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Energy-efficient revitalisation of an iconic work of corporate architecture

TÜV Rheinland

Client: TÜV Rheinland / Location: Cologne / GFA: 42,500 m² / Year of construction: 1974 / Revitalisation completed: 2017 / Green Building: DGNB Gold and LEED Gold

Services: Architecture, Revitalisation, Lead consulting


Standing 109 metres high, the TÜV Rheinland high-rise on Grauer Stein is one of Cologne's tallest buildings and has defined both the company and the city's skyline for more than 40 years. Designed in 1974 by the first HPP generation (HPP Hentrich-Petschnigg & Partner KG), the ensemble has now been given a comprehensive energy-efficient overhaul by the 4th HPP generation (HPP Architects). 

"It was our aim to produce a refurbished façade that was as close in appearance to the original as possible."

Remigiusz Otrzonsek, Senior Partner HPP

The striking shape of the TÜV tower is defined by the four office sections set at an angle of 45 degrees to one another, which are staggered in height and lean against the central, 109 m high circulation and supply core. 
The slab-shaped blocks of 16, 19 and 23 storeys rise above the flat building on the ground floor that houses the reception, conference and canteen areas, leaving one open-sided storey distance. They rest on a supporting structure that bundles the loads and distributes them through a very few supports. 


The tower's slab-shaped blocks rise above the expansive flat structure on the ground floor that houses the reception, conference and canteen areas, at a distance of one open-sided storey. 

High quality work for a testing and certification company
The energy, fire-protection and structural elements of the high-rise and low-rise buildings were renovated in accordance with the modern office building specifications and, above all, in line with the corporate identity of this company, that tests and certifies quality and safety. 

Work began in 2015, some of which took place during the course of day-to-day operations. 

The extensive construction works were based on the building's original form.


The renewed façade was designed as a double façade with openable panels. Thanks to the additional outer baffle panels, employees can open the windows themselves as required. This was not possible before and considerably improves comfort in the building. While high wind speeds are slowed down by the baffle panel layer, fresh air enters the rooms through integrated inflow and outflow slots. 
The protection afforded by this second shell and the use of high-quality insulated windows meet present-day thermal insulation requirements. 

Sensitive refurbishment, keeping close to the original
The timeless appearance of the glass-aluminium façade and the cladding of the core building with precast concrete elements were largely restored to their original state. 

left: external façade — right: ceiling detail

Working environments

The high-rise building offers the employees of TÜV Rheinland a total of more than 19,000 m² of modernised office space with approx. 800 workstations. The client's aim was to liberalise the corporation and consequently the working methods of its employees and to enhance their comfort. For example, the new working environments have been combined into larger units, making them more flexible.


"Through the energy-efficient refurbishment the energy consumption was reduced by 30 percent."

Energy-efficient refurbishment

A new façade composed of metal elements with triple glazing, internal solar shading and an outer baffle panel result in energy savings of up to one third compared to the previous situation. The high-rise building and the entire campus will be supplied with energy from a central underground heating plant on the site. Within the premises, heating and cooling are effected by means of new heating/cooling ceilings in the form of metal grid ceilings. 

The project, which was jointly developed by Drees & Sommer and the management of TÜV Rheinland Immobiliengesellschaft mbH & Co. KG increases the overall economic efficiency of the TÜV ensemble and, together with the comprehensive refurbishment by HPP, makes it ready for the future in terms of design and economy. The concept as realised, is modular and adaptable for the future. The renovated TÜV Tower was awarded LEED and DGNB Gold certification. 

Lobby TÜV Rheinland Köln

"Comprehensive refurbishment of an ensemble of buildings allows them to shine again and makes them economically and creatively fit for the future."

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