Protective walls are a well-known and efficient way to mitigate overpressure effects of accidental explosions (detonation or deflagration). For detonation there are multiple published studies, whereas for deflagration no well-adapted and rigorous method has been reported in the literature. This article describes the validation of a new modeling approach for fast deflagrations of H2. This approach includes two steps. At the first step, the combustion phase of vapor cloud explosion (VCE) involving a fast deflagration is substituted by equivalent vessel burst problem. The purpose of this step is to avoid the reactive flow computations. At the second step, CFD is used for computations of pressure propagation from the equivalent (non reactive) vessel burst problem. After verifying the equivalence of the fast deflagration and the vessel burst problem at the first step, the capability of two CFD codes such as FLACS and Europlexus are examined for modeling of the vessel burst problem (with and without barriers). Finally, the efficiency of finite and infinite barriers used for mitigation of the shock is investigated.