How do occupancy patterns affect a building's airflow balance, and what corrective actions are typical?

• A. Occupancy has no effect; only HVAC equipment matters.
• B. Occupancy patterns affect required supply airflow; mis-match leads to imbalance; adjust scheduling.
• C. Only temperature setpoints matter for balance.
• D. Occupancy affects only electrical load.

Answer: (B)

Occupancy drives how much ventilation and conditioning each space actually needs. When people come and go, the sensible and latent loads in a zone change, so the amount of supply air required to maintain comfort and air quality also changes. If the system keeps a fixed supply rate or schedule, some zones end up with too much air and others with too little, which throws the airflow balance off and can cause comfort issues or stale air in occupied areas.

The typical corrective action is to bring supply and ventilation in line with actual occupancy. This often means adjusting schedules and implementing demand-controlled ventilation, using occupancy or CO2 sensors to modulate outside air and zone dampers. After changes in occupancy patterns, rebalancing the system to verify and set the correct airflow in each zone is common. You may also tweak economizer and ventilation reset settings to maintain the proper balance across zones.