Invisible fire protection thanks to aquatherm red in new high-rise building on the UN Campus – Bonn has one more attraction: after a construction period of around four years, an 18-storey high-rise building has been erected on the UN Campus directly on the Rhine, in which the United Nations is to find another home. The building, which is located between the former high-rise building for members of parliament of the Bonn Republic (“Langer Eugen”) and the World Conference Center, scores not only in terms of sustainability and energy efficiency, but also in the area of security.
In order to create space for future growth, the Federal Real Estate Agency (Bundesanstalt für Immobilienaufgaben), the owner of the campus that forms the centre of the United Nations organisations in Bonn, had decided to build the new building. Under the direction of the Federal Office for Building and Regional Planning (BBR), a slender high-rise building with 17 upper floors and 3 basement floors was constructed on a footprint of approximately 20 x 30 metres; the 18th floor is a staggered floor that serves the building services. The total costs amount to about 75 million euros. Due to its relatively small footprint, the building, designed by Berlin architect Stefan Lippert, blends in with the existing buildings and encroaches as little as possible on the surrounding green area of the campus. A highlight is the glass outer skin of the office tower, which is interrupted by two-storey conservatories. These provide a connection to the surrounding green space and are used by approximately 330 employees as a place to meet and relax during breaks.
The building, which has a usable floor space of around 8400 square metres, is designed as an energy-saving passive house. A geothermal well serves as a regenerative energy source, and its water is used for cooling and heating via heat exchangers. The waste heat generated by the server room’s IT systems is also integrated into the energy cycle. In addition, the well water is used to flush the toilets in order to conserve the valuable resource of drinking water.
Space and architectural reasons
To provide the necessary safety in the event of a fire, aquatherm red was installed. This is the first plastic sprinkler pipe system to be certified by VDS Schadenverhütung GmbH, Europe‘s largest institute for corporate safety. The system comes from aquatherm, the world’s leading manufacturer of plastic piping systems made of polypropylene for plant construction and building services.
“aquatherm red was chosen for space and architectural reasons”,
explains Thomas Schwarz, head of the Eschweiler technical office of Caverion Deutschland GmbH and VDS specialist responsible for the North West Region. The company laid the wet system as a sprinkler line pipe and distribution line in the dimensions 63 mm and 75 mm directly in the concrete of the hollow core ceilings used in the property. Despite the air chambers used in this type of ceiling, which ensure a lower concrete requirement and thus lead to static and architectural advantages, the system could be easily integrated into the storey ceilings due to its flexibility. A total of around 2800 m of aquatherm red pipe was used, which, due to the space-saving and invisible method of installation in concrete, allowed the highest degree of design freedom with regard to the design of the ceiling.
The laying in concrete is made possible by the special material: aquatherm red pipe consists of the plastic polypropylene, specifically of the material fusiolen® PP-R FS developed by aquatherm. This material offers a high degree of safety due to its flame-retardant properties (building material class B1) and its corrosion resistance. For comparison: Metal sprinkler systems can only be installed in concrete using special protective measures. The reason for this is corrosion, which inevitably occurs when metal and moist concrete meet. The special protection of metal pipe systems makes installation in concrete complex and expensive.
Meeting deadlines thanks to prefabrication
Thanks to fusion, the aquatherm red system was joined to form a homogeneous, materially bonded and thus safe unit. The pipe and fitting were briefly heated using tools designed for this purpose and then simply joined together. In the construction project, strand pipes were also used, which were prefabricated directly in the aquatherm factory.
“Prefabrication contributed significantly to meeting the timed shell construction deadlines, as the elements were delivered on time and the welding on the formwork was reduced to a minimum,” says Thomas Schwarz. “No small-scale material logistics and stocking of individual parts were necessary on site. The assembly personnel could be continuously and effectively planned, deployed and kept on hand due to the prefabrication.”
The light weight of aquatherm red – especially compared to sprinkler systems made of steel pipes – additionally simplified the handling on the construction site.