1、Designation: D 6365 99 (Reapproved 2006)Standard Practice forthe Nondestructive Testing of Geomembrane Seams usingthe Spark Test1This standard is issued under the fixed designation D 6365; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of last 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 practice covers the nondestructive testing of fieldseams in geomembranes using the spark test.
3、 A suspect area isindicated by the generation of a spark. The test is applicable toseams made by the extrusion method, seams made by usingwelding tape (a strip of the same type of material as thegeomembrane, that is welded over adjacent sections ofgeomembrane to create a seam), or seams where it is
4、practicalto insert a conductive material in the seam just prior to orduring fabrication.1.2 The spark test may produce an electrical spark andtherefore can only be used where an electrical spark would notcreate a hazard.1.3 Unless the voltages and distances prescribed are care-fully adhered to, a “f
5、alse positive” indication may result. Thisfalse positive occurs when the arc distance is too large for thevoltage applied at the time and conditions of testing.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standa
6、rd does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate health and safety practices and to determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 AS
7、TM Standards:2D 4439 Terminology for GeosyntheticsD 4491 Test Methods for Water Permeability of Geotextilesby Permittivity3. Terminology3.1 Definitions:3.1.1 geomembrane, nan essentially impermeable geo-synthetic composed of one or more synthetic sheets.3.1.1.1 DiscussionIn geotechnical engineering,
8、 essen-tially impermeable means that no measurable liquid flowsthrough a geosynthetic when tested in accordance with TestMethods D 4491.3.1.2 seam, na permanent joining of two or more mate-rials.3.2 For definition of other terms, see Terminology D 4439.4. Summary of Practice4.1 To use this practice
9、a conductive material is inserted intothe field seam just prior to or during fabrication. The conduc-tive material in the seam is connected to the negative terminalof the test apparatus, and a positive voltage is applied acrossthe seam edge. A suspect area in the seam is indicated by aspark from the
10、 voltage source to the conductive material.5. Significance and Use5.1 Spark testing of geomembrane field seams is particu-larly useful in locations where other nondestructive test meth-ods are not practical, for example in tight corners or acircumferential seam around a pipe.6. Apparatus6.1 The test
11、 apparatus consists of a highvoltage, lowcur-rent source with a negative terminal for ground and a positiveterminal for a voltage applicator. A voltage applicator mayconsist of a handle and wire brush, conductive neoprenesqueegee, or other suitable applicator.6.2 The range of the high voltage source
12、 is typically 20 000to 35 000 V.6.2.1 The voltage required to cause a discharge (spark)between the positive electrode and the negative electrode wireis expressed by the formula.V 5 K=D (1)where:V = test voltage,K = a constant (V/(mm)1/2), andD = the distance from the edge of the extrusion bead on th
13、elower panel to the conductive material in mm.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 approved June 1, 2006. Published June 2006. Originallyapproved in 1999. Last previous
14、 edition approved in 1999 as D 6365 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM Intern
15、ational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2.2 If the voltage is not adequate due to underestimatingD, a false positive test (a seam with a suspect area resulting inno spark and testing as a good seam) may result.6.2.3 Good results have been obtain
16、ed using the test volt-ages and distances given in Table 1.6.2.4 The conductive material should be located 8 to 15 mmfrom the edge of the extrusion bead on the bottom geomem-brane to be a successful test.7. Procedure7.1 Before or as the seam is fabricated a continuous elec-trically conductive materi
17、al is inserted in the lapped area of thepanels 2 to 5 mm (0.1 to 0.2 in.) from the edge of the top panelof membrane. See Fig. 1.7.2 Prior to testing, it is necessary to connect the conductivematerial installed in the field seam to the negative terminal ofthe voltage source or a separate ground.7.3 S
18、et the voltage source to a voltage needed for theexpected distance. Typical distances and the required voltagesare given in Table 1. The user should verify the test voltage isadequate using a trial seam with a simulated defect prior totesting and also to verify that the test voltage will not damaget
19、he geomembrane.7.4 Check that the field seams and areas adjacent to theseams are dry prior to testing.7.5 Place the voltage applicator (such as a wire brush orconductive neoprene squeegee) connected to the positiveterminal of the voltage source, in contact with the geomem-brane at the seam.7.6 Move
20、the voltage applicator along the seam at a uniformrate of 6 to 9 m per minute. The voltage applicator must makeintimate contact with the seam being inspected.7.7 As the test progresses, the generation of a spark indi-cates a suspect area in the seam. It is desirable that equipmenthas an audible tone
21、 signal that occurs when a spark isgenerated.7.8 The suspect area is marked for repair.8. Report8.1 Report the following information:8.1.1 Identification of the geomembrane material, includingthe type of polymer, manufacturer, thickness, reinforced ornonreinforced sheeting, seam type used, ambient t
22、emperature,date of seam fabrication, date of seam evaluation, seam testedand results of seam evaluation.8.1.2 Voltage used.9. Keywords9.1 geomembrane; nondestructive; seams; testingTABLE 1 TEST VOLTAGE FOR VARIOUS EXPECTEDDISTANCESAExpected Distance D Test Voltage(in.) (mm) (V)0.250 6 20 0000.375 10
23、 25 0000.500 13 28 0000.625 16 31 0000.750 19 35 000AConstant K = 7900 volts/(mm)1/2D 6365 99 (2006)2FIG.1D 6365 99 (2006)3ASTM 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
24、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
25、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
26、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 States. 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).D 6365 99 (2006)4
