Heat Shrink Sleeves on Large OD Pipe

Using Heat Shrinkable Sleeves as Field Joint Coating on Large Diameter Pipe

Heat shrinkable sleeves are a widely adopted solution for protecting field joints on pipelines, especially large diameter pipes used in water, oil, and gas transmission. Their effectiveness, ease of installation, and compatibility with various pipe coatings have made them a standard in the industry for field-applied corrosion protection.

What Are Heat Shrinkable Sleeves?

Heat shrinkable sleeves are wraparound or tubular assemblies made from cross-linked polyolefin materials, typically polyethylene or polypropylene, with an adhesive layer. When heated, the sleeve shrinks to tightly conform to the pipe surface and the weld joint, forming a durable, continuous barrier against moisture and corrosion. The adhesive ensures a strong bond to both the steel and any existing factory-applied coatings, while the outer layer provides mechanical protection against abrasion and soil stresses.

Field Joint Coating on Large Diameter Pipe

Field joints are the sections where two pipe segments are welded together during installation. These joints are left exposed after welding and must be coated to restore the anti-corrosion protection provided by the factory-applied pipeline coating. Heat shrinkable sleeves are particularly advantageous for large diameter pipes because:

• They are available in wraparound designs, allowing easy application on large pipes without the need for specialized equipment.

• The sleeves can accommodate a wide range of pipe diameters, including very large pipes used in water transmission systems.

• Installation requires only basic surface preparation, minimal preheating, and standard tools such as propane torches.

Covalence Waterwrap: Designed for Large Diameter Applications

One of the leading products for large diameter water pipelines is Covalence® Waterwrap. This system is specifically engineered for the corrosion protection of field girth weld joints in buried water pipelines operating at ambient temperatures. Notably, Covalence Waterwrap can be used on pipes up to 144 inches (12 feet) in outside diameter, making it suitable for even the largest transmission mains.

Key Features of Covalence Waterwrap:

• Two-layer construction:

  • First layer: Visco-elastic, low preheat adhesive sealant

  • Second layer: Thick-walled, radiation cross-linked high-density polyethylene with a Permanent Change Indicator (PCI) for quality assurance

• Wraparound, ready-to-fit assembly: Facilitates rapid field application, even on large diameter pipes or complex geometries such as bends and replacement sections.

• Minimal preheating required: Reduces installation time and energy consumption.

• Compatibility: Works with standard pipe coatings and can be applied directly to bare or replacement pipe sections.

• Proven performance: Decades of use in the field have demonstrated reliable, long-term corrosion protection for large water pipelines.

Installation Overview

The installation process for heat shrinkable sleeves like Covalence Waterwrap typically involves:

• Cleaning and drying the pipe surface and weld area.

• Preheating the pipe to the recommended temperature.

• Wrapping the sleeve around the joint and securing the closure.

• Applying heat uniformly to shrink the sleeve and activate the adhesive, ensuring a tight, continuous seal.

Advantages for Large Diameter Pipe Projects

• Scalability: Suitable for pipes up to 144" OD, addressing the needs of major water infrastructure projects.

• Versatility: Can be used for field joints, bends, and repairs.

• Reliability: Provides mechanical and corrosion protection equivalent to or better than factory-applied coatings.

• Ease of Inspection: Features like the Permanent Change Indicator help verify correct installation.

Conclusion

Heat shrinkable sleeves are a proven, cost-effective solution for field joint coating on large diameter pipelines. Products like Covalence Waterwrap extend these benefits to the largest water transmission systems, offering robust corrosion protection, ease of installation, and compatibility with a wide range of pipe coatings and diameters—including pipes up to 144 inches in outside diameter. This makes them an essential technology for modern pipeline construction and maintenance.