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 | Mar 29, 2015
Elevator shafts a major source of heat loss in New York City
A typical New York apartment building loses thousands of dollars worth of energy every year from leaky elevator shafts that vent warm air at the top of the building and draw in cold air at the bottom, according to a new Urban Green Council report.
Green | Mar 22, 2015
6 myths holding back green building
Sustainable design has proven benefits, so why isn’t it more widely adopted?
Multifamily Housing | Mar 16, 2015
New Jersey Supreme Court puts control of affordable housing agency in the courts
The court said the state’s affordable housing agency had failed to do its job, and effectively transferred the agency's regulatory authority to lower courts.
Codes and Standards | Mar 16, 2015
San Jose adopts bird-friendly building standard
The standard includes avoiding large chunks of transparent or reflective glass and adding fritting.
Codes and Standards | Mar 12, 2015
Energy Trust of Oregon offers financial incentives for net-zero buildings
The organization is offering technical assistance along with financial benefits.
Codes and Standards | Mar 10, 2015
Real estate interests push Congress for Census funding
The groups have joined forces to urge Congress to fully fund the 2020 Census and the annual American Community Survey in its 2016 budget.
Codes and Standards | Mar 5, 2015
Charlotte, N.C., considers rule for gender-neutral public bathrooms
A few other cities, including Philadelphia, Austin, Texas, and Washington D.C., already have gender-neutral bathroom regulations.
Codes and Standards | Mar 5, 2015
FEMA cuts off funding to Indiana after Kokomo continues building stadium in flood zone
FEMA will withhold funding on $5.5 million worth of projects such as building tornado safe rooms in schools.
Codes and Standards | Mar 5, 2015
Construction problems at prison spur support to quash non-traditional project delivery in Iowa
Iowa lawmakers are investigating construction problems at the Fort Madison prison project and are scrutinizing rules regarding project delivery on state projects.
Codes and Standards | Mar 5, 2015
AEC industry groups look to harmonize green building standards, codes
The USGBC, ASHRAE, ICC, IES, and AIA are collaborating on a single green code.