Effect of mechanical ventilation on air infiltration rate in a concert hall

Abstract

Due to high occupant density, fresh air is essential for audience in a concert hall. Generally, mechanical ventilation system is used to supply outdoor fresh air. Apart from that, uncontrolled air leakage across building exterior (i.e., air infiltration) is also a source of outdoor fresh air. Though ASHRAE requires a positive pressure (i.e., zero infiltration rate) for mechanically ventilated rooms, positive pressure is difficult to be maintained under poor building airtightness or low mechanical ventilation rates. When the positive pressure is not achieved, the existence of air infiltration brings about outdoor air pollutants infiltrating indoors and excessive fresh air cooling/heating load. Therefore, to maintain a good indoor environment and an appropriate fresh air rate, the effect of mechanical ventilation on air infiltration rate must be figured out. This study investigates the variation laws of infiltration rate with mechanical ventilation rate in a concert hall. Infiltration rates under different mechanical ventilation rates were measured based on the particle mass balance method. It is concluded that the relationship between the two rates conforms to the theoretical model proposed by the authors’ previous study.