May 23, 2020

Ultraviolet Germicidal Irradiation (UVGI) – HVAC Solution

By Nancy Nichols, P.E.

As discussed in a previous blog, there are HVAC-related measures to potentially reduce the spread of pathogens, such as the coronavirus, that can be taken to supplement social distancing, surface disinfection, hand washing and other good hygiene practices.  One significant HVAC measure is increasing make-up air.  Another is Ultraviolet (UV) Germicidal Irradiation.  The Fresh-AIRE UV systems are tested and validated against bacteria, viruses, mold and fungus. [1] Our partner, Paradigm Plumbing , can answer questions specific to the Fresh-Aire UV system.

UV systems complement filtration.  Water droplets, which may contain viruses, can be captured by the filtration system and the viruses subsequently neutralized by UV.  Viruses that are air borne in the absence of water droplets can be neutralized by airstream disinfection.  UV systems are also used to reduce problematic molds and pathogens typically found within the HVAC system and drain pan so that they are not distributed throughout the envelope of the building.

Some of the factors potentially impacting efficiency of UV in reductions include the application (i.e., surface or air disinfection), air velocity and temperature, air recirculation rates, makeup air rates, dwell time, and specific biological target. These are factors incorporated into your engineered design for your building and HVAC system.  If you are designing a new space, either new construction or retrofit, you may also want to consider permanent ceiling air-filtration technology designed by the Danish firm Airlabs.  Team Engineering would be pleased to discuss your design with you.

[1] Fresh-Aire UV systems are installed within the HVAC system and are not intended to diagnose, treat, prevent or cure any disease. The systems have not been tested on coronavirus and is not a medical device.   Photo and information about Fresh-Aire UV systems is from https://www.freshaireuv.com/coronavirus-update/.