UVC Light Simulation for Room Disinfection System

Abstract

Viruses are minuscule parasites that have gained notoriety for causing diseases. However, these harmful pathogens can be inactivated using Ultraviolet-C (UVC) radiation that has a wavelength between 200 – 280 nm. The wavelengths of the UVC are responsible for germicidal effect as the proteins (e.g. RNA and DNA) absorb the maximum radiation in these wavelengths and damage the DNA of the viruses so that they cannot replicate. This project aimed to simulate the UVC light intensity in different room layouts to guide the evaluation of the effectiveness of surface disinfection system which consists of UVC lights. Besides determining the quantity and the installation layout of the UVC lights, the project also aimed to help visualisation of the coverage of UVC radiation and highlight any under-exposed area for optimum room disinfection using a simulation software. DIALux Evo 9.1 was used to simulate the light intensity in different room and lighting layouts. As the software only calculates normal visible light (wavelength 380 – 700 nm) intensity in the unit of Lux, a correlation between Lux and UVC dosage (mJ/cm2) must be established first. A minimum UVC dosage of 40 mJ/cm2 is required to achieve complete surface disinfection of microorganisms. The simulation was able to visualize the coverage of UVC radiation and to determine the optimum placement of UVC lights to ensure sufficient UVC dosage is delivered to every critical surface. The outcome of this project can help to guide the design of UVC room disinfection system especially in hospital wards setting to optimise room disinfection and reducing the risk of infection.