Water resistance of intumescent coatings for fire protection of steel structures

Abstract

This work aims to study the water resistance of intumescent coatings used for protection of steel structures. The vulnerability of the flame retardant system to water can compromise the performance of the coating due to the solubility of the components. In order to evaluate the water resistance of three selected commercial coatings available in the market, they were exposed to different environments (continuous condensation chamber at 40 ºC and immersion in water). The effects of the mentioned conditions in the flame retardant system were analysed by Thermogravimetry (TG), Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). In addition, to analyse the foam layer behaviour, the coatings exposed to the above mentioned conditions, were heated up to 750 ºC in a muffle furnace. The results obtained suggested that under high humidity environments the coatings can lose the components responsible for the intumescent process, with adverse consequences to the formation of the insulate barrier layer that protects the structure.