For a high pressure regulator with an overpressure protection device, what must the device limit the outlet pressure to when the regulator seat disc is removed?

The outlet pressure limit of 2.0 psig for a high-pressure regulator with an overpressure protection device is established to ensure safety during operation, especially when the regulator seat disc is removed. This limitation is crucial because it helps to prevent potentially hazardous situations that could arise from excessive gas pressure entering the downstream system.

When the regulator seat disc is removed, the regulator loses its ability to control the outlet pressure effectively. The overpressure protection device serves as a safety mechanism that engages to limit the outlet pressure to a predetermined safe level, which in this case is 2.0 psig. By enforcing this limit, the device protects both the equipment and the users from the risks associated with overpressure, such as leaks, ruptures, or catastrophic failures in the gas system.

Maintaining the outlet pressure at or below 2.0 psig allows for safe operation while mitigating the risks of pressure excursions that could lead to dangerous conditions in high-pressure systems.