Approach for modelling thermal properties of intumescent coating applied on steel members

Abstract

Thin intumescent coating (IC) are nowadays the dominant passive system used to protect structural steel in case of fire. This paper proposes a general procedure for modelling intumescent coating in both simplified and advanced calculation methods, starting from lab-scale test results. The small-scale tests were useful for identifying the parameters that mostly can affect the behaviour of the IC under fire and the salient temperatures, which characterize the IC thermal conductivity. Starting from these results, a standard multivariate linear regression analysis is applied, in order to obtain a general expression for calculating the thermal conductivity of IC, useful for performing analytical and numerical modelling of the IC. Indeed, the proposed formula was validated against both small-scale and real-scale experimental tests, obtaining a very good agreement between experimental and simulated data. The procedure proposed in the paper can be used both in the simplified calculations, according with the prescriptive based approach, and in advanced analyses, using the performance based criteria for structural fire safety.