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In the course of a standard inspection of the fire smoke extraction system, it was found in the area of the airlocks where the air volume at the extraction points does not correspond to the total exhaust air volume at the fan The approximately 20-year-old existing pipes, which were made of galvanised ventilation ducts and largely of self-ventilating promat shafts, had then to be sealed to ensure the necessary air exchange.


Building: Gasometer
City: Vienna, Austria
Date: October 2019
AEROSEAL Partner: Aeroseal Austria
Executing company: Direct order from company Gesiba
Target: Achievement of air tightness class „B“, so that the air volume reaches the exhaust points.
Preseal leakage: 104,4 l/s @ 500 Pa
Postseal leakage: 16,5 l/s @ 500 Pa
Reduction of leakage: 84,20 %


It was suspected that the major leak was in the main vertical pipe. Therefore, this area was first inspected and sealed. To do this, the two flue gas fans were closed off from the ventilation duct by metal plates. In the same way, a separating plate was installed at the lower point of the riser shaft to the selfventilating Promat ducts. After completion of the renovation work, the sealed ventilation line for air lock ventilation had almost reached tightness class „C“ (suitable for hospitals!!). In the course of the sealing, it was also determined that the remaining ventilation line still had much larger leaks. This renovation will be executed in a next step with some additional preparation work.