The Air is Clear – How Clean Air Comes into the Gasteig
Norbert Wiesmann, how is the Gasteig ventilated?
Our ventilation systems for the Philharmonic and Carl Orff Halls and their foyers work with modern heat recovery technology. These systems can operate with 100% outdoor air even in winter. The air is exchanged up to four times per hour. The conditioned outside air is introduced through openings in the floor and the room air is extracted upwards through separate ductwork that is fully isolated from the supply air ducts. This removes respiratory droplets in the room air, which are then channelled outside the building and cannot accumulate indoors.
What about the other areas in the Gasteig?
The ventilation in the city library, the classrooms of the adult education centre and the practice rooms of the University of Music works with air recirculation. In the past, to save on heating costs in winter, warm room air was recirculated and mixed with the cold outside air. To some extent, this can be done without affecting the indoor air quality. But since viruses such as the coronavirus spread mainly via the respiratory droplets in stale air, we retrofitted these systems to ensure public safety even in winter.
How does virus-safe air recirculation work?
The extracted warm room air flows past UV-C lamps installed in our ventilation systems. All the extracted room air that is mixed with the fresh air passes the UV-C lamps and is treated with the ultraviolet light they emit. UV-C has a specific wavelength that destroys the genetic material of viruses like SARS-CoV-2, making them harmless and unable to reproduce.
Why was it important to complete this retrofit before winter?
The need to mix recirculated room air to the fresh air only arises at an average daytime temperature below 10 °C. Below this temperature, the heating coils are no longer capable of heating the cold outdoor air sufficiently to maintain a pleasant room temperature. That’s why up to 50 percent of warm recirculated air must be mixed with it. And that is when the UV-C treatment of extract air comes into play. We completed the upgrade in all affected parts of the building just in time – including the underground car park, by the way.
Is there any danger to the public from the UV-C treatment?
It is completely harmless to people in the Gasteig, as the ultraviolet light is contained entirely within the ventilation ducts. Since ultraviolet radiation is harmful to the skin and eyes, the lamps cannot be placed in areas that can be accessed by people. For inspection and maintenance, we are only allowed to look into ventilation ducts that have UV-C lamps very briefly and wearing protective glasses.
Why can people trust the air quality in the Gasteig?
Scientific studies prove that UV-C radiation provides highly effective disinfection. At a certain light output per room volume, a large proportion of viruses are rendered harmless. To be on the safe side, we have chosen UV-C lamps with a very high output for the Gasteig. In addition, we also use the best available particle filters in our ventilation systems, which we regularly service and replace. In recirculation mode, we keep the amount of extract air in the supply air as low as possible, and numerous CO2 sensors in many locations in the Gasteig monitor the air quality. In short, our air couldn’t be better!
If you still have questions on the topic, please contact us at firstname.lastname@example.org
Interview and text by Maria Zimmerer
Photos: GMG/Benedikt Feiten