Influence of adjacent trapezoidal steel sheets on the fire behaviour of I-section profiles with intumescent coatings

The thermal protection effect of intumescent coatings is based on the development of a thermal insulation foam layer which delays the heating of the steel elements in case of fire. In practical usage intumescent coatings are often applied on I-section profiles located close to the exterior wall or roof, which is realised by space-enclosing elements e.g. trapezoidal steel sheets. Consequently, the flange of the I-section profile adjacent to the space-enclosing element is completely or partially covered. As a result the foaming process of the intumescent coating is restrained in fire situation and the protection system is not able to provide its full thermal protection effect. Besides small scale tests aiming on the analysis of the foaming process of intumescent coatings, fire tests on coated I-section profiles with and without adjacent trapezoidal steel sheet are presented in this paper in order to evaluate the heating behavior of intumescent coatings in this special configuration. In this first part of the paper an overview of the experimental investigations which were carried out in the DASt research project (IGF 17200 N) is presented first. In the second part numerical investigations, which enable the simulation of the high temperature behaviour of intumescent coatings taking into account the foaming process and the prediction of the heating of coated I-section profiles will be presented.