API Plans

Plan 75

Description: Plan 75 is a containment seal chamber which allows

draining of condensing leakage on Arrangement 2 dual seals. The

collection system is located below the seal chamber and uses an

orifice and a pressure transmitter to detect high vapor leak rates.

Typically used with contacting secondary containment seals.

Objective: Contain and vent leakage to collection system while

monitoring leak rate. Orifice sized to allow maximum leakage and

pressure alarm to shut down the pump if the leak rate is


Advantages: Best for processes

that condense at ambient

temperatures. Can be used with

Plan 72 to sweep the leakage into

the containment system. Lower

cost and maintenance than dual

liquid systems.