Considerations Before Using Trenchless Technologies in the Vicinity of Sewer Facilities Ohio Gas Association March 28, 2

1. 1 Considerations Before Using Trenchless Technologies in the Vicinity of Sewer FacilitiesOhio Gas AssociationMarch 28, 2008 Steve Farley Manager, Contractor Construction Duke Energy Dan Weakland Chief Officer of Safety, Quality & Regulatory Affairs Northern Pipeline Construction

2. 2 Gas Main Replacement Programs Gas Main Extensions for Development Gas Main Relocation for Street Improvements New Gas Services

3. 3 A Few Examples of Trenchless Technologies Employed by the Gas Industry

4. 4 Directional Drill

5. 5 Under Ground Piercing Tools

6. 6 Gas Main Replacement Programs Gas main replacement programs require installation around existing underground facilities utilizing trenchless technologies Most Cities and Counties will not allow perpendicular street cuts for each main to curb service without the costly grinding and paving of the entire street Trenchless Technologies are Needed to Control Cost

7. 7 Locate all Underground Facilities Locates typically included any underground facility that will conduct some type of electrical signal. A few examples are: Telephone Cable Gas Electric But what about the underground facilities that will not conduct an electrical signal? Sanitary Sewer Storm Drain Any non-metallic facility How are these facilities located?

8. 8 Changing Circumstances Due to Changes in Construction Damages to sewer mains and laterals when installing a gas main or service by excavating an open trench could be visually located and repaired The use of trenchless technologies along with plastic pipe creates a new set of risks

10. 9

11. 10

12. 12 What Happens When Laterals are Hit During Drilling / Boring Operations?

13. 13

14. 14 Did You Cause This?How Can You Be Sure?

15. 15 Headline:February 16, 2002Shocked Gas Company Pleads Ignorance The natural gas explosion that rocked a mobile home park on Wednesday shocked officials who say they never knew their gas line bisected the clay sewer pipe. A plumbing contractor was removing tree roots from a sanitary sewer line in the 127 unit mobile home park when the gas line was struck. �About the only time we know about sewer lines is when people call because they get backed up and have to call someone in to clean them,� said the Operations Manager with the Local Gas Company.

16. 16

17. 17 How Many Might Have Led To A Major Incident? Data provided by Northern Pipeline Construction Company

18. 18 LOW FREQUENCYHIGH SEVERITY

19. 19 What�s at Risk ?? Catastrophic Human Tragedy Huge Property Costs

20. 20 THE ROOT CAUSE The sewer districts may not be deemed the owners of the laterals to the home, and as such, they may have no obligation to mark them Homeowners may be exempted from locating nor do they have the expertise to locate the laterals on their property

21. 21 Challenges Sewer mains and laterals cannot be located using conventional methods Consideration must be made for developing a process for locating sewer mains and laterals

22. 22 Duke Energy Sewer Locate & Inspection Process Duke Energy has developed a comprehensive locating and inspection process for sewer mains and laterals Prior to the use of trenchless installation methods, all sewer mains and laterals must be located Upon completion of construction and prior to putting gas on the main, the sewer mains and laterals must be examined and recorded by camera for any conflicts All recordings are copied and sent to the local sewer district All recordings are verified by Duke personnel for accuracy and clear of all conflicts

23. 23 Camera Vehicle for Sewer Inspection

24. 24 Operator Console for Sewer Inspection

25. 25 Camera for Sewer Inspection

26. 26 Evolution of the Process for Locating & Inspecting Sewer Mains & Laterals Duke Energy will camera and locate sewer mains prior to construction utilizing trenchless technologies Duke Energy will also camera and locate sewer laterals to the sidewalks All curb to meter services are completed with open trench We have offset some of the cost by going beyond the requirement of merely locating prior to construction Main replacement is typically within areas with sewers from 40 to 140 years old Existing defects within the sewer mains and laterals will be recorded by camera

27. 27 Typical Sewer Locate & Inspection Process (continued) Typical defects are breaks, partial collapses, root damage, or conflicts with other utilities. The defects are passed on to the sewer district for repair before street restoration is completed Avoid the endless arguments of who is responsible for damages to the sewer main or lateral Sewer districts avoid the cost on the street restoration Some sewer districts appreciate the savings and reciprocate by cleaning the sewer mains in the area of next years replacement program The savings are realized by Duke Energy and sewer district customers

28. 28 Pay Units Pay units for the pre-locate and post-camera $/foot camera Camera footage is based on gas main footage Camera footage includes sanitary sewer, storm sewer, and sewer laterals Price includes the recording, copying, and all labor and equipment to operate the camera This includes a general cleaning required before the camera is placed in the sewer Heavy Cleaning Typically bid as time and equipment This is used for heavy deposits that cannot be cleared by a general cleaning

29. 29 Engineering annually contacts the Sewer Districts where construction will take place Provide a map of replacement construction areas Pre-construction meetings will also include: Local sewer districts Performing a camera inspection before construction activities saves on costly repairs

30. 30