In this paper computational fluid dynamics simulations (CFD) were carried out in order to investigate the efficiency of bund designs and top wall deflectors (breakwaters) under several tank failure modes. Investigation was performed over laboratory scale configurations, some of them were also experimentally studied. Simulations were performed using the Volume of Fluid (VOF) method and literature data were used for assessing the solver prior to investigate the different bund designs. Numerical and experimental results agreed, showing the suitability of numerical methods to predict overtopping. The amount of liquid lost showed a low dependency with the containment shape (square, circular or rectangular), but a high one with the bund height. On the contrary, the use of breakwaters showed to be a suitable and very efficient way to reduce liquid loss, although inducing significant extra mechanical efforts over the bund walls.