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August 2002 -42- 003 -2203 <br />6.1.6 Non - Destructive Testing <br />Poly -Flex performed non - destructive seam testing on completed seams and geomembrane <br />repairs. Non - destructive testing for seams included pressure testing of fission- welded seams, <br />and vacuum testing of extrusion welded seams and repairs. Golder monitored and documented <br />the non- destructive testing. <br />Prior to pressure testing of fusion seams, Poly -Flex heat - sealed both ends of the air channel <br />between the two tracks of the double wedge weld. Poly -Flex then inserted a pressure gauge in <br />one end of the sealed channel. Poly -Flex pressurized the air channel to approximately <br />30 pounds per square inch (psi) using an air pump. After pressure stabilization, Golder <br />monitored the gauge for a minimum of five minutes. The maximum allowable pressure drop <br />was 3 psi. <br />Poly -Flex and Golder verified fusion seam continuity before heat - sealing both seam ends, <br />completed pressure testing, and with the gauge left in place, cut the opposite end of the seam. If <br />the gauge pressure dropped to zero, the seam was determined to be continuous. In cases where <br />the seam was found to be discontinuous, the seam was subdivided into shorter sections until <br />continuous seam sections were located and passing pressure tests were performed, or the outer <br />edge of the seam was extrusion welded and vacuum tested. <br />If a pressure test failed, Poly -Flex checked the seam section for leakage, and repaired and <br />re- tested the seam. If Poly -Flex was unable to find the leak, the seam was divided into two <br />sections, with each section being tested to locate the area of concern This subdivision process <br />was repeated until the leak location was identified. If the leak area was not located, Poly -Flex <br />reconstructed the seam, and then vacuum tested the repair. <br />Poly -Flex tested extrusion welded seam sections with a vacuum box. Prior to vacuum box <br />testing, Poly -Flex applied a soap and water solution to the seam section. The vacuum box was <br />then placed over the seam area and energized with a vacuum pump capable of creating a <br />I NOO= 3V400 \CmWB02%003=3,0400.0474aM.dox Golder Associates <br />