Dual Plate Check Valves are compact, non-slam check valves featuring two spring-loaded semicircular plates that close quickly to prevent reverse flow. They are widely used in piping systems due to their short face-to-face dimensions, defined by standards like API 594 and ASME B16.10. The plates must be inspected for proper alignment and freedom of movement before installation. Testing involves a hydrostatic shell test and a low-pressure closure test, as specified by API 598, applied in the reverse direction to confirm that the spring mechanism and disc sealing surfaces provide the necessary seal against backflow.