RTS

Radio Télévision Suisse (RTS) is the French speaking branch of the Swiss Broadcasting Corporation. While well known in the French speaking part of Switzerland, RTS also has stations in Bern, Zurich and Lugano. In 2019, the two main TV channels of RTS scored a 1.2 million viewer count per week.

Recently, RTS made a decision to move its headquarters from its usual seat in Geneva to a new headquarters in Lausanne, within the EPFL campus. The new Lausanne building is an ambitious project design, four central buildings connected through a suspended platform, supported through a metal support system. We thought visiting the construction site and talking with the project developers would be an excellent on-the-field experience that could provide considerable insight.

We had the pleasure of meeting with Francesca Onorati, the Real Estate Project Manager of RTS, who explained to us the technical decisions taken for the design of the project in detail.

The new headquarters is to feature many different chambers and spaces for different functionalities and purposes, such as office spaces, recreational meeting points, news studios etc. A combination of different materials and techniques are used to achieve these functionalities. This fact guided our discussions.

A pertinent example is the sound insulation for the studios, where a double wall setup is used and the insulation is put in between these walls. The insulation material in question is mineral wool, a material with a lambda value of 0.032-0.044 w/mK (comparable to glass wool), while having a very performant sound insulation function. The double wall system is set as such that the insulation material between the walls acts as a spring, absorbing the sound vibrations in the environment. This specific example is a clear case of material choice and material use for maximising a given function. We realised that we would need to imagine our material in such setups as well.

We asked how the choice of one insulation material over another one is guided. We were told that the price and the technical requirements are the primary concerns. The architects design wall systems, with specific insulation performance requirements and specific desired thicknesses. Plus, the overall u-value of the building is calculated after the windows are installed as well, making this value partially dependent on the performance of the insulation material in the walls. Only a handful of insulation materials usually qualify for these requirements and considerations, and the one that is the most financially feasible is then chosen.

The same thought process also guides the choice for which labels to aim for (or not). Usually, project designers aim for the highest possible labels. This is due to the fact that it is not possible to know which recommended labels will become mandatory in the future, and the highest labels guarantee that the building will not be obsolete for a long time.

Rather interestingly, we also learnt that the project developers for RTS had considered but ultimately decided against pursuing the Minergie label, a well-known classic Swiss label for energy efficiency in buildings that we have encountered multiple times in our Human Practices work. The reason, we were told, was both the cost of meeting the label’s requirements for this specific project, but also the fact that the windows (an insulation system in their own right) would have to remain closed at all times to meet the overall label requirements for this specific project.