Why Air Movement Matters for Classrooms
Since the advent of COVID-19 in early 2020, parents, administrators, and facilities teams have been more attentive to the indoor air quality in classrooms. Long notorious as an easy place for germs to spread among children who don’t always pay the closest attention to proper handwashing or mouth-covering, classrooms are now subject to in-depth studies of indoor air quality and how to improve it.
The Environmental Protection Agency (EPA) suggests that most people spend about 90% of their time indoors. Indoor air quality ((IAQ) affects health in general, but some populations, like children and the elderly, are more vulnerable to the adverse effects of poor IAQ. The EPA recommends the use of natural ventilation with air movement through windows and doors to improve indoor air quality.
In 2021, researchers at the Massachusetts Institute of Technology (MIT) reviewed classroom configurations to uncover modifications to improve air safety for students and staff. The study found that aerosol concentrations in limited airflow rooms, like classrooms, were much higher than anticipated. Using computational fluid dynamics, the group reviewed nine classrooms using HVAC systems and five using open windows. In one set of simulations, the group found that opening windows to bring outside air in using window baffles to deflect the air downward mimics a displacement ventilation scenario where the fresh air comes in from the bottom and draws the air upward with aerosols moving with it toward the ceiling. However, bringing in fresh air from windows does have an associated energy penalty and isn’t possible for every classroom since some schools have classrooms with interior walls only.
Another possibility the MIT group recommended to improve indoor air quality in classrooms is using high-efficiency filters to recirculate the HVAC air supply when the usage of fresh air isn’t possible.
The reality is that most classrooms, either due to lack of windows or temperatures that are higher or lower, simply cannot open windows to increase the flow of fresh air and improve indoor air quality. However, since we know that fresh air increases air movement and improves IAQ, how can we in the HVAC world work to improve airflow in classrooms?
Price Industries recommends using displacement ventilation and displacement chilled beams, which allows for substantial airflow. Both methods offer low maintenance, lower operating costs, and, important specifically to classrooms, lower noise levels than traditional mixing ventilation methods.
Daikin Applied knows how important ventilation is for schools. They offer a school HVAC design guide specifically for design engineers, covering IAQ, energy efficiency, sound, and more.
Greenheck has an increased focus on decreasing the risk of disease transmission through proper design and operation of HVAC systems. They offer a variety of air movement products, including supply and exhaust fans, blowers, ceiling exhaust fans, HVLS fans, and circulators to improve comfort, health, and safety.
In truth, many of our manufacturing partners are intent on improving indoor air quality in classrooms and in all the indoor spaces we share. We’re all intent on providing clean, safe air for classrooms. If you’re looking to either update an existing K-12 HVAC system or are designing a new school, please contact one of our sales engineers in North Carolina, South Carolina, Virginia, or Tennessee for expert assistance in HVAC system design and selecting the appropriate equipment for your application.
// about the author
Kelly Patterson is a lifelong learner and the marketing director at the Hoffman family of companies. There is nothing she likes more than talking about commercial HVAC systems and extraordinary customer service.