Text description provided by the architects. The office building of Rijkswaterstaat (RWS) houses offices, a crisis centre, state archives and a 100% guaranteed computer centre which, in case of emergency, can direct all the sluice gates of the province of Zeeland, including the Delta works. Use is made of sustainable building processes, natural materials and energy-saving technology. The available natural resources of water, sun and earth are harnessed to the maximum in and around the office.
One of the demands of the client was a layout that allows for flexible use. Paul de Ruiter's design meets this demand in two ways. Firstly, the flexible construction, both structural and in relation to utility systems, means that the building can be divided up in many different ways and can be split into large units that can be rented out. Secondly, the design provides all 450 RWS employees, who often spend a great deal of time working "in the field", with their "own" workplace by means of flexible workstations.
The design of the RWS office building fulfils an important communicative role, both internally and externally. The building expresses that Rijkswaterstaat is not an inaccessible and technocratic institution where decisions are taken behind closed doors, but that it is an easily accessible, low-threshold organisation with a clear and open structure. Communication is also stimulated among the employees in the building itself. Glass partitions between corridors and office spaces together with flexible workstations, wide corridors with sitting areas, coffee corners, meeting spots provide many opportunities for contact and exchange.
The design is strongly geared to the needs of the people who work in the building. For example, it is situated as far as possible from the noisy and busy road. And it makes the most of the location being both surrounded by nature and close to the old city centre of Middelburg by creating high-quality workplaces all with fabulous views. Heating, cooling, ventilation, acoustics and sun blinds are designed in such a way that they contribute to the comfort and health of the people working in the building. The integration of ‘active concrete' into the design means that lowered ceilings are not needed so that the office spaces have a pleasant height of three meters. Because of the reverberation the high walls can cause they are cladded with especially developed sound absorbing plates.
The client's express wish for a transparent building resulted in the use of a lot of glass. The southern façade consists of 50% glass, while the northern façade is 100% glass. The glass façades not only have a high aesthetic quality, they also admit a lot of daylight and provide a superb view. By incorporating extra fanlights above the windows on the sun side facing the canal, daylight can enter from an high angle and penetrate deeply into the building by the reflection of the slats and the white ceilings. The horizontal slats at the canal side are a defining feature of the building. They not only ensure that the heat of the sun is kept out of the building, but also that the distribution of daylight inside is optimized so that less artificial lighting is needed.
Existing techniques are used in an innovative manner to create a low-energy building, without sacrificing its economic viability or its architectural quality. The use of ‘active concrete' in combination with underground cold/heat storage creates a constant and comfortable working climate and results into an energy saving of 40% to 50% over traditional cooling and heating methods.
Active concrete regulates the temperature in the building in an innovative and energy-saving manner. Cold water pipes are fit in the concrete floors of the upper storeys, which are also the ceilings of the storeys below them, and these activate the concrete mass. When the office space heats up, the floor/ceiling absorbs a great deal of the heat, while at the same time releasing coolness. The active surfaces allow the ventilation rate to be drastically reduced.
In winter the cold is stored in the cold/heat storage about 65 meters below ground level and used in summer to cool the floors/ceilings. The heat carried away in the summer is stored underground in a separate storage. In winter heat pumps bring the heat back into the building. This system guarantees a pleasant working temperature in every season, without extra energy being required.