A check valve should be installed between the piston air compressor and the gas storage tank. A vent pipe should be installed between the compressor and the check valve. The vent pipe should be equipped with a silencer. There should be no shut-off valve installed between the piston air compressor and the gas storage tank. When installation is required, a safety valve must be installed between the compressor and the shut-off valve. Check valves and shut-off valves should be installed on the exhaust pipe of the centrifugal air compressor. A vent pipe must be installed between the compressor and the check valve. A surge regulating valve and muffler should be installed on the vent pipe. As for the safety valve that must be installed on the gas storage tank, I have never heard of installing a vent pipe.