An experimental study of the thermal performance of a novel intumescent fireprotection coating

The thermal performance of a novel intumescent coating was investigated at a laboratoryscale. A combination of small and large-scale tests was performed in order to fullyunderstand the behavior of the coating. For small-scale testing, experiments were conductedusing thermogravimetric analyses. These experiments were run at several heating rates in anitrogen atmosphere. The results showed that the thermal degradation of the coating occurredin different stages, and, the main mass loss took place around 300°C. Furthermore, thecurrent work showed that oxygen doesn’t exert any significant effect during the early stagesof degradation of the materials; however, its interference can be noted past the attainment ofthe peak value for mass loss rate curve.For large-scale testing, the experiments were carried out in a cone calorimeter using astainless steel plate as a platform to support the test specimen. The back surface temperatureand expansion height of the intumescent coating were measured as a function of time. Severalfactors such as heat flux, distance to cone heater and coating thickness were also investigated.The results showed that the normalized expansion height of intumescent coating wasconsistent at different heat flux levels. Hence the expansion of the coating can be consideredto be dependent only on the mass loss rates and not the value of the external heat flux.Also, results from the cone tests, permit the formulation of an experimental protocol forevaluating of the thermal shielding efficiency of the intumescent coatings. The resultsshowed that the data obtained using a cone calorimeter with 2.5 cm of distance cannot becompared with other distances, such as 4 or 6 cm. The present work also showed that thevalues of the relevant parameters did not differ significantly at distances to the cone heaterabove 4 cm.In a second evaluation, the new intumescent coating was applied to polyurethane andGypsum boards, for study using cone calorimetry. The use of the coating led to a decrease inthe peak of heat release rate for combustion of polyurethane. The application of a coatinglayer can be used to decrease the overall requirement of thickness of the Gypsum boardwithout compromising its thermal insulation performance.