Plan 72 (Low Pressure Gas Panel)
Buffer/Barrier
Plan 72 for secondary containment uses an external low pressure buffer gas, usually nitrogen, regulated by a control panel that injects it into the outer seal cavity.
Why do we use it?
- When an arrangement 2 plan is required
- When the outboard seal requires additional protection against inboard seal leakage
- To reduce process fluid emissions to atmosphere
- When the buffer region is prone to icing
- When an inert gas (N2) supply is available
Advantages:
Introduction of a buffer gas like nitrogen reduces fugitive emissions, prevents icing on cold applications, and provides for some cooling to the outboard seal.
General:
Plan 72 is normally used with Plan 75 for primary seal leakage that is condensing, or with Plan 76 for non-condensing leakage.
