Here is a link to a Press Release from a UVC light manufacturer that contains a lot of information related to UVC lights and their effectiveness: Effectiveness of UVC Light to Mitigate Coronavirus (COVID-19)
You may also refer to some of the ASHRAE documentation to determine the best application for your building or systems:
- Filtration and Disinfection Guidance on the ASHRAE COVID-19 site
- Chapters in ASHRAE Handbook
- ASHRAE Journal article: Ultraviolet Germicidal Irradiation – Current Best Practices (2008, Martin et al)
- For upper room systems –NIOSH guidelines (2009)