A stairwell pressurization system is interconnected to a fire alarm forsimultaneousoperation. As a result, when the fire alarm system is sounding, thepressurization system is usedto create a positive pressure in the stairwell and prevent smoke orsubstantially reduce any smokepenetration into the stairways. The system includes one or more fans which areoperated at thesame time as the existing fire alarm system. The operation of the fans forcessmoke free air fromoutside the building into the top and bottom of each stairwell. This creates apositive air pressurein the stairwell, which prevents the movements of smoke from the buildinghallways andcommon areas into the stairwells, creating a safe area for individuals to exitthe building. Thesystem maybe further configured to turn off any secondary roof top ventilationsystem whichprovides airflow to the building hallways or common areas. This advantageouslyreducespressure from the common and hallway areas, resulting in enhanced airflow fromthe pressurizedstairwells into the hallways. In case of stairwell exit doors being openedsimultaneously,pressure sensors in the stairwells are used to sense a pressure drop. Uponsensing a pressuredrop, the sensors are used to provide control signals to the fans to operateat increased power andspeed until the pressure in the stairwell is returned to a desired level.
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