EVALUATION OF SURFACE AND AIR DISINFECTION EFFECTS USING UV RADIATION SIMULATION

The ultraviolet germicidal irradiation (UVGI) systems have been recommended and applied as a countermeasure against the spread of infectious diseases such as H5N1 influenza and tuberculosis mostly in North America and Europe. In this study, the UV rate constants which mean how easily microbes could be killed by UV were experimentally identified. Then, the germicidal efficiencies of in duct (ID)-UVGI systems were evaluated by calculating the UV intensity distributions on the surfaces of drain plats and cooling coils using the sophisticated ray-tracing code, RADIANCE. And the air disinfection efficiencies of ID-UVGI systems were also evaluated by calculating the spatial UV intensities in the air handling unit. The results showed that the microbes on the surfaces could be eliminated up to 99% with less than 2 hours' UV radiation. However, the fungi in the air passing through air handling units were estimated not disinfected well, as the UV rate constants of fungi are low and the residence time is too short. The validation of RADIANCE showed good agreement with measurement, but the UVC sensors need cosine calibration with 254nm, the main wavelength of germicid al lamps.