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
| Nov 9, 2012
Higher bar on LEED may not be harder to reach
The U.S. Green Building Council expects to substantially revise LEED next year, requiring builders beginning in 2015 to take new and more-detailed steps to get buildings certified.
| Nov 9, 2012
CSI’s sustainability practice group offers webinar on EPA's WaterSense Program
The Construction Specification Institute’s sustainability practice group is offering a webinar Nov. 20 on EPA’s WaterSense Program, featuring Lynn Gilleland, drinking water specialist with EPA’s New England office.
| Nov 9, 2012
Mayor in Calif. wants to expedite permits for $1B worth of projects
The mayor of San Jose, Calif., plans to issue new construction permits worth an estimated $1 billion in the next six months to spur job creation and create revenue for the city.
| Nov 9, 2012
Jury awards N.Y. roofer $2 million for injuries after construction site fall
A roofing worker from Cortland County, N.Y., has been awarded $2 million in damages due to the injuries he sustained from a 60-foot fall at a dormitory construction site.
| Oct 31, 2012
Investigators look into crane severely damaged by Sandy in Manhattan
Investigators are examining a construction crane collapse atop a $1.5 billion luxury high-rise in midtown Manhattan due to high winds during Hurricane Sandy.
| Oct 31, 2012
Construction error suspected in Miami-Dade College garage collapse
A construction error is the chief suspect in the partial collapse of a parking garage at Miami-Dade College in Doral, FL.
| Oct 31, 2012
New European laws on timber will go into effect in March 2013
A new European Union timber regulation prohibits the “placing on the market of illegally harvested timber or timber products derived from such timber.”
| Oct 31, 2012
MIT models show roofs' capacity for solar energy in Cambridge, Mass.
A new mapping tool from the Massachusetts Institute of Technology and a Boston design firm can calculate rooftops' capacity for solar energy.
| Oct 31, 2012
Demand for living roofs, walls to reach $7.7 billion by 2017
The demand for green roofs and living walls is expected to climb from $5.3 billion in 2011 to $7.7 billion in 2017, according to a report from Lux Research.
