Safely Occupying Indoor Environments During COVID-19

RT-397 found that the following best practices contributed to reoccupying buildings safely during a pandemic (SP-397, p. 2):

1. Install MERV-13 filters. – MERV 13 filters support removal of 95% of all airborne particles in a commercial building (CDC, ASHRAE, EPA).
2. Install HEPA air cleaners. – High-quality air filtration eliminates 99.7% of airborne particulate matter in commercial buildings (CDC, EPA, ASHRAE).
3. Ventilate ahead of reoccupancy. – Air out the building by running the HVAC system at maximum power for at least one to two hours to enhance filtration and ventilation of air within the building (CDC, USGBC).
4. Increase the intake of outdoor air into the building. – Open or otherwise utilize operable windows and ceiling fans to increase the flow of outdoor air into the building. Increase outdoor intake by the ventilation system (CDC).
5. Maintain consistent ventilation within closed areas. – Enhance the movement of air introduced from outdoors. Continuously run exhaust fans (CDC, EPA).
6. Install portable air purifiers. – Apply portable air cleaners and purifiers. Minimize airborne contaminants, especially in closed areas such as elevators (CDC, EPA, ASHRAE).
7. Use cleaning products that contain disinfectants on the EPA’s List N. – Listed active ingredients include hydrogen peroxide, citric acid, L-lactic acid, peroxyacetic acid, sodium bisulfate, ethanol, and isopropanol (and also called isopropyl alcohol) (USGBC, EPA, CDC).
8. Provide personal protective equipment at building entrances. – Proper use and disposal of PPE will support minimizing the spread. Wearing an N95 filtering facepiece respirators, surgical mask, or any tight face mask is a significant approach that can prevent airborne transmission by more than 90% (CDC, OSHA, NIOSH).
9. Install motion sensors to minimize the need to touch surfaces. – Incorporate non-contact or touchless controls for light, doors, water faucets, and other commonly used objects to minimize frequent touching (CDC, EPA).
10. Install non-contact temperature assessment devices at building entrances. – Enhance virus control and prevention by monitoring the temperature of every individual who enters the building (FDA).

RT-397 found that the following best practices are currently being deployed during the ongoing pandemic (presentation to Fall 2021 Board of Advisors Meeting, slide 18):

• Enhanced filtration is widely deployed.
• As vaccination rates increase, some of the outdoor air recommendations seem to be less prevalent in practice.
• Cleaning with disinfectants is widely deployed.
• Temperature checkpoints seem to be less and less common.