LOPA - Most Common Mistakes
LOPA - Most Common Mistakes
What are the most common mistakes which can happen during SIL determination using LOPA?
Re: LOPA - Most Common Mistakes
I will make sure that I don't leave any common mistakes which we do during LOPA for SIL determination.
1. Treating Basic Process Control System (BPCS) as Independent When It Is Not
2. Giving Credit to Operator Response Without Verifying Reality
3. Double Counting IPLs
4. Using Unrealistic Initiating Event Frequencies
5. Confusing Safeguards With IPLs
6. Ignoring Common Cause Failure
7. Wrong Consequence Severity Selection
8. Applying Generic PFD Values Blindly
9. Not Defining the Scenario Properly
10. Assuming a PSV Always Eliminates Risk
11. Ignoring Enabling Conditions
12. No Validation of Time Available for SIS Action
13. Treating HAZOP Recommendations as IPLs
14. Poor Documentation of Assumptions
15. SIL Inflation Due to Weak LOPA Discipline
1. Treating Basic Process Control System (BPCS) as Independent When It Is Not
2. Giving Credit to Operator Response Without Verifying Reality
3. Double Counting IPLs
4. Using Unrealistic Initiating Event Frequencies
5. Confusing Safeguards With IPLs
6. Ignoring Common Cause Failure
7. Wrong Consequence Severity Selection
8. Applying Generic PFD Values Blindly
9. Not Defining the Scenario Properly
10. Assuming a PSV Always Eliminates Risk
11. Ignoring Enabling Conditions
12. No Validation of Time Available for SIS Action
13. Treating HAZOP Recommendations as IPLs
14. Poor Documentation of Assumptions
15. SIL Inflation Due to Weak LOPA Discipline
Re: LOPA - Most Common Mistakes
Quite an extensive list!
Double counting IPLs mean considering alarm high & high-high twice or how this mistake can be done?
Double counting IPLs mean considering alarm high & high-high twice or how this mistake can be done?