BIOMETA

In order to face the current environmental, climatic and health challenges and in a context of high expectations in the building sector in terms of thermal and acoustic insulation, whether for renovation or new construction, the BIOMETA project aims to develop vegetal wools with optimised performances through a multi-disciplinary and multi-scale approach. Indeed, despite their many advantages, such as their multi-functional performances directly related to their porous microstructure and their capacity to store atmospheric carbon dioxide, several obstacles still limit their use: their flammable nature and their thickness, which is generally greater than more conventional materials. In order to provide appropriate solutions, BIOMETA has ambitious objectives, the main ones being (1) the identification and use of bio-based flame retardants compatible with vegetal wools; (2) the optimization of the material performances for a reduced thickness in order to compete with conventional materials; (3) the development of a method for the joint global optimization of acoustic and thermal performances including the fireproofing treatment and the reduction of the thickness of vegetal wools. To do this, the project is organized into 6 Tasks. Tasks 0 and 5 correspond respectively to the management of the project and the dissemination of results. Task 1 focuses on characterising the dimensions of treated and untreated fibres at the microstructural level in order to assess the effect of flame retardants on both fibres and materials. Task 2 focuses on the laboratory characterization of the acoustic, hygrothermal and mechanical properties of the materials, as well as on the development and application of modelling approaches by micro-macro homogenisation in order to simulate these performances. Task 3 is dedicated to the identification and use of biobased flame retardants compatible with vegetal wools and fire tests to verify their effectiveness. Finally, in Task 4, the solutions offered by the metamaterial approaches are adapted to the case of vegetal wools in order to optimize their acoustic properties for a reduced thickness of the insulation panels. This task also includes the wall-scale characterisation of the optimized vegetal wools prototypes produced during the project. To carry out the BIOMETA project, a tightly-knit team with multi-disciplinary skills that are adapted and relevant to the objectives has been formed around the scientific coordinator (CS). Thus, it includes the BIOGEO Pole (UMRAE and Cerema's BCI group), within which the SC carries out its activities and which is specialized in the characterization and modelling of the acoustic and hygrothermal properties of bio- and geo-based materials. The team also includes the CPDM laboratory of the Gustave Eiffel University, the LTDS of the ENTPE site, the CETELOR attached to the University of Lorraine, specialized in the manufacture of vegetal wools and the Matéria Nova laboratory specialized in fire tests. The knowledge, methods and innovative tools developed in the BIOMETA project will be widely disseminated to the scientific community, but also to building professionals and the general public. In addition, all the innovations of the BIOMETA project related to the development of fire-treated vegetal wools with optimised performance will enhance their potential. They will also contribute significantly to the broadening of the field of application of these materials by making them compatible with all types of applications in the building envelope for use in public buildings, homes and work spaces.