Swing check valves are automatic non-return valves, preventing backflow (or water hammer) through a hinged disc that swings open with forward flow. Design specifications often align with API 594 (Check Valves) and API 6D for pipeline applications, with pressure-temperature ratings derived from ASME B16.34. The main focus of inspection and testing is to confirm the valve’s seating and closure mechanism. Per API 598, this requires a hydrostatic shell test and a low-pressure closure test, applied in the reverse direction of flow, to ensure the seal meets the required leakage class.