Ventilation rates of classrooms as an example of authentic inquiry in STEM

Abstract

Ventilation has always been closely linked to thermal comfort, which affects productivity of building occupants. In view of the COVID-19 pandemic, heightened attention has been brought to the ventilation of classrooms, an important factor in evaluating the risk of school-based transmission of the SARS-CoV-2 coronavirus. This study investigates the ventilation rates of different types of classrooms in a school, located in the Bukit Timah area of Singapore. Using an Arduino sensor with a carbon dioxide sensor and the model of carbon dioxide decay, it was found that the air changes per hour (ACH) is ideal for all classrooms above ground when the windows were open, regardless of whether the fans were turned on. On the other hand, when the only ventilation is the air conditioner, there was low and insufficient ACH for any classroom regardless of its location. For rooms which were partially underground and enclosed, this problem was resolved similarly by turning on the fans and opening the windows, where cross ventilation yields ideal ACH. The exception was the case when two of these partially underground rooms were combined into one, where the ACH was only at a bare minimum even when the windows were opened and fans were turned on.