1、Designation: D 7002 03Standard Practice forLeak Location on Exposed Geomembranes Using the WaterPuddle System1This standard is issued under the fixed designation D 7002; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This standard is a performance-based practice for elec-trical methods for detecting leaks in exposed geomembranes.For
3、clarity, this document uses the term “leak” to mean holes,punctures, tears, knife cuts, seam defects, cracks and similarbreaches in an installed geomembrane (as defined in 3.1.5).1.2 This standard can be used for geomembranes installed inbasins, ponds, tanks, ore and waste pads, landfill cells, land
4、fillcaps, canals and other containment facilities. It is applicable forgeomembranes made of materials such as polyethylene,polypropylene, polyvinyl chloride, chlorosulfonated polyethyl-ene, bituminous geomembrane, and any other electrically-insulating materials.1.3 This standard does not purport to
5、address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 4439 Term
6、inology for GeosyntheticsD 6747 Guide for Selection of Techniques for ElectricalDetection of Potential Leak Paths in Geomembranes3. Terminology3.1 Definitions:3.1.1 artificial leak, nan electrical simulation of a leak ina geomembrane.3.1.2 electrodes, nthe conductive plate that is placed inearth gro
7、und or in the material under the geomembrane or aconductive structure, such as a copper manifold, that is placedin the water puddle on the geomembrane.3.1.3 electrical leak location, na method which useselectrical current or electrical potential to detect and locateleaks.3.1.4 geomembrane, nan essen
8、tially impermeable mem-brane used with foundation, soil, rock, earth or any othergeotechnical engineering related material as an integral part ofa man made project, structure, or system.3.1.5 leak, nfor the purposes of this document, a leak isany unintended opening, perforation, breach, slit, tear,
9、punc-ture, crack, or seam breach. Significant amounts of liquids orsolids may or may not flow through a leak. Scratches, gouges,dents, or other aberrations that do not completely penetrate thegeomembrane are not considered to be leaks. Leaks detectedduring surveys have been grouped into five categor
10、ies:3.1.5.1 holesround shaped voids with downward or up-ward protruding rims.3.1.5.2 tearslinear or areal voids with irregular edgeborders.3.1.5.3 linear cutslinear voids with neat close edges.3.1.5.4 seam defectsarea of partial or total separationbetween sheets.3.1.5.5 burned through zonesvoids cre
11、ated by meltingpolymer during welding.3.1.6 leak detection sensitivity, nthe smallest leak that theleak location equipment and survey methodology are capableof detecting under a given set of conditions. The leak detectionsensitivity specification is usually stated as a diameter of thesmallest leak t
12、hat can be reliably detected.3.1.7 current, nthe flow of electricity or the flow ofelectric charge.3.1.8 water puddle, nfor the purposes of this document, awater puddle is a small pool of water being contained andpushed by a squeegee installed on the leak location system.3.1.9 squeegee, nfor the pur
13、poses of this document, asqueegee is a device used to contain and push water on top ofan exposed geomembrane. It may consist of a handle and atransverse piece at one end set with a strip of leather or rubber.3.1.10 metalized geotextile, na geotextile incorporatingmetallic strips that can conduct ele
14、ctrical current.4. Summary of Practice4.1 The Principle of the Electrical Leak Location MethodUsing the Water Puddle System:1This practice is under the jurisdiction of ASTM Committee D35 on Geosyn-thetics and is the direct responsibility of Subcommittee D35.10 on Geomembranes.Current edition approve
15、d Dec. 1, 2003. Published December 2003.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.1 The principle of the electrical leak location method isto place a voltage across a geomembrane and then locate areaswhere electrical curren
16、t flows through discontinuities in thegeomembrane and at seams.4.1.2 Fig. 1 show a diagram of the electrical leak locationmethod of the water puddle system for exposed geomem-branes. One output of an electrical excitation power supply isconnected to an electrode placed in a water puddle created onto
17、p of the geomembrane. The other output of the power supplyis connected to an electrode placed in electrically conductivematerial under the geomembrane.4.1.3 Measurements are made using an electrical currentmeasurement system, the magnitude of the current beingrelated to the size of the leak. An elec
18、tronic assembly is usuallyused to produce an audio tone whose frequency is proportionalto the current flow.4.2 Leak Location Surveys of Exposed Geomembrane Usingthe Water Puddle System:4.2.1 The water puddle detection system usually consists ofa horizontal water spray manifold with multiple nozzles
19、thatspray water onto a geomembrane, a squeegee device to pushthe resultant puddle of water, and a handle assembly as shownin Fig. 2. A pressurized water source, usually from a tank truckparked at higher elevation, is connected to the spray manifoldusing a plastic or rubber hose. Figs. 3 and 4 show o
20、ne exampleof such an apparatus.4.2.2 Direct current power supplies (usually a 12 or 24 voltbattery) have been used for leak location surveys. An alternat-ing current (output requirement of 12 to 30 volt AC) could beused.4.2.3 For leak location surveys of exposed geomembrane,the water puddle created
21、is pushed systematically over thegeomembrane area to locate the points where the electricalcurrent flow increases.4.2.4 The signal from the probe is typically connected to anelectronic detector assembly that converts the electrical signalto a detector and an audible signal that increases in pitch an
22、damplitude as the leak signal increases.4.2.5 When a leak signal is detected, the location of the leakis then marked or measured relative to fixed points.4.2.6 The leak detection sensitivity can be very good for thistechnique. Leaks smaller than 1 mm in diameter are routinelyfound, including leaks t
23、hrough seams in the geomembrane.4.2.7 The survey rate depends primarily on the manifoldand squeegee width and the presence of wrinkles and waves inthe geomembrane.4.3 Preparations and Measurement Considerations:4.3.1 There must be a conductive material below thegeomembrane being tested. Leak locatio
24、n survey of geomem-brane have been conducted with a conductivity of a subgradeequivalent to sand with moisture greater than 0.7 % (byweight). A properly-prepared subgrade typically will havesufficiently conductivity. Under proper conditions and prepa-rations, geosynthetic clay liners (CGLs) can be a
25、lso adequate.4.3.2 Measures should be taken to perform the leak locationsurvey when geomembrane wrinkles are minimized. For flex-ible geomembranes, sometimes the wrinkles can be flattenedby personnel walking on them immediately in front of thesurvey. For surveys with wrinkles in rigid geomembranes,
26、theleak location survey should be conducted at night or earlymorning.4.3.3 For lining systems comprised of two geomembraneswith only a geonet or geocomposite between them, the methodis not applicable. For lining systems comprised of twogeomembranes separated by a metalized geotextile, the methodis a
27、pplicable.4.3.4 For best results, conductive paths such as metal pipepenetrations, pump grounds, and batten strips on concreteshould be isolated or insulated from the water puddle on thegeomembrane. These conductive paths conduct electricity andmask nearby leaks from detection.4.3.5 The system speci
28、fications are presented in Table 1.5. Significance and Use5.1 Geomembranes are used as barriers to prevent liquidsfrom leaking from landfills, ponds, and other containments. Forthis purpose, it is desirable that the geomembrane have as littleleakage as practical.5.2 The liquids may contain contamina
29、nts that if releasedcan cause damage to the environment. Leaking liquids canerode the subgrade, causing further damage. Leakage can resultin product loss or otherwise prevent the installation fromperforming its intended containment purpose.5.3 Geomembranes are often assembled in the field, eitherby
30、unrolling and welding panels of the geomembrane materialtogether in the field, or unfolding flexible geomembranes in thefield.5.4 Geomembrane leaks can be caused by poor quality ofthe subgrade, poor quality of the material placed on thegeomembrane, accidents, poor workmanship, and carelessness.5.5 E
31、lectrical leak location methods are an effective qualityassurance measure to locate previously undetected or missedleaks and check the integrity of a liner.6. Practices for Surveys with Water Puddle System6.1 A realistic test of the leak detection sensitivity should beperformed and documented as par
32、t of the leak location survey.An actual or artificial leak can be used. The leak locationequipment and procedures should be demonstrated to be able todetect the artificial or actual leak when water puddle is passedover the leak on the geomembrane.6.2 Artificial LeakIf an artificial leak is used, it
33、shall beconstructed by drillinga1mmdiameter hole in approximatelythe center of a piece of geomembrane. The piece of geomem-brane should have a width of at least twice the width of thesqueegee, and a length of at least four times the width of thesqueegee. The hole should be drilled, and the drill bit
34、 recipro-cated in the hole so the geomembrane material is removedrather than displaced. The artificial leak shall be placed on asubgrade that is prepared to be the same as the subgrade underthe actual geomembrane. When surveying leak detection onexisting containment facilities, a geomembrane sample
35、equiva-lent to the liner installed should be used.6.3 Actual LeakIf an actual leak is used, it shall beconstructed by drillinga1mmdiameter hole in the installedgeomembrane that is to be tested. For double geomembranes,D7002032measures must be taken to ensure that the secondary geomem- brane is not d
36、amaged. The hole must be drilled at least theFIG. 1 Diagram of the Electrical Leak Location Method for Surveys with Water Puddle on Exposed GeomembraneD7002033FIG. 2 Diagram of Electrical Leak Water Puddle SystemD7002034width of the squeegee from the edge of the geomembrane. Thehole should be drille
37、d, and the drill bit reciprocated in the holeso the geomembrane material is removed rather than displaced.6.4 The excitation power supply and the water supply shallbe turned on, and the water puddle detection system shall bepushed over the artificial or actual leak at a speed equal to thedesired pro
38、duction survey speed.6.5 If the resultant signal is at least 10 percent of the fullscale reading of the detector electronics, the leak detectionequipment and procedures shall be considered to be success-fully demonstrated.6.6 The leak location survey shall be conducted using thesame water puddle det
39、ection system speed as that used for thecalibration.6.7 Periodic testing of the integrity of the electrical circuit isrecommended. It is recommended to check every 15 to 20 minthe integrity of electrical circuit by contacting (touching) thesubgrade with the equipment squeegee unit or by using an ext
40、raelectrical cable well-connected to the subgrade. As a minimum,this check shall be conducted at the beginning and end of eachday of survey. If the equipment fails to pass the leak detectionsensitivity test, then the area surveyed with that set of equip-ment in the period since the previous leak det
41、ection sensitivitytest shall be repeated.7. Report7.1 The leak location survey report shall contain the follow-ing information:FIG. 3 Photograph of a Water Puddle Leak Location EquipmentFIG. 4 Photograph of Leak Location EquipmentD70020357.1.1 Description of the survey site,7.1.2 Climatic conditions
42、,7.1.3 Type and thickness of geomembrane,7.1.4 Liner system layering,7.1.5 Description of the leak location method,7.1.6 Survey methodology,7.1.7 Identification of equipments and operators,7.1.8 Results of artificial leak test,7.1.9 Specific conditions of survey,7.1.10 Location, type and size of det
43、ected leaks, and7.1.11 Map of the surveyed areas.8. Keywords8.1 electrical leak location method; geomembrane; leakdetectionASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expr
44、essly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revise
45、d, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may
46、attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United State
47、s. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 SpecificationsWater Puddle Leak Detection Techniqu
48、esgeomembranes HDPE, VLDPE, PVC, fPP, bituminous, CSPE, CPE U applicableEPDM, GCL X not applicableexposed U applicablecovered X not applicablecharacteristics training time 1 dayset up time and calibration time 1 to 3 hmeasurement time instantaneousleak location time 10 min maxsubgrade moisture (by w
49、eight) equivalent to sand with 0.7 %average survey speed (horizontal surface) 500 m2per hour per operatorpower supply 12 or 24 volts DC or ACseams all types: welded, tape,adhesive, glued and other U applicable: project specificjunctions at synthetic pipes and accessories U applicable: project specificat permanent structure U applicable: project specificsurvey during construction phase (installation of GM) U applicableafter installation (exposed) U applicableafter soil covering X not applicablepresence of large wrinkles and waves X not applicableslopes U applicable: p
