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Section 02776 <br />Geomembrane <br />C. Seaming Procedures <br />d. Remove seaming sheets and excess geomembrane trimmed to provide required <br />overlap. <br />3. Use conventional extrusion welding as a secondary method for seaming between adjacent <br />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. <br />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 be <br />placed on previous extrusion welds. <br />1. General Seaming Procedures <br />a. Areas to be seamed shall be cleaned and free of moisture, debris, or any marking <br />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 in <br />order to achieve a flat overlap. The cut fish mouths or wrinkles shall be seamed <br />and any portion where the overlap is inadequate shall then be patched with an <br />oval or round patch of the same geomembrane extending a minimum of six (6) <br />inches beyond the cut in all directions. <br />d. Extend seaming to the outside edge of panels placed in the anchor trench. <br />C:\AMEC_CCSV\Phase 5 VLF \PSSA Cert Report \Appendices\Appendix E \SPECS \02776.rl doc <br />Page 16 of 22 September 3, 2008 <br />Revision 1 <br />