What is the maximum allowable drop of the mercury column during a vacuum service test in five minutes?

In the context of vacuum service tests, the maximum allowable drop of the mercury column is set to ensure the integrity and safety of the system being tested. A drop of 10 inches is established as a standard limit, as this indicates that the vacuum system can maintain a sufficient level of vacuum without significant leaks or flaws present.

Allowing for a 10-inch drop reflects the operational capabilities of the equipment, confirming that it can sustain a reliable vacuum under normal conditions. This standard ensures that any potential issues can be detected during the test phase, which is critical for maintaining operational safety and effectiveness in real-world scenarios. Exceeding this limit could suggest a compromise in the vacuum system's integrity, potentially leading to operational failures.