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Forward Compost Facility Stormwater Improvements <br />02778 12 HDPE GEOMEMBRANE <br />B. Seam Layout. 1. Orient seams parallel to line of a maximum slope, i.e., orient down not across slope. 2. Minimize number of field seams in corners, odd-shaped geometric locations and outside corners. 3. Keep horizontal seams (seams running approximately parallel to slope contours) at least 5 feet away from toe or crest of slope, unless approved by DESIGN ENGINEER. No horizontal seams shall be allowed on the slope. 4. Use seam numbering system compatible with panel number system. 5. Shingle panels on all slopes and grades as directed by QA/QC CONSULTANT. 6. Longitudinal seams shall not be allowed in the LCRS trenches. <br />C. Seam Welding Personnel. 1. Provide at least one welder (master welder) who has experience welding over 5 million square feet of geomembrane using the same type of welding apparatus in use at site. 2. Qualify personnel performing welding operations by experience and by successfully passing field welding tests performed on site. 3. Master welder will provide direct supervision over other welders. <br />D. Seam Welding Equipment. 1. Extrusion welder: equipped with gauges showing temperatures in extruder apparatus and at nozzle. Temperature at nozzle may be measured by external temperature gauges. 2. Hot wedge welder: Automated variable speed vehicular mounted devices equipped with devices adjusting and giving temperatures at wedge. Pressure controlled by spring, pneumatic, or other system that allows for variation in sheet thickness. Rigid frame fixed position equipment is not acceptable. 3. Maintain adequate quality of welding apparatus in order to avoid delaying the project. 4. Use power source capable of providing constant voltage under combined line load. <br />E. General welding procedures: 1. Do not commence welding until trial weld test sample, made with the equipment to be used passes trial weld test. 2. Clean geomembrane surface of grease, moisture, dust, dirt, debris, and other foreign material. 3. Overlap panels a minimum 3 inches for extrusion and 4 inches for hot wedge welding. 4. Do not use solvents or adhesives unless product is approved in writing by the DESIGN ENGINEER. 5. Provide adequate material on weld to allow peel testing of both sides of double wedge weld. 6. Extend welding to the outside edge of all panels. 7. If required, provide a firm substrata by using a flat board, a conveyor belt, or similar hard surface directly under the weld overlap to achieve firm support.