Geomembrane Liner Installation Guide

An important step in projects involving geomembrane liners is to understand the benefits of the product and the best course of action at each step of the installation. Installation of geomembrane liners is typically performed by qualified engineers and technicians for welding and installation techniques, site preparation, proper installation procedures, etc. This article will provide you with a guide to the installation of geomembranes.

Product Selection and Quality Control

Before starting the installation, evaluating product samples is essential regardless of existing specifications. Stringent manufacturing quality control must be adhered to, ensuring that the product complies with U.S. standards. The geomembrane liners should undergo a cosmetic inspection, confirming they are new and devoid of any physical defects like holes, blisters, or visible contaminants. Additionally, the final product should arrive as a continuous sheet without any factory welds in the roll.

If the selected product passes these quality checks, you're set to prepare the job site for installation.

Pre-installation Preparation

Formulate an HDPE geomembrane installation strategy based on the design of the geomembrane lining system. Purchase quality HDPE geomembrane materials that align with the design specifications. Ground Treatment: Diligently eliminate sharp objects from the ground that could harm the geomembrane, fill in potholes, level the soil surface, and repair any slopes.

Installation Environment: Ensure outdoor temperatures are above 5℃, with wind no greater than level 4, while avoiding rain or snow. Welding Tools: Prepare welding equipment which typically includes HDPE liner welders, hot air torches, sanders, vacuum testers, inflatable leak detectors, portable balers, and other necessary accessories.

Best Practices for Geomembrane Placement

Once the geomembrane is on-site and ready, initiate the laying process. Follow these best practices to achieve optimal installation results: first, deploy only as much geomembrane as can be anchored and welded within the same day to minimize unnecessary exposure.

Secondly, avoid driving vehicles over exposed geomembranes. If ground equipment is necessary, deploy only approved low-ground-pressure vehicles that will not damage the liner. Thirdly, use sandbags or comparable ballast to keep the geomembrane liner securely in place during installation. Fourthly, ensure the liner spans voids or depressions in the roadbed; these regions should be graded to maintain close contact with the roadbed, thereby reducing wrinkles and waves. Install the geomembrane during optimal ambient temperatures to prevent excessive thermal expansion and contraction.

Lastly, confirm that there is an overlap of at least 3 inches between geomembrane sections for effective welding and testing.

Geomembrane Welding

Once all sections are adequately placed and secured, commence welding the panels together. Welding is ideal when the surface temperature of the geomembrane exceeds 0°C; while out-of-spec methods are possible, they necessitate extra precautions for safe and competent welding on-site. Fusion welding equipment is preferred, although extrusion welding can suffice if needed.

Perform quality control testing alongside the welding process.

Geomembrane Installation Quality Control Procedures

Considering that environmental conditions significantly influence weld quality, it is prudent for welding technicians to perform a test weld before engaging in any actual welding. This test should adhere to ASTM D 6392, utilizing the same equipment and conditions akin to those used in manufacturing. The test weld sections should be cut and evaluated according to the minimum acceptable weld strength values.

Production welds must undergo nondestructive testing before covering the geomembrane. Areas failing the test should be marked, repaired, and retested. Various nondestructive testing methods, such as vacuum chambers, pneumatic, or spark testing equipment, may be utilized.