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A LEAK DETECTION SYSTEM USING SPARKTESTABLE GEOMEMBRANE "Holiday" or "spart~' testers wen: originally developed m detect defects on "Holidays" in pipe coatings. For a number of years, they have been used to detect pin holes in extrusion weld beads on liner seams. The ' procedure is simply a matter of imbedding a thin copper wire in an extrusion weld bead and apptying a high potential (12,000 to 20,000 volts) between the wire and a brass brush. As the brush is passed over the weld, any pin holes cause a spark which can be seen visually, and an alarm is sounded. CLC now makes it possible to use this simple technology to test every square inch of an installed liner in a dry state. The co-exWsion technology which made possible textured liner and mulficolored layered finer is ' used to add a thin (approximately 5 mil) electrically conductive layer to the standard liners, using electrically conductive carbon black The liner is installed with the electrically conductive layer on the bottom and standard non-conductive layers on the top. The spark test equipment may be connected directly to the conductive layer by the use of clamps or may reach the conductive layer through an earth ground. A wide (2- ' 6') brass brush is passed over the liner surface and, as in a seam test, any pin hole will cause a spark which triggers an alarm. The test equipment includes a marking system to define the edge of each pass of the brush so that each pass of the brush should overlap the previous pass. The equipment provides output ' signals for an audible alarm. This signal is used to mark the location of the defect for repair, and provide a strip chart record of the test. ~ The system is simple, yet it provides a multitude of advantages. 1. Current flow is minuscule; therefore, the system is safe for personnel and no heat is generated when a spark occurs. ' 2. The extremely high voltage eliminates the need for a conductive fluid to penetrate the defect and provide a current path. Even the most minute defects can be located. 3. Most welds are automatically spark tested when the liner is tested. (This comes as a bonus to the nomral non-destructive and destructive weld testing.) 4. Since the conductive layer is an integral part of the liner, there are no areas where the elecUical potential does not exist 5. Primary liners can be tested as easily as secondary or ground contact liners. 6. Complex configurations such as pipe boots can be completely tested. ' 7. Water puddles or dirt on the liner do not affect the test In the case of a water puddle, the entire puddle will become charged and wi11 spark To locate the leak the water is removed and the area re- tested. 8. No water pumping is required. 9. Repairs can be re-tested quickly and easily. 10. The test is fast One walking operator pn best 12 ace per hour and for large areas, a vehicular mounted test device could easly cover 1-12 to 2 aces per hour. ' 11. Operator skill requirements are minimal. ' 12. Chemical resistance is completely retained as are all other properties. In the case of exposed liners in ponds and similar applications, the liner can be re-tested at any time in the future. ' 25