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 | Aug 10, 2020
Concrete Institute and Post-Tensioning Institutes expand partnership
Will collaborate on new structural post-tensioned concrete code requirements.
Codes and Standards | Aug 6, 2020
SpeedCore demonstrates excellent fire resistance without additional fire-protective coatings
New York City approves metal-concrete product for all five boroughs.
Codes and Standards | Aug 5, 2020
Designing, redeveloping communities for zero energy needed to address climate change
District heating and cooling systems boost efficiency.
Codes and Standards | Aug 4, 2020
Virginia is the first state to adopt COVID-19 worker safety rules
Include social distancing requirements, notifications when co-worker tests positive, timelines to return to work after recovery.
Codes and Standards | Aug 3, 2020
Report aids local governments on policy options, pathways to electrify new buildings
Document focuses on switching appliances and equipment away from natural gas, propane.
Codes and Standards | Jul 30, 2020
Institute for Market Transformation acquires Energy-Efficient Codes Coalition
Goal is to achieve net-zero construction by 2050.
Codes and Standards | Jul 29, 2020
Crackdowns grow on construction firms that fail to follow COVID-19 guidelines
States, cities, and OSHA enforce social distancing, hand-washing regulations.
Codes and Standards | Jul 28, 2020
California utility adopts climate emergency declaration
Sacramento-region company commits to working towards carbon neutrality by 2030.
Codes and Standards | Jul 27, 2020
Updated Energy Plus and OpenStudio building energy modeling tools released
Software offers performance enhancements.
Codes and Standards | Jul 23, 2020
North Carolina will stop relying on FEMA flood mapping
State will identify flood zones on its own.