At what pressure should valve leakage not occur during testing?

The appropriate pressure at which valve leakage should not occur during testing is less than 1 and 1/2 times the rated service pressure using dry air as the test medium. This approach ensures that the valve is subjected to a pressure that is sufficient to evaluate its integrity and performance without exceeding a level that could cause damage or compromise the valve. By conducting the test at this specified pressure, any leakage that might occur can be identified, ensuring that the valve can safely operate under normal conditions.

Testing at less than the rated service pressure would not provide an adequate assessment of the valve's ability to hold pressure at operational levels. Testing at exactly the rated service pressure may not reveal weaknesses that could lead to leaks under real-world pressures. Testing at twice the rated service pressure typically exceeds the safety margins designed for standard operation, potentially resulting in damage or failure of the valve.

Thus, testing at a pressure level that is 1 and 1/2 times the rated service pressure provides a balanced approach, confirming the valve's reliability while safeguarding against failure scenarios during normal operation.