Variations in test conditions can significantly affect the performance of intumescent coatings. This study examines the impact of different furnace setups and atmospheric conditions on the fire resistance performance and char morphology of an epoxy-based intumescent coating. The results reveal notable differences in char morphology and thermal insulation properties across various setups. This work underscores the complexity of testing in large industrial furnaces, where significant differences were observed based on the steel shape and location. The chars produced in lab-scale furnaces resembled those in the outer flanges of H-columns tested in the industrial furnace, suggesting that similar thermal conditions were achieved. Samples tested under different atmospheric conditions showed differences in the pore size distribution, with smaller pores in the char exposed to inert conditions. This work highlights the sensitivity of intumescent coatings to testing conditions and emphasizes the need for developing test methods that can accurately simulate standardized heating curves.
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