Review and application of engineering design models for building fire smoke movement and control
Mingchun Luo, Yanfu Zeng, Ling-chu Su, Xinyan Huang
Abstract
Since the 1970s, researchers developed semi-empirical models to describe fire smoke movement inside building, but there are three major issues. Firstly, several plume models are available to estimate the smoke production rate and the capacity of the smoke extraction fan, but their discrepancy or accuracy is unclear. Secondly, the phenomenon of stratification affects the vertical transportation of smoke, and influence the activation time of the detectors and the efficiency of the smoke extraction system. A stratification model is available from literature to calculate the maximum height that the smoke can rise, but it cannot cover all design scenarios. Thirdly, the size of the smoke reservoir has been regulated in fire regulation. The regulation does not consider the factors that strongly affect the movement of smoke in the reservoir, such as the ceiling height, reservoir shape, smoke temperature, etc. These models are difficult to directly apply for a practical design project, and some clauses of the fire regulation do not address the requirements correctly and become a hurdle of design. This paper depicts the cases encountered during the design in the past decades and provides detailed process of solving these issues. The approach of the design process demonstrates how fire engineers further develop the fire models and fill the gap between research and engineering practice. This paper systematically examines the fire smoke models for the plume, vertical transportation of the smoke, the ceiling jet, and smoke spreading underneath the flat ceiling, and provides practical solutions for each of the smoke development stages.