Atrium of the Cologne office building Rhine Halls & Rhine Parc

Description

Film roof puts TV broadcaster into just the right light!
Since the summer of 2008, a highly transparent film roof from CENO TEC made of the high performance material Dyneon™ ETFE spans the atrium of the ”Bürohäuser Köln Rheinhallen” (North side) and of the “Bürohäuser Köln Rheinpark“ (South side). With a total floor space of 160.000m2, this is currently Europe’s largest superstructure construction site, where the new headquarters of the RTL Media Group and the new location of the HDI Gerling Insurance Company will be housed within sight of the famous Cologne Cathedral and Cologne’s “Altstadt” [oldest part of town].

When built, back in 1928 on commission from the mayor of Cologne at the time, Konrad Adenauer, the Rhine Halls were considered to be the most modern exhibition halls in all of Germany. Now eighty years later, they are being converted to a modern office complex for the TV broadcaster RTL and the Gerling Insurance Company, which is part of the Talanx Group.
The design created by the Cologne architectural office of Hentrich-Petschnigg & Partner GmbH & Co.KG divides the Rhine Halls into two halves along the north-south axis with a 150m long by 26m wide, light-flooded atrium. The biggest cushions have a dimension of 26m x 24.3m, 26m x 29.7m and 26m x 33.7m. After the original building complex, which with its distinctive brick facade is protected as a historical monument, was renovated, a highly transparent film roof made of DyneonTM ETFE was spanned over the atrium.

The highly transparent roof consists of five multilayered film cushions of roughly 26m by 30m each. They are distinguished by their exceptionally high light transmittance of around 90% for the visible spectrum. In addition, they guarantee 100% protection against harmful UV-C radiation. The distinctive highlight of the roof is that cables are used to suspend the film cushions over the 26m wide atrium. The cables, placed every 60cm to form a kind of web, give the entire construction exceptional stability yet a feeling of lightness. The films of DyneonTM ETFE have a tensile strength of 11.5kN/m while weighing only 1 to 1.5 kg/m2. They are extremely tear and puncture-resistant as well as resistant to hail stones.

The company CENO TEC GmbH, located in Greven, handled the entire project planning for construction of the roof, fabricated the ETFE film cushions, built the steel structures, cables and blower system, and completely installed the roof. The films themselves were produced with a thickness of 250µm by the Upper Bavarian company NOWOFOL Kunststoffprodukte GmbH & Co.KG. In addition to a performance life of at least 25 to 35 years, the films made of DyneonTM ETFE feature very high resistance to the most diverse environmental factors such as UV radiation, chemicals, solvents and various climatic and weather conditions. To manufacture the films, NOWOFOL needs neither stabilizers nor plasticizers which can evaporate over time thus negatively affecting the excellent properties of the roof construction. The extremely smooth surface of the film does not provide fungus or bacteria a place to take hold even after years of use. It is virtually self-cleaning with just a simple rain shower. An additional feature of the CENO TEC film cushions made of Dyneon ETFE is that they have excellent sound and thermal insulating properties. A further benefit of films made of DyneonTM ETFE, especially for large structures, is that they feature very low flammability and are classified as fire class B1.

Description of the environmental conditions