Machine rooms of a state district power plant (GRES) are sizeable. Heat impact on the structures of the building in the case of a real fire can significantly differ from the impact in the case of a standard fire. Therefore, the calculation of fire resistance of building structures should be conducted not only in conditions of a standard fire but of a real fire as well.
The objective of the study is the theoretical evaluation of the actual limits of fire resistance of load-bearing building structures of the machine room of the main building of the Nizhneturinskaya GRES in conditions of standard and real fire regimes. Numerical experiments to calculate the heating of load-bearing building structures in the case of a standard fire and the case of the most hazardous scenario of the real fire development have been conducted in the framework of the study.
A field 3-dimensional model to calculate fire hazardous factors and a non-stationary thermal conductivity equation have been applied. The obtained results have been analyzed. The field model adapted to the space-planning solutions of the machine room has been described. The most hazardous scenario of the development of real fire in case of combustion of the turbine oil spill in the sector of the machine room with the lowest height of ceiling has been chosen.
The temperature fields in the gaseous environment of the machine room at different moments are presented. It has been detected that the heating of reinforced concrete structures of the machine room ceiling is significantly uneven due to the 3-dimensional gas dynamic pattern of fire.
Dependencies of temperatures of the frame of reinforced concrete load-bearing structures of the ceiling on the time of standard and real fires in the most heated section of the ceiling have been obtained. It has been determined that the maximum temperature of the frame in the case of the standard fire is lower than in the case of real fire.
Due to the features of the 3-dimensional thermal gas dynamic pattern of fire in machine rooms of the GRES, the fire resistance of load-bearing building structures in these premises must be determined in both conditions of standard fire and real fire, considering the most hazardous scenario of its development.
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