Study of positive pressure ventilation in room fires using a small-scale model

Abstract

Positive pressure ventilation (PPV) is commonly used for blowing out smoke and thus enhancing the visibility inside a fire scene. However, there are different views on operating PPV for firefighting and rescue. Ventilation arrangements that include the locations of PPV and exhaust openings in a room should be carefully investigated for better understanding of the efficiency of PPV in firefighting. In this study, scale modeling tests in a 1:10 room model were performed to study different ventilation arrangements in using PPV. Experiments of three fire scenarios were conducted, including (i) a single propanol pool fire, (ii) a center pool fire surrounded by four propanol pools, and (iii) a single pool fire surrounded by wood cribs. Ventilation arrangement was varied to study the temperature changes and fire spread patterns. It is observed that the ventilation arrangements would determine whether PPV is effective in firefighting of room fires. In employing PPV, the use of an opposite exhaust opening would give a clear environment without fire spread, while operating PPV would give a bigger fire in the room when there is no exhaust opening.