Does COVID Have You Wondering About Your Building’s IAQ?

We now know that filtration and ventilation are key to reducing the risk of spreading COVID-19. But how do you know how much is adequate, and exactly which steps to take to improve?

The World Health Organization (WHO) recently released its “Roadmap to improve and ensure good indoor ventilation in the context of COVID-19” for those of us who could use a little handholding. The document outlines the minimum ventilation and airflow requirements for three use types—health care, non-residential, and residential—and even includes guidance about how to assess your ventilation systems. (Hint: start by checking your system’s technical manual to verify system capacity.) A series of “key questions” then leads users through more strategies to improve indoor air quality, such as boosting air mixing and cleaning or upgrading filters.

WHO provides versions of the roadmap for both mechanical and natural ventilation systems because the strategies involved differ. For example, a non-residential building with a mechanical ventilation system is advised to run its HVAC system on maximum outside airflow for two hours before and after it is occupied. In non-residential buildings reliant on natural ventilation, occupants must open the windows before and after occupied times, and for roughly 15 minutes when entering the room.

Although WHO was slow to acknowledge airborne transmission, this resource acknowledges the role that properly designed and managed HVAC systems can play.