Do we supply adequate outdoor air to buildings occupancy?

This research aims to evaluate the adequacy of mechanical ventilation, in buildings with air handling unit-variable air volume (AHU-VAV) HVAC configuration, in maintaining acceptable indoor air quality (IAQ). Occupancy and ventilation data from an academic building in Ottawa, Canada were analyzed. Zone-level occupancy was estimated based on Wi-Fi device count and simultaneous CO₂ and motion detector data. Concurrent zone-level ventilation rates were obtained from the building automation system (BAS). The data were analyzed and the per person ventilation rates were modelled. The results indicated that some zones experienced under-ventilation (less than 10 L/s-person) during 34% of occupied hours while other zones were over-ventilated for many of the occupied hours. The measured occupancy and corresponding ventilation issues shed new light on the importance of considering heterogeneous occupancy distributions during building design.