Presentation on theme: "WRGC Pinpointing Underground Gas Leaks"— Presentation transcript:
1WRGC Pinpointing Underground Gas Leaks Ron Six, Instructor Senior Utility Consultant AEGIS Insurance Services, Inc.201/
2Associated Electric Gas Insurance Services A E G I SAssociated Electric Gas Insurance ServicesBefore 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.First Response
3AEGIS Background Information Utility Mutual Insurance Company(member owned)Formed in 1975 by 22 gas utilitiesElectric Utilities began joining in 1977375 members – 95% utilities and related energyAEGIS is a mutual insurance company formed nearly 30 years ago.Discuss slide.First Response
4Our main job is notfinding & fixing leaksOur main job ispublic safety
5PinpointingIs not an exact science. It is a developed skill which is learned and perfected through your mistakes and your successes.
6Major Causes of Leaks Corrosion Mechanical failure Improper installationImproper designFaulty materials3rd Party Damage - “Dig-Ins”
7ASH ST #682 #686 4” Plastic Main 45 PSI Water Main Dead Cast Iron Gas MainFirst Response
8The “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.
9Our main job is notfinding & fixing leaksOur main job ispublic safety
11Evaluating The LeakWhere is the gas?wheristhegas?
12Evaluating The LeakWHERhere is the gas?ow much is there?xtent of hazard (migration)elation to other structuresvaluate/evacuate
13Factors Affecting Gas Migration Soil typeSoil moistureSurface coverLine pressureDepth of burialLeak size and ageChange in elevation=slopePath of least resistance
14Centering = Where is the gas? Pinpointing = Where is the leak?The leak must be centered before it is pinpointed
15Be Careful – “Don’t make a leak, looking for a leak.” Centering The LeakProbe holes must be of sufficient depthTest all available openings“Zero out” N-S-E-WYou must have sufficient information to make a good judgementBe Careful – “Don’t make a leak, looking for a leak.”
17Methods Of Locating The Line MapsRecordsSystem experienceElectronic locators1. Basic principles of operation2. Inductive vs. Conductive3. Overcoming problems
18Consistency = 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)
19PLACEMENT OF DRILL HOLES Where and how many?What size test holes?How deep?How far apart?
29Never purge near foundation #404#402#400Never purge near foundation30% Foundation WallConcrete Sidewalk90% CurbPurge Away From FoundationThis will draw the gas away from the building and block the gas from migrating to the foundation wall8” CI UPOLD MAIN STREET
30Grade 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.
32Maple Street 60% Gas 15% Gas Curb Service Line 8-10’ 8” Steel UP CWP 70%50%75%8-10’Maple Street60% Gas15% Gas
33Maple Street 60% Gas 15% Gas Curb Service Line Slope 8” Steel UP CWP 40%35%45%0%15%50%10%Maple Street60% Gas15% GasCurbSlope
34Using The Soil Purger In The Pinpointing Process Purge from a hole where you know that the leak is notPlug holes near purge pointDense soil or moisture – time the purge/purge each holeUse it only when all other methods have failed
35Test Methods Combustible gas indicator Natural ventilation 1. Top & bottom of hole2. Time the readingsNatural ventilation1. Wait…let holes ventBlow pipe – vapors/soap top of holeOdor
36Never use near foundation of building Use Of Soil PurgerShould not be used on every leakOperation:1. In the pinpoint process2. As a safety tool –Never use near foundation of building3. Residual gasChoosing a purge point is the keyTechniques
3710% Gas In Sewer Manhole6” Steel UPASH STREETCURB LINE
38Gas Readings In Manhole Is gas in the sewer or just using the manhole as a venting point?Test top and bottomPercent gas readings will generally not be sewer gasManholeCGI TestCGI Test
39“Make Your Mark” Using Your Experience Using Test Results Using System DesignRemember: It is much cheaper to drill than to dig.Do you have enough holes to give you enough information about the leak?
40The Dry Hole Probe along the pipe Expose all of the pipe, not just the topLearn from your mistakesUse the hole to your advantage… no one “hits” them allIs it our gas?
416” Low Pressure Cast Iron High School4” High Pressure Steel25% gas in sewer manholeK-Street6” Low Pressure Cast Iron15% curb65697167
42Checking After The Repair Did we find “the” leak?Residual gas – when will it go away?Cleanup/plugging the test holesImportance of proper documentation
43Stray 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 gasUse of charcoal filterUse of collection bottles/bagsResponsibilities regarding stray gas“Reasonable person concept”
44Chromatographic Analysis Comparison No EthaneCO2MethaneSewer GasNitrogenEthaneNatural Gas
45Remember: The Job Is Not Completed Until all paperwork/documentation is completed:NeatlyThoroughlyAccuratelyYou may do everything right, but you may be judged by what is or is not documented
47AEGIS 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.CLICKFirst Response