Effect of Liner Albedo on UVC Irradiation Control

Ultraviolet germicidal irradiation (UVGI) has been used successfully for the sterilization of tools and whole environments. The advantages of this method are numerous. There does not need to be any physical contact with the artifact to be sterilized; the procedure is quite fast and allows for covering large areas. As a drawback, the cost of these systems is often still prohibitive, and the necessity of the light to hit the surface to be effective might leave residual contamination in the shadowed areas within lumens. To avoid potential shadows, the internal surface of an environment can be covered with specific reflective materials appropriate for the wavelength of the irradiation source. We designed a cost-efficient sterilization chamber that uses UVC for decontamination (SHIVA, Small High-Intensity ultra-Violet Antimicrobial chamber.). The design focuses on a decontamination chamber easy to manufacture for rapid deployment. The device can also be used by the general public for sanitizing non washable materials. We tested the control of irradiation dose, based on different types of materials lining the internal part of the sterilization chamber. The reflectance of the material in the UVC Spectrum was critical for the increase of irradiation dose at the target. We tested 3 lining materials (Teflon, Aluminum, and Vinyl) using an 8W UVGI fluorescent lamp in the Ultra Violet-C (UVC) wavelength range, with peak irradiation at 254.3 nm. Variations between linings could provide a variation in dosage up to 30%. We observed that Vinyl reflectivity in the UVC range is close to 90% and provides the best compromise between the price of the lining, and the final irradiation dose provided to the samples. An increase in total irradiation allows for a more energy-efficient system that could utilize batteries rather than electrical energy from an outlet; hence improving portability.