Research of the mechanism of protecting wood with intumescent coating

Abstract

The object of research is intumescent coatings for wood, which, under the influence of high temperatures, are capable of forming a coked cellular material layer on the wood surface, which prevents the passage of temperature to the material. One of the most problematic areas in the application of these coatings is the unknown efficiency of the application and their performance characteristics. The effectiveness of wood fire protection in building structures and wood products is determined by the level of their ability to withstand thermal effects and is determined by the schedule of components under the influence of temperature with the absorption of heat and the formation of non-combustible gases. Thermal destruction of protected wood was carried out and volatile destruction products were identified, and a change in the components was obtained, namely, during thermal decomposition of fire-protected wood, the amount of combustible gases decreases and the amount of inert gases increases in the reverse order. To establish the effectiveness of wood protection with the given coating, it is necessary to conduct research on the wood flammability. In the course of the study, standardized equipment in accordance with DSTU 2289 was used. It was experimentally established that the treated wood is characterized by a low weight loss (2.2 %) and a flue gas temperature of less than 200 °C, and also belongs to hardly combustible materials. This is due to the fact that the coating, when exposed to high temperatures, forms a significant swelling coefficient and contributes to the formation of a heat-insulated coke layer, which prevents the wood from burning out, and the passage of high temperature to the material. Thanks to this, it is possible to obtain wood with indicators that do not spread a flame on the surface, and with a moderate smoke-forming ability. Compared with similar known inorganic-based coatings, characterized by low adhesion to wood with fluctuations in temperature and humidity, it provides such advantages as lower coating consumption and its weather resistance.