Exploring the Fire Behaviour of Intumescent Coatings for Steel Structures Under Different Exposure Conditions

The paper compares the performance at elevated temperatures of three water based intumescent coatings (IC) exposed to constant heat flux in a cone calorimeter with the performance of a water-based IC which has been heated in a gas furnace according to the standard and the smouldering nominal heating curves, during a previous experimental program. The tests herein presented were carried out on steel plates, with different thickness to vary their section factors, protected with IC layer characterized by different dry film thickness. Despite the IC activated at about 120 °C regardless the heating conditions (i.e., under the cone or in the gas furnace), the type of heating affected the structure of the IC char that formed during the heat exposures: both the expansion of the IC and its equivalent thermal conductivity seems to be dependent on the fire exposure scenarios.