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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 />IvIANiIFACTURER's instructions no more than one (1) hour prior to <br />seaming operations. <br />e. Prevent exposed grinding mazks adjacent to an extrusion weld. Do not <br />extend exposed grinding marks more than one-quarter (1/4) inch from seam <br />azea. CERTIFYING ENGINEER may request that any and all abraded <br />areas be covered with exwdate. <br />f. Extrusion weld all cross seam tees to a minimum distance of four (4) inches <br />on each side of the tee. <br />g. For extrusion welds, the edge of the top sheet shall be beveled by grinding <br />the edge of the sheet to approximately a 45 degee angle. Extrusion welds <br />can not 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 dtrectty under the <br />seam overlap to achieve proper support if required. <br />c. Cut fishmouths or wrinkles at the seam overlap along the ridge of the <br />wrinkle in order to achieve a flat overlap. The cut fishmouths or wrinkles <br />shall be seamed and any portion where the overlap is inadequate shall then <br />be patched with an oval or round patch of the same geomembrane extending <br />a minimum of 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 />D. Field Trial Seams <br />1. Trial seams shall be conducted at the beginning of each seaming period and within <br />thirty (30) minutes of commencement of seaming, at the CERTIFYING <br />ENGINEER'S discretion, and immediately following any work stoppage (i.e., lunch, <br />weather conditions, etc.) of thirty (30) minutes or more for each seaming apparatus <br />used that day. Each Seamer shall make at least one trial seam each day. <br />2. Testing shall include visual observation of a trial seam on the geomembrane material. <br />The INSTALLER will mark the trial seam with date, ambient air temperature, <br />welding machine number, welding technician identification, and machine temperature <br />and speed. For extmsion welding, the INSTALLER will include the noule and <br />extrusion settings and welding technician identification. The remainder of trial seam <br />• should be cut in two pieces; one to be retained in CC&Y's archive; and one to be <br />retained by the INSTALLER. <br />Section 02776 Page [ 5 of 20 October 25, 2000 <br />Geomembrane Golder Associates Revision 8 <br />1 \00\2201\0100\CERTREP0802NPPENDS\APPE\993-209902]]61R8 DOC <br />