Slovakian experience – challenges in relighting Demänovská Liberty Cave and Ice Cave

Slovakian experience – challenges in relighting Demänovská Liberty Cave and Ice Cave

Situated in Low Tatra Mountains, Demänovská cave system is the largest cave system in Slovakia, with more than 40 kilometers of interconnected underground passages. From more than ten caves that are part of this system, two of them are famous to the public: Liberty Cave – developed as a show cave and opened for the public in 1924, currently the most visited cave in Slovakia and Ice Cave – first open to the public in the 19th century and reopened with new stairs and electrical lighting in 1952.

Considering the history of these caves and the age of the existing installations, it was necessary to bring them up to date and install a new and efficient lighting system, a laborious work which was performed by Cave Lighting in cooperation with the local electrical company Voltatech a.s. . Going over the bureaucratic and design part that took some years to complete, the actual installation began in November 2022.

The first one to receive a new lighting system was Ice Cave. As the name very clearly suggests, the cave is… very cold! As the installation works took place during the winter, between November 2022 and March 2023, the first challenge for Cave Lighting team was the extreme cold, temperatures in the cave ranging between well below zero degrees in the entrance parts to a maximum of 3 degrees Celsius in the deeper part of the cave. The access to the cave is not very easy, requiring a real mountain hike in not quite favorable conditions, on a steep trail often covered by ice and snow, cave entrance being almost 100 m above the bottom of the valley. Once in the cave, things are not better, because from the entrance the visitors path goes down for almost 50 meters and up again towards the exit, which is at the same elevation with the entrance, anyone who wants to go through the cave having to climb up and down over 650 steps. As the tour path also has a lot of twists and turns, together with the elevation difference, makes it very challenging to find a good placement for luminaries to get a good balance between good lighting and blinding the visitors. Another thing that had to be considered was the future ice forming in a lot of parts of the cave, which made impossible to place the luminaries on the ground and on the walls of the cave so many of the luminaries had to be installed far away from the walls and cave formations, on the handrail and on the suspended visitors path itself, not the ideal location for light sources if you want to create a modern tridimensional lighting and avoid a flat looking more traditional type of lighting. Last but not least, in the deep part of the cave the spaces are very large and the ceiling height is considerable, necessitating the use of ropes and specific climbing equipment for the installation of lamps and control units. Anyway, the Cave Lighting team managed to find a way to mitigate all of this and finish in time the installation of the new lighting system, together with the switching system, a brand-new light and music show and audio system for comment points. The cave was reopened for the public in May 2023 and the final programming of the new system was finished later in the year.

In March 2023, Cave Lighting team started the installation for the Liberty Cave, which presented a new set of challenges. Again, for this cave there is no direct access from the parking lot and the cave can be reached the entrance can be reached on a 400 m long path with elevation span of 67m. The cave itself is huge, the long tour path has a length of more than 2 kilometers, and you have to climb 1.118 stairs, making it a challenge in itself to reach the deeper parts of the cave and go back to the surface. The morphology of the cave is very diverse, with different galleries and halls, from low and narrow passages with delicate formations to huge galleries and domes of impressive size. Being such a large cave and with a very long touristic route, but beautifully decorated with almost every type of speleothems you can think of, one of the first challenges is choosing the points of interest that are to be highlighted, as it is impossible to illuminate everything, both from a logistical point of view and to avoid boredom and eye fatigue of visitors. Other specific challenge of this cave is the high humidity, relative air humidity going to 99 percent and a lot of water dripping from the walls and ceilings, including a permanent waterfall from the ceiling of one of the big domes (which was illuminated with several lamps placed directly under the waterfall). Combined with the ambient temperature, which is higher than in the Ice Cave but is not going over 6 – 7 degrees Celsius makes an interesting working environment.  The lighting of the underground river that crosses the cave at the lowest level of the route and the impressive galleries crossed by it proved quite challenging as well, and in the big dome the continuous noise of the river over the huge space of the hall made communication between the team members almost impossible. Anyway, after almost 5 months of hard work the installation of the new luminaries by Cave Lighting team was finished in July 2023. In the following months the electrical connections were also made by the local electrician team from our partner Voltatech a.s. and the final programming of the tour lights and shows was completed in September 2023.

For carrying out this complex project Cave Lighting has mobilized one of the largest teams so far, the activities being coordinated by the on-site project manager Alejandro Hernaiz, the other team members being Dan Ciulpan, Tudor Marin, Andrei Daniel, Cristian Nitulescu, Tomas Jassus, Radu Puscas, Oleg Klimchuk, Vladimir Lyevashov. The complex programming was made possible by Vladimir Vashkevich. Installation of the new high voltage power supply, including new power cable, electrical cabinets, generators, etc. and the electrical connections for the low voltage installation was made by a numerous local team coordinated by Voltatech a.s. electrical company. The light + music shows in both caves, total 8 shows, have been designed and realized by Jan Ptacin.

This project has proved to be challenging from beginning to end for everybody involved, the challenges being both of an objective nature, related to the difficulties represented by the caves themselves, and the subjective nature inherent in a long and difficult project that requires the collaboration of a large number of people, but the end result is worth it, the most famous and visited show caves in Slovakia having now a new and modern LED lighting system, to provide the many visitors with a new and exciting experience for the years to come. The works in Demänovská cave system will continue with in Peace Cave, the third cave that will be opened to the public in the near future.

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