The challenge was to incorporate modern LED lighting in the various areas of sacred buildings like the cathedral such that at first glance it is invisible, but still contemporary and intelligently controllable. The cathedral is an integral part of Graz's "Stadtkrone" (City Crown), along with the castle, the Alte Universität (Old University), and the mausoleum. It was therefore important for the episcopal building department's architect to set accents with artificial light as appropriate for different occasions and liturgical celebrations.
The cathedral's current lighting dates back to the 60s. This system has been repeatedly supplemented or modified in specific areas over time. It was time to create a modern lighting concept during the general renovation of Graz Cathedral. The core idea was to deliver a contemporary presentation of the cathedral with its magnificent architecture and furnishings and to create the right light for the respective liturgical celebrations. For this purpose, wide variety of lighting situations were programmed and can be operated easily. In addition, great flexibility to create additional lighting situations as required remained.
The greatest challenge for the retrofitting of lighting, especially in religious buildings, is the protection of historical monuments. Very often frescoes or architectural elements are located in areas where the installation of lighting elements would also be ideal, but which must not be touched. Here the challenge for the lighting concept is to find a solution that creates an optimal lighting situation while integrating the lighting elements into the room without destroying it. In Graz Cathedral the architects identified a modern solution in coordination with the Federal Office for the Protection of Monuments and XAL's lighting designers.
Two types of luminaires were custom-made for optimal integration of the lighting into the historical walls. Cylindrical pendant luminaires were developed for the cathedral's central nave. A suspended, ring-shaped track system with a considerable diameter of five metres was designed for the side aisles. The XAL CAVO spotlights JUST 45 and SASSO 80 were used for the four ring luminaires.
The five cylindrical luminaires in the central nave were each fitted with MOVE IT JUST 55 and SASSO 100 spotlights. Technologically, the lighting solutions are characterised by direct and indirect components that make it possible to create the desired lighting moods. An innovative custom solution, which was technologically, creatively, and economically perfected by XAL's Lighting Design Team thus met all requirements.
One of the requirements for Graz Cathedral was to be able to create individual lighting moods for the various liturgical celebrations. This meant that the cathedral’s entire electrical installation was converted to a bus system. A total of 600 DALI addresses have been created for the simplest possible control of the programmed scenarios.
The specified requirement profile was implemented to the greatest satisfaction. The cooperation of all those involved, including the Federal Office for the Protection of Monuments, worked well. We have succeeded in implementing the architect's ideas by means of innovative custom solutions. In Graz Cathedral, details can now be viewed that were previously not even noticeable due to the existing light situation. Another positive aspect of the new lighting is the lower energy consumption thanks to the switch to LED lighting.
Arch. DI Peter Grabner, Episcopal building department
The diocese Graz-Seckau’s building deparment accompanies and supports the parishes in their building projects. The tasks range from project development to monitoring and controlling the accounting during the execution of the construction projects. The individual projects range from conversions and extensions as well as renovations of secular buildings such as parsonages to the restoration and reconstruction of churches.