Thermal mass application
Environment is a key priority for the city of Créteil near Paris. When architects Agence Nicolas Michelin et Associés were selected to design a building comprising a kindergarten, primary school and leisure centre, the priority was to create a sustainable building. This building was developed following the guidelines of the French H.Q.E (High Environmental Quality) program with the goal of minimising energy consumption while meeting the requirements of local regulations in terms of thermal insulation and acoustics in order to create a comfortable learning environment.
In order to minimise energy consumption, several techniques were implemented including the use of the building’s thermal mass, solar panels and green roof. Thermal mass relates to the ability of a building to store the heat it receives and re-use it when necessary. In order to optimise thermal mass, it is necessary to use materials with a high inertia – like concrete – which need to remain uncovered. This design therefore does not enable the use of suspended ceilings which are traditionally used in education buildings to achieve optimum acoustics, usually by reducing reverberation time. Indeed, the various materials used in the building (concrete, glass, hard floors) are extremely reverberant and the only option was to absorb sound but not cover up the ceiling entirely. Rockfon’s Coloral Acier/Fibral-Polar Aluminium ceiling panels were selected and installed in ceiling island configurations at a distance of 20cm from the concrete deck and on 50% of the surface. This construction has the benefit of enabling the air to flow freely in the room for thermal mass activation while absorbing sound on both sides of the panels. In classrooms, the distribution of the islands in the room was carefully studied by Aline Gaulupeau, acoustician at Peutz Associates, in order to not absorb too much sound above the teacher and to therefore enable the sound to travel to all corners of the room.
Mrs. Gaulupeau carried out on-site “before and after” measurements and is fully satisfied with the final solution; the reverberation time was, on average, halved and final results were above her expectations. From an aesthetic point of view, Architect Mr. Lorch strongly wanted to implement a solution that differed from traditional, white, 600 x 600mm ceiling tiles and is extremely pleased to have found a solution that – thanks to its colour, format (2400 x 600mm) and layout – gives the impression of floating in mid-air and harmonises with the rest of the building.