What is UVC Light?
How UVC Disinfection Works?
CELLS THAT CANNOT REPLICATE, CANNOT INFECT.
Because of the spectral sensitivity of DNA & RNA, it’s only the UVC region of the electromagnetic spectrum (200-280 nm) that demonstrates this germicidal property. Hence, when biological organisms are exposed to UVC, it gets absorbed by the DNA, RNA and proteins of their cells. This absorption disrupts their replication process and ruptures their cells’ walls due to which they fail to multiply.
Ensuring Complete Inactivation
Table 1 Log Reduction Value (LRV)
Disinfection is quantified by inactivation rates or Log Reduction Value (or LRV). Log reduction is a simple mathematical term used to express the relative number of live microbes eliminated by disinfection.
UV Dose (or fluence) is the amount of UV radiation a microbe is exposed to and depends on the intensity of UV radiation and exposure time. A number of biological studies have produced widely accepted typical UV dose requirements for most commonly targeted microbes in disinfection.
1 mWs/cm2 = 1 mJ/cm2
1 milliwatt-second / square cm = 1 millijoule / square cm
UVC Dosage Chart
Verifying UVC Exposure
The UVC Dose Indicator is a safe and efficient tool used to verify UVC exposure levels when using ultraviolet devices for surface disinfection. They are calibrated to indicate color changes up to 100 mJ/cm² .When exposed to UVC rays, the yellow indicator changes to orange and pink, which has been correlated to an accumulated dose sufficient to kill MRSA and C. Diff, respectively.
(Click image to enlarge)
Effectiveness of UVGI on Viruses
Top view of the UVGI solution mounted on the LD robot.
Illustration of the efficacy of the UVGI in relation to the size of the LD robot.
Based on the chart, as an example, if we need to irradiate the influenza A virus on surfaces, we would need a light energy of at least 6600 μJ/cm².
This would mean, within a radius of 1524mm, if light intensity of 24,000 μJ/cm² is dissipated constantly for 1 minute, we can destroy 99.9% of the influenza A virus.