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C <br />L` <br />C. Perform trial seam welds as follows: <br />1. Perform trial welds on samples of geomembrane to verify the performance of <br />welding equipment, seaming methods, and conditions. <br />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 />11. When repeated trial weld fails, do not use welding apparatus and welder until <br />deficiencies or conditions are corrected and two consecutive successful trial <br />welds are achieved. <br />Forward Landfill WMU FU -14 HIGH DENSITY POLYETHYLENE <br />Is 02778 12 (HDPE) GEOMEMBRANE <br />