Grumpy Old Teacher (GOT) has been writing about classroom ventilation for a few weeks now: Update: Dispatch from the Covid Trenches (February 12, 2021), Veni, Vidi, Vici (February 19, 2021), and C’est La Vie (February 20, 2021) complete with pictures.
Not surprisingly, for those who can do so, opening a window will improve ventilation in the sense of mixing outdoor air with the indoor air. Perhaps surprisingly for those who don’t spend their time in schools, many teachers are unable to open their windows, their classrooms don’t have windows, or they are forbidden to open windows because of security concerns.
Those open windows improved ventilation in GOT’s classroom such that the CO2 readings dropped by more than half after students had been in the room for three hours. By students, GOT means a full classroom of 30. There’s no physical distancing going on in the classrooms at his school.
Many other teachers are not so lucky. After the CDC added ventilation advice to their Covid guidelines, social media erupted with lots of comments.
The comments were negative, mainly falling along the lines of teachers whose rooms had no windows, the windows were wired, screwed, painted shut or boarded over, the openings were so narrow that students could not jump through them if they were so inclined, etc.
While GOT is critical of the CDC for its constantly-changing guidelines, which, despite their protests, seem to change to meet the political desires of the White House, both current and previous administrations, he doesn’t join those sneering at the advice.
Open a window if you can. It helps. What also helps is being able to keep the HVAC fan on, which necessitates that the adult in the room has access to the controls and can actually change the settings. That’s not always possible because the Internet of All Things has meant that school systems can control the room’s atmosphere from far away, even delegating the job to a third party contractor thousands of miles away.
And now we’re getting to it. Why criticize the CDC for issuing common sense advice? What was also included in that advice was this:
- Turn off any demand-controlled ventilation (DCV) controls that reduce air supply based on occupancy or temperature during occupied hours. In homes and buildings where the HVAC fan operation can be controlled at the thermostat, set the fan to the “on” position instead of “auto,” which will operate the fan continuously, even when heating or air-conditioning is not required.
- Open outdoor air dampers beyond minimum settings to reduce or eliminate HVAC air recirculation. In mild weather, this will not affect thermal comfort or humidity. However, this may be difficult to do in cold, hot, or humid weather.
- Improve central air filtration:
- Increase air filtration external icon to as high as possible without significantly reducing design airflow.
- Inspect filter housing and racks to ensure appropriate filter fit and check for ways to minimize filter bypass.
- Check filters to ensure they are within their service life and appropriately installed.
- Ensure restroom exhaust fans are functional and operating at full capacity when the building is occupied.
- Inspect and maintain local exhaust ventilation in areas such as kitchens, cooking areas, etc. Operate these systems any time these spaces are occupied. Consider operating these systems, even when the specific space is not occupied, to increase overall ventilation within the occupied building.
- Consider portable high-efficiency particulate air (HEPA) fan/filtration systems to help enhance air cleaning (especially in higher risk areas such as a nurse’s office or areas frequently inhabited by persons with higher likelihood of COVID-19 and/or increased risk of getting COVID-19).
- 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).
- Consider using ultraviolet germicidal irradiation (UVGI) as a supplement to help inactivate SARS-CoV-2, especially if options for increasing room ventilation are limited. Upper-room UVGI systemspdf icon can be used to provide air cleaning within occupied spaces, and in-duct UVGI systems can help enhance air cleaning inside central ventilation systems.
The CDC advice was less telling teachers to open a window than it was telling DISTRICTS TO DO THEIR JOB!
Sorry for the shouting, but GOT needs to cut through the noise surrounding this issue.
Why aren’t school districts sending their maintenance staffs into the classrooms (when they are occupied) to take readings to identify the rooms in need of immediate mitigation measures with the ventilation?
Why aren’t school districts giving control of the thermostat back to the people who are in the room?
Why aren’t school districts using their CARES act money, and there is more coming as the latest relief bill moves through Congress, to purchase portable HEPA-filtering appliances for classrooms? Also, appliances that provide ultraviolet gemicidal irradiation?
Why are school districts failing to be proactive?
That’s where our attention needs to be. Let’s hold our school districts, school boards, superintendents, chiefs of schools, and all other high leaders accountable to make our schools safe.