1. WRGC Pinpointing Underground Gas Leaks
Ron Six, Instructor Senior Utility Consultant AEGIS Insurance Services, Inc.
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2. Associated Electric Gas Insurance Services
A E G I S
Associated Electric Gas Insurance Services
Before I begin my presentation, some of you may not be familiar with AEGIS, so let me take just a moment to tell you who AEGIS is.
AEGIS is an acronym that stands for Associated Electric and Gas Insurance Services.
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3. AEGIS Background Information
Utility Mutual Insurance Company
(member owned)
Formed in 1975 by 22 gas utilities
Electric Utilities began joining in 1977
375 members – 95% utilities and related energy
AEGIS is a mutual insurance company formed nearly 30 years ago.
Discuss slide.
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4. Our main job is not
finding & fixing leaks
Our main job is
public safety

5. Pinpointing
Is not an exact science. It is a developed skill which is learned and perfected through your mistakes and your successes.

6. Major Causes of Leaks Corrosion Mechanical failure
Improper installation
Improper design
Faulty materials
3rd Party Damage - “Dig-Ins”

7. ASH ST #682 #686 4” Plastic Main 45 PSI Water Main
Dead Cast Iron Gas Main
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8. The “Find and Fix Syndrome”
The cure for this is to ask yourself a question “Where is the gas”? If you can answer the question that the gas is not affecting people and it is not affecting property you are cured. You must ask yourself this question on every leak before you get into the “repair” mode.

9. Our main job is not
finding & fixing leaks
Our main job is
public safety

10. Detect
Pinpoint
Repair

11. Evaluating The Leak
Where is the gas? w h e r is
the
gas?

12. Evaluating The Leak W H E R
here is the gas?
ow much is there?
xtent of hazard (migration)
elation to other structures
valuate/evacuate

13. Factors Affecting Gas Migration
Soil type
Soil moisture
Surface cover
Line pressure
Depth of burial
Leak size and age
Change in elevation=slope
Path of least resistance

14. Centering = Where is the gas?
Pinpointing = Where is the leak?
The leak must be centered before it is pinpointed

15. Be Careful – “Don’t make a leak, looking for a leak.”
Centering The Leak
Probe holes must be of sufficient depth
Test all available openings
“Zero out” N-S-E-W
You must have sufficient information to make a good judgement
Be Careful – “Don’t make a leak, looking for a leak.”

16. Recent Natural Gas Incidents
Springfield, MA

17. Methods Of Locating The Line
Maps
Records
System experience
Electronic locators
1. Basic principles of operation
2. Inductive vs. Conductive
3. Overcoming problems

18. Consistency = Success Exact location of main, services etc.
Size of test hole (aeration is the key)
Depth of test hole (must be consistent)
Location of test holes (same side of main)
Instrument use (consistency in testing)

19. PLACEMENT OF DRILL HOLES
Where and how many?
What size test holes?
How deep?
How far apart?

20. Size of the Test Hole
½” Test Hole ” Test Hole

21. From the 1” Test Hole vs. the ½” Test Hole
Size of the Test Hole
½” Test Hole ” Test Hole
4x’s the Aeration
From the 1” Test Hole vs. the ½” Test Hole

22. The Size of the test hole is critical
Pinpointing with a ½” test hole
Pinpointing using a 1” test hole

23. Minnich Hornet Drill

24. SAVE ANOTHER MISSED EXCAVATION

25. OLD MAIN STREET #400 #402 #404 30% Gas @ Foundation Wall
90% Curb
Concrete Sidewalk
4” Bare Steel 45 PSI
OLD MAIN STREET
#400
#402
#404

26. Use Of Soil Purger (cont’d)
The soil purger is your best friend or worst enemy, depending on where and how it is used
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27. Types of Soil Purgers

29. Never purge near foundation
#404
#402
#400
Never purge near foundation
30% Foundation Wall
Concrete Sidewalk
90% Curb
Purge Away From Foundation
This will draw the gas away from the building and block the gas from migrating to the foundation wall
8” CI UP
OLD MAIN STREET

30. Grade 1 Leak Repairs (Did you find “a” leak or did you find “the” leak
You must not leave a Grade 1 Leak indication as long as the conditions that got you there are still present. If the readings went from 30% gas to 3% gas at the foundation it is still a technical Grade 1 leak. Purge the soil, get the readings to 0%, wait and make sure that the readings do not return.

31. 60% Gas
Curb
8” Steel UP CWP
Maple Street
15% Gas

32. Maple Street 60% Gas 15% Gas Curb Service Line 8-10’ 8” Steel UP CWP
70%
50%
75%
8-10’
Maple Street
60% Gas
15% Gas

33. Maple Street 60% Gas 15% Gas Curb Service Line Slope 8” Steel UP CWP
40%
35%
45% 0%
15%
50%
10%
Maple Street
60% Gas
15% Gas
Curb
Slope

34. Using The Soil Purger In The Pinpointing Process
Purge from a hole where you know that the leak is not
Plug holes near purge point
Dense soil or moisture – time the purge/purge each hole
Use it only when all other methods have failed

35. Test Methods Combustible gas indicator Natural ventilation
1. Top & bottom of hole
2. Time the readings
Natural ventilation
1. Wait…let holes vent
Blow pipe – vapors/soap top of hole
Odor

36. Never use near foundation of building
Use Of Soil Purger
Should not be used on every leak
Operation:
1. In the pinpoint process
2. As a safety tool –
Never use near foundation of building
3. Residual gas
Choosing a purge point is the key
Techniques

37. 10% Gas In Sewer Manhole
6” Steel UP
ASH STREET
CURB LINE

38. Gas Readings In Manhole
Is gas in the sewer or just using the manhole as a venting point?
Test top and bottom
Percent gas readings will generally not be sewer gas
Manhole
CGI Test
CGI Test

39. “Make Your Mark” Using Your Experience Using Test Results
Using System Design
Remember: It is much cheaper to drill than to dig.
Do you have enough holes to give you enough information about the leak?

40. The Dry Hole Probe along the pipe
Expose all of the pipe, not just the top
Learn from your mistakes
Use the hole to your advantage… no one “hits” them all
Is it our gas?

41. 6” Low Pressure Cast Iron
High School
4” High Pressure Steel
25% gas in sewer manhole
K-Street
6” Low Pressure Cast Iron
15% curb 65 69 71 67

42. Checking After The Repair
Did we find “the” leak?
Residual gas – when will it go away?
Cleanup/plugging the test holes
Importance of proper documentation

43. Stray Gas Is it lighter or heavier than air?
Is there ethane in the sample?
Is it a hazard?
What is sewer gas/decomposition gas?
Natural gas vs. stray gas
Use of charcoal filter
Use of collection bottles/bags
Responsibilities regarding stray gas
“Reasonable person concept”

44. Chromatographic Analysis Comparison
No Ethane
CO2
Methane
Sewer Gas
Nitrogen
Ethane
Natural Gas

45. Remember: The Job Is Not Completed
Until all paperwork/documentation is completed:
Neatly
Thoroughly
Accurately
You may do everything right, but you may be judged by what is or is not documented

46. Be Alert
Be Prepared
Be Safe

47. AEGIS Insurance Services, Inc. Thank You Please visit our website @ www.aegislink.com
Thank you for the opportunity to speak with you today and to participate in your conference.
The Loss Control Division is here to contribute to your continued success.
Thank you.
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