Evaluating Positive Pressure Ventilation In Large Structures: High Rise Pressure Experiments(NISTIR 7412) NIST
One hundred and sixty experiments were conducted in a thirty story vacant office building in Toledo, Ohio to evaluate the ability of fire department positive pressure ventilation (PPV) fans to pressurize a stairwell in a high rise structure in accordance with established performance metrics for fixed stairwell pressurization systems. Variables such as fan size, fan angle, setback distance, number of fans, orientation of fans, number of doors open and location of vents open were varied to examine capability and optimization of each. Fan size varied from 0.4 m (16 in) to 1.2 m (46 in) Fan angle ranged from 90 to 80. The setback distance went from 0.6 m (2 ft) to 3.6 m (12 ft) One fan to as many as nine fans were used which were located at three different exterior locations and three different interior locations. Fans were oriented both in series and in parallel configurations. Doors throughout the building were opened and closed to evaluate the effects. Finally a door to the roof and a roof hatch were used as vent points. The measurements taken during the experiments included differential pressure, air temperature, carbon monoxide, metrological data and sound levels. PPV fans utilized correctly can increase the effectiveness of fire fighters and survivability of occupants in high rise buildings. In a high rise building it is possible to increase the pressure of a stairwell to prevent the infiltration of smoke if fire crews configure the fans properly. Although many factors contribute and need to be considered for effective PPV operations, properly configured PPV can achieve stairwell pressures that are high enough to meet or exceed the performance metrics for fixed smoke control systems.