COVID-19 HVAC Systems

HVAC

Depending on the type of HVAC system in your building, below are some HVAC measures to implement for the short term and long term to reduce the potential spread of contaminants.

Short Term Measures:

Pressurization - Implement pressurization control and/or enhance your current practices to properly pressurize your workspace, both internal zones with respect to adjacent areas. 

Filtration – Change out standard filters with antimicrobial coated filters. 

Increase Airflow - Both recirculated and outside air to accommodate new sanitization procedures. 

Demand Control Systems - Deactivate demand control systems that normally limit the concentration of outside air. 

Operating Hours - Operate systems longer and with higher outside air content to flush spaces due to increased use of cleaners.  Utilize temperature setbacks to increase the amount of outside air introduced during unoccupied periods. 

24/7 Systems - Since they have a higher risk of contamination, operate ventilation systems serving communal spaces such as toilet rooms continuously (24 hours/day). 

Cleaning – Clean equipment exposed within workspace same as any other surface.  Clean and disinfect duct systems.  Initial deep cleaning followed by periodic disinfections. 

Portable Air Purifiers – Portable units that may either be rented or purchased to combine antimicrobial, HEPA filtration and/or ionization technologies that will help you bridge the time period between your immediate and long-term objectives. 

Long Term Measures:

Enhanced Filtration – In addition to antimicrobial filters, the use of HEPA/ULPA filters may be considered but must be balanced against capabilities of existing systems and/or ability to augment them.   

Bi-polar Ionization - Duct mounted units to provide continuous cleaning and sanitization of the airstream.  Based upon your system, these may need to be deployed at strategic locations. 

UVC Lights – Alternate method to sanitize duct systems.  These also need to be strategically placed to increase effectiveness, but also shield occupants from direct contact. 

FAR-UV Lights – Utilizes a different wavelength of UV light spectrum than UVC lights.  Destroys viral, bacteria, and fungal cells in seconds, faster than UV-C lamps.  Also safe in the presence of humans.

Duct Sanitization System – As an alternate to ionization and UVC lamps, install a piped system to periodically chemically sanitize your ductwork systems via injection nozzles spaced throughout your system. 

Authors

Scott M. Davis, PE
Director of Mechanical Eng.
Charles B. Kensky, PE
Executive Vice President