What Does Wrap-Around Corrosion Protection Mean?
Wrap-around corrosion protection is a method where buried and exposed metal is encircled by a corrosion-protective material. This material is wound over the metal, preventing the surface from physically coming into contact with the corrosive environment.
The material used has an elastic protective adhesive which bonds to the metal substrates and common pipeline coatings. The materials come in many forms and designs, and have a strong outer covering which can withstand harsh mechanical and corrosive environments.
Corrosionpedia Explains Wrap-Around Corrosion Protection
Wrap-around corrosion protection is simple and commonly used on pipelines where normal coatings are unable to offer adequate protection. This may include:
- Sections where there are bends or joints between pipes
- Welded or repaired sections
- Pipe elbows
- Other irregular configurations
Another application is in the splash zone, which is one of the most severe marine corrosive environments. Corrosion in this zone is accelerated by the alternating wet-dry conditions, high oxygen content and seawater condensation. Effective protective methods use either heavy duty, zinc-aluminum alloy/organic or nickel-copper alloy coatings, which involve complex and expensive procedures.
Wrap-around corrosion protection is mostly done in the field, and some of the methods used are:
- Heat shrink sleeves - Used for field coatings of welded pipe joints, bends, branches and repair of damaged coatings. Also used for factory coatings of bends and branches.
- Butyl mastic tape system - Used for complex shapes and sizes where a heat shrink sleeve cannot be easily applied. This includes ferrules, domestic tapping, self-insulating joints and electrical connections to pipes.
- Petrolatum tape wrapping system - Used for the coating of valves, expansion and flanged joints
- Bitumen tape system - Used in the field for joints and pipe repairs where using a heat shrink sleeve might not be practical due to limited access to the pipe or where a naked flame cannot be used