1. Supplementing Risk Basked Inspection Programs with Integrity Operating Windows (IOWs)
Vishal Lagad - Sr. Corrosion Engineer
Asset Integrity
Lloyd’s Register Energy, Americas
October 9, 2013

2. Venue safety information
Safety overview
Location of emergency exists

3. Overview Review plant reliability goals IOW and RBI basics
Benefits of an IOW program
Supplementing RBI program with IOWs
Examples in refinery application
Q & A

4. Plant Reliability Goals
Ensure equipment performs it’s required functions for a specific time period
Maximize equipment availability
Optimize maintenance
Reduce risk and potential for leak/rupture
Provide early recognition of equipment risks due to process deviations
In short - No surprises!

5. Risk Based Inspection - RBI
Uses past operating conditions and inspection data to make future predictions
Captures risk at a snap shot in time
What happens when process conditions change?

6. Existing Industry Standards
Importance of monitoring operating conditions
API RP 580 Section 6.4
“It may be worthwhile to monitor key process parameters to determine whether operations are maintained within boundaries”
API 510 Section 6.2
“The likelihood of failure assessment should be repeated each time equipment or process changes are made”
API 584 – Best practices, guidelines for IOWs
Second Draft in review

7. Process & Operational Impact
Processes are not always stable
Feedstock variations
Upsets
When changes to operating conditions affect key process variables
New damage mechanisms may be introduced
Corrosion rates may accelerate
These excursions are typically unaccounted and their impact not considered

8. IOW Concepts
IOWs are allowable operating limits for a process variable
Established to manage corrosion and other damage mechanisms
Different from SOL, Alarms for Pressure integrity (MAWP etc.)
Requires a response within established timeframes if limit is exceeded
Failure to bring the operating condition within the IOW limit within established timeframe will result in damage to the equipment outside of acceptable limits

9. IOW Limits

10. Remaining Life (years)
An Illustration
Temperature
Breached IOW level for 3 months
IOW – Critical High / SOL
IOW – Standard High
Expected Risk Profile
Risk
Acceptable Risk Level
Remaining Life (years)
Actual
Remaining
Life
Expected Remaining Life
Early failure 4 10 25
Time (years)

11. Benefits of an IOW Program
Proactive approach to managing reliability and risk
Real time notification of an increased risk
Allows for timely intervention when process conditions change
Extends operating life of an asset
Enhances safety
Cost savings - reduced inspection costs and capital expenditures

12. IOW Implementation Team
Multidisciplinary team of SME’s
Corrosion Engineer / specialist
Process Engineer
Reliability Engineer / RBI specialists
Operations personnel
Plant inspector
Others – chemical treatment vendor, license technology specialists

13. Steps in Establishing an IOW Program
Collect and Review Data
Collect and review data
Create corrosion loops or circuits
Corrosion study
Damage mechanism review
Establish IOW Limits
Implement IOW program
Identify actions and responsibilities
Process historian and Alarm configuration
Create Corrosion Circuits / Loops
Corrosion Study and IOW Limits
Implement IOW Program

14. Create Corrosion Loops / Circuits
Areas that have similar operating conditions, corrosion mechanisms, and materials

15. Implement the IOW Program
Recommend Standard, Critical, and Informational limits
Select response times for each IOW limit based on IOW Risk Matrix
Other Considerations
Review IOW limits in conjunction with operating limits already established for safety (e.g. via HAZOP) and product quality before implementing
Consider instrumentation currently in place and sampling points
Client participation and commitment is essential

16. Example - IOW for Creep Damage in Heater Tubes
Heater coils not susceptible to creep under normal conditions
Flame instabilities can create locally hot areas
Fouling can result in greatly reduced heat transfer
Result – temperatures exceeding creep threshold temperature

17. Creep Damage in 321 SS Heater Tubes
Normal TMT T = 800 °F
Lower limit for creep T = 1000 °F (API 579)
Design temperature T=1050 °F
2000 hour (12 week) creep life T = 1210 °F (API 579 Omega)
Rapid deterioration T >1450 °F (API 530)

18. Supplementing RBI - Risk Matrix for Assessing IOWs
IOW Limit:
Critical: ˚F
Standard: ˚F
Response times:
Critical IOW: 60 min
Standard IOW: 24 hr
Creep threshold: T = 1000 °F
Design temp: T=1050 °F
2000 yr. creep life: T=1210 °F
Rapid deterioration: T >1450 °F

19. Another example of IOWs – much closer to the heart!
High Blood Pressure
33.6% of US adults 20 years of age have hypertension.
The prevalence of hypertension is nearly equal between men and women.
Approximately 78% are aware of their condition, 68% are using antihypertensive medication, and only 44% of those treated had their hypertension controlled.
Controllable variables
Obesity /Sedentary lifestyle
Tobacco / Alcohol abuse
Excess dietary sodium
Excessive alcohol intake
Stress
Cholesterol

20. An “RBI Approach” + IOWs for Healthcare!
Traditional RBI Approach
Assess individuals aged above 40
Focus on family and medical history
Treat symptoms with medications
Incorporating IOWs
Yearly annual checkups for all age groups
Preventive care education – focus on monitoring
Physical activity
Eating habits
Stress
Cholesterol levels
Smoking / Alcohol abuse

21. IOW Limits - Other Considerations
Is the limit practical – are operators constantly going to be responding to alarms?
Balance between constantly reacting to alarms and having enough response time to prevent damage
Consider which instruments or controls are already in place that could be used for monitoring
Consider using information limits that do not generate operator alarms but capture and document a deviation

22. Summary
IOWs enhance traditional RBI programs by providing a proactive approach to managing reliability and risk
Implementing an IOW program can provide better control and more confidence in managing the damage mechanisms
Permits alternative feedstock/operations considerations by more clearly understanding the operating limits
Can lead to improved facility safety and cost savings in terms of inspections and capital expenditures

23. Thank you – Questions?