Positive Pressure Ventilation for fighting wind-driven high-rise fires: Simulation-based analysis and optimization

In high-rise buildings wind can greatly impact fires, creating extremely dangerous and life-threatening environments for both the firefighters and the building's occupants. Positive pressure ventilation (PPV) is found to be a successful tactic, not only to mitigate wind driven fires in high-rises, but also to significantly improve firefighters' safety. The efficacy of PPV is strongly influenced by various parameters, mainly structural layouts, wind conditions, and fan deployment configurations. To optimize the application of PPV in high-rise fires, this paper investigates the impact of wind speed (0-10 m/s; 0-5 Beaufort wind scale) and relevant operational parameters on temperatures and smoke conditions using computational fluid dynamics model - the Fire Dynamics Simulator (FDS 5.0). The temperature results demonstrate that the effectiveness of PPV decreases with increasing wind speed necessitating the use of wind control devices (WCDs) in conjunction with deployment of PPV fans to mitigate the flow of heat and reduce the temperatures at primary vantage points (stairwell and public hallway). This tactic ultimately provides a safer environment for firefighters.