Heat-Shrink Sleeves vs. Pipeline Tape: What's the Difference?
When a steel pipeline is constructed, the field welds between individual pipe sections must be protected against external corrosion.
Although the mainline pipe may arrive at the jobsite with a factory-applied coating, the girth weld area is typically left uncoated until welding is completed.
Once the weld is finished and inspected, contractors must apply a field joint coating that protects the exposed steel and connects to the adjacent factory coating.
Two established approaches are heat-shrinkable sleeves and cold-applied pipeline tape systems.
Both technologies are used for corrosion protection, but they rely on different materials and installation mechanisms.
Understanding those differences can help contractors, engineers, and pipeline owners select the appropriate system for their project.
What Is a Heat-Shrinkable Pipeline Sleeve?
A heat-shrinkable sleeve is a factory-manufactured coating assembly designed to shrink around a pipeline when heated.
Covalence heat-shrink sleeves combine a radiation-crosslinked polymer backing with a specially formulated adhesive.
The backing is expanded during manufacturing and retains the ability to recover toward its original dimensions when heated.
During installation, the sleeve is positioned around the field joint and heated using an approved torch or other specified heating equipment.
As the backing shrinks, it applies pressure to the adhesive, helping establish contact with the prepared steel and adjacent factory-applied coating.
The result is a protective coating designed to resist moisture penetration, corrosion, and mechanical damage.
Covalence manufactures different sleeve systems for different pipeline applications, including two-layer and three-layer products.
What Is a Cold-Applied Pipeline Tape System?
A conventional cold-applied pipeline tape system uses an adhesive-coated backing that is wrapped around the pipe without heat recovery.
Many systems use polyethylene backing materials combined with butyl rubber-based adhesives.
Depending on the product, installation may involve three components:
A liquid primer applied to the prepared steel.
An innerwrap that provides the primary corrosion protection barrier.
An outerwrap that provides additional mechanical protection.
The tape is generally applied in a spiral pattern with a specified overlap.
Unlike a heat-shrink sleeve, a conventional cold-applied tape does not contract around the pipe when heated.
Its performance depends on the adhesive system, surface preparation, wrapping tension, overlap, and other installation requirements.
Both technologies can provide effective corrosion protection when properly selected and installed.
Difference #1: How the Coating Contacts the Steel
One of the most important differences is how each system establishes contact with the pipe surface.
Heat-Shrink Sleeves
With a heat-shrink sleeve, the backing contracts around the pipe as heat is applied.
This recovery generates pressure against the adhesive.
Depending on the product, the adhesive softens or flows during heating and conforms to the prepared steel and adjoining factory coating.
The shrink recovery helps maintain contact around the circumference of the joint.
Cold-Applied Tape
With conventional cold-applied tape, the adhesive contacts the steel or primed substrate as the tape is wrapped around the pipe.
Wrapping tension and pressure help establish contact.
The installer must maintain the specified tension and overlap while avoiding wrinkles and trapped air.
The key difference is that a heat-shrink sleeve uses thermal recovery to press its adhesive against the pipe, while cold-applied tape relies on its adhesive properties and the wrapping process.
Neither method eliminates the need for proper surface preparation.
Difference #2: Two-Layer vs. Three-Layer Systems
Not all heat-shrink sleeves have the same construction.
Covalence offers both two-layer and three-layer field joint coating systems.
Two-Layer Covalence Sleeves
A typical two-layer Covalence sleeve consists of:
A corrosion protection adhesive, often a visco-elastic butyl-based material.
A radiation-crosslinked polyethylene backing.
An example is Covalence WPCT.
WPCT is designed for corrosion protection of field girth welds and uses a low-preheat adhesive combined with a heat-shrinkable polyethylene backing.
Another example is Covalence WPC100M, a mastic-based wraparound sleeve for specified pipeline applications.
Three-Layer Covalence Sleeves
A three-layer Covalence system incorporates:
A two-component liquid epoxy primer.
A high-shear-strength copolymer adhesive.
A radiation-crosslinked polyethylene backing.
Examples include Covalence HTLP60 and HTLP80.
These products are designed to recreate the structure and performance characteristics of factory-applied three-layer polyethylene coatings at field joints.
During installation, the sleeve is applied over the wet epoxy primer and heated.
As the epoxy cures, it forms bonds with the steel and adhesive system.
The combination is intended to provide corrosion protection and resistance to mechanical stresses.
Conventional Tape Systems
A typical cold-applied tape system may also contain three components: primer, innerwrap, and outerwrap.
However, the construction and installation mechanism are different from a three-layer heat-shrink sleeve.
The number of components alone does not determine which system is more suitable.
Difference #3: Installation Equipment
Installation equipment is another practical difference.
Heat-Shrink Sleeve Installation
A conventional Covalence heat-shrink sleeve installation generally requires:
Approved surface preparation equipment
Temperature measurement equipment
Suitable heating equipment
Application rollers or other specified tools
Inspection equipment
For a three-layer system, the contractor also needs equipment and procedures for mixing and applying the epoxy primer.
Proper heating technique is important.
The installer must achieve uniform recovery without underheating or overheating the sleeve.
Cold-Applied Tape Installation
A conventional cold-applied tape installation generally requires:
Surface preparation equipment
Primer application tools, when specified
Manual or mechanical wrapping equipment
Tools for controlling tension and overlap
Inspection equipment
Cold-applied tape eliminates the heat-shrink recovery step.
This can be advantageous where open-flame heating is restricted or difficult.
However, the absence of torch heating does not mean that tape installation is automatically simpler in every situation.
Maintaining correct overlap and tension can be challenging, particularly on large or irregular surfaces.
Difference #4: Mechanical Protection
Pipeline coatings must withstand more than moisture exposure.
They may encounter mechanical stresses during handling, lowering-in, backfilling, and other construction activities.
Heat-shrink sleeves use a polymer backing to protect the underlying corrosion barrier.
The backing thickness, adhesive properties, and overall system construction vary by product.
For example, Covalence DIRAX incorporates fiberglass reinforcement to improve abrasion and wear resistance during horizontal directional drilling installations.
Conventional cold-applied tape systems often use a separate outerwrap to protect the inner corrosion barrier.
The mechanical performance of a tape system depends on the specified materials and installed construction.
Neither heat-shrink sleeves nor cold-applied tapes should be considered universally more damage-resistant.
The correct comparison is between specific products tested under relevant conditions.
Difference #5: Operating Temperature
Operating temperature is a critical coating selection factor.
Pipeline coatings must remain suitable for the temperature of the transported product and surrounding operating environment.
Covalence manufactures heat-shrink sleeve systems with different temperature ratings.
For example:
Covalence WPCT: Published maximum operating temperature of 65°C (149°F).
Covalence HTLP60: A three-layer system for pipelines operating up to 65°C (149°F), subject to the exact product configuration.
Covalence HTLP80: A three-layer system designed for higher-temperature pipeline applications, with ratings dependent on the specific version and product data sheet.
Conventional cold-applied tape systems also have defined operating temperature limitations.
A tape suitable for one application may not be appropriate for a higher-temperature pipeline.
Contractors should always compare the published maximum operating temperature of the exact products under consideration.
Difference #6: Field Joint Geometry
The shape of the area being coated can affect product selection.
Straight pipe field joints are relatively simple compared with elbows, tees, valves, and other irregular components.
Wraparound heat-shrink sleeves are commonly used for straight field girth welds.
Certain heat-shrink products can also be used on replacement pipe sections and large-radius bends.
Cold-applied tapes can be useful for some irregular geometries because they can be applied in overlapping spiral wraps.
However, complex shapes can also create challenges involving wrinkles, gaps, and inconsistent coverage.
The correct choice depends on the geometry and the manufacturer's approved application.
Covalence also offers specialized products for bends and other coating applications, so contractors should not assume that a conventional straight-pipe sleeve is the only heat-shrink option.
Difference #7: Installation Inspection
A completed coating should be inspected before the pipeline is placed into service.
Both heat-shrink sleeves and tape systems require appropriate quality control.
Heat-Shrink Sleeve Inspection
Inspection may include:
Surface preparation verification
Preheat temperature checks
Sleeve positioning and overlap
Proper shrink recovery
Closure patch installation
Adhesive flow at edge of sleeve
Holiday testing where required
Certain Covalence sleeves incorporate Permanent Change Indicators (PCI).
These are visual indicators built into the backing that help installers evaluate the heating process.
For example, Covalence WPCT has a dimpled backing that provides a permanent visual indication associated with heat application.
Cold-Applied Tape Inspection
Inspection may include:
Surface preparation verification
Primer condition and coverage
Tape tension
Spiral overlap
Wrinkles and trapped air
Coating thickness where applicable
Holiday testing where required
In both cases, inspection should follow the applicable product instructions and project specification.
Which System Is Better for Horizontal Directional Drilling?
Horizontal Directional Drilling, commonly called HDD, can subject pipeline coatings to significant abrasion and mechanical stresses.
The pipe may contact soil, rock, and other materials while being pulled through the borehole.
For these applications, the selected field joint coating must be capable of withstanding the anticipated pullback conditions.
Covalence DIRAX is a specialized heat-shrink sleeve designed for HDD pull-through applications.
DIRAX uses a three-layer construction consisting of:
A two-component liquid epoxy primer
A high-shear-strength copolymer adhesive
A fiberglass-reinforced heat-shrinkable polyethylene backing
The system also incorporates a wear cone to help protect the leading edge of the sleeve during pullback.
This distinguishes DIRAX from conventional field joint sleeves that are not specifically designed for the same mechanical demands.
Cold-applied tape systems should only be considered for HDD applications when the specific product and installation configuration are qualified for the expected conditions.
A general-purpose pipeline tape should not be assumed to provide the same protection as an HDD-specific coating system.
Which System Is Better for Large-Diameter Pipelines?
Large-diameter pipelines introduce practical challenges involving heating, coating application, and installation time.
Covalence offers products such as WPCT for large-diameter pipeline field joints.
WPCT uses a low-preheat adhesive and heat-shrinkable backing.
Its wraparound design allows installation after the pipe sections have been welded together.
Cold-applied tape systems can also be applied to large-diameter pipelines, including by mechanical wrapping equipment.
The most appropriate choice depends on several factors:
Pipe diameter
Field joint width
Factory-applied coating
Operating temperature
Surface preparation requirements
Available installation equipment
Construction schedule
Project specifications
Rather than assuming one technology is always faster or less expensive, contractors should compare the actual installation procedures and total installed costs.
Can Heat-Shrink Sleeves and Tape Systems Be Used on the Same Pipeline?
Yes, different coating technologies can be used on the same pipeline project when the specifications permit.
For example, a pipeline may have a factory-applied mainline coating, a heat-shrink sleeve at a girth weld, and an approved tape-based repair or coating system at another location.
However, the different materials must be compatible.
The contractor must consider:
Adhesion between coating materials
Operating temperature limits
Surface preparation
Overlap requirements
Mechanical performance
Inspection procedures
The final coating system should satisfy the pipeline owner's requirements.
What Should Contractors Compare Before Selecting a Coating?
The best approach is to evaluate the actual application rather than compare coating categories in general terms.
Before selecting a heat-shrink sleeve or cold-applied tape system, determine:
What is the pipeline's maximum operating temperature?
What factory-applied coating is already on the pipe?
Is the application a field joint, repair, bend, or rehabilitation project?
Will the pipe be installed by conventional trenching or HDD?
What surface preparation can be achieved?
Are there restrictions on open-flame heating?
What mechanical stresses will the coating encounter?
What inspection and testing requirements apply?
Which coating systems are approved by the pipeline owner?
The answers will help narrow the product selection.
Covalence Heat-Shrink Sleeves From Joint Specialists Inc.
Joint Specialists Inc. supplies Covalence heat-shrinkable corrosion protection products for pipeline construction and rehabilitation.
JSI's Covalence product offering includes:
WPCT: Two-layer heat-shrink sleeve for specified field joint coating applications.
WPC100M: Heat-shrink sleeve for selected higher-temperature applications.
HTLP60: Three-layer heat-shrink sleeve designed to recreate the protection of factory-applied three-layer polyethylene coatings.
HTLP80: Three-layer system for higher-temperature field joint applications.
DIRAX: Fiberglass-reinforced heat-shrink sleeve designed for horizontal directional drilling.
TPS: Tubular heat-shrink sleeve for specified distribution pipeline applications.
JSI can assist contractors and purchasing departments with product selection discussions, material requirements, and quotations.
For assistance with Covalence heat-shrink sleeves, contact:
Steve Simpson
Joint Specialists Inc.
Phone: 936-321-3333
Email: steve@jsicoatings.com
When requesting a quotation, please include the pipe outside diameter, factory-applied coating, operating temperature, number of field joints, and applicable coating specification.
We welcome the opportunity to assist with your next pipeline coating project.
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