Passing the pressure test does not guarantee leak test success

First, let’s clarify the purpose of the pressure test.

The pressure test is conducted to ultimately verify the overall strength and reliability of a pressure vessel. It assesses the manufacturing quality, the strength and rigidity of each pressure-bearing component, the sealing of weld joints and connection surfaces, and other aspects under conditions that exceed the vessel’s design pressure. For large vessels manufactured on-site, the pressure test also serves to check for any foundation settlement issues. Additionally, it provides validation for the structural design.

Pressure testing of pipeline product

Thus, passing the pressure test only confirms the overall strength and reliability of the pressure vessel. It does not detect any potential minor leaks in the vessel.

The leak test, on the other hand, depends on the nature of the medium contained in the vessel and the safety requirements for its use. National regulations and standards specify the requirements for different types of media. For instance, vessels containing highly toxic or extremely hazardous substances are required to undergo a leak test after passing the pressure test. The vessel can only be certified after passing the leak test.

Therefore, even after a vessel passes the pressure test, a leak test must still be conducted according to the relevant requirements. It is important to note that while a vessel may pass the pressure test, it may still fail the leak test.