Toward a Test Protocol for Surface Decontamination Using a Mobile Whole‐room UVGI Device^†

Abstract

Mobile whole-room UVGI devices are used in healthcare settings to control surface-borne pathogens. Unfortunately, no standard method comparing the efficacy of these devices is available. We accessed the effect of shadows on UVC 254 nm inactivation. The evaluation of a mobile whole-room UVGI device used spores of Bacillus atrophaeus as a surrogate for Clostridium difficile and Staphylococcus aureus as a surrogate for MSRA. Inactivation after 10 min of exposure varied significantly depending on whether the spores received direct UV exposure (4.3 log reduction), both direct and reflected UV exposure (3.0-4.0 log reduction) or reflected UV exposure alone (<1.0 log reduction). The susceptibility (z-value) for inactivation of B. atrophaeus spores on a glass surface was estimated to be 0.00312 m 2 J −1 . Staphylococcus aureus microbial log reductions were approximately 5.5 for direct UV exposure, 3.6-5.2 for both direct and reflected UV exposure and approximately 2.75 for only reflected UV exposure. Our measurement of reflected dose ranged from 0.46% to 1.47%. Based on our findings, B. atrophaeus spores should be considered as a model organism for testing the impact of shadows on mobile whole-room UVGI device inactivation. Optimizing the reflected component of whole-room UVGI is important, especially for UVC-resistant organisms.

RoboCoV Cleaner: An Indoor Autonomous UV-C Disinfection Robot with Advanced Dual-Safety Systems

“…Following a comprehensive analysis of the current state of scientific literature pertaining to disinfecting robots, a notable and captivating trend emerges, as seen in Table 3. The G-Robot [19] demonstrates that there is a noticeable trend towards the integration of robotic arms with various degrees of freedom in addition to the prevalent categorizations of mobile [18,20,23,24] and static bases [22] for these robots. Within the context of movable and static base systems, a common structure arises, the same as the commercial ones, distinguished by the presence of vertically oriented UV-C lights in [18,20,22], etc.…”