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 16, 2018
Nearly a quarter of opioid overdose deaths attributable to construction workers
Massachusetts public health study finds pressure to work in pain contributes to problem.
Codes and Standards | Aug 15, 2018
ICC creates new committee on building safety and security
Will include experts from many different disciplines.
Codes and Standards | Aug 14, 2018
Philadelphia adopts 2018 IECC energy code, while state opts for 2015 code
City is one of the first jurisdictions to adopt newest code.
Codes and Standards | Aug 9, 2018
Denver’s goal of 100% renewable energy by 2030 includes net zero energy buildings
Community solar programs for low income residents part of plan.
Codes and Standards | Aug 8, 2018
Too much parking in U.S. cities proving costly
As car ownership rates drop, excess parking seems more wasteful.
Codes and Standards | Aug 7, 2018
International Fire Safety Standards (IFSS) Coalition created
Professional associations and building standards organizations join forces.
Codes and Standards | Jul 31, 2018
Workers allegedly held in captivity by construction subcontractor in San Jose pay theft case
Contractor pays $250,000 in back wages in Dept. of Labor enforcement action.
Codes and Standards | Jul 17, 2018
Heat island effect can turn deadly in extreme conditions
Of all the impacts of global climate change, it’s extreme heat that kills more Americans each year than any other weather-related event.
Codes and Standards | Jul 17, 2018
NIMBYism, generational divide threaten plan for net-zero village in St. Paul, Minn.
The ambitious redevelopment proposal for a former Ford automotive plant creates tension.
Codes and Standards | Jul 17, 2018
In many markets, green features are more of a requirement for apartment renters
Renters in many U.S. cities have come to expect green features in apartments that they rent, with an eye toward energy efficiency and healthy indoor air.
