Description

Even though the transfer of the Federal Environmental Agency [Umweltbundesamt] from Berlin to Dessau was decided in May 1992, the complexity of the planning process has delayed the move until at least the year 2004. Conceived as a demonstration project, the ecologically exemplary new agency building is to set the standard for environmentally friendly and at the same time inexpensive construction. The design by sauerbruch hutton architects demonstrates, in their inimitable style, a clever balancing act between technical and economic necessities on the one hand and high-quality architecture on the other. Thus this innovative project points the way to the future in three ways: it contributes to sustainable urban development, notwithstanding stereotypical private offices it provides a lively and comfortably sensuous work environment, moreover it demonstrates the implementation of a great variety of technologies for ecological and energy-saving construction.

The “Gasviertel” [gas district] east of Wörlitz Station was chosen for the future site. As the name suggests, the site was formerly occupied by the town’s gasworks, which caused considerable soil contamination. The site lies at the interface between city and countryside. For this reason, sauerbruch hutton architects took advantage of disused railways in order to create a landscape, a green feature that forms a link with the city centre and develops the transition to the Dessau-Wörlitz gardens to the north. This newly landscaped park, into which the looped structure of the Federal Environmental Agency’s offices naturally integrates itself, unites the existing historical buildings and draws the public into the ministry, which pursues an open door policy.

The agency, first founded in 1974, is divided into a central department and four others with particular responsibilities, from ‘Environmental Planning & Strategies” through “Environment & Health” and “Environmentally Compatible Technologies” to “Safety of Chemicals and Gene Technology.” The private offices for a staff of 800, as specified by the client’s brief, are arranged as a sweeping loop around the agency’s “heart and lungs,” a landscaped central atrium. In spring, summer and autumn, this serves as a meeting point or informal workplace, while in winter it provides a thermal buffer for the adjoining offices. Lightweight bridges divide the space into four ‘office gardens’ that promise a lively, cheerful workspace. At the ground floor level, ‘crags’ executed in exposed concrete are rooms for special purposes, such as numeric or paper document storage, that blend with the landscape and supply additional dynamics.

In order to create a counterweight to the separate cell-like offices, the overall conception focuses on communication between staff members. The bridges are organisational reference points as well as social centres. They mark the access to the vertically organised departments and at each bridgehead is space for a wide variety of joint activity. In addition to vertical access, the meeting rooms and kitchens for each department are located here. In order to devote more space to these common areas, there is no hierarchical graduation of office size. The slender office floor plan and glazed corridor walls create a high degree of transparency and allow optimum daylight into all areas. Ceiling lights provide infinitely variable artificial light dependent on the available amount of daylight. The agency entrance area is developed as a spacious forum with public facilities. Among these are the freestanding amorphous volume of the lecture hall, the library (adjoining an existing old building) and the exhibition areas. The central department located here deals with publications and documentation concerning the environment while providing the usual administrative functions.

The intention of this exemplary project is to demonstrate innovative yet feasible approaches to ecological building. The focus is on the agency’s power consumption, which amounts to 80% of the total energy required for realisation and operation of the building over its predicted lifetime. Therefore, in addition to the compact external form (S/V = 0.25) obligatory in Central Europe, the energy concept provides for a high degree of thermal protection, “intelligent” services, reduced electricity consumption, together with the exemplary use of renewable resources and ecological building materials. Furthermore it provides for minimal heat loss due to ventilation (which is mainly natural) and for the reduction of external and internal heat loads, achieved in part by excellent use of daylight and good solar protection.

A flexible ventilation system controlled by intelligent building technology was designed for the building. Depending on the time of year, the unit occupancy and the necessary sound insulation, the system regulates air intake via a five-kilometre network of pipes, a geothermal mass heat exchanger, or by window ventilation. The low-pressure generated by natural convection in the atrium aids in extracting waste air from the offices. The waste air is drawn into the atrium via vents on the doors and discharged from the building, or when appropriate, to the centrally located heat exchangers. This pattern of air circulation assures the hygienically necessary exchange of air in spite of windows being closed due to high external noise levels, and allows additional supplementary heating of cold winter air.

The selection of all building materials took into account their ecological footprint. Thus, for example, concrete was used for the supporting structure, clay and glass for the partition walls, and wood-panelling elements insulated with cellulose fibre for the façades. The proportion of glass in the 40-centimetre thick, heavily insulated exterior wall, amounts to only 30%. In addition, the selection of triple glazing with solar protection between the two external layers achieves a degree of thermal insulation more than twice that required by the regulations currently in force in Germany. The buffer effect of the atrium enables the proportion of transparent glass in the adjoining façades to be almost 60%. Louvres on the atrium roof provide solar protection, and when necessary serve as light-deflecting elements to improve the exploitation of daylight across the structure’s narrow 11.8 metre footprint. In order to satisfy the intentions for the project, at least 15% of the building’s operational energy requirements are to be met by renewable resources. Photovoltaic panels integrated in the folded roof structure of the atrium together with solar collectors, enables this criteria to be achieved.

The new Federal Environmental Agency building will give rise to a brand of architecture implementing ecological building technology. While ecology and technology are important components of the project model’s qualities, architecture remains the principal consideration with a masterly interplay of materials, colours, and forms.

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Originally published in: Rainer Hascher, Simone Jeska, Birgit Klauck, Office Buildings: A Design Manual, Birkhäuser, 2002.