Abstract: A modular energy barrier system has at least one energy barrier module. The module has a substantially rigid casing and an energy absorbing filler material. The casing has at least one frangible side. The filler material is disposed inside the casing. The casing is adapted to be connected to a base support so that the module is interposed between the base structure and an energy source and the at least one frangible side of the casing is oriented to face energy released by the energy source.