|Guidelines are ever changing, but both ASHRAE (the standard setting body in the US for heating, AC and refrigeration) and REHVA (the European equivalent) have been coming out with some warnings and recommendations.|
ASHRAE’s Environmental Health Committee says we need to take the threat of virus spreading through the HVAC systems seriously:
ASHRAE Statement on airborne transmission of SARS-CoV-2:
- “Transmission of SARS-CoV-2 through the air is sufficiently likely that airborne exposure to the virus should be controlled. Changes to building operations, including the operation of heating, ventilating, and air-conditioning systems, can reduce airborne exposures.”
- Source document
REHVA describes 3 methods of transmission:
- Small droplets from people coughing, sneezing, talking, and breathing, can remain active in the air for 3 hours in indoor air.
- Large droplets also caused by people sneezing and coughing settle on surfaces where they can remain active for 2-3 days. People contract the virus by touching these surfaces and then touching their eyes, nose or mouth. If within about 6 feet of a person who sneezes, coughs, or even talks, the virus can be inhaled directly.
- Restroom transmission. Flushing a toilet creates droplets which can get on surfaces or into the air and infect people.