A wide range of equipment (boilers, furnaces, reformers, etc.) in industrial processes use fired combustion chambers to retrieve heat from a fuel. Although these systems have been used since long time and their safety has been significantly improved, explosions related with disturbances in the firing chamber still occur with certain frequency. The experimental testing of these explosions is challenging due to the complex design and large volume of combustion equipment, along with the presence of internal elements (heating tubes, burners, ignitors) and explosion relief panels. Moreover, empirical explosion evaluation methods may lack accuracy by not considering overpressure reflections and the effects of internal elements. Computational Fluid Dynamics (CFD) models are becoming nowadays accessible and runnable with ordinary desktop computers. In the present work, GEXCON FLACS software has been used to evaluate the effects of explosions inside combustion chambers. The results obtained confirm the potential utility of CFD simulations to analyze this type of explosions.