Experimental study on fire characteristics in a double long-narrow confined space connected by multiple lateral doors

A series of experiments were carried out within a scaled-down, elongated, and narrow space featuring multiple lateral doors. These experiments aimed to thoroughly examine the fire characteristics both inside the enclosed compartment and within the connected tunnel, which were induced by the fire occurring in the compartment. It shows that the classic maximum temperature model obtained from a single confined space underestimates or overestimates the values in the carriage and tunnel, and the three-region plume law cannot effectively cover the temperature values inside the carriage, the prediction relations for the double confined space scenario are proposed. The rate of temperature decrease beneath the ceiling in the double long-narrow confined space is greater than in a single confined space, with a significantly reduced impact of HRR on the decay rate. The study also provides a segmented characterization of the influence of HRR on temperature attenuation. Additionally, distinct flame extension and spillover patterns are observed at different fire source locations. These include ceiling jet flame overflow primarily from the upper part of the lateral door and direct overflow from the entire door height. The study's findings offer valuable insights for fire assessment and control in complex confined rail systems.