Learning by Research

Thesis Title: Housing design through sonic experiments - COLEXSON 1.1 scale prototype to experiment future soundscapes from a naturally ventilated housing.

This thesis was conducted at LASA, an acoustics design office, under an ANRT-CIFRE convention. It is part of the research work on sound environments carried out by the AAU-CRESSON laboratory at E.N.S.A. Grenoble, and by the “Habitat of the Future” chair, which aims to design the housing of tomorrow. This is “action research”, as the aim of this thesis is to transform reality through tangible experimentation, while at the same time generating knowledge about these transformations.
A building's sound comfort is a major criteria for guaranteeing a good quality of life. Regulations and architectural practice deal with noise phenomena mainly through the notions of nuisance and noise against which to insulate. Yet the majority of existing buildings do not offer satisfactory sound comfort. How can we design buildings based on the experience of sound? This research is situated in the interdisciplinary fields of architecture, urban and architectural acoustics, and the experience of city ambiences. It is addressed to those involved in architectural and urban projects, both as project owners and project managers. In the process of creating a project, the project owner is the person who commissions the project, while the project manager is the person who designs and carries out the project (architects, engineering consultants, landscape architects, etc.). The aim of this research is to provide them with practical tools for sound design and decision-making, right from the competition phase. All this leads to the following question: how can we introduce listening into the design of collective housing so that it meets the challenges of tomorrow's city and contributes to a good quality of life, while at the same time engaging architects?
To answer this question, we began our research by studying intermediate spaces in built projects. These are all the spaces located between the city and the apartment, such as balconies, entrance halls, building courtyards and so on. We're interested in these spaces because they're not covered by acoustic regulations, even though they're where the sounds of the outside world (the city) and the inside world (inside the apartment) are heard. The ways in which they open up to the city and interact with each other in an architectural project shape the day-to-day sound ambiance perceived from the apartment. Using scientific methods developed by CRESSON and acoustics from LASA, we studied three categories of intermediate spaces in historic and contemporary architectural projects: transitional spaces (hall, inner courtyard, etc.), outdoor spaces around dwellings (shared terrace, roof, balcony, etc.) and the built envelope (double skin, window).

Then, to address the sound quality of tomorrow's homes, we looked at how our urban sound environments might evolve. Tomorrow, we'll be experiencing more and more heatwaves, and dense cities will be all the more inclined to encourage these phenomena. This raises a number of questions about the quality of living together. How can we live in this density with the sounds of the outside world? Looking ahead to a post-carbon city subject to numerous climatic hazards, we have imagined a diversity of uses, mixed-use programming, soft mobility (hybrid and electric motors in particular), and the proximity and neighborliness brought about by density. In this context, how can we cool a dwelling with natural ventilation, while offering residents the ability to modulate their listening? How can the porosity of the apartment be envisaged while guaranteeing acoustic comfort?
We are convinced of the importance of experimentation in answering all these questions and integrating listening into the architectural project process. To this end, we have tested a number of concrete tools that can be grasped by those involved in a project. The sound analysis method for architectural projects was applied to a concrete case study in Villeurbanne (69), macro-lot B, right from the initial design phases, in order to anticipate its sound ambiances. Experimentation with these ambiences from a naturally ventilated dwelling and from its intermediate spaces was incorporated into the design of a 1:1 scale prototype of ECHAfaudage SONore - ECHASON. A 1.1-scale prototype is a life-size realization of an object, in this case an architectural construction, that can be experimented and tested. As the entire project could not be realized, two prototypes of the Ouvrant de Ventilation Naturelle Acoustique - O.V.N.A. - integrating sound filtering were built and tested with project participants. They involve experimenting with a standard window and a second window in a built-up block, integrated into a facade, which allows air to pass through with a high degree of sound attenuation. This is a low-tech device enabling residents to directly influence their thermal, aeraulic and acoustic comfort. Several soundtracks anticipating the intermediate spaces of macro-lot B were tested with future residents of this project. All the innovative results developed in this research led to the drafting of three specifications for integrating the sound dimension into future architectural and urban planning competitions.
So, by first rejecting the idea that sound in the city is merely a nuisance, a noise that can be measured in decibels, we can open up a multitude of ways of conceiving through sound. The quality of the sound environment must be integrated into housing design in the same way as considerations of sunlight, air quality and summer comfort. This represents a social, economic, environmental and health challenge. It is in this sense that this work defends the idea of designing housing through listening, not just in a defensive or corrective way, but rather in a creative and committed way.

Key words: soundscape, low-tech acoustic device, acoustic natural ventilation, density, urban sounds, 1.1 scale prototype, , sound comfort, listening anticipation, summer comfort

Doctoral School: ED SHPT - Humanities, Political and Territorial Sciences
Research laboratory: Laboratoire Ambiances Architectures Urbanités (CNRS/UGA - ENSAG-UGA/ENSAN/Centrale Nantes)
Thesis supervision: Olivier BALAY and Samuel TOCHON DANGUY

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