Ventilation for reduced indoor spread of Covid 19 and similar diseases : A literature review focusing on hospital environments

Sammanfattning: Today, a significant portion of individuals’ time is spent indoors, estimated at approximately 90% of their total time. This raises concerns about the transmission of Coronavirus Disease 2019 (COVID-19) instigating Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and similar viruses and highlights the critical role of ventilation systems in indoor environments, which this study aims to investigate. Narrowing the focus to healthcare facilities, particularly hospitals in Sweden, the study includes the importance of ventilation systems in safeguarding the health safety and well-being of patients, healthcare workers in hospitals. To effectively combat the spread of the SARS-CoV-2 virus, it is crucial to have a thorough understanding of its viral characteristics, with a specific centre on airborne transmission size, virus longevity, and quantum of infection. Furthermore, it is essential to recognize the major impact of ventilation rate, thermodynamic factors such as temperature and humidity, as well as pollutants in effectively mitigating the transmission of SARS-CoV-2 and similar pathogens.  The comprehensive findings of this literature review underscore that, for hospitals in Sweden, a Heat Recovery Ventilation (HRV) system incorporating a plate heat exchanger is the most suitable ventilation system for this specific objective. Moreover, the recommended ventilation strategy is specifically tailored for implementation in wards or isolated rooms, where it is ideal for the incoming air to originate from the patient’s room floor, while the exit point is preferably located near or at the ceiling. In the context of this study, identified effective solutions involve the utilization and combination of high-efficiency filters and ultraviolet (UV) technology installed within ventilation system unit, particularly when an air recirculation system is used. Additionally, the implementation of RM3 (Rheem’s third generation products) UV-C technology for indoor use can be achieved without considerable intervention in ventilation system, depending on the type of ventilation system being utilized. In summary, this study enhances understanding of the complex relationship between ventilation systems, COVID-19 transmission and similar diseases, the optimization of thermodynamic factors, and selection of effective and practical measures. It provides valuable insights for designing effective ventilation strategies across various indoor environments, with a specific attention on healthcare facilities.