Refers to PES equipment status. After successful operations as plant approved equipment, the plant wants to elevate the PES to "plant approved safety." This is desired so the plant may utilize its PESs in critical applications where appropriate. The plant meets with the PES producer and jointly develops the following strategy:
- The producer agrees to provide a plant approved safety controller "spin off" from the plant approved PES.
- The producer "freezes" the "spin off" PES from any changes without the mutual consent of the plant.
- All problems with the commercial PES are jointly reviewed (e.g., producer and plant) for impact on the "spin off" PES design.
- The producer provides all unsafe failure modes of the plant.
- The producer quantifies each unsafe failure mode for the plant.
- The plant develops a program to continuously qualify the PES.
With the proper development of the above data, the PES is classified "plant approved safety."