Module 15 - Operations, Maintenance, Modification

Question 1

What is the operators responsibilities?

Answer 1

Broadly - Operate and maintain the SIS to preserve functional safety

Specifically:

1. Train operators and maintainers
2. Manage bypasses
3. Proof test
4. Monitor design assumptions
5. Control modifications

Question 2

What is the operators responsibilities?

Answer 2

Broadly - Operate and maintain the SIS to preserve functional safety

Specifically:

1. Train operators and maintainers
2. Manage bypasses
3. Proof test
4. Monitor design assumptions
5. Control modifications

Question 3

What must operators be trained in at a minimum?

Answer 3

1. What does each SIF do?
2. What hazardous event does each SIF protect against?
3. How should the operator respond to SIS faults and alarms?
4. Use of bypasses and resets

Question 4

Why do we proof test?

Answer 4

Because the probability a SIF has failed increases with time. Proof testing exposes undetected dangerous failures

Question 5

What is the ideal proof testing methodology?

Answer 5

End to end testing

Question 6

Is partial proof testing allowed?

Answer 6

Yes, partial testing is allowed if we ensure overlap such that eventually the Proof Test Coverage is sufficient and all elements are tested

Question 7

What are some additional proof testing considerations?

Answer 7

1. Inspect for deterioration
2. Ensure detailed procedures and checklists have been developed for SIF inspection
3. Focus on minimising common mode and systematic failures

Question 8

How can we monitor for design discrepancy?

Answer 8

Collect data continuously and check a random subset at a periodic interval

Question 9

What is the typical modification process?

Answer 9

1. Modification request
2. Impact analysis
3. Authorisation
4. Repeat at required point as far back in the lifecycle as the change affects