The Logic Behind The Magic. “Emergency Shutdown System (ESD) Operating Philosophy 2"

Resetting philosophy

Further to a shutdown, the related ESD levels need to be individually and manually reset by the Operation Console operator. The ESD level can be reset only if the upper ESD level is in normal condition.

Resetting sequence is as follows :

·         The operator is informed on the ESD and process displays that the ESD level can be reset

·         ESD level alarm return to normal conditions only when all ESD causes have disappeared or have been inhibited and the ESD level reset is carried out on the ESD display of theOperation Console

 Field equipment reset

Unless otherwise specified, SDVs/BDVs valves are locally manually reset.

Resetting sequence is as follows :

·         ESD logic is reset at Operation Console

·         Valve is manually reset (permissive reset)

·         Valve is actuated at Operation Console

Local permissive resets are input to the ESD system.