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1 <br />' 4.2.9.4 Field Seaming <br />All seams shall be oriented parallel to the maximum slope; i.e., oriented down (not across) the <br />slope. Seams shall be numbered with a numbering system which is compatible with the panel <br />' numbering system. <br />The Contractor shall minimize the number of field seams in comers, off-shaped geometric <br />locations and outside comers. All corners of ponds will be triangulated with off-set tie-in <br />connections. <br />' No seaming shall be performed when deployed liner material has a temperature, as measured <br />' by a contact thermometer, which is in excess of 110°F or less than 40° F. <br />Panels shall be overlapped by a minimum of four inches. Procedures used to temporarily bond <br />' adjacent panels together shall not damage the geomembrane and shall not be detrimental to seam <br />weld material. <br />All tie-in "T" connections of liner panels shall be patched with a minimum 12-inch diameter <br />patch. Welding of the VLDPE membrane shall be performed prior to burial of the membrane <br />' in all ditches. <br />Solvents and adhesive shall not be used for seaming or temporary bonding of membranes. <br />' During the installation and repair of all HDPE geomembtane, only approved seaming methods <br />shall be accepted (extrusion fillet welds and fusion bonding). <br />During the preparation of seams for welding, the Contractor shall: <br />' - Clean surface of grease, moisture, dust, dirt, debris or other foreign material; <br />- Clean surface of oxidation by disc grinder not more than 1 hour before seaming; <br />- Use number 80 grit sandpaper for disc grinding; <br />- Patch areas where grinding reduces the sheet thickness by more than 4 mils; <br />- Seams, cuts, and scratches shall be repaired by a single extrudate bead; <br />- Grind liner surface beyond we]d bead. The ground area should extend 1116 to 1!8 inch <br />beyond the extrudate bead; <br />' -is- <br /> <br />