Benefits of UV-C Lights in Fraser-Johnston® Commercial Equipment

The Benefits of UV-C Lights in Fraser-Johnston® Commercial Units

UV-C lights are a proven technology that can help to irradiate a surface or airstream. In the HVAC industry, UV-C lights have commonly been used to help with surface decontamination of coils and drain pans where various spores could grow. Surface decontamination helps to keep the growth down or kill any growth that has accumulated. An added benefit is that UV-C lights can help to keep the coil clean and maintain the efficiency of the unit. It has been common for the HVAC systems to use UV-C lights installed for surface decontamination on the downstream side of the coil. This allowed for the light to penetrate the wet side of the coil while exposing the drain pan to the UV-C light as well. 

The current pandemic has many people looking into the use of UV-C lights as an in-duct airstream disinfection option. While airstream disinfection is not new, it hasn't been as widely adopted in HVAC systems. Airstream disinfection requires a significantly greater level of intensity than typical surface decontamination. As an example, air disinfection irradiance levels can exceed 1000 µW/cm^2. In comparison, surface irradiance may be down around 100 µW/cm^2. When designing an in-duct air disinfection system, it is important to understand the irradiance level as well as the time that the particles are exposed to the UV-C light. Bringing in the time factor modifies the units from micro-Watts /cm^2 to micro-Joules /cm^2 (where Joules = Watts * Seconds). 

The level of UV-C intensity required for the application depends on what spore or virus needs to be inactivated. With the recent pandemic, there have been a lot of discussions about how to treat SARS-CoV-2. In October 2021, the ASHRAE Epidemic Task Force laid out the Filtration and Disinfection guide which defined UV-C intensities for SARS-CoV-2. The intensities laid out were 611 µJ/cm^2 for 90% inactivation, and 1500 µJ/cm^2 for 99% inactivation. 

Fraser-Johnston offers UV-C lights on several packaged rooftop units to help meet the increasing Indoor Environmental Demands. UV-C lights are an available option on Relia™ Core 100, Relia™ Core, Relia™ Pro, and Relia™ Choice RTUs through the Modification (Mod) Shop. 

For additional information on the Filtration and Disinfection 10-21-2021 update as laid out by the ASHRAE Epidemic Task Force, please click here.