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provide any information on seam strength. Continuity testing shall be carried out as the seaming work progresses, not at the completion of field seaming. Visual Inspection All seams shall be visually evaluated by the Contractor and/or Liner Subcontractor as the installation progresses and again at completion of the installation. Defective and questionable sections shall be clearly marked and repaired as necessary. Vacuum Box Testing If the fillet weld, extrusion lap weld or single hot -wedge fusion lap weld technique is used to weld seams, the Contractor and/or Liner Subcontractor shall further test all seams and repairs in the VFPE by vacuum box. The vacuum box shall be an American Vacuum Seam Tester, Series A100 as manufactured by American Parts and Service Company, Alhambra, California, or -an -approved equal. All vacuum box testing shall be done in the presence of the Geotechnical CQA Monitor. The area to be tested shall be cleaned of all dust, "debris, dirt and other foreign matter. A soap solution shall be applied to the test area with a brush, paint roller or spray bottle and a minimum vacuum of 10 inches of mercury (Hg) (5 psi) shall be induced and held as long as necessary to visually inspect and mark for repair any suspicious areas as evidenced by bubbles in the soap solution. Spark Testing If the fillet weld is used to weld seams, the Contractor and/or Liner,Subcontractor may, in lieu of vacuum box testing, test all seams and repairs in the VFPE liner by using a high voltage spark detector, similar to Tinker and Rasor H®liday-Detector (Model AP -W). The setting of the detector shall be 20,000 volts. In order to conduct this test, all seams to be tested shall be provided with.24730.gauge copper wires properly embedded in the seams and grounded. All spark testing shall be done in the presence of the Geotechnical CQA Monitor. All-de€ectiveareas-shall be marked for repair. Air Pressure Test If the double hot -wedge welding technique is used, the Contractor and/or Liner Subcontractor shall further test all seams in the VFPE lining by using the air pressure test which consists of inserting a needle with gauge in the air space between welds. Air shall be pumped to 40 psi within the weld void and held for at least 5 minutes. If the pressure loss exceeds 2 psi within the weld void during air pressure testing, the outside weld edge (not free edge) shall be sprayed with a soap solution and visually examined for bubbles. If no bubbles appear, the problem is with the inside weld and the seam is acceptable. If any bubbles -25- C:\2001-048\FINAL COVER_CQA.DOC\08/20/01 Geologic Associates