Designation: D 6365 – 99 (Reapproved 2006)
Standard Practice for
the Nondestructive Testing of Geomembrane Seams using the Spark Test 1 This standard is issued under the fixed designation D 6365; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript supers cript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Sco Scope pe
3.1.1 geomembrane, n—an esse essential ntially ly impe impermea rmeable ble geosynthetic composed of one or more synthetic sheets. 3.1.1.1 Discussion—In geo geotec techni hnical cal eng engine ineeri ering, ng, ess essenentially tia lly imp imperm ermeab eable le mea means ns tha thatt no mea measur surabl ablee liq liquid uid flow flowss through a geosynthetic when tested in accordance with Test Methods D Methods D 4491. 4491. 3.1.2 seam, n—a permanent joining of two or more materials. 3.2 For definition definition of othe otherr term terms, s, see Termi erminolo nology gy D 4439. 4439.
1.1 This practice practice covers the nonde nondestruc structive tive testing testing of field seams in geomembranes using the spark test. A suspect area is indicated by the generation of a spark. The test is applicable to seams made by the extrusion method, seams made by using weld we ldin ing g ta tape pe (a st stri rip p of th thee sa same me ty type pe of ma mate teri rial al as th thee geome geo memb mbran rane, e, th that at is wel welded ded ov over er adj adjac acen entt se secti ction onss of geomembrane to create a seam), or seams where it is practical to ins insert ert a con conduc ductiv tivee mat materi erial al in the sea seam m jus justt pri prior or to or during fabrication. 1.2 The spa spark rk tes testt may produce produce an ele electr ctrica icall spa spark rk and therefore can only be used where an electrical spark would not create a hazard. 1.3 Unles Unlesss the voltages voltages and distances distances prescribed prescribed are care care-fully adhered to, a “false positive” indication may result. This false positive occurs when the arc distance is too large for the voltage applied at the time and conditions of testing. 1.4 The values values stated in SI units are to be regarded regarded as the standard. The values given in parentheses are for information only. standa ndard rd does not purport purport to add addre ress ss all of the 1.5 This sta safe sa fety ty co conc ncer erns ns,, if an anyy, as asso soci ciat ated ed wi with th it itss us use. e. It is th thee responsibility of the user of this standard to establish appro priate health and safety practices and to determine the applicability of regulatory limitations prior to use.
4. Summ Summary ary of Practice Practice 4.1 To use this this practice a conductive conductive material is inserted inserted into the field seam just prior to or during fabrication. The conductive material in the seam is connected to the negative terminal of the test apparatus, and a positive voltage is applied across the seam edge. A suspect area in the seam is indicated by a spark from the voltage source to the conductive material. 5. Signi Significanc ficancee and Use 5.1 Spark testing testing of geom geomembr embrane ane field seam seamss is particularly useful in locations where other nondestructive test methodss ar od aree no nott pr prac acti tica cal, l, fo forr ex exam ampl plee in ti tigh ghtt co corn rner erss or a circumferential seam around a pipe. 6. Appa Apparatus ratus 6.1 The test apparatus apparatus consi consists sts of a high– high–volt voltage, age, low–curlow–current source with a negative terminal for ground and a positive terminal term inal for a volta voltage ge appli applicato cator. r. A volt voltage age appl applicato icatorr may consis con sistt of a han handle dle and wir wiree bru brush, sh, con conduc ductiv tivee neo neopre prene ne squeegee, or other suitable applicator. 6.2 The range of the high voltage voltage source is typically typically 20 000 to 35 000 V. 6.2.1 6.2 .1 The vol voltag tagee req requir uired ed to cau cause se a dis discha charg rgee (sp (spark ark)) between the positive electrode and the negative electrode wire is expressed by the formula.
2. Referenced Documents 2.1 ASTM Standards: 2 D 4439 Terminology for Geosynthetics D 4491 Test Methods for Water Permeability of Geotextiles by Permittivity 3. Terminology 3.1 Definitions:
5 K = D V 5
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This practice is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.10 on Geomembranes. Curren Cur rentt edit edition ion app approv roved ed Jun Junee 1, 200 2006. 6. Pub Publish lished ed Jun Junee 200 2006. 6. Ori Origin ginally ally approved in 1999. Last previous edition approved in 1999 as D 6365 – 99. 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@
[email protected] astm.org. g. For For Annual Annual Book of ASTM volume information, refer to the standard’s Document Summary page on Standards volume Standards the ASTM website website..
where: V = test volta voltage, ge, K = a constan constantt (V/(mm) (V/(mm)1/2), and D = the distanc distancee from the edge edge of the extrusion extrusion bead bead on the lower panel to the conductive material in mm.
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D 6365 – 99 (2006) 6.2.2 If the volt voltage age is not adequate adequate due to underestima underestimating ting D, a false positive test (a seam with a suspect area resulting in no spark and testing as a good seam) may result. 6.2.3 Good results results have been obtained obtained using the test voltages and distances given in Table 1. 1. 6.2.4 The conductive material material should be located located 8 to 15 mm from the edge of the extrusion bead on the bottom geomembrane to be a successful test.
are given in Table in Table 1. 1. The user should verify the test voltage is adequate using a trial seam with a simulated defect prior to testing and also to verify that the test voltage will not damage the geomembrane. 7.4 Che Check ck that the field seams seams and areas areas adj adjace acent nt to the seams are dry prior to testing. 7.5 Pla Place ce the voltage voltage applicat applicator or (su (such ch as a wir wiree bru brush sh or conduc con ductiv tivee neo neopre prene ne squ squeeg eegee) ee) con connec nected ted to the pos positi itive ve terminal of the voltage source, in contact with the geomembrane at the seam. 7.6 Move the voltage applicator applicator along the seam at at a uniform rate of 6 to 9 m per minute. The voltage applicator must make intimate contact with the seam being inspected. 7.7 As the test progresse progresses, s, the gener generatio ation n of a spark indicates a suspect area in the seam. It is desirable that equipment hass an au ha audi dibl blee to tone ne si sign gnal al th that at oc occu curs rs wh when en a sp spar ark k is generated. 7.8 The suspect suspect area is marke marked d for repa repair ir..
7. Pro Procedur ceduree 7.1 Befor Beforee or as the seam is fabr fabricate icated d a conti continuous nuous elecelectrically conductive material is inserted in the lapped area of the panels 2 to 5 mm (0.1 to 0.2 in.) from the edge of the top panel of membrane. See Fig. 1. 1. 7.2 Prior to testing, testing, it is necessary to connect the conductive conductive material installed in the field seam to the negative terminal of the voltage source or a separate ground. 7.3 7. 3 Se Sett th thee vo volt ltag agee so sour urce ce to a vo volt ltag agee ne need eded ed fo forr th thee expected distance. Typical distances and the required voltages
8. Repo Report rt 8.1 Repor Reportt the following following info informat rmation: ion: 8.1.1 Identification of the geomembrane geomembrane material, material, including the type of polym polymer, er, manufacturer manufacturer,, thick thickness, ness, reinforced reinforced or nonreinforced sheeting, seam type used, ambient temperature, date of seam fabrication, date of seam evaluation, seam tested and results of seam evaluation. 8.1.2 Voltage used.
TABLE 1 TEST VOLTAGE VOLTAGE FOR VARIOUS EXPECTED DISTANCESA Expected Distance D Distance D (in.) (mm) 0.250 0.375 0.500 0.625 0.750 A
Constant K = 7900 volts/(mm)
6 10 13 16 19
Test Voltage (V) 20 25 28 31 35
000 000 000 000 000
9. Keyw Keywords ords 9.1 geomembrane; nondestructive; nondestructive; seams; testing
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D 6365 – 99 (2006)
1 . G I F
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D 6365 – 99 (2006)
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