A Guide to Fusion Welding Geomembranes: What You Need to Know

What is Geomembranes?

Geomembranes are a very low permeability synthetic membrane liner or barrier commonly used to control fluid (or gas) migration in a human-made project, structure, or system. They are thin, flexible sheets made from polymers like polyethylene, polypropylene, and PVC, known for their strong chemical resistance, durability, and impermeability. These qualities make them essential in numerous industries for containment and environmental protection.

What is a Geomembrane Used For?

Geomembranes have a wide range of applications across various industries and scenarios. Some common uses include:

• Environmental Protection: Geomembranes serve as barriers to prevent soil and water contamination. They are used in landfill liners, wastewater treatment ponds, and to stabilize earth and secure landfills, ensuring containment of hazardous or municipal wastes and their leachates.

• Agriculture: They are employed in agricultural applications for lining irrigation ponds, preventing soil erosion, conserving water, and stabilizing the earth.

• Mining: Geomembranes find use in the mining industry to contain tailings and prevent the seepage of hazardous materials into the environment.

• Aquaculture: They create impermeable pond liners, ensuring water retention in fish farms and preventing seepage.

• Civil Engineering: Geomembranes play a vital role in construction projects by acting as waterproof barriers in tunnels, reservoirs, and foundations, as well as stabilizing the earth where needed.

What is Fusion Welding of Geomembranes?

Fusion welding involves using a hot metal wedge (hot shoe) attached to a mobile unit. This wedge is positioned between two overlapping liner sheets, heating their surfaces above the melting point of polyethylene.

The fusion welding process typically includes the following steps:

• Cleaning and preparing the geomembrane surfaces to be joined.

• Heating the geomembrane surfaces to their melting point using a hot wedge or extrusion welding equipment.

• Pressing the heated surfaces together to create a uniform fusion.

• Cooling and solidifying the fused area to form a strong, watertight seal.

What Temperature Do You Weld Geomembranes?

Specifications for Thermal Welding PVC Geomembranes

Temperature（C）	Temperature（F）	Hold Time (seconds)
35	95	30
37.5	100	30
40.5	105	30
43.5	110	30

Fusion welding geomembranes is a fundamental process in industries where containment and environmental protection are paramount. Understanding what geomembranes are, their applications, the fusion welding technique, and temperature requirements is essential for ensuring the successful implementation of geomembrane-based solutions. By adhering to proper welding procedures and temperature guidelines, you can create robust, impermeable seals that safeguard the environment and infrastructure.