Pressure relief valves are the last line of defence against overpressure events. Three standards govern how they are tested, inspected, and certified:

• API 527 — covers seat tightness testing for metal- and soft-seated valves. Defines the maximum allowable leakage rate in bubbles per minute.
• API 576 — provides recommended practice for inspection of pressure-relieving devices in service, including in-situ verification intervals.
• ASME PTC-25 — the performance test code that defines how capacity and set-pressure accuracy are verified on the test bench.

At RP Valve we maintain a UKAS-accredited test rig capable of certifying valves against all three. Get in touch if you'd like a tour of the facility.