Evaluating methods for preventing smoke spread through ventilation systems using fire dynamics simulator

Fires in enclosures equipped with mechanical ventilation remain one of the key issues for fire safety assessment in multifamily homes and industries. Therefore, a wide variation of methods for preventing smoke spread through the ventilation system exist and are applied, in performance-based designs. Through the use of the heating, ventilation and air conditioning (HVAC) model in the fire dynamics simulator, several different common and less common methods for preventing smoke spread in the ventilation system were tested. The effects on smoke spread with changing building leakage and fire growth rates were also investigated. The results were evaluated by determining the total soot spread from the fire room to other compartments connected to the ventilation system, as well as soot/thermal load on the fans and system in general. The maximum and average heat release rate was also of interest and hence compared between systems. It was found that, while many methods perform similar, a few proven methods, such as fire and smoke dampers, performed very well with very little smoke spread to the rest of the system. The study should be considered as an introduction to implementing a similar methodology in specific cases because different ventilations systems will present very different challenges and weaknesses.