A Study on Thermal Environment and Fire Safety in Buildings with Large Space

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The outer-wind influences strongly on a thermal environment and an early stage of fire in large buildings with large openings (ex.atrium and cavity space). This study investigates the thermal environment and the early stage of the fire in those buildings by some model experiments with scaling-law and full-scale field experiements. Additionally, in order to examine the validity of a normal k-epsilon turbulence fire model, these experimental results are analyzed by it numerically. From these discussions, it presents the valid design method to the problem of fire in buildings. Conclusions are as follows. (1) The model experiment with scaling law can be used to predict, in an approximate manner, the early stage of the fire in the atrium with large openings. (2) From the model experiments, the process of the stage of fire changes strongly according to the differences of the size of the area, the outer-wind direction and velocity. (3) From the full-scale experiments, the size of opening area at bottom of cavity space has considerable effects on heat and smoke movements in it. (4) The computational air flow and temperature in the cavity space by using the standard high-Reynolds number k-epsilon model are locally higher than the experimental results, because the computational results by the model with Boussinesq approximation overestimate the highly-buoyancy flows. On the whole, however, the trends and averages of the calculated results generally correspond to the experiemental results when the proper amount of heat convection element from heat source to its surrounding air is known.