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This article presents a method to model the overall fire protection performance of an intumescent coating under different post-flashover furnace fire conditions. Intumescent coatings are reactive fire protection materials, and their fire protection performance, among which the maximum expansion ratio is the key indicator, depends on the heating condition. The aim of this research is to find one common set of properties to enable the intumescent coating fire protection performance to be predicted across different heating conditions on the intumescent coating. The obtained properties are implemented in a model to predict the global expansion process of intumescent coating and the protected steel substrate temperature under various furnace temperature-time curves. This model has previously been demonstrated by the authors to provide accurate results for cone calorimeter tests under different levels of radiant heat flux (50 and 65 kW m 22) and with different combinations of steel plate thickness (5, 10 and 20 mm) and intumescent coating dry film thickness (0.4, 0.8 and 1.2 mm). This article will present the experimental results of post-flashover furnace fire tests under different fire temperature-time relationships (slow, fast and standard) for the same combinations of steel plate thickness and dry film thickness as used in the cone calorimeter tests. A comparison between the prediction and experimental results indicates that the steel plate temperature results are typically within 10% and the final expanded thickness within 20% of each other.

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This paper presents the results from four fire tests carried out on one-way spanning unbonded post-tensioned concrete floor slabs. The elevated temperature tests are augmented with the results from two additional tests carried out to failure, on slabs with identical geometry and tendon reinforcement, at ambient temperature. The fire tests highlighted the different structural response between using limestone and Thames gravel aggregates and different restraint conditions to longitudinal thermal expansion. It is shown that slabs with Thames gravel aggregates have a much higher deflection compared to slabs with limestone aggregates. The restrained slabs had lower vertical deflection compared to the equivalent unrestrained slabs. In all the fire tests, cracks directly inline and parallel to the tendons occurred owing to thermal stresses at relatively low tendon temperatures, which were not observed in the ambient tests. In one fire test, which was taken to overall collapse, it was shown that the strength reduction factors for tendon reinforcement currently used in the European design codes is conservative. The test data, comprising tendon strains, vertical and horizontal displacements and temperatures through the slab, will allow validation of developed computer models to predict the behaviour of unbonded slabs under fire conditions.