Ventilation Counts, says CDC’s COVID Rules for Schools

November 23, 2020
Frank Diamond

Consult with experts in heating, ventilation, and air conditioning (HVAC) when determining the safety of the school environment, the CDC recommends.

The coronavirus disease 2019 (COVID-19) pandemic put infection preventionists (IPs) in the spotlight and might present expanded employment opportunities for IPs in business, government and schools.

Airflow matters when it comes to keeping schools safe for children, teachers, and staff. And school officials should make sure that their ventilation systems work properly to ensure the delivery of clean air and the dilution of possible contaminants in the air, according to updated guidelines by the US Centers for Disease Control and Prevention (CDC). Consult with experts in heating, ventilation, and air conditioning (HVAC) when determining the safety of the school environment, the CDC recommends. School officials should also adhere to recommendations from the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE).

Paula J. Olsiewski, PhD, an expert in safe ventilation standards for hospitals, tells Infection Control Today® that she welcomes the update. “I am delighted to see that CDC has updated their COVID19 guidance for schools to include HEPA portable air cleaners and a range of other steps to improve ventilation, based on ASHRAE guidance,” says Olsiewski, a contributing scholar at the Johns Hopkins Center for Health Security. “This will keep everyone safer indoors.”

However, Olsiewski wishes that the CDC had gone a bit further. The guideline update “was limited and did not include portable air cleaners … and on Twitter I was actively pushing for portable air cleaners in schools,” she said.

School administrators should review ASHRAE guidelines for schools and universities that deal with ventilation strategies for different types of buildings and what should be in place for occupancy. The CDC guidelines say:

  • “Consider running the HVAC system at maximum outside airflow for 2 hours before and after the school is occupied.
  • Ensure restroom exhaust fans are functional and operating at full capacity when the school is occupied.
  • Inspect and maintain local exhaust ventilation in areas such as restrooms, kitchens, cooking areas, etc.
  • Use portable high-efficiency particulate air (HEPA) fan/filtration systems to help enhance air cleaning (especially in higher risk areas such as the nurse’s office).
  • Generate clean-to-less-clean air movement by re-evaluating the positioning of supply and exhaust air diffusers and/or dampers (especially in higher risk areas such as the nurse’s office).
  • Consider using ultraviolet germicidal irradiation (UVGI) as a supplement to help inactivate SARS-CoV-2, especially if options for increasing room ventilation are limited.
  • Ventilation considerations are also important on school buses.”

Of course, just what a particular school can do about ventilation depends on how much money can be spent on an upgrade. When it comes to something like opening a window, moving around outdoor air dampers, inspecting and maintaining local exhaust ventilation: these cost nothing to do.

Then, it costs $100 or less to use fans along with the open windows, or repositioning exhaust or supply diffusers to redirect airflow. Then there’s adding a portable HEPA system ($500) to adding an upper room UVGI ($1500).