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
| Oct 13, 2011
New Law: California Building Standards Commission Must Include Green Expert
A new California law, AB 930, requires that one member of the California Building Standards Commission be “experienced and knowledgeable in sustainable building, design, construction, and operation.”
| Oct 13, 2011
AGC Urges Repeal of 3% Withholding On Government Contracts
The U.S. House of Representatives is planning a vote in October on a bill to repeal the 3% withholding requirement on all federal and state contracts for goods and services.
| Oct 13, 2011
House Bill Would Block New OSHA Regulations
Proposed riders in a U.S. House of Representatives spending bill would block the Occupational Safety and Health Administration (OSHA) from issuing controversial workplace safety and health regulations.
| Oct 11, 2011
AIA introduces five new documents for use on sustainable projects
These new documents will be available in the first quarter of 2012 as part of the new AIA Contract Documents service and AIA Documents on Demand.
| Oct 7, 2011
GREENBUILD 2011: UL Environment releases industry-wide sustainability requirements for doors
ASSA ABLOY Trio-E door is the first to be certified to these sustainability requirements.
| Oct 6, 2011
Taking tenant behavior into account on building energy codes
Over the past few years, Seattle, San Francisco, Austin, and Washington, D.C., have passed laws requiring property owners to measure and disclose their energy use, which would help place a market value on a building’s efficiency and provide a benchmark for improvements.
| Oct 6, 2011
Constructed properly, green roofs hold up well in a hurricane
The heavy rains and high winds of Hurricane Irene didn’t cause any problems for a Con Edison green roof in New York City. The roof contains sedum, a plant that adapts well to drought and handles periods of heavy rain well.
| Oct 6, 2011
RoofPoint: A new green standard for roofs
Structured much like other rating systems, RoofPoint, establishes green standards specifically for roofs.
| Oct 6, 2011
Roofers critical of new OSHA harness rules
Roofers say a new OSHA rule requiring all residential roofers to wear a safety harness makes workers less safe, and is causing lost business for those who comply with the rule.
| Oct 6, 2011
Florida county proposes saving on construction costs by trumping city regulations
This summer, Pinellas County, FL wanted to save money on an $81 million public safety complex in Largo by using the county’s own building regulations and permit fees, not the city’s more expensive fees.
