A tornado for smoke ventilation

Feb 12, 2016
When fires break out, it is toxic gases and smoke that present the greatest danger to people. The Mercedes-Benz Museum has a particularly effective smoke ventilation system. This is based on the world's largest artificial whirlwind, which is centrally activated in the atrium.
The smoke ventilation system is tested once each year. Then the air in the atrium of the Mercedes-Benz Museum becomes a roaring whirlwind, with noise levels up to 130 decibels. That is the noise level of an aircraft preparing for take-off. The air is sucked powerfully from the exhibition areas into the atrium, where it forms a whirlwind and flows upwards.
Ventilators under the ceiling then vent the rush of air, which can have a volume of up to 80,000 cubic metres per hour. And that is precisely the purpose of the spectacular storm: rapidly and effectively venting smoke from the Mercedes-Benz Museum in critical situations. Fortunately the system has never been used in earnest.
The entire Museum is a fire lobby
The so-called Tornado, which entered the Guinness Book of Records as the world's largest artificially produced whirlwind in 2007, is part of the innovative fire protection concept in the Mercedes-Benz Museum. Given the open-plan architecture of the building, a division into different fire lobbies separated by fire doors was not an option. Instead the entire interior is treated as a fire lobby with an enclosed space of more than 200,000 cubic metres.
This innovative solution ensures that this enormous volume extending 42 metres high and covering eight storeys is ventilated in a controlled manner in a fire. The whirlwind is generated by a total of 144 air nozzles inset into the walls of the atrium. These rotate the incoming air masses until they form a whirlwind normally only seen in nature. During test operation, with no smoke in the air, the whirlwind cannot be seen at all. The 34-metre high whirlwind only becomes visible when artificial smoke is added – as happened in 2007 in the presence of the Guinness Book jury.
A storm in a model
The development work for this innovative solution also included impulses from the venting of welding gases in industry, for example.At the time when the Museum was built, there was however no previous experience with a system of such a size. To test the effectiveness of the Tornado, a 1:18 scale replica of the Mercedes-Benz Museum with its complex geometry was built.
Airflow tests in the 2.50-metre high miniature version of the Museum showed that it worked. They also revealed necessary changes such as the installation of smoke baffles and sails to prevent secondary turbulences in the atrium. The house operating rules also take the smoke ventilation system into account: no objects may be placed within a five-metre radius of the centre of the atrium, as they would disturb the aerodynamics of the whirlwind.
In 2005 the complete system was activated for the first time in a late-night test, and observed by the expectant planners. After a few minutes there were sighs of relief: the artificial whirlwind was generated as planned, sucking the air into the centre of the atrium and venting it into the open air up above. The unique solution for the new Mercedes-Benz Museum had proved effective.
Entry in the Guinness Book of Records: In October 2007 Michael Bock, General Manager of the Mercedes-Benz Museum GmbH, was presented with the certificate for the world´s highest artificially created whirlwind in the Mercedes-Benz Museum, Stuttgart by Olaf Kuchenbecker.
Whirlwind in the Mercedes-Benz Museum, Stuttgart: The world´s highest artificially created whirlwind is part of the fire protection system.
Spectacular presentation: In the event of a fire, the artificial whirlwind in the atrium of the Mercedes-Benz Museum in Stuttgart will vent the smoke from the entire building.