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
| Mar 30, 2012
Chicago may allow people to live in retail spaces
The Chicago City Council’s Zoning Committee approved a zoning change that will allow up to 50% of work space in low-intensity business districts to be used for living space.
| Mar 30, 2012
LEED growing fast in the housing rental market
Last year, developers of 23,000 U.S. multifamily housing units applied for LEED certification.
| Mar 30, 2012
Forest Stewardship Council critical of proposed LEED 2012 changes
According to the Forest Stewardship Council (FSC), the third draft of LEED 2012, if approved as written, would represent a step backward from the current Certified Wood Credit.
| Mar 22, 2012
Symposium on water efficiency: How much more water can be saved?
The Third International Emerging Technology Symposium by IAPMO and the World Plumbing Council features a session on water efficiency.
| Mar 22, 2012
Broker doesn’t have to inform contractor that insurer went broke, California court rules
A California appellate court ruled that an insurance broker did not have a duty to inform a subcontractor that a project’s insurer had gone bankrupt.
| Mar 22, 2012
Public agencies shouldn’t negotiate project labor agreements, says AGC official
When a public agency rather than the contractor negotiates a PLA with unions, it interferes with the right of employers and workers to reach their own agreements on working conditions and benefits, says Steve Isenhart, president of the Associated General Contractors of Washington.
| Mar 22, 2012
Proposed rule would let crane operators get licenses without prior city experience
The Bloomberg administration is considering letting operators of giant tower cranes get their license without requiring that they first run cranes as apprentices in the city for three years.
| Mar 22, 2012
Bill would reintroduce “opt-out” provision in lead paint law
The Lead Exposure Reduction Amendments Act of 2012 (S2148) would restore the "Opt-Out" provision removed from the Environmental Protection Agency's Lead Renovate, Repair and Painting (LRRP) rule in April 2010.
