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<br />The FTB requirement is very important. With a fully integrated, continuous <br />connection through the seam, no weld bead sheet or sheedsheet interface exists. <br />Such an interface might be sepazated by absorbed chemicals, causing failure of the <br />seam. <br />[n addition to the FTB criterion a minimum stress level is specified. This is <br />important in order to protect against legitimate tearing of a thin portion of <br />polymer in the weld (as might occur if the weld is off center). <br />The minimum stress levels are necessazily lower than tensile yield strengths of the <br />parent sheet because of the different configuration of the test specimens during <br />destructive testing. Bending movements come into play along with straight <br />tensile stresses especially as sheets are bent back in peel. These bending <br />movements depend on the shape of the welds which can vary even within the <br />same welding technique. The minimum stress values are based on the average <br />performance values of the passed weld specimens tested in the laboratory. <br />3.3.8.7 Procedures for Destructive Test Failure <br />The following procedures shall apply whenever a sample fails a destructive test. <br />ILPI has two options: <br />1) Reconstruct the seam between any two passed test locations, <br />2) Trace the welding path to an intermediate location (IO feet maximum from <br />the point of the failed test in each direction) and take a small sample for an <br />additional field test at each location. If these additional samples pass the <br />field test, then full laboratory sample are taken. If these laboratory <br />samples pass the tests, then the seam is reconstructed between these <br />locations. If either sample fails, then the process is repeated to establish <br />the zone in which the seam should be reconstructed. <br />All acceptable seams must be bounded by two locations from which <br />samples passing laboratory destructive tests have been taken. <br />ILPI shall document all actions taken in conjunction with destructive test <br />failures; e.g., capping of failed seam azea. <br />3.4 Defects and Repairs <br />3.4.1 Identification <br />All seams and non-seam azeas of the geomembrane shall be examined by ILP[ for <br />identification of defects, holes, blisters, undispersed raw materials and any sign of <br />25 <br />