To the questionnaire of temperature change in the reactional camera at testing of test species from wood

Abstract

Purpose.  Investigation of temperature changes in the reaction chamber when testing samples from wood.  Methodology.  Theoretical and practical studies of fire resistance, increase of fire resistance and processes of heat and mass transfer during combustion of wooden constructions, simulation of combustion processes in conditions of developed fire. Findings. Studies have shown that a significant amount of  heat  is  introduced  into  the  reaction  chamber  when  combusted,  as  evidenced  by  a  significant  increase  in  temperature  throughout  the chamber. In samples treated with liquid glass, the process of raising the temperature is slower than in the raw samples, Their temperature exceeds the temperature calculated according to the standard temperature curve of the fire. This indicates that under the flame retardant coating of liquid glass with a thickness of up to 1 mm, the process of decomposition and burning of wood is active. In this, a significant part of heat is allocated, which is indicated by an increase in temperature compared with the temperature in the chamber without specimens. It was established that the process of  combustion of samples processed in warehouses 1, 2, 3 proceeds  identically in accordance  with the general laws. At the initial stage there is a sharp increase in temperature, and then the process of combustion becomes more smooth. This is due to the fact that in the initial period of time (1-2 min) due to inertia, the coating does not expose instantly, but with some delay, because for this it needs a significant warming up to a temperature of 3000C and above. And during this time, simultaneously with the heating of the fire protection coating is an intensive process of heating the upper layers of wood and its active decomposition which is reflected in the increase in temperature on the surface of the samples. Then there is a swelling of the coating. The expanded coating reduces the heat transfer to the wood, which also affects the reduction of the burning rate under the coating (the temperature on the surface of the coating rises, but the increase is more smoothly than at the beginning of the test).  Originality.  Based on the conducted analytical studies and modeling of the heat-mass  transfer  process,  the  effect  of  combustion  on  the  change  of  the  parameters  of  combustibility  and  fire  resistance  of  wood  is revealed. Practical value. It is to increase the safety of the operation of construction objects, the safety of evacuation of people and safety of  emergency  rescue  works  due  to  the  application  of  developed  effective  compositions  that  reduce  the  combustibility  of  materials  and increase the time for safe operation of structures in extreme conditions.