DHBW Stuttgart

D+H inspires: Innovative smoke extraction concept with triangular louvers

For more than 50 years, D+H has played a decisive role in projects that involve extraordinary demands on smoke and heat exhaust ventilation (SHEV). One example is the new building of the Faculty of Engineering of the Baden-Wuerttemberg Cooperative State University (DHBW) in Stuttgart, which will be occupied in 2023 and is a defining subcomponent of the unique campus in the heart of the city. The university and the University of Applied Sciences, along with the refectory and university library, are immediate neighbours. The basic idea of the 3XN architectural office: the atrium, as a central meeting point, compensates for the lack of outside space regardless of the weather and characterises the new building with its impressive glass dome.

The glass roof consists of over 500 triangular or rectangular elements, with no two windows at right angles to one another. The standard triangular elements have a side length of 2.50 metres, a rise of 2 metres and an average weight of 160 kilograms. 24 elements were installed that can be opened for the special SHEV solution. This is because the fire protection concept requires four roof openings to be equipped with so-called ‘natural smoke and heat exhaust ventilators’ (NSHEV) in accordance with EN 12101-2. Independently of the power supply, they conduct the smoke and hot gases generated in the event of a fire out of the building.

The biggest challenge was to implement the architect's requirements: there was no certified NSHEV system for triangular windows in the world and the angle of installation with the wind loads complicated the design conditions. D+H developed a smoke extraction concept that included the triangular windows. D+H recommended that the smoke extraction cross sections of the system be checked and certified by the I.F.I. Institute for Industrial Aerodynamics in Aachen as a certified body. A model on a scale of 1:10 was used to check the suction power at the individual sashes.

Now, six triangular windows arranged in a circle protect each other from the wind. D+H developed a wind-dependent control concept for this based on an average value from two weather stations (north/south). Two CPS-M control panels were installed and the scenarios were parameterised in the SCS software from D+H. The D+H service and sales partner Hübler Sicherheit und Service GmbH took care of the electrical work and installation.

The result: the 24 opening elements are combined into four groups of six elements. The sashes open in a tulip shape and are controlled individually and independently of the wind direction to ensure the required smoke vent cross-section in the event of a fire – and thus to provide life-saving fresh air.