A series of six experiments was conducted in a highrise apartment building in Chicago, Illinois. One experiment on each of the fire floors utilized portable fans and the other utilized a large truck or trailer mounted fan. The two experiments on the third floor examined the effects of wind driven fire conditions. All of the experiments created high temperatures and dense smoke conditions in the hallway. Numerous configurations were used during the experiments and the ability of the fans to keep smoke and heat out of the stairwell was analyzed. The minimum design pressures of NFPA 92A were used as baselines to compare to the actual pressures measured.In this limited set of experiments portable fans and mounted fans were able to quickly clear the stairwell of smoke and maintain a pressure high enough to prevent smoke infiltration into the stairwell. Positive pressure ventilation fans utilized correctly can increase the effectiveness and safety of fire fighters and survivability of occupants in high-rise buildings. When configured properly PPV fans can meet or exceed previously established performance metrics for fixed smoke control systems.