API RP 591 Evaluation

AP RP591 Evaluation – Engineering Testing

RP591 MeasurementsUnited Valve has performed more API RP591, “Process Valve Qualification Procedure”, tests than any other company in the industry. We began valve qualification testing before there was even an official API qualification document. Representatives from our company participated in the creation and revision of every RP591 update. Our engineers and NDE department, in concert with some key end-user stakeholders, created the NDE requirements that exist today in RP591. The radiography requirements were a result of R&D performed in our X-ray radiography facility.

Overview of RP 591 Testing Process

API Recommended Practice 591 provides testing procedures and acceptance criteria for evaluating a manufacturer’s valves. The basic test procedure requires that a number of valves be randomly selected from a distributor or manufacturer’s stock. First the valves are pressure tested in accordance with API 598 or other applicable test documents. Next, the valves are subjected to an extensive visual and dimensional inspection, followed by radiography of the castings. Chemical analysis and hardness tests are also performed on several critical components. One of the most critical evaluations for gate valves is the stem to ball/wedge/plug tensile test. This test is designed to determine the first point of failure between the shaft and the closure member. To meet the requirements of RP 591, the first point of failure must occur outside the valve pressure boundary.

Testing Industrial Valves for Major Refiners and Manufacturers

United Valve is certified by major refiners to perform RP591 testing. The test results are used to help determine possible inclusion on their acceptable manufacturers list (AML). We perform RP 591 testing for both end-users and manufacturers. Our integrated NDE capabilities, along with decades of valve experience, give us the ability to verify quality and find problems or idiosyncrasies with a particular valve design. Work with one of the most experienced teams in the industrial valve testing industry.