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11. Weld only when ambient temperature, measured 6 inches above the <br /> geomembrane,is between 40 degrees Fahrenheit and 104 degrees Fahrenheit. <br /> 12. If the GEOSYNTHETICS CONTRACTOR seams at ambient temperatures <br /> below 40 degrees Fahrenheit and above 104 degrees Fahrenheit, then the <br /> GEOSYNTHETICS CONTRACTOR must demonstrate and certify that such <br /> methods produce seams which are entirely equivalent to seams produced at <br /> ambient temperatures above 40 degrees Fahrenheit and below 104 degrees <br /> Fahrenheit, and that the overall quality of the geomembrane is not adversely <br /> affected. In addition, a change order to the contract between the OWNER <br /> and the Installer is required which specifically states that the seaming <br /> procedure does not cause any physical or chemical modification to the <br /> geomembrane that will generate any short or long term damage to the <br /> geomembrane. Then, the temperatures in the above quality assurance <br /> procedure will be modified accordingly. <br /> 13. Seaming below temperatures of 32 degrees Fahrenheit must include <br /> preheating methods approved by the QA/QC CONSULTANT. <br /> F. Defects and Repairs. <br /> 1. Examine all welds and non-weld areas of the geomembrane for defects,holes, <br /> blister,undispersed raw materials, and any sign of contamination by foreign <br /> matter. The surface of the geomembrane must be clean at the time of the <br /> examination. <br /> 2. Repair and non-destructively test each suspect location both in weld and <br /> non-weld areas. Do not cover geomembrane at locations which have been <br /> repaired until test results with passing values are available. <br /> G. Extrusion Type of Welding. <br /> 1. Use procedures to tack bond adjacent panels together that do not damage <br /> geomembrane and allow CQA tests to be performed. <br /> 2. Purge welding apparatus of heat-degraded extrudate before welding. <br /> 3. Bevel top edges of geomembrane a minimum of 45 degrees and full thickness <br /> of geomembrane before extrusion welding. <br /> 4. Clean seam welding surfaces of oxidation by disc grinder or equivalent not <br /> more than 30 minutes before extruding weld. Change grinding discs <br /> frequently. Do not use clogged discs. <br /> 5. Do not remove more than 4 mils of material when grinding. <br /> 6. Grind across,not parallel to, welds. <br /> 7. Cover entire width of grind area with extrudate. <br /> 8. When restarting welding, grind ends of all welds that are more than <br /> 5-minutes old. <br /> FORWARD LANDFILL 02778 <br /> HIGH DENSITY POLYETHYLENE <br /> 16 (HDPE)GEOMEMBRANE <br />