Abstract: An overpressure protective device for passively blocking flow of gas at a selected pressure setpoint includes a valve, a valve stem, and vacuum-filled bellows coupled to the valve stem. The vacuum-filled bellows are configured such that expansion and/or contraction of the bellows as a result of pressure changes present at the valve are harnessed to passively move the valve stem to operate the valve and block pressures higher than a preconfigured pressure setpoint. If the process pressure drops below the pressure setpoint, the overpressure protective device operates the valve to again permit flow of pressurized gas through the valve.