The evaluation of the fire-retardant efficiency of intumescent coatings of steel structures exposed to high-temperature gas flows

Introduction. High-temperature gas flows often occur in case of a fire at oil and gas facilities; gas flows out of holes, cracks, ruptures in depressurized items of equipment and pipelines. The fire-retardant efficiency of intumescent coatings of steel structures, exposed to high-temperature gas flows, plummets. Hence, the task of developing a methodology for the adequate assessment of their fire-retardant efficiency is relevant. Goals and objectives. The purpose of the study was to develop a methodology for evaluating the fire-retardant efficiency of intumescent coatings for steel structures exposed to high-temperature gas flows and experimentally evaluate the fire-retardant efficiency of various intumescent coatings. The following research-focused tasks were solved: the evaluation of the velocity of high-temperature gas flows leaving depressurized items that normally operate under pressure; the analysis of the methodology designated for identifying the fire-retardant efficiency of intumescent coatings of steel structures in a calm (sedentary) gaseous medium; the development of a method for evaluating the fire-retardant efficiency of intumescent coatings of steel structures exposed to high-temperature gas flows; the experimental evaluation of the fire-retardant efficiency of various intumescent coatings in a high-temperature gas flow. Methods. The velocity of high-temperature gas flows, leaving depressurized items that normally operate under pressure, has been calculated. The co-authors have analyzed the established methodology used to identify the fire-retardant efficiency of intumescent coatings of steel structures in a steady (sedentary) environment, where gas temperature in a furnace is the only factor taken into account. The co-authors propose a method for evaluating the fire-retardant efficiency of intumescent coatings of steel structures exposed to high-temperature gas flows, which takes into account gas flow temperature and velocity. To evaluate the fire-retardant efficiency of an intumescent coating exposed to a high-temperature gas flow, a coefficient of relative fire resistance is introduced. An experimental evaluation of various intumescent coatings is carried out. It shows a substantial fire- retardant efficiency decrease in a high-temperature gas flow that fosters the hydrocarbon temperature regime. Results and discussion. Mutual aerodynamic and thermal effects of a gas flow substantially reduce the fire- retardant efficiency of intumescent coatings of steel structures, and this is proven by the results of experiments conducted according to the proposed method. The method for evaluating the fire-retardant effectiveness of intumescent coatings of steel structures takes into account the temperature and velocity of a gas flow that affects the sample. Conclusions. It is relevant and necessary to evaluate the fire-retardant efficiency of intumescent coatings of steel structures at oil and gas facilities, operating under pressure, since a substantial decrease in their fire-retardant efficiency is observed in high-temperature gas flows.