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 | Nov 25, 2019
Real estate professionals say coworking is not a flash in the pan
More than 60% say coworking space is in their portfolios.
Codes and Standards | Nov 22, 2019
Utility’s proposal threatens California’s rooftop solar mandate
Would allow customers to use solar farms instead of installing their own PVs.
Codes and Standards | Nov 21, 2019
Number of LEED commercial building projects surpasses 100,000
More than 2.6 million sf of space being certified each day.
Codes and Standards | Nov 19, 2019
Most U.S. voters support licensing standards for architects
NCARB survey shows strong support for architecture as a licensed profession.
Codes and Standards | Nov 18, 2019
Cambridge, Mass., teams up with utility on energy retrofit program
Buildings large than 25,000 sf targeted in initiative to further carbon neutrality goal.
Codes and Standards | Nov 14, 2019
Resistance to Toronto’s ‘smart city’ reveals pitfalls of such ambitious projects
Concerns over data privacy, governance, feasibility prompt criticism.
Codes and Standards | Nov 13, 2019
Heat pumps, strategic energy management could be next major focuses for efficiency
After lighting, efficiency experts look to new opportunities to boost energy efficiency.
Codes and Standards | Nov 12, 2019
National Infrastructure Performance Council to address ‘national security crisis’
Coalition wants to double annual level of infrastructure investment.
Codes and Standards | Nov 11, 2019
Major cities are adopting new building performance standards
Initiatives can include multiple standards.
Codes and Standards | Nov 11, 2019
U.S. hotel construction pipeline continues its year-over-year growth
In its eighth consecutive quarter of growth, projects currently under construction stand at 1,729 projects/235,278 rooms.