ВИЗНАЧЕННЯ ЗАКОНОМІРНОСТЕЙ ЗНИЖЕННЯ ГОРЮЧОСТІ ДЕРЕВИНИ З ВРАХУВАННЯМ ОСОБЛИВОСТЕЙ ЇЇ ГОРІННЯ І ТЕРМООКИСНОЇ ДЕСТРУКЦІЇ

Abstract

This study explores the mechanism and processes behind thermal oxidative destruction and the formation of char and pyrolysis layers in wood. The task addressed is to establish patterns of wood combustibility and features in the formation of pyrolysis and char layers at heating in order to improve the effectiveness of fire protection. The experimental results established that for untreated wood the average depth of the pyrolysis layer is 4 mm for birch and 7 mm for pine, while the char layer reaches 8 mm and 12 mm, respectively. When applying a fire-retardant coating, these values decrease to 1 mm (pyrolysis) and 2 mm (char) for birch, and to 2 mm (pyrolysis) and 4 mm (char) for pine. Thus, the use of fire-retardant compositions leads to a reduction in the depth of thermal oxidative destruction by 3–4 times and a significant decrease in the intensity of char formation. The findings indicate that fire-retardant coatings modify the mechanism of thermal decomposition of wood, limit heat and mass transfer processes, reduce the release of combustible gaseous products, as well as promote the formation of a thinner but more stable protective char layer. A quantitative relationship between the depth of pyrolysis and char layers and the type of wood (birch, pine) under surface fire-retardant treatment has been established. The results show a reduction in combustibility parameters compared to untreated samples. The findings could be used in the design and optimization of fire-retardant compositions, as well as for improving fire protection measures for wooden structures