Geomembrane Liner Installation Guide

An important step in projects involving geomembrane liners is understanding the benefits of the product and the best course of action at each step of the installation. Installation of geomembrane liners is typically carried out by qualified engineers and technicians who are skilled in welding and installation techniques, site preparation, and proper installation procedures. This article provides a comprehensive guide to the installation of geomembranes.

Product Selection and Quality Control

Regardless of specifications, it is advisable to test product samples. Quality control in manufacturing is vital to ensure compliance with U.S. standards. Geomembrane liners should pass aesthetic inspections and be free from physical defects, such as holes, blisters, or signs of contamination. Additionally, the final product should be supplied as a continuous sheet with no factory welds in the roll.

Once the product passes all quality control checks, you can prepare the job site for installation.

Pre-installation Preparation

Develop an installation plan for HDPE geomembranes based on the geomembrane lining system design. Procure high-quality HDPE geomembrane products that adhere to design specifications. The ground surface must be treated: remove sharp objects that could damage the geomembrane, fill potholes, and level the soil.

Ensure the installation environment meets the following conditions: an outdoor temperature above 5°C, wind speed below level 4, and no rain or snow.

Gather all necessary welding tools for geomembranes, which generally include an HDPE liner welder, hot air torch, sander, vacuum tester, inflatable leak detector, portable baler, and other essential accessories.

Best Practices for Geomembrane Placement

Once your geomembrane arrives, you can begin laying it on the roadbed. Here are some tips for optimal installation results:

• Deploy only the amount of geomembrane that can be anchored and welded in one day to avoid unnecessary exposure.
• Avoid driving vehicles over exposed geomembranes. If ground equipment is required, use only approved low ground pressure vehicles.
• Utilize sandbags or similar ballast to temporarily secure the geomembrane liner during installation.
• Ensure the liner contacts the roadbed closely, especially in voids or low-lying areas. Smooth out waves and wrinkles by installing the geomembrane at optimal ambient temperatures to minimize thermal expansion and contraction.

Finally, check for overlaps between geomembrane sections for welding and testing, ensuring overlaps are no less than 3 inches.

Geomembrane Welding

Once all sections are placed and anchored, proceed to weld the panels together. Ideally, welding should occur when the surface temperature is above 0°C. Welding can occur outside of these parameters with additional precautions. Fusion welding equipment is recommended, though extrusion welding can be used if necessary.

Conduct quality control testing alongside the welding process.

Geomembrane Installation Quality Control Procedures

Environmental conditions can greatly affect weld quality. It is recommended that welding technicians perform a test weld prior to each weld, following ASTM D 6392 standards. This test should use the same conditions, equipment, and materials as the manufacturing process. Samples of the test weld should be cut and tested to ensure minimum acceptable weld strength values.

Production welds should be tested using non-destructive methods before covering the geomembrane. Any areas that fail the test should be marked, repaired, and retested. Non-destructive weld testing methods may include vacuum chambers or pneumatic testing equipment.