Reopening Schools in the Middle of a Pandemic

On July 7, President Trump reiterated his call to open public schools this fall. “We want to reopen the schools,” Trump said. “We don’t want people to make political statements or do it for political reasons. They think it’s going to be good for them politically, so they keep schools closed. No way.” Apparently he believes that children aren't susceptible to the virus, that they can't carry the virus back into their homes and communities, and that even if they are susceptible, they don't get as sick as the elderly who are frequently after-school caregivers. 

The reality is that COVID-19 is a highly contagious airborne pathogen, and that groups of people in enclosed spaces create a perfect petri dish in which the virus can thrive and spread quickly. Experts in building systems design recognize the contribution of HVAC (heating, ventilation, and air conditioning) systems to the spread of airborne diseases. Over decades, they have developed standards for design and operation of such systems in hospitals, where infection control matters. Such systems in operating suites, critical care units, and isolation rooms are designed, installed, and operated under very exacting regulations in order to keep patients and hospital staff safe and healthy. Even in the rest of the hospital, systems use 100% outside air, meaning that no air is recirculated in the building.

Schools, on the other hand, are not designed with the spread of highly virulent airborne pathogens like COVID-19 in mind. There are minimum ventilation standards, and in recent years the concept of ventilation effectiveness has taken hold. That basically means some percentage of the air coming through the air handling system is outside air, and that room air distribution (the registers in the ceiling) are designed and positioned to better mix the air from the air handling system in the room. But the systems don't have the capacity typically to operate with 100% outside air, which is expensive. Besides, only schools built in the last 20 or 30 years are designed with these considerations in mind, and we know that most schools are older than that in most areas of the country.

That said, there are ways to improve ventilation, and thereby improve the indoor environment where students, faculty, and staff spend their days. ASHRAE- the American Society of Heating, Refrigeration, and Air Conditioning Engineers - issued a Position Paper in April with recommendations for building systems operation in a pandemic. Those recommendations include installing high-efficiency particle filtration (HEPA filters), a 2-hour outside air flush of the building every morning before opening the building to its occupants, and increased outside air throughout the occupied period.

Yet implementation of these recommendations will not come without a cost:

- Many air handling systems are not sized to accommodate the thicker HEPA filters, meaning modification to filter housings

- Some air handler motors/fans might not be able to operate properly with the increased static pressure introduced by the HEPA filters, meaning replacing motors or fans

- Increasing the outside air to the building means increased costs to heat or cool that ventilation air (called tempering in the business)

- All this also increases personnel costs to monitor and manage the ventilation systems operation

I realize this is pretty dense for the lay person. But these highly technical considerations are essential, in my view, to reduce the risks to our children, their teachers and administrators and custodians and cafeteria workers, all those families, and the community at large. The only question is whether we have the willingness to pay.