1、Designation: D7002 10D7002 15Standard Practice forElectrical Leak Location on Exposed Geomembranes Usingthe Water Puddle SystemMethod1This standard is issued under the fixed designation D7002; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice, practice is a performance-based standard for electrical methods, covers detecting
3、an electrical method forlocating leaks in exposed geomembranes. For clarity, this practice uses the term “leak” to mean holes, punctures, tears, knife cuts,seam defects, cracks, and similar breaches in an installed geomembrane (as defined in 3.2.5).1.2 This practice can be used for geomembranes inst
4、alled in basins, ponds, tanks, ore and waste pads, landfill cells, landfill caps,canals, and other containment facilities. It is applicable for geomembranes made of materials such as polyethylene, polypropylene,polyvinyl chloride, chlorosulfonated polyethylene, bituminous geomembrane, and any other
5、electrically insulating materials. Thispractice may not be is best applicable for locating geomembrane leaks where the proper preparations have not been made duringthe construction of the facility.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are inc
6、luded in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior t
7、o use.2. Referenced Documents2.1 ASTM Standards:2D4439 Terminology for GeosyntheticsD6747 Guide for Selection of Techniques for Electrical Leak Location of Leaks in GeomembranesD7703 Practice for Electrical Leak Location on Exposed Geomembranes Using the Water Lance Method1 This practice is under th
8、e jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.10 on Geomembranes.Current edition approved July 1, 2010Jan. 1, 2015. Published September 2010January 2015. Originally approved in 2003. Last previous edition approved in 20032010as D700203.D70
9、0210. DOI: 10.1520/D7002-10.10.1520/D7002-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is
10、 not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropr
11、iate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D7953 Practice for Electrical Leak Location on Exposed Geomembra
12、nes Using the Arc Testing Method3. Terminology3.1 Definitions:3.1.1 For general definitions used in this practice, refer to Terminology D4439.3.2 Definitions of Terms Specific to This Standard:3.2.1 artificial leak, nan electrical simulation of a leak in a geomembrane.3.2.2 conductive-backed geomemb
13、rane, na specialty geomembrane manufactured using coextrusion technology featuring aninsulating layer in intimate contact with a conductive layer.3.2.3 current, nthe flow of electricity or the flow of electric charge.3.2.4 electrical leak location, na method which uses electrical current or electric
14、al potential to detect and locate leaks.3.2.4 electrodes, nthe conductive plate that is placed in earth ground or in the material under the geomembrane or aconductive structure, such as a copper manifold, that is placed in the water puddle on the geomembrane.3.2.5 leak, nfor the purposes of this doc
15、ument, a leak is any unintended opening, perforation, breach, slit, tear, puncture,crack, or seam breach. Significant amounts of liquids or solids may or may not flow through a leak. Scratches, gouges, dents, orother aberrations that do not completely penetrate the geomembrane are not considered to
16、be leaks. Leaks Types of leaks detectedduring surveys have been grouped into five categories:include, but are not limited to: burns, circular holes, linear cuts, seamdefects, tears, punctures, and material defects.3.2.5.1 burned through zonesvoids created by melting polymer during welding.3.2.5.2 ho
17、lesround shaped voids with downward or upward protruding rims.3.2.5.3 linear cutslinear voids with neat close edges.3.2.5.4 seam defectsarea of partial or total separation between sheets.3.2.5.5 tearslinear or areal voids with irregular edge borders.3.2.6 leak detection sensitivity, nthe smallest le
18、ak that the leak location equipment and survey methodology are capable ofdetecting under a given set of conditions. The leak detection sensitivity specification is usually stated as a diameter of the smallestleak that can likely be reliably detected.3.2.7 poor contact condition, nfor the purposes of
19、 this practice, a poor contact condition means that a leak is not in intimatecontact with the conductive layer above or underneath the geomembrane to be tested. This occurs on a wrinkle or wave, under theoverlap flap of a fusion weld, in an area of liner bridging and in an area where there is a subg
20、rade depression or rut.3.2.8 probe, nfor the purposes of this practice, any conductive structure that is attached to a power source.3.2.9 squeegee, nfor the purposes of this document, a squeegee is a device used to contain and push water on top of anexposed geomembrane. It may consist of a handle an
21、d a transverse piece at one end set with a strip of leather or rubber.rubber,or a roller apparatus.3.2.10 water puddle, na small pool of water placed on the geomembrane to create a conduit for current to flow through anyleaks.4. Summary of Practice4.1 Principle of Electrical Leak Location Method Usi
22、ng the Water Puddle System:4.1.1 The principle of the electrical leak location method is to place a voltage across a geomembrane and then locate areas whereelectrical current flows through discontinuities in the geomembrane and at seams.4.1.2 Fig. 1 shows a diagram of the electrical leak location me
23、thod of the water puddle system for exposed geomembranes. Oneoutput of an electrical excitation power supply is connected to an electrode placed in a water puddle created on top of thegeomembrane. The other output of the power supply is connected to an electrode placed in electrically conductive mat
24、erial underthe geomembrane.4.1.3 Measurements are made using an electrical current measurement system, the magnitude of the current being related to thesize of the leak. An electronic assembly is usually used to produce an audio tone whose frequency is proportional to the currentflow.4.2 Leak Locati
25、on Surveys of Exposed Geomembrane Using the Water Puddle System:4.2.1 The water puddle detection system usually consists of a horizontal water spray manifold with multiple nozzles that spraywater onto a geomembrane, a squeegee device to push the resultant puddle of water, and a handle assembly as sh
26、own in Fig. 2.Apressurized water source, usually from a tank truck parked at higher elevation, is connected to the spray manifold using a plasticor rubber hose. Figs. 3 and 4 show one example of such an apparatus.4.2.2 Direct current power supplies (usually a 12 or 24 volt battery) have been used fo
27、r leak location surveys. An alternatingcurrent (output requirement of 12 to 30 volt ac) could be used.D7002 1524.2.3 For leak location surveys of exposed geomembrane, the water puddle created is pushed systematically over thegeomembrane area to locate the points where the electrical current flow inc
28、reases.4.2.4 The signal from the probe is typically connected to an electronic detector assembly that converts the electrical signal toa detector and an audible signal that increases in pitch and amplitude as the leak signal increases.4.2.5 When a leak signal is detected, the location of the leak is
29、 then marked or measured relative to fixed points.4.2.6 The leak detection sensitivity can be very good for this technique. Leaks smaller than 1 mm in diameter are routinelyfound, including leaks through seams in the geomembrane.4.2.7 The survey rate depends primarily on the manifold and squeegee wi
30、dth and the presence of wrinkles and waves in thegeomembrane.4.3 Preparations and Measurement Considerations:4.3.1 Proper field preparations and other measures shall be implemented to ensure an electrical connection to the conductivematerial directly below the geomembrane is in place to successfully
31、 complete the leak location survey.4.3.2 There shall be a conductive material below the geomembrane being tested. Leak location survey of geomembrane havebeen conducted with a conductivity of a subgrade equivalent to sand with moisture greater than 0.7 % (by weight). Aproperly-prepared subgrade typi
32、cally will have sufficiently conductivity. Under proper conditions and preparations, geosyntheticclay liners (GCLs) can be adequate as conductive material. There are some conductive geotextiles with successful field experiencewhich can be installed beneath the geomembrane to facilitate electrical le
33、ak survey (that is, on dry subgrades, or as part of a planardrainage geocomposite).4.3.3 Measures should be taken to perform the leak location survey when geomembrane wrinkles are minimized.NOTE 1The leak location survey should be conducted at night or early morning when wrinkles are minimized. Some
34、times wrinkles can be flattenedby personnel walking or standing on them as the survey progresses.4.3.4 For lining systems comprised of two geomembranes with only a geonet or geonet geocomposite between them, to makethe method feasible a conductive layer such as a conductive geotextile shall be insta
35、lled under the geomembrane or integrated intothe geonet geocomposite.4.3.5 For best results, conductive paths such as metal pipe penetrations, pump grounds, and batten strips on concrete should beisolated or insulated from the water puddle on the geomembrane.These conductive paths conduct electricit
36、y and mask nearby leaksfrom detection. See also Guide D6747.4.3.6 Depending on specific construction practices and site conditions, other preparations and support may still be needed tosuccessfully perform the leak location survey.4.3.7 The system specifications are presented in Table 1.4. Significa
37、nce and Use4.1 Geomembranes are used as barriers to prevent liquids from leaking from landfills, ponds, and other containments. For thispurpose, it is desirable that the geomembrane have as little leakage as practical.4.2 The liquids may contain contaminants that, if released, can cause damage to th
38、e environment. Leaking liquids can erode thesubgrade, causing further damage. Leakage can result in product loss or otherwise prevent the installation from performing itsintended containment purpose.4.3 Geomembranes are often assembled in the field, either by unrolling and welding panels of the geom
39、embrane materialtogether in the field, unfolding flexible geomembranes in the field, or a combination of both.FIG. 1 Diagram of the Electrical Leak Location Method for Surveys with Water Puddle on Exposed GeomembraneWater Puddle MethodD7002 1534.4 Geomembrane leaks can be caused by poor quality of t
40、he subgrade, poor quality of the material placed on the geomembrane,accidents, poor workmanship, manufacturing defects, and carelessness.4.5 Electrical leak location methods are an effective and proven quality assurance measure to detect and locate leaks.5. Significance and Use5.1 Geomembranes are u
41、sed as barriers to prevent liquids from leaking from landfills, ponds, and other containments. For thispurpose, it is desirable that the geomembrane have as little leakage as practical.5.2 The liquids may contain contaminants that if released can cause damage to the environment. Leaking liquids can
42、erode thesubgrade, causing further damage. Leakage can result in product loss or otherwise prevent the installation from performing itsintended containment purpose.5.3 Geomembranes are often assembled in the field, either by unrolling and welding panels of the geomembrane materialtogether in the fie
43、ld, or unfolding flexible geomembranes in the field.5.4 Geomembrane leaks can be caused by poor quality of the subgrade, poor quality of the material placed on the geomembrane,accidents, poor workmanship, and carelessness.5.5 Electrical leak location methods are an effective and proven quality assur
44、ance measure to locate previously undetected ormissed leaks and check the integrity of a liner.5. Summary of Exposed Geomembrane Electrical Leak Location Methods5.1 Principles of the Electrical Leak Location Methods for Exposed Geomembranes:5.1.1 The principle of the electrical leak location methods
45、 is to place a voltage across a geomembrane and then locate areaswhere electrical current flows through leaks in the geomembrane.5.1.2 Currently available methods include the water lance method (Practice D7703), the arc testing method (Practice D7953),and the water puddle method.TABLE 1 Specificatio
46、nsWater Puddle Leak Detection TechniquesSummary of Water Puddle MethodGeomembranes Bituminous, CSPE, CPE, EIA, fPP, HDPE, LLDPE, LDPE, PVC, VLDPE U applicableEPDM, GCL X not applicableExposed U applicableCovered X not applicableConductive-backed Geomembrane U applicableACharacteristics Training time
47、 1 daySet up time and calibration time 1 to 3 hMeasurement time instantaneousLeak location time 10 min maxSubgrade moisture (by weight) equivalent to sand with 0.7 %Average survey speed (horizontal surface) 500 m2 per hour per operatorPower supply 12 or 24 volts dc or acSeams All types: welded, tape
48、, adhesive, glued and other U applicable: project specificSeams All types: welded, tape, adhesive, glued and other U applicable: project specificJunctions At synthetic pipes and accessories U applicable: project specificJunctions At synthetic pipes and accessories U applicable: project specificAt pe
49、rmanent structure U applicable: project specificAt grounded conducting structures X not applicableSurvey 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: project specificDesiccated subgrade (conductivity equivalent to sand with 0.7 % moisture) X not applicableInsufficiently conductive subgrade X not applicableDuring the service life (if exposed) U applicableDuring the service life (if exposed) U project
