The purpose of partial stroke testing is to exercise, and test shut down valves without disturbing the production. The valve will typically be closed 20% for a short time and fully opened again. The test will ensure the valve function is tested and working as required. When Partial Stroke Testing is successfully implemented it offers serval production benefits including an extension between compulsory plant shutdowns and insight in potential valve failures.
Partial Stroke Testing is most often used on high integrity emergency shutdown valves (ESDVs) in applications where closing the valve will have high-cost burden yet proving the integrity of the valve is essential to maintaining a safe facility.