An experimental study of intumescent fire protection coatings

The use of intumescent coatings plays an important role in the fire protection of structural elements. When submitted to elevated temperatures an intumescent coating undergoes thermochemical reactions that promote a higher thermal protection. To evaluate the behaviour of an intumescent coating, a set of experimental tests made on coated steel plates are performed in a cone calorimeter. These tests are performed with different heat fluxes and intumescent thicknesses. A simple and an advanced model, based in the Finite Difference Method, are presented and applied to determine the intumescent surface temperature evolution, considering the initial thickness and the intumescence variation. The intumescence effective thermal conductivity is estimated by solving the inverse heat transfer problem, considering the temperature in the steel equal to the experimental measured values. When the intumescence thickness variation is taken into account in the numerical model a higher thermal conductivity is expected, when compared with the constant thickness model.The authors acknowledge the financial support from the Portuguese Science and technology Foundation, project PTDC/EME-PME/64913/2006, “Assessment of Intumescent Paint Behaviour for Passive Protection of Structural Elements Submitted to Fire Conditions”, and fellowship SFRH/BD/28909/2006