Passive auto-catalytic recombiners (PARs) may be used in the future as safety devices inside confined areas for the removal of accidentally released hydrogen. In the presented study, it was investigated whether a PAR designed for hydrogen removal inside an NPP containment would principally work inside a typical surrounding of hydrogen or fuel cell applications. For this purpose, a hydrogen release scenario inside a garage - based on experiments performed by CEA in the GARAGE facility (France) - has been simulated with and without PAR installation. For modeling the operational behavior of the PAR, the in-house code REKO-DIREKT was implemented in the CFD code ANSYS-CFX. The study was performed in three steps: First, a helium release scenario was simulated and validated against experimental data. Second, helium was replaced by hydrogen in the simulation. This step served as a reference case for the unmitigated scenario. Finally, the numerical garage setup was enhanced with a commercial PAR model. The study shows that the PAR works efficiently by removing hydrogen and promoting mixing inside the garage. The hot exhaust plume promotes the formation of a thermal stratification that pushes the initial hydrogen rich gas downwards and in direction of the PAR inlet. The paper describes the code implementation and simulation results. Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.