characterization and modeling of smoldering fire behavior in bio-based insulation materials

The building sector is showing increasing interest in the use of biobased materials. These materials derived from renewable natural resources, mainly of plant origin, have a low carbon footprint and help to limit the environmental impact of construction. In addition, most of these materials have good insulation properties and help to regulate the indoor climate of buildings. From the point of view of fire behavior, these bio-based materials need to be subjected to standard tests to validate their fire risk classification. To date, most studies have focused on fire reaction [1]. Furthermore, smoldering fire is a slow, flameless combustion that is particularly common in porous fuels such as biobased insulation, and it is a major concern for firefighters. Smoldering is a complex phenomenon that has been relatively little studied. Moreover, few studies provide an in-depth description of smoldering fires in insulating materials. It is therefore essential to improve our understanding of this phenomenon to anticipate and reduce its occurrence and, consequently, the risk of fire in buildings.

In recent years, the use of biobased concrete for insulation has attracted growing interest in the building sector. These eco-materials, which combine plant-based materials and a mineral binder, aim to insulate building by promoting the use of renewable and local resources, while also contributing to the storage of carbon. Although biobased concretes are helping to meet the new challenges imposed by sustainable development, their use is hampered by a lack of knowledge about their fire behavior. Some studies [2–5] indicate that smoldering fire is one of the most critical and specific fire-related phenomena and needs to be better understood to prevent its consequences in buildings.

The MODEFIRE thesis aims to carry out multiphysics simulation and experimental tests to provide a deep understanding of the mechanisms governing smoldering fire in insulating biobased concretes, and subsequently to propose protective solutions. To carry out this project, the issues addressed can be summarized in the following objectives:

Material characterization: when a material is exposed to a rise in temperature, its thermo-physical properties change as a function of temperature. In addition, porous fuels decompose as a function of temperature. This leads to changes in material properties. The tests will be carried out to characterize the thermo-physical properties of insulating biobased concretes in order to provide the input parameters for modelling.

Multiphysics predictive modeling: to reduce the cost of experimental tests and provide a decision-making tool for smoldering fire protection, a reliable predictive numerical model is needed. Understanding and developing a multiphysics model to predict the mechanisms governing smoldering fire in the material is essential and will be developed in this thesis.

Smoldering fire tests: to date, the mechanisms governing smoldering fire are not yet well understood and need to be studied rigorously. This thesis aims to understand the smoldering fire behavior, its propagation within the material and the influencing parameters. These tests will allow to validate the model developed.

Influence of smoldering barriers: the last objective is to study smoldering fire protection solutions. More specifically, different configurations of smoldering barriers will be studied. Numerical approaches will be used to validate the optimum configuration for limiting/avoiding the propensity of smoldering fire.

Thesis will take place at the Material Research Center of Mines Alès (C2MA) - https://www.imt-mines-ales.fr/ . The C2MA is one of the three research centers at IMT Mines Alès. Its expertise concerns the development of materials for building, transport and packaging industry with a focus on bio-based materials to minimize their impact on the environment. It provides the strategic link between training, research and economic development activities in these areas. The candidate for the proposed thesis will work with members of two C2MA teams: the DMS team (Durabilité des éco-Matériaux et des Structures), which contributes to the thermo-physical characterization and predictive multiphysics modeling of materials behavior under various stresses, and the PCH team (Polymer Composites and Hybrids), whose objective is the development of low-impact multifunctional materials and contributes to the analysis of fire behavior in materials.

The candidate should have a Master’s or Engineering Degree, with strong skills in modeling, materials, and transfer phenomena, as well as a strong interest in numerical simulation and experimental analysis. Knowledge of the fire behavior of materials would be appreciated.