In Line Inspection Lessons Learned Eloy J. Blanco Al Verbrugge Senior Engineer Senior Engineer

1. In Line Inspection Lessons Learned Eloy J. Blanco Al Verbrugge Senior Engineer Senior Engineer

2. Introduction • MidAmerican Energy Company (MEC) is primarily a LDC • Operating in Iowa, Illinois, South Dakota, and Nebraska • 797 miles of transmission lines

3. MidAmerican Energy Pipeline System

4. Threat Assessment • EC & IC are threat to all of MEC’s pipelines • SCC is not a threat to any of our pipelines at this point • For MEC, ILI tools is the preferred method to assess a pipeline for Time-Dependent Threats (External Corrosion, Internal Corrosion, Stress Corrosion Cracking). MEC believes that Pressure Testing is not an applicable assessment method for Time Dependent Threats.

5. Criteria for In Line Inspection (ILI) • Number of segments and footage of HCA’s • Growth in the area • Existing condition of the pipeline • Cost

6. Criteria for ILI • Existing Condition If pipeline was built to handle ILI tools, the line will be pigged regardless of the footage of HCA’s or growth in the area.

7. Criteria for ILI • The next item to be considered was the total number of HCA segments and their footage. • If the line is not piggable, it would have to have a significant footage of HCA’s to be considered for pigging.

8. Criteria for ILI • Next, the growth along the pipeline was considered.

9. Criteria for ILI • Finally, the costs associated with modifying the line to handle ILI tools was incorporated into the decision making process.

10. Lines to be pigged • DSMS632-16” Line built in 2003. MAOP 800 psig. Can accommodate tools, no launcher/receiver • IAQC619-16” built in 1996. MAOP 960 psig. Verify if tee installed after original installation is barred; modify piping at terminus to handle L/R • ICCR691-16” Line built in 1991. MAOP 720 psig. No launcher/receiver; replace L/R 90o elbows installed during relocation; modify piping at terminus to handle L/R skids

11. Lines to be pigged • ICCR664-12 & 16” line built in 1959 & 1964. MAOP 600 psig. Significant amount of work required. Due to the amount of work, the line will be pigged in four stages. • ICCR653-10” line build in 1953. MAOP 600 psig. Significant amount of work required. Due to the amount of work require, the line will be pigged in three stages.

12. Line Modifications • None of our lines had launchers/receivers • Looked at three alternatives: • Rent launcher/receivers • Build permanent launcher/receivers • Build a temporary launcher/receiver skids that could handle 10”/12”/16”

13. Launcher/Receiver

14. Line Modifications • Since ICCR653 & ICCR664 run parallel to each other, parallel segments were taken out of service for modifications sequentially. This was done to minimize inconvenience to property owners. • Nevertheless, numerous pipeline shutdowns were required to perform the required modifications.

15. Line Modifications • Cost of gas is a significant item. Modifications to Lines ICCR653 and ICCR664 in 2007, required approximately $70,000 of gas to be vented to the atmosphere.

16. Line Modifications • Replaced non-standard port valves • Replaced standard elbows with hot bends. Original decision was to replace only bends tighter than 45o. Big Mistake! • Replaced box sags • Non-barred tees-tees were dug up and x-rayed • No field bends-fittings used instead

17. ROW Clearing • Had to do approximately 4 acres of clearing at a cost of $77,000.

18. Environmental & Permitting Concerns • Need to allow time for environmental and permitting

19. Existing Drawings • The availability and status of drawings is a problem with older lines • One set of drawings indicated that tees were barred , another indicated that they were not barred • Indicated bends, however the angle of the bends was not always indicated. Had to dig them out to determine. • Transition for wall thickness changes not indicated

20. ROW Availability • ROW availability is a problem • $100k at three sites • One location is still being negotiated • Temporary access may be an option

21. Running the Tool • ILI vendor availability-Although ILI vendors are extremely busy, MEC has not had any problems with scheduling the runs. • Run the tool on line or off line? • Speed control for ILI tools is essential (typically 3-5 mph) • If you use air, make sure it is dry air!

22. Running the Tool • Contact large customers early in the planning process • Develop contingency plan

23. Running the Tools • All vendors will tell you that their tool can make it thru standard radius elbows.

24. Running the Tool • Found a crushed elbow. Had to be cut out to remove the tool (cleaning tool with a tracker).

25. Running the Tool • Tracking the tool-use as many AGM’s as you can

26. Cleaning • Develop a line cleaning program. • MEC had to run over 30 cleaning pigs in one section of line.

27. Results • Results of a tool run on DSMS626 showed that that the line, as expected, was in excellent condition • Results on a section of ICCR664 showed, surprisingly, that the line is in excellent condition also. • No corrosion wall loss greater than 10% was found. • Manufacturing defects ~20% wall loss were found

28. Summary • Replace all l/r elbows • In your estimate, do not forget: • Gas vented • ROW clearing • ROW acquisition • Allow time for: • Permits • Environmental concerns • ROW acquisitions • If you use air to propel the tools; make sure it is dry • Use plenty of AGM’s • When you do your assessment, use features or AGM’s to locate anomalies