API Plan 75


Leakage of condensate from inboard seal of a dual containment seal is directed to a liquid collector.


1 Can be used with Plan 72 with buffer gas or with Plan 71 without buffer gas systems.

2. Collection can be redirected to process fluid by using separate pumping device.

3. Can be used in single containment seal also.

4. Test connection is provided to check the inner seal by closing the block isolation valve while pump is in operation and noting the time / pressure build-up relationship in the collector.


1. Duties with condensing leakages.

2. Hazardous, toxic fluids.

3. May also be used for non-condensing leakages. In such cases, the collector can help in collecting condensate from the vapour recovery system.


1. Ensure that collection system is located below the seal drain with sloping pipelines.

2. Drain port should be at bottom of containment seal to allow the leakage to flow to the collection system.

3. Collection system should always be vented releasing vapors of process liquid to vapour recovery system.

4. Valves that are installed should be accessible to operator relative to ground clearance and other obstructions.

5. A flow control orifice is required to create back pressure on collection system and to have effective condensation of vapors.

6. Pressure switch should be set at a gauge pressure of 0.7 bar.

API - 75 4TH Edition 30 secs