Sustainably best
The stunning new headquarters building for KfW Bank in Frankfurt, which features extensive use of Wicona unitised curtain walling, has won a major global architectural award.
The prestigious accolade for the World’s Best Tall Building has been awarded to the KfW project by the Council for Tall Buildings and Urban Habitat (CTBUH) – the leading international authority on the design, construction and development of tall buildings.
This is the second time the CTBUH has recognised a Wicona project. In 2009 the Tornado Tower in Doha, another application of Wicona unitised curtain walling, was presented with the award for the Best Tall Building in the Middle East.
The CTBUH awards highlight projects from across the world that have made ‘extraordinary contributions to the advancement of tall buildings and the urban environment, and that achieve sustainability at the highest and broadest level’.
Described as a ‘remarkable building’, the $85m KfW scheme was designed by architects Sauerbruch Hutton to combine form, colour and sustainability. With a primary energy consumption of just 98kWh/m2, it is also one of the world’s most sustainable office buildings.
The building, known as Westarkade, provides office space for 700 staff and a conference centre. Its base is a curved four-storey podium connected to the bank’s adjacent buildings on several levels. A 10-storey tower rises above the podium in a ‘flowing’ form that responds to the prevailing wind direction and orientation of the sun, maximising natural day light and achieving the best possible views for the occupants of the neighbouring KfW buildings.
The scheme’s most distinctive feature is its bespoke double skin facade constructed using Wicona’s aluminium unitised curtain walling.
The envelope consists of an encircling ‘sawtooth-shaped cavity’ which encloses automated blinds to reduce solar gain and control glare. The exterior is defined by a skin of fixed tempered glass panels and colourful ventilation ‘flaps’ in red, blue and green, helping to create a striking aesthetic. The internal facade has alternating opening and fixed glazed units.
This dynamic facade solution negates the effect of variable pressures around the building, allowing natural ventilation all year round and for the occupiers to open the windows on the inner skin while avoiding both draughts and heat loss.
A roof-mounted weather station linked to the building management system monitors wind speed and direction, and controls the facade’s outer ventilation flaps. This solution introduces fresh air when required and creates a zone of constant pressure surrounding the inner skin of curtain walling. Air can then be drawn into the offices via floor vents or the occupier-controlled windows.
Peter Murray, one of the CTBUH judges, said: “The streamlined form of the building integrates itself into its surrounding context, while simultaneously standing out through the playful use of colour. Whereas many buildings use colour as a way to mask an otherwise unremarkable building, here it contributes an additional rich layer to what is already a remarkable building.”
