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.
