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Evaluating Positive Pressure Ventilation In Large Structures: School Pressure and Fire Experiments (NIST TN 1498)



Stephen Kerber, Daniel M. Madrzykowski


A series of experiments was run in a masonry educational building examining the ability of fire service Positive Pressure Ventilation (PPV) fans to limit smoke spread or to remove smoke from areas where potential occupants may be located. The PPV fans are able to accomplish this by creating pressures higher than that of the fire to manage where the smoke and hot gases flowed in the building. Preliminary experiments examined the pressure increase created by portable fans and mounted fans in different configurations and locations. The two main fire scenarios included a long hallway with classrooms and a gymnasium. Both scenarios included fires that produced a large amount of smoke and hot gases, and instrumentation was placed to assess tenability criteria and how PPV tactics can either increase or decrease tenability. Measurements included temperature, pressure, thermal imaging and video views. In the limited series of experiments in the long hallways of this masonry educational building, the use of positive pressure ventilation to increase pressure to reduce temperatures, limit smoke spread and increase visibility was effective. This series of experiments demonstrated that fire service positive pressure ventilation fans can be used successfully in large structures to increase tenability of potential victims and improve conditions for firefighting crews.
Technical Note (NIST TN) - 1498
Report Number


ventilation, structures, schools, pressure, experiments, fans, fuel load, temperature, smoke, visibility, occupants, uncertainty, smoke spread, scenarios, high temperature gases, instruments, masonry


Kerber, S. and Madrzykowski, D. (2008), Evaluating Positive Pressure Ventilation In Large Structures: School Pressure and Fire Experiments (NIST TN 1498), Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 20, 2024)
Created July 1, 2008, Updated November 10, 2018