Structural steel is rapidly replacing concrete as a sustainable, recyclable framework for large modern buildings. A major problem faced by steel is its reduction in strength in fires. Once the temperature reaches 550°C it ceases to be able to support its design load which can lead to catastrophic collapse. Our collaborator, CPG Europe is a major manufacturer of fire protective intumescent coatings. Intumescent coatings, which appear as a thick paint layer, are designed to swell to 100 times their thickness in the event of a fire, providing one or two hours’ insulation to maintain the structural integrity of the steel. This project will review the composition of the whole coating and address the need to change various components. The cone calorimeter will be used to investigate the swelling at various stages in the process, in order to optimise formulations. The results will be compared with those from the large-scale furnace tests.