As scientists learn more about the COVID-19 virus, opinions are changing on how it is spread from person to person, and that has implications for how to reopen buildings safely.
Emphasis to date on protocols for reopening buildings has focused on surface cleaning and occupant density. But, if as some scientists suspect, the virus can live for at least three hours in aerosols—tiny particles that can be carried through the air for long distances—HVAC systems could play a key role in spreading the virus. There are opposing views on whether aerosols actually can transmit the virus, but if they do, then ventilation systems could spread the virus through unfiltered re-circulation of indoor air.
In April, ASHRAE addressed the issue of possible aerosol transmission with recommendations that include:
· Maintain a relative humidity of 40% to 60% inside buildings instead of the usual 20% to 40%.
· Install air filters rated at least at MERV-13.
· Minimize re-circulation of indoor air, and bring in outside air either by mechanical means or by opening windows.
The humidity recommendation was made because higher humidity makes aerosols heavier, causing them to drop to the floor faster. ASHRAE has also recommended that the intake of outside air be set to the highest level permitted by the mechanical equipment. Some specialists recommend a full re-commissioning process for reopening buildings.
Related Stories
Codes and Standards | Sep 21, 2017
After construction crane collapses during Irma, regulations questioned
Cranes rated for 140 mph winds didn’t hold up to 100 mph gusts.
Codes and Standards | Sep 20, 2017
Energy efficiency measures pay off in some not-so-obvious ways
Access to better financing, tax incentives, rent premiums, among the benefits to greener buildings.
Codes and Standards | Sep 19, 2017
Benchmarking regulations prompt jump in green certified properties
2016 saw a slight rise in total certified U.S. green office space.
Codes and Standards | Sep 18, 2017
Changes likely to come to federal wetlands regulations
However, states may step up regulations as feds relax them.
Codes and Standards | Sep 14, 2017
Gentrification means a new mindset for city planners
Rising rents elicit reexamination of zoning principles.
Codes and Standards | Sep 13, 2017
OSHA issues extension for compliance with crane operator certification requirements
Comments on proposed rule sought through Sept. 29.
Codes and Standards | Sep 12, 2017
Washington, D.C. is first LEED Platinum city in the world
All city government buildings are powered by renewables.
Codes and Standards | Sep 11, 2017
Natural solutions would be most effective flood resilience policies for Houston
New green infrastructure should be part of rebuild.
Codes and Standards | Sep 8, 2017
Los Angeles luxury high-rise is first U.S. apartment building to achieve WELL Multifamily certification
Hollywood Proper Residences have verified indoor air and water quality features.
Codes and Standards | Sep 7, 2017
More than half of Houston properties at high or moderate risk of flooding are not in FEMA flood zone
Properties outside of these zones are not required to carry flood insurance.