Modeling fan-driven flows for firefighting tactics using simple analytical models and CFD

Airflow control has become a large part of the tactical toolbox that firefighters use to combat fires. Control of airflow requires managing the impact of environmental conditions (i.e., wind) and optimally using mechanically generated flows from fans to drive air and combustion products through predetermined vents. This article discusses the ability of analytical and computational models to predict flow variables associated with the use of positive pressure ventilation. To make these predictions, it is shown that various levels of approximation and a knowledge of (the often neglected) structure leakage rates are required. This study details experiments and simulations of airflow rates associated with fan-induced pressure differences between the environment and a structure.