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 | Oct 26, 2017
Boston’s Old South Church asks tower developer for $19 million for casting shade
Request highlights ongoing conflict between developers and residents over right to sunshine.
Codes and Standards | Oct 24, 2017
Asphalt roofing design guide now available in digital form
Recently updated Modified Bitumen Design Guide can be viewed on smartphones and tablets.
Codes and Standards | Oct 23, 2017
Energy efficiency investments on the rise; will increase next year
Survey of facility management executives shows onsite renewables, energy storage will spike in 2018.
Codes and Standards | Oct 20, 2017
AIA contract document updates include new BIM, digital data provisions
Documents are structurally different from 2007, 2008 versions.
Codes and Standards | Oct 19, 2017
IAPMO seeks proposals for 2021 Uniform Plumbing Code, Uniform Mechanical Code
The deadline is March 16, 2018.
Codes and Standards | Oct 18, 2017
States impacted by hurricanes are improving their energy efficiency policies
Florida, Texas, rise in ACEEE state energy efficiency scorecard.
Codes and Standards | Oct 17, 2017
Updated versions of EnergyPlus and OpenStudio building energy modeling tools released
Open-source apps include enhancements for urban-scale modeling.
Codes and Standards | Oct 16, 2017
New, comprehensive insurance exhibit released in AIA 2017 contract document updates
Will allow AIA to make updates more frequently as insurance market changes.
Codes and Standards | Oct 12, 2017
New AIA contract document designates responsibilities for sustainable projects
Roles of architects, contractors outlined in E204–2017.
Codes and Standards | Oct 11, 2017
Data, transparency are keys to next steps in green building, says USGBC chief
Monitoring and comparing performance are critical to advancing sustainability goals.