Project Images OCPS virus mitigation Project Summary Orange County Public Schools (OCPS) chose Hanson to provide commissioning for new and renovated schools throughout the county. While Hanson was executing its commissioning work, the COVID-19 pandemic emerged in the U.S., presenting the need for a response in public buildings to protect occupants from the highly infectious coronavirus. Because of Hanson’s experience in this area and the fact that Hanson engineers are active nationally on the ASHRAE Epidemic Task Force, OCPS enlisted Hanson to develop a report examining the potential benefits of installing ultraviolet germicidal irradiation (UVGI) and/or portable fans with high-efficiency particulate air (HEPA) filter units in OCPS schools as an option for mitigating the spread of coronavirus and other viruses. Hanson was also asked to provide guidance on filtration systems for the district. Hanson based its recommendations and analysis on Epidemic Task Force guidance. Hanson conducted the UVGI and portable HEPA filter unit analysis for several typical instances in various OCPS facilities, including classrooms in newer buildings, where the air-handling unit uses bipolar ionization and classrooms in older and portable buildings whose air-handling units do not use bipolar ionization. Hanson’s analysis regarding UVGIs and PHFUs considered the effect of cost, lead times, maintenance concerns, system longevity and the impact of noise and virus transmission mitigation. Hanson’s analysis regarding filtration included various filtration levels and the efficacy of each under different conditions.