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stress concentrations unless otherwise approved by The Owner's Representative. When <br /> full roll lengths do not extend past the toe of the slope, panel ends may be seamed <br /> provided the panel end is cut at an angle greater than 450 to minimize seam stress. In <br /> comers and areas of irregular geometry, the number of seams should be minimized. <br /> A seam numbering system compatible with a panel numbering system shall be employed. <br /> 5.4.0 Panel Overlap for Seaming <br /> Controlled overlapping of adjacent sheets shall produce approximately 3 inches of <br /> overlap for extrusion welds and 4 inches of overlap between sheets for wedge welded <br /> seams. <br /> 5.5.0 Seam Preparation <br /> CLC shall verify that. <br /> Prior to seaming,the seam area is clean and free of moisture, dust, dirt, debris of any <br /> kind,and foreign material, and seams are aligned with the fewest possible number of <br /> wrinkles or"fishmouths". <br /> All areas to receive extrusion welds shall first be lightly/evenly ground with a hand held <br /> grinder with a 60 or 80 grit disc to roughen the surface while removing all surface shine. <br /> The grinding is performed parallel to the seam and controlled such that grinding marks <br /> do not extend more than 0.25 inches outside the area of the weld bead area. Sixty mil or <br /> thicker liners should have the edge of the top sheet beveled by grinding to approximately <br /> a 450 angle.This grinding preparation shall be completed no more than one (1) hour <br /> prior to extrusion welding. Grinding preparation does not apply to wedge welding. <br /> 5.6.0 Wedge Welder Seaming Procedure <br /> A smooth insulating plate or fabric is shall be placed beneath the hot welding apparatus <br /> both before and after usage. <br /> Unless otherwise specified, the general seaming procedure used by CLC shall be as <br /> follows: <br /> The rolls of geomembrane shall be overlapped by approximately four inches(100 mm) <br /> for fusion welding and three inches for extrusion welding. <br /> Welding can occur once the panels to be joined have been brought into their exact plan <br /> position for final installation. <br /> "Fishmouths"or wrinkles at the seam overlaps shall be cut along the ridge of the wrinkle <br /> in order to achieve a flat overlap. The cut"fishmouths"or wrinkles shall be seamed and <br /> any portion where the overlap is inadequate shall then be patched with an oval or round <br /> patch of the same geomembrane extending a minimum of 6 inches beyond the cut in all <br /> directions. <br /> Power to the drive motor shall remain switched-off off when positioning the machine to <br /> make a seam. <br /> When starting a new weld,the machine shall be manually placed into the overlapped <br /> sheet of material. The sheets shall then be guided between the idlers and the wedge <br /> element, and into the drive/nip rollers. <br /> Created by Colorado Lining International 1-800-524-8672 7 <br />