Fire protection of substrates such as steel or composite can be achieved with reactive insulation coatings which react when exposed to fire increasing their thermal insulation properties, thereby protecting the underlying substrate. It happens with intumescent coatings which expand and form an insulative layer at the surface of the substrate upon heating. The intumescence process results from a combination of charring and foaming at the surface of the substrate. The charred layer acts as a physical barrier which slows down heat and mass transfer be- tween gas and condensed phase. The formation of an intumescent char is a complicated process involving several critical aspects: rheology (expansion phase, viscoelasticity of char), chemistry (charring) and thermophysics (limitation of heat and mass transfer). This approach will be examined in the talk considering classical intumescent paints and new silicon-based coatings. The resistance to fire of intumescent coating protecting steel or composite is typically measured by a curve 'temperature as a function of time' and usually requires large scale equipment. Those tests are very expensive and time consuming. It is the reason we have developed reliable, repeatable and fast small scale tests. Examples for protecting steel (building applications) using small furnace delivering ISO 834 and UL-1709 temperature/time curves will be presented. Composites used for roofing and for aircraft applications will be also covered in the talk. The associated fire scenarios are flame spread evaluated by a mini Steiner tunnel (roofing) and jet fuel fire mimicked by a propane burner (10kW propane burner) delivering a heat flux of 200 kW/m~2 on the material. The fire behaviour of the materials according to the different fire scenarios will be presented and discussed.
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