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Ron Six, Instructor Senior Utility Consultant AEGIS Insurance Services, Inc. 201/417-2487 WRGC Pinpointing Underground Gas Leaks.

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Presentation on theme: "Ron Six, Instructor Senior Utility Consultant AEGIS Insurance Services, Inc. 201/417-2487 WRGC Pinpointing Underground Gas Leaks."— Presentation transcript:

1 Ron Six, Instructor Senior Utility Consultant AEGIS Insurance Services, Inc. 201/ WRGC Pinpointing Underground Gas Leaks

2 A E G I S A ssociated E EE E lectric G GG G as I II I nsurance S SS S ervices

3 Utility Mutual Insurance Company (member owned) Formed in 1975 by 22 gas utilities Electric Utilities began joining in members – 95% utilities and related energy AEGIS Background Information

4 Our main job is not finding & fixing leaks Our main job is public safety

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

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

7 #682#686 Dead Cast Iron Gas Main Water Main 4” Plastic Main 45 PSI ASH ST

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 PinpointRepair

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

12 Evaluating The Leak here is the gas? W H E R E 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

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? 19

20 Size of the Test Hole ½” Test Hole 1” Test Hole

21 Size of the Test Hole ½” Test Hole 1” 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 holePinpointing using a 1” test hole 22

23 Minnich Hornet Drill

24 S AVE A NOTHER M ISSED E XCAVATION

25 30% 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

27 Types of Soil Purgers

28

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

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 15% Gas 8” Steel UP CWP Maple Street Curb

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

33 8” Steel UP CWP Service Line 40% 35% 45% 0%15% 50% 45%10%0% 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 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 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 Manhole CGI Test 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

39 Using Test Results Using System Design Using Your Experience “Make Your Mark” Remember:It is much cheaper to drill than to dig. 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 High School K-Street 6” Low Pressure Cast Iron 4” High Pressure Steel 67 25% gas in sewer manhole 15% curb

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 Ethane No Ethane Natural Gas Sewer Gas Methane Nitrogen CO 2 Chromatographic Analysis Comparison

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. AEGIS Insurance Services, Inc. Thank You Please visit our


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