As experts in LED technologies, and due to the COVID-19 outbreak we receive a lot of questions about UV disinfecting lighting. In the paragraph below we will try to explain in simple words how this works and what you should consider if you have an idea in this field.
Q: How exactly does the virus die?
A: UV Light rays break connections in protein thus making them non-functioning. In the same manner, it is widely accepted that UV light also breaks virus molecules. There is no current complete proof that UV light specifically destroys novel Covid-19 but in theory and together with tests done on another virus one can assume it does destroy Covid-19.
Q: Which UV light should be used for killing a virus?
A: Tests on other viruses show the best wavelength to destroy it is at about 260nm
+/- 10nm. The 1st graph shows damage to a virus vs. wavelength, peaking at 260nm.
Q: Is UV light safe?
A: The simple answer is no. UV-C light in the range of 260nm is considered damaging to human tissue exactly as it is damaging the virus. The more accurate answer is that it also depends on the power density and the duration of the exposure. As a rule of thumb, if it is effective in killing viruses it is damaging to human tissue.
As you can see on the 2nd graph, The threshold of human tissue exposure is pretty much lowest at the 260nm range. This means that this wavelength is most dangerous to human tissue
Q: How deep does UV penetrate?
A: it hardly penetrates at all. It reaches only the outermost layer of your skin. But be aware that even so, it is a health hazard, which can lead to sunburn or even cancer. The eyes are also very sensitive to this form of light even though it is invisible.
Q: Design measures?
According to the above written, one can design any closed box or compartment with UV-C light sources inside to disinfect within this closed compartment.
→ has to be closed to protect human tissue
The light needs to “hit” all surfaces which need to be disinfected.
→ light doesn’t penetrate so all-around light sources.