics. On the basis of 1:1 scale models, numerous variants of the secondary lenses and reflectors were assessed and optimised to optical perfection in order to achieve the best lighting situation. For the delicate support structure, galvanic nickel plating with a high-gloss finish was selected as the most aesthetically pleasing surface in a process that was again assisted by original-size models.

Production

All of the luminaires were preassembled, electronically and mechanically tested as well as cleaned and packed at the BURRI production base in Glattbrugg, with the highest degree of care and professionalism throughout. During the entire production period, all employees worked exclusively with special white gloves to avoid fingerprints and other contaminants on the highly sensitive nickel-plated surfaces. The larger ring segments required transportation in two parts with a special supporting construction.

For final on-site assembly, a mobile lifting platform was used to hoist up the luminaire and affix it to the respective connection points. Finally, all glass parts were cleaned and inserted by hand through the slots in the frame structures.

GTranslate