A vented corn starch dust explosion in an 11.5 m³ vessel is studied by comparing experiments, simulations and thestandards. The reduced explosion overpressure inside the vessel is recorded using two pressure sensors installed on theinner wall of the vessel. 3D Unsteady Reynolds-Averaged Navier-Stokes simulations of the experiment are performedusing the Flame Speed Closure (FSC) model and its extended version. The FSC model predicts the influence of turbulenceon premixed combustion, and the extended version allows for self-acceleration of a large-scale flame kernel, which isassociated with the combustion-induced thermal expansion effect. Such an extension is highly relevant to large-scaleindustrial application. The explosion overpressure-time trace computed using the extended FSC model agrees reasonablywell with the experimental data. Furthermore, the effect of vent size and ignition location on the explosion overpressureis studied by comparing the simulation results and the standards. The developed numerical tool and model is especiallyuseful for scenarios, which are not addressed in the standards, and it deserves further study in simulations of other largescalesdust or gaseous explosions together with comparison with experiments.