Mathematical model for intumescent coatings growth: application to fire retardant systems evaluation

Intumescent coatings are designed to react when they are heated, by building up a swollen multi-layered insulating structure. The substrate onto which they are applied is then actively protected. In a military framework, it is crucial to provide efficient protection to a wide range of devices and vehicles, which must be able to sustain intense thermal conditions such as fires or explosions. For this purpose, the behaviour of intumescent paints under exposure to high thermal fluxes is investigated. In order to develop and validate a model describing heat transfers in materials protected by intumescent coatings, experimental simulations of different types of radiative aggressions were carried out. A 45 kW solar furnace was used as a heat source, which allowed simulating fires and explosions. Temperature ranges and kinetics calculated by the model are similar to those observed and measured during the experiments. The mathematical model, initially developed for fire simulations, also proves efficient in the case of thermal fluxes induced by brief, violent explosions. However, the results show that a better identification of each layer's thermal properties is needed to improve the accuracy of the model. For this purpose, an experimental identification campaign using the solar furnace has to be developed.