why partial stroke test is required
Partial stroke testing (or PST) is a technique used in a control system to allow the user to test a percentage of the possible failure modes of a shut down valve without the need to physically close the valve.n addition to ESDVs PST is also used on High Integrity Pressure Protection Systems or HIPPS. Partial Stroke Testing is not a replacement for the need to fully stroke valves as proof testing is still a mandatory requirement.