Desenvolvimento e caracterização de uma câmara de radiação UVC para inativação de microrganismos em superfícies

Abstract

This work aims to conduct out a study on the performance of UVC radiation in the inactivation of microorganisms, based on the development of an automated surface disinfection chamber using UVC radiation. Irradiance mapping inside the chamber was performed to determine the minimum operating conditions ensuring efficient disinfections. The development of its equipment, even though there are other options available on the commercial market, meets the specific demands of scientific researchers and professionals from institutions in the health area, which can be modified at any time. In the specific case of the COVID-19 pandemic, the disruption of global supply chains has led to a shortage of PPE, especially N95 respirators, which are essential for controlling the transmission of respiratory diseases. In the pandemic that broke out in March 2020, society was faced with the need to reuse N95 respirators for health professionals and thus created the scenario where these PPE needed to be disinfected to be reused. This work, in turn, seeks to develop a formatted system for the disinfection of N95 respirators, other PPE's and any other material of interest that the equipment contains inside. The chamber was designed to operate optimally in order to irradiate the greatest number of parts simultaneously. For this purpose, a structure was designed inside a chamber with nine rotating axes intended to hold a maximum of nine suspended objects, in addition to others that can be placed on the internal base of the equipment. The equipment is automated and has an electronic structure and a control interface via WiFi (2,4 GHz). Repeatability tests were performed to assess irradiance at 27 points chosen at 3 different levels. Based on this evaluation, the distribution of radiant energy flux inside the chamber was characterized through interpolation using thin-plate splines, and the point of minimum irradiance was identified at a value of 2.03 mW/cm². The tests were performed with simultaneous recording and monitoring of changes in temperature and air humidity, since these variables can interfere with the susceptibility of microorganisms to UVC radiation. Based on data available in the literature that identify the doses of UVC radiation to inactivate SARS-CoV-2, it is possible to estimate that the developed chamber is capable of inactivating the new coronavirus in less than 1 minute of operation.