A pressure vessel for storing a gas for use in airbag protection systems in passenger transport has an outflow valve connected to the housing of the pressure vessel at a predetermined breaking zone and contains a piston which extends to a pyrotechnic system arranged in the vessel interior. Influencing the outflow characteristic of the gas flowing out of a pressure vessel into an airbag in a controlled manner during the opening movement of the outflow valve is attained because the outflow valve contains a control body which adjoins the predetermined breaking zone and extends in the direction of the pyrotechnic system and the cross-section of which changes in the axial direction of the outflow valve.