The global pandemic of the SARS-CoV-2 (COVID-19) virus has necessitated the reanalysis of the measures taken to avert the viral dispersion within indoor and outdoor environments. Ventilation systems play a key role in reducing the spread of the virus to the patrons of indoor environments. The application of UV-C lamps within the internal ducting of the ventilation systems has been prevalently applied to subdue the spread of airborne viruses within an indoor environment. Yet, an optimal configuration of the lamps remains elusive to improve the killing rate of the virus. The current study endeavors to fill this research void by attempting to conduct a parametric evaluation based on the various configurations of UV-C lamps within the internal duct system (0.6m by 0.6m by 3m). Computational Fluid Dynamics (CFD) approach has been adopted in this study to capture the flow features of the virus-laden flow over the UV-C lamps within the internal duct. The Euler-Lagrangian approach was applied to model the viral particles flowing within the duct system. The lamp configurations differed by the number of UV-C lamps, the distance, and the orientation between each lamp. From the numerical study, the effect of different lamp configurations on the killing rate of the virus was predicted by assessing the corresponding UV dosage. CFD prediction from this research established that the number and positioning of UV-C lamps have a direct impact on achieving the required UV dosage to diminish the spread of the virus within the internal duct system.