Studies on smoke filling and smoke control systems in atria

Abstract

This thesis is focused on the studies of smoke filling and smoke control system in atria, using both numerical and experimental methods. Systematic studies were carried out in four phases, from fundamental knowledge to engineering applications. Theoretical background of smoke filling and smoke control system in atria was gethered in literature review with published papers and research reports. The fire codes on smoke control system in atrium buildings in Britain and USA, as well as the fire codes applied in China, Hong Kong, Australia and Japan, etc. were reviewed and avluated. Also, the performance-based fire codes dealing with the atrium buildings were studied. An understanding on the engineering concept of atrium smoke filling and control system was established with the survey on the architectural characteristics and the smoke control design in some typical atrium buildings in Hong Kong. Some of the fire plume models available in the literature were reviewed. The technical basis of the algorithms was reviewed and capabilities of these plume models within the atrium building were evaluated as well. The principles of smoke control system and aspect of smoke movement in atrium buildings were studied with zone model simulations on natural smoke filling process in atria using the FIRST program. The results of simulations with different plume models, fire powers, atrium types and atrium space volumes would be useful to identify the possible fire hazards, as well as to determine the suitable plume model for difference types of atria, or to develop a new plume model for atrium and other large volume spaces. A fire field model CC-EXACT was developed from the NIST CFD-model EXACT for studying atrium fires. Using the CC-EXACT, numerical simulations on smoke filling process in typical atria, smoke flows of the balcony spill plume and smoke movement in airport terminal were studied. Satisfactory results with temperature distribution and airflow pattern induced by the fire were achieved from the numerical simulations of CC-EXACT. It was determined that the fire field model CC-EXACT could be used as an alternative method to predict the smoke behavior even with sprinkler when there are difficulties in performing hot smoke tests. Experimental studies on natural smoke filling were performed in the PolyU/USTC atrium, and experimental apparatus were developed for the burning tests. Hot smoke tests were perfromed to better understand the smoke filling process, and to evaluate the plume equation available for developing a smoke filling model for atria.