Sustainable School: One of the most rigorous programmes ever devised ensured that this French school is environmentally appropriate in multiple ways. It has many lessons to teach - Brief Article

Architectural Review, The, Jan, 2002 by Peter Blundell Jones

The new Lycee at Caudry near Cambrai in north-east France involved the most stringent design and construction ecological competition yet for a school in France. All aspects were considered: running energy. embodied energy, lighting, environmental quality, rainwater, sustainability, toxicity of materials, long and short term pollution, potential re-use and recycling, even waste management on the building site.

A government department called HQE (Haute Qualite Environmentale) prepared a table of 67 performance criteria, and competitors were invited to bid for the minimum environmental load they could achieve. If awarded the contract, they might stray outside the figure for this or that item, but would have to make up the loss elsewhere. Adding all together they were obliged to meet their chosen figure, with a financial penalty imposed for every point in which they fell short. Performance was to be measured on site after completion, so predictions had to be accurate. Main contractor Caroni-Sogea took, as Kroll put it, mad risks', but the figure was achieved. An enormous amount of research and technical work had to be done, different aspects of the design being shared between Kroll's office (A. U. A. I. Brussels), a second architect's office Quatr'A of Lille, and three offices of technical consultants, Tribu. Sodeg and Alain Bornarel.

Kroll stresses the need for a holistic approach, drawing no hard lines between physical and psychological issues, cultural and technical ones, or between the well-being of the individual and that of the planet. These concerns interact in complex ways, so stringent energy demands were not allowed, for example, suddenly to dictate the whole design of the school as with the famous glass wall at Wallasey, or with a huge hemispherical form for minimal surface area. Rather, Kroll went for his usual complexity and differentiation, and it makes the story complicated. The ecological design affects the form, but in ways not obvious at a glance. East-west alignment of both main teaching blocks is perhaps the strongest move, which gives them north and south faces. Southern exposure is needed for maximum solar gain, but is also more manageable with shading devices in summer because the sun is high. It is important too for the ecological concept that the linear blocks have a shallow plan-depth for daylighting.

Ecological design also profoundly affected landscape treatment, with green roofs, newly made ponds to the east, and a hillside to the west. Roof strategy was to grow vegetation on all low-pitched or flat ones not paved for access. This increases insulation and avoids the need for surface treatment, while the vegetation absorbs rain like a sponge, reducing or at least delaying run-off. It also increases the biomass, replacing lost ground with more [CO.sub.2] absorbing plants, though oddly this item was missing from the French bureaucrats' list, but Kroll did it anyway. The ponds, besides being wildlife habitats, are reservoirs for the rainwater system, supplying water for flushing lavatories and absorbing excessive run-off that could cause flash floods elsewhere. The low hill, another ecological habitat, shades the building from the west, the most difficult side for unwanted solar gain. It also absorbed all foundation soil from the site, so none needed to be carried off (so transporting energy) or dumped elsew here (generating pollution).

As in earlier projects (see for instance AR March 1987), Kroll considered that the school should be a group of buildings rather than a single monolith, and that the parts should have recognizable identities. The complex shows both that it houses a varied community engaged in many tasks, and that it is in itself a small city. Excessive scale and long labyrinthine corridors were avoided by focusing the whole institution on a single central court, open to the public but using the administrative offices as a gatehouse for symbolic control. Paved as the main concourse, the court was ordered in the traditional French way (for 'those who love order', Kroll says) with a grid of plane trees for summer shade. Glass canopies along the edge provide shelter for pupils moving from class to class. North of the court is a linear block for general teaching which ends to the west in the specialized arts tower with its cascading roofs. Opposite is the largest block, used for teaching technical subjects: sciences, laboratories, workshops. In the most publicly accessible corner north of the entrance are assembly hall and information centre (library and IT). The pointed building to left of the entrance is the pupils' common room. In the most protected position centre rear of the court is the vulnerable infirmary, and in the north-west corner the school restaurant and kitchen.

Going against the rules of the original competition, Kroll persuaded the municipality that staff accommodation should extend an existing housing street to the south-west, integrating them into the local community. In keeping with the principles of his earlier work, there was user participation as soon as the competition was over when, as Kroll put it, the 'cold skeleton' of the competition programme could be 'fleshed out' in discussions with teachers. While this resulted in no major changes of layout, there were many developments in detail.