Cause & Consequence
Specific Incident Equipment
High Pressure Train
The isolation was initially set up correctly. The isolation then had to be retagged and in doing this one vent valve was left in an open state.
Some valves required for isolation of train 2 were not uniquely identified to enable correct cross referencing with P&IDs
There was no record that the initial isolation had been checked by a second Isolating Authority (IA).
Uniquely Number all valves associated with the isolation and update the P&ID’s.
Implement a rolling programme for isolation integrity checks, checking drawings and valve numbering.
All isolation must be checked by a second person to ensure their integrity is secure.