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
| Aug 14, 2014
Mississippi county rejects adoption of state building code
The county board of supervisors voted unanimously to opt out of the state building code.
| Aug 14, 2014
Boards at odds over North Carolina county’s CM-at-Risk policy
Some local small contractors are not pleased with the school board’s CM-at-Risk policy that was instituted in 2007. The county’s board of commissioners has offered a sympathetic ear to their complaints
| Aug 14, 2014
2014 National Electrical Code now effective in 12 states; 11 more to come online by January
The National Fire Protection Association (NFPA) says that the 2014 edition of the National Electrical Code(NEC) is now effective in 12 states: Alabama, Colorado, Idaho, Maine, Massachusetts, Minnesota, New Mexico, Rhode Island, South Dakota, Vermont, Washington and Wyoming.
| Aug 14, 2014
CDC report highlights need for heat acclimatization to prevent worker deaths
CDC supports OSHA’s analysis suggesting that the primary risk factor for heat fatalities is the lack of acclimatization programs.
| Aug 8, 2014
California revives study of earthquake faults
California reinstituted an ambitious plan to study dangerous earthquake faults and create zoning maps that could restrict development.
| Aug 6, 2014
Loudoun County, Virginia may dump green building requirements
Loudoun County, Va., supervisors may do away with a county policy that requires LEED Silver certification on new county buildings.
| Aug 6, 2014
$300 million mixed-use project in Chicago’s medical district wins key approval
The Illinois Medical District Commission approved a 1.16 million-sf, $300 million mixed-use project in Chicago’s Illinois Medical District.
| Aug 4, 2014
Facebook’s prefab data center concept aims to slash construction time in half
Less than a year after opening its ultra-green, hydropowered data center facility in Luleå, Sweden, Facebook is back at it in Mother Svea with yet another novel approach to data center design.
| Jul 31, 2014
LEED Dynamic Plaque gives owners and tenants ability to monitor building performance
The LEED Dynamic Plaque could aid certified buildings in maintaining performance with up-to-date information about water and energy use, waste reduction efforts, occupant experience, and other green performance categories.
| Jul 31, 2014
Gypsum Association releases updates to wallboard repair standards
The Gypsum Association released updates to both GA-221 Repair of Joint Ridging and GA-222 Repairing Screw or Nail Pops standards publications.