Применение огнезащитных пропиточных композиций для снижения пожарной опасности деревянных конструкций с различными сроками эксплуатации

Abstract

The article presents the results of a study on the development of fire-retardant impregnating compositions for reducing fire hazard of protecting wooden structures (WS) of different lifespan. Basic scientific notion in the present work, connected with the possibility of influence of fire retardants (fire retardants) on the formation of coal residue, its structure and properties within the first minutes of fire exposure with the aim of reducing fire hazard properties of WS is not only at the initial stage, but maintaining the thermal stability and the cohesiveness of WS in conditions of prolonged fire. The results of the study using thermal analysis showed that during the development and application of fire retardants for wood long life the defining characteristics are speed and the heat of oxidation of the coal residue. This is due to the specific behavior of the long-term operation wood under fire conditions. Designed compounds effectively reduce these characteristics. So the heat of coal oxidation residue for long - term operation wood (81 years) with the composition containing dimetilfosfit and modifying additives, is reduced to 1.27 times in comparison with coal modern wood. It is shown that with increasing period of operation of WS up to 200 years, the effectiveness of this flame retardant in the reduction of the characteristics of thermal analysis is preserved. It is determined that the flame retardants can have an impact on the formation of coal residue, its structure and properties and also to reduce heat effect (20-80 °C) throughout the experiment and intensity of WS charring (1.07-1.29 times) in the conditions of fire tests according to GOST 30403-2012, despite a small amount of flame retardant in the surface layer of the structure. The effectiveness of flame retardants is also evident in the reduction of ignition time by WS in standard temperature conditions of a fire. Fire-retardant treatment of WS compounds allows to increase the resistance of structures to flammability to 1.4-1.8 times. Mechanism of fire retardant effect is evident in change of main phases of wood thermal decomposition as well as in impact on the structure and properties of formed coal layer and it’s oxidizing capacity and heat effect in term of WS fire testing. This is extremely important because these characteristics are closely interrelated with the extent of thermal damage, charring, and the intensity of heat dissipation WS, which determine ultimately their fire danger and fire resistance.