Technique to improve performance of positive pressure ventilation tactic in High-Rise fires

Abstract

Positive Pressure Ventilation (PPV) is a firefighting tactic that can assist firefighters in venting of smoke and high temperature combustion products in a more efficient manner and make the fire-rescue/suppression operation safer than without PPV. The pressure created by PPV operation must be greater than that of created by spread of fire. In real-life structures such as high-rise buildings, considering the leakages and size of stairwells, it becomes difficult to achieve the desired pressure at upper floors using PPV operation. With the help from FDNY (Fire Department of New York), on-site tests and computer simulation techniques were performed to study the behavior of PPV tactic. A technique was developed that significantly increases the positive pressure level achieved by a typical PPV operation. The efficacy of this technique was tested by conducting on-site experiments and numerical simulation methods using computational fluid dynamics software-Fluent 12.0 and NIST's Fire dynamic simulator (FDS 5.0). The results of on-site experiments and numerical simulation methods found to be in close agreement with each other and confirmed the efficacy of this technique in improving the performance of typical PPV operation. This paper describes the results obtained from these on-site tests and numerical simulation methods. As FDNY is in the phase of implementing this instrument to ease and improve the PPV deployment operation, numerical simulation methods have been used to optimize this technique and the analysis discussed in this study also simplifies the PPV fan deployment operation for firefighters.