After a research letter found that air conditioning blew droplets around a restaurant in China, infecting three families, people began wondering if air conditioning could spread infection.
Experts say in commercial buildings, ventilation systems should use outdoor air if they can.
HVAC industry association REHVA told its engineers to stop recirculating air in buildings where there had been an outbreak of COVID-19, the disease caused by the coronavirus.
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Forecasters are saying the heat is going to be scorching in America this summer, and some experts are wondering what this means for commercial businesses contemplating reopening.
Gyms have outlined a range of measures to make their spaces safer. Gold’s Gym suggested spacing treadmills further apart. Anytime Fitness will place markers on the floor so people stand far apart. Equinox’s executive chairman Harvey Spevak said they are not opening yet, but he expects they may ask people to book time in the gym, to limit capacity.
None of the re-opening gyms have touched on the subject of what they will do about air conditioning, nor have the retail stores, movie theaters, and social clubs that are will soon be accepting customers in states like Georgia and Idaho.
But a study, published in early April, has raised questions about whether those plans should take air-conditioning into account.
According to the report, nine people were infected with the coronavirus in mid-January after dining on neighboring tables in the same restaurant in Guangzhou, China. The researchers concluded one of the diners had an asymptomatic case, and the air-conditioning unit blew her viral droplets across the room.
The research triggered different responses from the boards that advise the air-conditioning industry.
In the US, ASHRAE said AC units should not be shut down in the summertime, writing: “Unconditioned spaces can cause thermal stress to people that may be directly life threatening and that may also lower resistance to infection.”
Their European counterpart (REHVA) said the opposite: they told engineers to stop recirculating air in buildings where there had been a COVID-19 outbreak.
According to scientists who study ventilation, both of those perspectives are valid. Here’s what business owners should consider:
Keep windows open, or use an AC unit that brings in air from outside
In a recent study, researchers at the University of Oregon and the University of California, Davis, teamed up to study how to limit the spread of the novel coronavirus in built environments. They concluded, much like REHVA, that the safest way to ventilate a space is to open a window.
“The droplets that may have viruses follow the air very easily so they will go right out the window,” said Ana Rule, assistant professor at the department of Environmental Health and Engineering at the Johns Hopkins Bloomberg School of Public Health.
Qingyan Chen, a mechanical engineering professor at Purdue University, agrees. Where it’s not possible to open a window, Chen recommends that supermarkets, gyms, movie theaters, and other commercial buildings supply their ventilation systems with 100% outside …read more
Source:: Business Insider