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ameO <br /> 3. Use conventional extrusion welding as a secondary method for seaming between <br /> adjacent panels and as a primary method of welding for detail and repair work. <br /> a. Purge heat-degraded extrudate from barrel of extruder under the following <br /> conditions: <br /> 1. Prior to beginning a seam. <br /> 2. Whenever extruder has been inactive. <br /> b. Place a smooth insulating plate or fabric beneath hot welding apparatus after <br /> usage. <br /> C. Use clean and dry welding rods or extrudate pellets. <br /> d. Complete grinding process without damaging geomembrane according to <br /> MANUFACTURER's instructions no more than one (1) hour prior to seaming <br /> operations. <br /> e. Prevent exposed grinding marks adjacent to an extrusion weld. Do not extend <br /> exposed grinding marks more than one-quarter (1/4) inch from seam area. <br /> CERTIFYING ENGINEER may request that any and all abraded areas be <br /> covered with extrudate. <br /> f. Extrusion weld all cross seam tees to a minimum distance of four(4) inches on <br /> each side of the tee. <br /> g. For extrusion welds, the edge of the top sheet shall be beveled by grinding the <br /> edge of the sheet to approximately a 45-degree angle. Extrusion welds cannot <br /> be placed on previous extrusion welds. <br /> C. Seaming Procedures <br /> 1. General Seaming Procedures <br /> a. Areas to be seamed shall be cleaned and free of moisture, debris, or any <br /> marking on the geomembrane. <br /> b. Use a flat board, a conveyor belt, or similar hard surface directly under the seam <br /> overlap to achieve proper support if required. <br /> C. Cut fish mouths or wrinkles at the seam overlap along the ridge of the wrinkle <br /> in order to achieve a flat overlap. The cut fish mouths or wrinkles shall be <br /> seamed and any portion where the overlap is inadequate shall then be patched <br /> with an oval or round patch of the same geomembrane extending a minimum of <br /> six(6)inches beyond the cut in all directions. <br /> d. Extend seaming to the outside edge of panels placed in the anchor trench. <br /> e. Do not field seam without the Seaming Supervisor present. <br /> Section 02776 Page 16 of 22 May 9,2012 <br /> Geomembrane Revision 1 <br />