Can humidity help reduce the spread of COVID-19 in schools?
With some schools possibly reopening in the fall, K-12 leaders need to ensure their buildings are safe during the coronavirus era. And carefully controlled indoor humidity levels can help reduce the spread and transmission of COVID-19 in schools.
Nonhealth buildings, such as school facilities, should keep the relative school humidity levels between 40% and 60% during the pandemic, since moisture can reduce the amount of viruses in the air and on surfaces, according to the ASHRAE, an association that advances the design and construction of HVAC systems.
“When someone with COVID-19 coughs into a humidified space, the droplets will grab that moisture and either stay their original size or become larger,” says David Baird, senior applications engineer at DriSteem, a provider of humidification, evaporative cooling, and water treatment solutions. “Compared to large droplets, smaller particles stay in the air and remain on surfaces longer, and go deeper into the body, which increases the risk of contracting a virus and the severity of the infection.”
Tackling humidity and the coronavirus
To start, school leaders should assess the relative school humidity levels in each building by installing sensors. Once a humidifying solution has been installed, leaders can use the data collected from these sensors to determine how much to increase (or even decrease) humidity levels to stay within the 40-60% range.
Next, K-12 leaders can identify the energy sources their buildings already use to guide their decisions on what solution to adopt. “If you have a central boiler, you can use a steam-based system that can boil water like a tea kettle and send this pressurized water into these spaces,” says Baird. Other options include natural gas or a combination of humidity and cooling.
Using an air handler to change school humidity levels
An air handler, which recirculates air, can be installed near the central boiler, for example, to recirculate the pressurized water. Adding a HVAC component to the handler will disperse this recirculated air into the building. “Some handlers accept HVAC components, but if there isn’t enough space, the component can be put into a supply duct right off the discharge,” Baird says.
Another option involves pairing a central air handler with conditioning boxes that are installed in every classroom. “These boxes have individual temperature controls, but create steam clouds, which some people can think is smoke, so that can be a concern depending on the age of students,” says Baird. “You also don’t want students to be touching that piece of equipment, so keeping these boxes out of sight is beneficial.”
Some units can be installed outside a window, for example, but schools need to ensure their solutions are designed for outdoor use.
“Humidification is common sense science,” says Baird. “It is a practical solution to reducing the spread of the coronavirus and will help protect the students, faculty and staff in your schools.”
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