What Does
Heat-Shrink Sleeve Mean?
A heat-shrink sleeve is a corrosion protective coating for pipelines in the form of a wraparound or tubular sleeve that is field applied.
Heat-shrinkable sleeves are the most widely used technology in the world today for field-girth weld corrosion protection because they’re easy to install, provide excellent protection, and are cost-effective.
A heat-shrink sleeve is also known as a heat-shrinkable sleeve or a shrink sleeve.
Corrosionpedia Explains Heat-Shrink Sleeve
Heat shrink means just that—when heat is applied to the sleeve, it shrinks in size and conforms to the surface it surrounds. A heat-shrink sleeve starts out with a thick extruded polyolefin sheet (polyethylene or polypropylene) that is formulated to be cross-linkable.
Heat-shrink sleeves have an adhesive that sticks the sleeve to the material and the factory-applied mainline coating, and also acts as a corrosion protective layer. The backing provides mechanical protection against abrasion and soil stress forces after the pipeline is buried. Heat wrap tape may used in addition for pipe bends, or as an alternative method for wrapping the whole pipe.
For example, when steel pipelines are built, they commonly consist of 10-12 meter long sections of steel pipe that had a protective coating applied in the factory. The factory leaves an uncoated area at each end of the pipe, called a cutback, so that when welding the pipe sections together, the coating is not damaged. Heat-shrinkable sleeves are then applied onto the cutback at the field weld, or field joint, during the construction of a pipeline.
Heat-shrink sleeves have a very wide range of applications. The ease of use makes heat-shrink sleeves a convenient option. In addition, heat-shrink sleeves have the well-known advantages associated with plastics materials—good insulation and chemical resistance, toughness, flexibility and excellent colorability.
Properly specified and applied heat-shrink sleeves can provide corrosion and mechanical protection that is equal to or superior to the mainline coating, be it a tape, epoxy or multi-layer polyolefin. It resists impact, abrasion and ultraviolet light as well as cathodic disbondment and dielectric breakdown.