Ventilation characteristics of an air-conditioned office building in Singapore

The primary functions of mechanical ventilation systems include the delivery of outdoor air to the occupants, the removal of indoor contaminants and the maintenance of thermal comfort conditions in the occupied zones. Air exchange effectiveness can be employed to characterise the ventilation air mixing within a room. This paper presents our findings pertaining to air exchange effectiveness values in a seven-storey office building. Tracer gas analysis, based on concentration decay method, is employed to determine these values. The results indicate air flow patterns in the occupied zones which approximate “perfect mixing”. The measured concentration levels of indoor air pollutants are also found to be within reasonable limits.