API Plans

Plan 74

Description: Plan 74 is an external control system supplying

BARRIER gas (typically Nitrogen) at greater pressure than the

process pressure being sealed, to an Arrangement 3 dual gas seal.

Objective: Prevent process from

leaking to the atmosphere.

Remove moisture, filter the gas

and regulate the pressure to the

seal. Best for hazardous, nonpolymerizing,


fluids, light hydrocarbons and


Advantages: For processes that

do not tolerate a liquid barrier.

Can be used with LIFT OFF seal

faces that generate no heat or

wear and can have significantly

increased seal life. Lower cost

and maintenance than dual

liquid systems.