Temperature distribution of the straight bar, fixed into a heated plane surface

Summary The authors present the first stage of their theoretical and experimental investigations focused on the fire protection of the steel structures using intumescent paint. In this initial stage, their results concerning the temperature distribution law (the theoretical law is validated by effective meticulously conducted measurements) are described. Their original testing bench destined to perform high‐accuracy monitoring of the temperature distribution along straight bars, having a given αg angular positioning with respect to the vertical direction is also described. By involving this testing bench in meticulously conducted experiments, the authors obtained both the effective temperature distribution along the bars and also validated the theoretical (exponential) thermal distribution law. By searching experiments, they also validate the m = const. hypothesis with respect to the massive cross‐sectional bars. Among their further goals, one can mention the searching experimental analysis on the validity of the m = const. hypothesis for the tubular cross‐sectional bars, followed by a combined experimental and numerical analysis of the 2‐D and 3‐D (unprotected and protected with intumescent paint layer) structures, as well as the paint layer's thickness optimisation, too.