Исследование изменений свойств огнезащитных покрытий интумесцентного типа методом термомеханического анализа

Introduction. Fire protection of metal structures is one of the urgent problems of increasing fire resistance of structures, for which purpose intumescent type materials are currently used, which have a limited service life. At the same time, technical documentation on fire protection means has no data on the preservation of properties of the created fire protection system depending on the terms and conditions of operation. The aim of the study is to approve the method of thermomechanical analysis to assess the preservation of fire protection properties of the fire protection system during its operation. Theoretical foundations. In modern conditions, experimental assessment of the preservation of properties of fire protection means, as a rule, is not carried out, the manufacturer is limited to conducting tests to determine the values of fire protection effectiveness of fire protection means, which contradicts the requirements of national standards. At the moment, there are no standardized test methods for the preservation of fire protection properties of fire protection means depending on the terms and conditions of operation in our country. Methods. Optimal parameters for testing fire protection products using the thermomechanical analysis (TMA) method were determined, and changes in fire protection products subjected to climatic aging were investigated. The authors suggest using of universal parameter with accurate physical explanation — the coefficient of volumetric expansion, instead of rather subjective and inaccurate parameter — the swelling coefficient. Results and discussions. Specimen aging process demonstrates significant changes in the coating, for example heat-protective foam layer formation, which leads to the situation when fire protection system is not effective in ensuring required fire resistance limit under operating conditions. The coefficient of volumetric expansion for the specimen with climatic aging is reduced by more than 40 % when used for six or more years. Conclusions. The study demonstrates that heat-insulated layer of a fire-retardant coating during operation for more than three years is significantly reduced. The use of thermomechanical analysis method can serve as an ad ditional proof for the effectiveness of fire protection product, both within the framework of construction control and real operating conditions.