Geomembrane Installation Guidelines

Polyethylene Installation Guideline

Handling and Storage: Polyethylene, including HDPE and LLDPE geomembranes as specified with formulated sheet densities of 0.940 g/cc or greater for HDPE and 0.939 or less for LLDPE, is robust yet requires careful handling to prevent damage. It’s essential to store rolls or sheets off the ground, covered, and away from direct sunlight to avoid degradation by UV radiation. This specification encompasses geomembranes with both smooth and textured surfaces, highlighting the need for proper storage to maintain their integrity.

Joining Techniques: The method of joining polyethylene components, whether for HDPE or LLDPE geomembranes, varies by application and includes butt fusion, socket fusion, electrofusion, and mechanical joining. Each technique has specific procedures that must be followed meticulously to ensure a strong and leak-proof connection, as outlined in the English Installation Guide.

Butt Fusion: Ideal for HDPE geomembranes, this method involves heating two planed surfaces against a heated plate before fusing them together under pressure, ensuring a durable bond as per the specifications.

Socket Fusion: Used for both HDPE and LLDPE geomembranes, socket fusion involves heating both the external surface of the pipe and the internal surface of the fitting before pushing them together, a technique detailed in the installation guide for achieving optimal results.

Electrofusion: This technique, applicable for both HDPE and LLDPE geomembranes, uses electrically conductive fittings to create a homogenous bond between pipe sections, as specified in the installation instructions.

Mechanical Joining: Mechanical fittings can be used when thermal fusion is not feasible for HDPE and LLDPE geomembranes. It’s crucial to ensure the fittings are compatible with polyethylene and meet the application’s pressure requirements, as outlined in the installation guide.

Laying and Embedment: Proper laying and embedment are crucial for the longevity of polyethylene piping systems, including those made from HDPE and LLDPE geomembranes. Avoid sharp bends and ensure the trench bed is smooth and free from sharp objects. Use appropriate bedding materials to support and protect the pipe, following the guidelines specified for these materials.

Testing and Inspection: After installation, conduct thorough testing and inspection to ensure the integrity of the system, including HDPE and LLDPE geomembranes. This may include pressure testing for piping systems to check for leaks and visual inspections for sheet applications, as recommended in the installation guide.

Maintenance and Repair: While polyethylene, including HDPE and LLDPE geomembranes, is low maintenance, regular inspections can help identify potential issues before they become significant problems. For repairs, specific techniques such as patching or welding can be used, depending on the damage’s nature and extent, with detailed procedures provided in the installation guide.

Guideline for Installation of Factory Fabricated Lightweight < 0.64 mm (25 mil) Thickness Geomembranes

This guideline serves as an installation manual for factory-fabricated fabric-supported lightweight geomembranes, specifically those less than 0.64mm or 25 mil in thickness, as measured by ASTM standards D5199, D751, or D1777. It aims to establish a minimum set of standards for site installation, while acknowledging that, due to the complexity and specific requirements of each project, a qualified design engineering firm may sometimes be necessary to oversee the design and installation specifications of the geomembrane.

Surface Preparation:The initial step involves preparing the installation surface to ensure it is smooth, devoid of sharp objects, and properly compacted. This precaution is crucial to prevent any damage to the lightweight geomembrane during and after its installation, aligning with the Factory Fabricated Lightweight Installation Guidelines to safeguard the material’s integrity.

Deployment: In accordance with the guidelines, geomembrane panels should be carefully deployed following the installation design. It’s important to avoid dragging the panels across the surface to prevent abrasion or punctures, which could compromise the geomembrane’s effectiveness. Appropriate lifting equipment and techniques should be employed to precisely position the panels, ensuring a smooth deployment process as recommended for lightweight geomembranes.

Seaming: For these lightweight geomembranes, thermal fusion or extrusion welding are the recommended seaming methods to ensure a durable bond. It’s essential to rigorously test seams for integrity, employing methods such as air pressure testing or vacuum testing. This step confirms the seam’s strength and impermeability, adhering to the guidelines’ emphasis on ensuring the geomembrane’s long-term performance.

Anchorage and Protection: Following the guidelines, it’s critical to secure the geomembrane edges and overlaps to guard against wind uplift or displacement. After the installation, protecting the geomembrane from potential damage during subsequent construction activities is paramount. This can be achieved by covering it with a protective geotextile or a layer of soil, as suggested, to maintain the geomembrane’s condition and functionality.

Guideline for Installation of Factory Fabricated Heavyweight > 0.64 mm (25 mil) Thickness Geomembranes

Pre-Installation Considerations: Before embarking on the installation process, it’s crucial to grasp the project’s unique demands, including soil conditions, anticipated loads, chemical exposure, and environmental influences. This initial evaluation will steer the choice of the suitable geomembrane type and the installation approach. Specifically, when dealing with factory-fabricated fabric-supported heavyweight geomembranes (exceeding 0.64 mm or 25 mil in thickness as measured by ASTM D5199, D751, or D1777), this guideline serves as a foundational resource, outlining a minimum set of standards for site installation. Nonetheless, the complexity and specific requirements of the project may necessitate the expertise of a qualified design engineering firm for the design and installation specifications of the geomembrane.

Deployment Strategies: The deployment of heavyweight geomembranes, particularly those that are factory-fabricated and fabric-supported, necessitates meticulous planning and execution. Their significant thickness and weight demand the use of specialized equipment and skilled personnel for handling and positioning the geomembrane panels. It is imperative to avoid any actions that might stress or damage the material, such as dragging it across abrasive surfaces or sharp edges, to ensure adherence to the Factory Fabricated Heavyweight Installation Guidelines.

Seaming Techniques: The durability of a geomembrane system is significantly dependent on the seam quality. For heavyweight geomembranes, including those specified in the Factory Fabricated Heavyweight Installation Guidelines, thermal fusion welding, extrusion welding, and adhesive seaming are prevalent techniques. While each method has its particular requirements and applications, the overarching goal is to secure a watertight seal that resists physical and environmental challenges.

Testing and Quality Assurance: Following installation, conducting comprehensive testing of the seams and the geomembrane itself is critical. Techniques such as air pressure testing, vacuum testing, and non-destructive seam testing are utilized to verify that the installation conforms to the rigorous standards mandated for environmental safeguarding and longevity. This step is in alignment with the minimum standards set forth in the Factory Fabricated Heavyweight Installation Guidelines, ensuring the geomembrane’s performance and durability.

Protection and Anchorage: Protecting the geomembrane from mechanical harm post-installation is paramount. Typically, a protective layer, like a geotextile or a soil layer, is applied. Furthermore, anchorage systems are implemented to protect the geomembrane against wind uplift and displacement, securing its stability over time. This measure is in accordance with the Factory Fabricated Heavyweight Installation Guidelines, which emphasize the importance of safeguarding the geomembrane to maintain its integrity and functionality.

Guideline for Installation of Factory Fabricated Compounded  0.25 to 1.52 mm (10 – 60 mil) Thickness Unsupported Geomembranes

This document serves as an installation guideline for factory-fabricated compounded unsupported geomembranes ranging in thickness from 0.25 to 1.52 mm (10 – 60 mil). It encompasses a variety of polymers including Chlorosulfonated Polyethylene (CPSE); Polyvinyl Chloride (PVC) and its alloys with other polymers; Ethylene Interpolymer Alloy (EIA) alloys; nitrile or other rubber types; as well as blends and alloys with compatible polymers; and Ethylene Propylene Diene Monomer (EPDM). This guideline aims to establish a minimum standard for site installation of these materials.

Installation Steps:

Subgrade Preparation: The first step involves preparing the subgrade by clearing it of debris, leveling any irregularities, and ensuring it provides a stable and uniform base. The subgrade should be compacted and graded to facilitate drainage away from the geomembrane, adhering to the standards set for the installation of factory-fabricated compounded 0.25 to 1.52 mm (10-60 mil) thickness unsupported geomembranes.

Geomembrane Deployment:The geomembrane panels should be carefully unrolled following the layout plan. It’s crucial to avoid unnecessary stretching or folding that could compromise the integrity of the material. This step is particularly important when working with the specified polymers, ensuring the geomembrane’s optimal performance.

Seaming and Welding:Panels are joined using thermal or chemical welding techniques to create strong, watertight seams. Performing seam tests is essential to confirm the welds’ integrity, a critical aspect of ensuring the durability and effectiveness of geomembranes made from CPSE, PVC, EIA alloys, and other specified materials.

Anchorage and Termination:To counteract uplift or displacement from environmental forces, the geomembrane’s edges and terminations must be securely anchored. This may involve embedding the edges in trenches or using concrete structures for anchorage, as recommended for the types of geomembranes outlined in this guideline.

Protection and Covering:A protective layer is installed over the geomembrane to guard against mechanical damage and UV degradation. The choice between a geotextile fabric, a soil layer, or a combination thereof depends on the project requirements and the specific properties of the geomembranes being installed.

Post-Installation Inspection and Maintenance:

Following the installation, a thorough inspection is conducted to identify and rectify any defects or issues. Regular maintenance checks are crucial for monitoring the geomembrane’s condition over time, particularly after exposure to significant weather events or chemicals, to maintain the integrity and functionality of the installed geomembranes as per the guideline’s standards.