Impact of Room Location on UV-C Irradiance and UV-C Dosage and Antimicrobial Effect Delivered by a Mobile UV-C Light Device. (23rd March 2016)

• Record Type: Journal Article
• Authors: Boyce, John M.; Farrel, Patricia A.; Towle, Dana; Fekieta, Renee; Aniskiewicz, Michael
• Is Part Of: Infection control and hospital epidemiology. Volume 37:Number 6(2016)
• Page Start: 667
• Page End: 672
• Publication Date: 2016-03-23
• Subjects: Nosocomial infections -- Epidemiology -- Periodicals; Health facilities -- Sanitation -- Periodicals; Hospital buildings -- Sanitation -- Periodicals; Cross Infection -- Periodicals; Epidemiology -- Periodicals; Hospitals -- Periodicals; Infection Control -- Periodicals; 614.44
• DOI: 10.1017/ice.2016.35
• Languages: English
• ISSNs: 0899-823X

Abstract

Abstract : OBJECTIVE: To evaluate ultraviolet C (UV-C) irradiance, UV-C dosage, and antimicrobial effect achieved by a mobile continuous UV-C device. DESIGN: Prospective observational study. METHODS: We used 6 UV light sensors to determine UV-C irradiance (W/cm 2 ) and UV-C dosage (µWsec/cm 2 ) at various distances from and orientations relative to the UV-C device during 5-minute and 15-minute cycles in an ICU room and a surgical ward room. In both rooms, stainless-steel disks inoculated with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile spores were placed next to sensors, and UV-C dosages and log10 reductions of target organisms achieved during 5-minute and 15-minute cycles were determined. Mean irradiance and dosage readings were compared using ANOVA. RESULTS: Mean UV-C irradiance was nearly 1.0E-03 W/cm 2 in direct sight at a distance of 1.3 m (4 ft) from the device but was 1.12E-05 W/cm 2 on a horizontal surface in a shaded area 3.3 m (10 ft) from the device ( P <.001). Mean UV-C dosages received by UV-C sensors located at different distances and orientation relative to the device varied significantly during 5-minute cycles and during 15-minute cycles ( P <.001). Log10 reductions ranged from >4 to 1–3 for MRSA, >4 to 1–2 for VRE and >4 to 0 log10 for C. difficile spores, depending on the distance from, and orientation relative to, the device with 5-minute and 15-minute cycles. CONCLUSION: UV-C irradiance, dosage, and antimicrobial effect received from a mobile UV-C device varied substantially based on location in a room relative to the UV-C device. Infect Control Hosp Epidemiol 2016;37:667–672