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2. No seaming equipment or welder will be allowed to perform production <br /> welds until equipment and welders have successfully completed trial welds. <br /> 3. Frequency of trial welds: <br /> a. Minimum of two trial welds per day with one prior to the start of <br /> work and one at mid shift. <br /> b. When directed by the CQA Inspection Personnel. <br /> C. Every 2 hours when using a wedge weld to weld across seams. <br /> d. Minimum one trial weld per person per shift. <br /> e. When ambient temperature changes more than 10 degrees Fahrenheit <br /> since previous trial weld. <br /> 4. Make trial welds in the same surroundings and environmental conditions as <br /> the production welds, i.e., in contact with subgrade. <br /> 5. Make trial weld sample at least 3-feet long and 12-inches wide with the seam <br /> centered lengthwise. <br /> 6. Cut two 1-inch wide test strips from opposite ends of the trial weld. <br /> 7. Quantitatively test specimens, first for peel adhesion, and then for bonded <br /> seam strength (shear) (ASTM D6392). <br /> 8. A single or double wedge weld specimen is considered passing when the <br /> following results are achieved. For double-wedge welding,both welds must <br /> pass in peel and shear. <br /> a. The break is a film tearing bond (FTB). <br /> b. The break is ductile. <br /> C. The peel strength is 70 percent minimum of the specified sheet yield <br /> strength for wedge welded or flat welded seams and 60 percent <br /> minimum of the specified sheet yield strength for extrusion welded <br /> seams. There is no more than 10 percent separation of the weld. For <br /> wedge welds the width of the weld is equal to the width of the nip <br /> roller. <br /> d. The shear strength is 90 percent of the specified sheet yield strength <br /> for all weld types. When testing set grips back 2 inches from the edge <br /> of the weld.Minimum elongation between the grips must be 2 inches. <br /> 9. A trial weld sample is considered passing when specimens pass peel and <br /> shear tests. <br /> 10. Repeat the trial weld in its entirety when any of the trial weld samples fail in <br /> either peel or shear. <br /> FORWARD LANDFILL 02778 <br /> HIGH DENSITY POLYETHYLENE <br /> 12 (HDPE)GEOMEMBRANE <br />