DGNB Seal of Quality - Sustainable in Every Respect
Text: Frank Peter Jäger/Christian Hunziker
It’s not the big centres of technology that have their nose ahead, but a small town in east Germany. Of the 28 buildings that were awarded the seal of quality of the German Society for Sustainable Building (DGNB) at the beginning of the year, the Paul Wunderlich House in Eberswalde, Brandenburg, had the best overall score. Completed in 2007, this seat of the district administration and the state council of Barnim sets a new scale for sustainable building. Not just ecological aspects are involved: the DGNB, which was responsible for developing the seal for sustainable building in conjunction with the Federal German Ministry for Building, understands “sustainability” in a comprehensive sense. The seal is meant to highlight “buildings that are particularly environmentally friendly, healthy and economically efficient and that save resources”.
The seal is awarded on the basis of a catalogue pided into five categories and comprising a total of 49 criteria. These are related to ecological and economic quality, as well as to socio-cultural and functional aspects, technical efficiency and process quality. With this approach, the DGNB seal differs from other evaluative systems that have established themselves internationally. For example, the British BREEAM (Building Research Establishment Environmental Assessment Method) also takes account of planning management and aspects such as health and comfort; but the main emphasis is placed on ecology. The LEED standard (Leadership in Energy and Environmental Design) developed in the US is oriented to the environment, but it makes far lower overall requirements than the German certificate. A look at the inpidual criteria of the DGNB seal shows just how comprehensive it is. Evaluated under the heading “ecology” are not just the consumption of primary energy and fresh water, but also general climatic aspects like the creation of ozone and a potential for overfertilization. Other criteria are the quality of the indoor air, the comfort offered to cyclists, sound insulation and ease of recycling. The inpidual points are differently weighted and ultimately form part of an overall evaluation that, in the event of success, determines the award of a seal in gold, silver or bronze.
First projects to receive awards
The Paul Wunderlich House in Barnim by the Berlin architects GAP did very well in its assessment, particularly in respect of process quality. Ecologically, too, this administrative building with a net floor area of more than 19,200 m2 was above ave¬rage; for example, in its exploitation of geothermal heat-transfer technology. Since pile foundations were necessary anyway, the energy planners had the gmi team install water-bearing pipes in roughly 500 of the piles. In winter, these convey geothermal heat into the building, while in summer, they serve cooling purposes. An ingeneous ventilation concept, energy-efficient light fittings and a highly insulated building skin also help to ensure that the Paul Wunderlich House uses only about a third of the energy of a comparable office building in a conventional form of construction.
The “etrium” in Cologne, which was also awarded the DGNB Seal in Gold, can be operated to conserve resources in a similar way. The architectural practice Benthem Crouwel, represented in Amsterdam and Aachen, designed an office building that complies with passive-building standards by requiring 70 per cent less primary energy than a conventional structure of this kind. Optimum daylighting through the central atrium, the use of rainwater for flushing WCs, and a large-area photovoltaic installation on the roof (with an annual capacity of 30,000 kWh of electricity) are further contributions in this respect.
An important role in the certification procedure is played by the planning and process phases. At this juncture, an auditor comes on the scene, a specialist trained by the DGNB who accompanies the entire certification process. Günter Löhnert from the Solidar Planungswerkstatt in Berlin sees himself as a “coordinator”. In the project for the Paul Wunderlich House, he assumed the role of an auditor. Commissioned by the building client, it was his responsibility to see that all the parties involved were drawn into the conduct of the scheme. GAP architect Thomas Winkelbauer saw no rival competence in this. He describes Löhnert as “a kind of coach” who helped to avoid conflicting goals between the various parties. “A building like this,” Winkelbauer says, “can be built only if everyone in the planning team works closely together.”
Criticism from clients and investors
Now and then, one also hears criticisms voiced about the DGNB seal. These come in particular from the parties who look after the interests of clients and investors. A lot of project developers see things quite differently, however. “In future, only buildings with a high level of sustainability will be successful and be able to assert themselves on the market in the long term,” says Stephan Kleber, member of the management of Vivico project developers, who had three of his own schemes certified. Henner Mahlstedt, too, chairman of the building concern Hochtief Construction, says: “Green building is not an ¬option: it’s an obligatory programme.” In Löhnert’s opinion, what is called for now is a step-by-step development of the system that has already been introduced. With certain criteria, for example, benchmarks are needed. But as the DGNB states, it wants to present an updated version of the certification system this year anyway. It also plans to include not just administration and office buildings in the evaluative process, but existing structures and housing as well.
Award of preliminary certificates
The DGNB seal of quality is also awarded to buildings that have not yet been built. A preliminary certificate of this kind has been issued to the project Europe Plaza, an office building in the urban development area Stuttgart 21, which is at present being planned by the Cologne office of JSWD Architects. From the very outset, the investor, Fay Projects, sought to gain certification for the scheme and therefore drew up clear goals in advance. “Sustainable buildings,” Fay managing director Ralph Esser argues, “are not just environmentally friendly and save resources. They are also economically efficient.” In terms of the “long-term value stability”, the “thermal comfort” and “the quality of the external space in relation to the building”, the project was awarded the maximum possible points.
JSWD project architect Thorsten Burgmer is delighted with this result, for he understands sustainability in a comprehensive sense. The proposed atrium, for example, will allow natural ventilation and at the same time provide a high-quality leisure space. In addition, there will be great flexibility: since the building will have four access cores, each standard floor can be pided into as many as eight leasable segments where every conceivable form of office will be possible, from cell to open-plan types. At present, one is working at full speed to coordinate the proposed technical components and constructional elements with each other, spurred on by the ambition to achieve an even higher number of points in the certification of the finished building than at the planning stage.
According to Burgmer, the DGNB criteria are a good counterpart to the planning standards already existing at JSWD. The implementation of the DGNB guidelines is nevertheless a complex matter, as can seen in the facade, according to Burgmer: “If one chooses stone from Portugal because it has a lower price, this can result in additional points under the heading of economy, but it can also earn minus points from an ecological point of view ¬because of the transport.”
For advocates of the DGNB seal of quality it is by no means inconsistent that a preliminary certificate can be issued, even though the implementation of the scheme is not fixed in detail. In their eyes, the importance of this lies in the fact that it can be applied as a kind of planning handbook. Günter Löhnert, auditor for the Paul Wunderlich House, describes it as follows: “The seal of quality serves as a means of optimizing the planning and development of the project.” For the architect Thorsten Burgmer, the challenge lies in complying with as many requirements as possible in terms of the sustainability of the building – and in the end still “coming up with something beautiful”.