Air flow simulation was used for a collaborative project to reduce the risk of virus propagation inside the St. Francis Hospital in Marange-Silvange in northeastern France – the country’s second largest region impacted by COVID-19.  The project, part of Dassault Systèmes’ 3DEXPERIENCE Lab OPEN COVID-19 online community is the latest one to leverage collective intelligence on the 3DEXPERIENCE platform to quickly solve critical issues during the COVID-19 pandemic Francis hospital needed to convert a floor into an area to accommodate COVID-19 patients and wanted to reduce the risk of virus propagation inside 3D modeling made it possible to reassemble the partitions and the walls of the area concerned to quickly provide an idea of the hospital’s current layout  Dassault Systèmes’ team of scientists and analysts then used SIMULIA computational fluid dynamics simulation applications to simulate different air flow fields within the building enabling hospital directors to understand how the corridors were important vectors of propagation The team made assumptions about patient behavior and the floor’s ventilation and air conditioning systems including air leaks in the windows and doors  They studied different options by simulating reduced ventilation as well as strategic opening of windows to understand the impact of fresh air on air flow and the concentration of virus particles  Throughout the project and using the 3DEXPERIENCE platform and the medical community provided feedback  Hospital technicians are testing with sensor equipment from local industrial companies to validate the different simulations