Dependence of the smoke-generating ability and toxicity of combustion products of fire-retarded wood on the method of its processing

At present, worldwide wooden housing is developing quite intensively, but one of the factors constraining the widespread use of wood in construction remains its high fire hazard. The objective of this work is to investigate the regularities of the processes of smoke generation and release of toxic products of thermal decomposition under the impact of incident heat flux of different power on the finishing materials made of fireproof wood for subsequent prediction of their behavior under various modes of fire in buildings. Two different in chemical composition biological flame retardant agents, applied to pine wood by surface treatment and deep impregnation methods, were chosen as research objects. Evaluation of smoke-generating parameters was carried out using a standard method according to GOST 12.1.044-89 Clause 4.18. Evaluation of combustion products toxicity was carried out by experimental and computational method according to GOST 12.1.044-2018 Clause 13. As a result of researches, a functional relationship between the smoke generation coefficient in the smoldering combustion mode and the toxicity index during thermal oxidative decomposition of flame retardant wood treated with different methods and compositions was obtained. From the data obtained, it follows that wood treated with deep impregnation has a lower risk in terms of both smoke generation and release of thermal decomposition toxic products, practically over the entire range of thermal exposure. The following results were obtained in the course of the research performed: – the possibility of achieving the coefficient of smoke generation and toxicity index of combustion products of flame retardant wood, corresponding to the regulated parameters of fire-proof use on the escape routes has been determined; – dependences of smoke generation and toxicity of combustion products of flame retardant wood on the intensity of thermal exposure have been found out; – the need to take into account the dynamics of change in the smoke-generating capacity and toxicity of combustion products at different thermal flux densities affecting the finishing materials in the spread of a fire in the room has been justified.