Minimize the Risk of Virus Transmission Through HVAC Systems

By Saagar Patel

The health, safety and welfare of our community is paramount to ESD. We urge everyone to implement CDC best practices during this pandemic, as outlined below.

Attention can also be given to the building’s HVAC in reducing risk associated with transmission of an airborne virus.

The transmission associated with coughing, sneezing and shouting can produce small airborne particles if connected to another host (such as dust). To date, there are no known COVID-19 cases that have resulted from airborne transmission. However, per ASHRAE, HVAC systems can change operation in the following ways to help alleviate these concerns by diluting the indoor air with more outdoor air and cleaning the indoor air with filtration media:

• Dilute the indoor air with more outdoor air:
  • During times of low occupancy, increase the overall ventilation by:
    • going to full economizer mode to increase outside air delivery and eliminate any recirculation
    • Increasing outdoor air damper positions
    • Disabling any demand control ventilation (DCV)
  • Increase hours of operation of systems to provide additional time for ventilation dilution
• Clean the indoor air with filtration media:
  • Upgrade to higher filter ratings on central air distribution systems
  • Utilize portable air purifying (HEPA or UVGI) systems for high-traffic areas
    • ASHRAE’s position document suggests that temporary air purifiers in high traffic areas may be beneficial, however if the existing ACH rates are high (6-10) this may not be impactful

While your building’s HVAC can assist in reducing the spread of a virus, please also review the best practices shared by the CDC and ASHRAE in your facility:

• CDC and ASHRAE best practices
  • Hygiene and Social Distancing
  • Increasing frequency of surface cleaning and disinfection. The CDC has a list of cleaning products to consider
  • Increase hand sanitation stations
  • Encourage bottle filling instead of water fountains and clean frequently
  • Consider shut down of food preparation and warming areas
• Clean Known Contaminated Areas

ESD has observed facility operations and management teams implementing the CDC’s best practices above prior to preoccupancy. With a mission of Improving Society Through the Built Environment, ESD has developed a Rapid Building Wellness Assessment checklist to foster a dialogue about actions building owners, operators and tenants can take to welcome the workforce back and prepare for the future.

Please reach out to Saagar Patel for a copy of the checklist and to explore an assessment for your unique building or workplace.