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Forward Compost Facility Stormwater Improvements <br />02778 10 HDPE GEOMEMBRANE <br />C. Perform trial seam welds as follows: 1. Perform trial welds on samples of geomembrane to verify the performance of welding equipment, seaming methods, and conditions. 2. No seaming equipment or welder will be allowed to perform production welds until equipment and welders have successfully completed trial welds. 3. Frequency of trial welds: a. Minimum of two trial welds per day with one prior to the start of work and one at mid shift. b. When directed by the CQA Inspection Personnel. c. Every 2 hours when using a wedge weld to weld across seams. d. Minimum one trial weld per person per shift. e. When ambient temperature changes more than 10 degrees Fahrenheit since previous trial weld. 4. Make trial welds in the same surroundings and environmental conditions as the production welds, i.e., in contact with subgrade. 5. Make trial weld sample at least 3-feet-long and 12-inches-wide with the seam centered lengthwise. 6. Cut two, 1-inch-wide test strips from opposite ends of the trial weld. 7. Quantitatively test specimens, first for peel adhesion, and then for bonded seam strength (shear) (ASTM D6392). 8. A single or double wedge weld specimen is considered passing when the following results are achieved. For double-wedge welding, both welds must pass in peel and shear. a. The break is a film tearing bond (FTB). b. The break is ductile. c. The peel strength is 70 percent minimum of the specified sheet yield strength for wedge welded or flat welded seams and 60 percent minimum of the specified sheet yield strength for extrusion welded seams. There is no more than 10 percent separation of the weld. For wedge welds the width of the weld is equal to the width of the nip roller. d. The shear strength is 90 percent of the specified sheet yield strength for all weld types. When testing set grips back 2 inches from the edge of the weld. Minimum elongation between the grips must be 2 inches. 9. A trial weld sample is considered passing when specimens pass peel and shear tests. 10. Repeat the trial weld in its entirety when any of the trial weld samples fail in either peel or shear. 11. When repeated trial weld fails, do not use welding apparatus and welder until deficiencies or conditions are corrected and two consecutive successful trial welds are achieved.