Covalence Shrink Sleeves

 Covalence Heat Shrink Sleeves for Field Joints

In the oil and gas industry, protecting pipelines from corrosion is critical to long-term performance and safety. One of the most vulnerable points on a pipeline is the field joint—the exposed area created when two factory-coated pipe segments are welded together during construction. This uncoated zone must be properly protected in the field using a coating that restores corrosion resistance, bonds reliably to the adjacent factory-applied coatings, and withstands environmental and mechanical stresses. One of the most trusted solutions for this purpose is Covalence™ heat shrink sleeves, formerly known as Raychem.

Covalence heat shrink sleeves have been used worldwide for decades to protect field joints on pipelines coated with Fusion Bonded Epoxy (FBE), 3-Layer Polyethylene (3LPE), 3-Layer Polypropylene (3LPP), and other common coating systems. These sleeves consist of a cross-linked polyolefin backing combined with a high-performance adhesive layer. When heated, the sleeve shrinks tightly around the joint, and the adhesive melts, forming a durable, moisture-resistant seal that prevents corrosion.

The benefits of Covalence sleeves are numerous. They offer excellent adhesion to bare steel as well as to factory coatings, ensuring a continuous protective barrier across the field joint. Installation is efficient and consistent; technicians wrap the sleeve around the pipe, apply heat using a torch or induction equipment, and the sleeve conforms tightly to the surface. This quick and repeatable process minimizes downtime on the job site and supports project efficiency.

Covalence sleeves are also designed to withstand the tough conditions pipelines often face. Once installed, they resist impact, abrasion, and soil stress, making them suitable for use in demanding scenarios such as directional drilling, rocky terrain, or road crossings. The company offers a range of sleeve products to meet various pipeline conditions and requirements. For example, DIRAX sleeves are specifically designed for horizontal directional drilling, WPCT sleeves are used for moderate-temperature buried pipelines, WPC100M is suited for standard field joint applications, and TPS sleeves are sold as tubular or slip on shrink sleeves.

Another important advantage of Covalence products is their compatibility with global industry standards. These sleeves are designed to meet or exceed specifications from organizations such as ISO, CSA, and AWWA, and are approved by many of the world’s leading oil and gas pipeline operators. Their performance has been validated in countless projects across a wide range of environmental conditions—from arctic climates in Alaska and Russia to high-temperature installations in the Middle East.

The application process for Covalence heat shrink sleeves involves several key steps. First, the weld area must be cleaned to the specified standard, usually near-white metal blast. Then, the surface is preheated to activate the adhesive and ensure proper bonding. The sleeve is positioned around the joint with overlap onto the adjacent coating, and heat is applied to shrink the sleeve and flow the adhesive. After installation, the sleeve conforms tightly to the pipe surface and forms a reliable seal. A visual inspection and optional holiday testing confirm the success of the installation.

In summary, Covalence heat shrink sleeves offer a field-proven, reliable, and efficient solution for protecting field joints on oil and gas pipelines. Their strong adhesion, mechanical resilience, ease of installation, and global track record make them a preferred choice among pipeline engineers and contractors. As oil and gas infrastructure continues to expand and age, using proven technologies like Covalence ensures pipelines remain protected and operational for decades to come.

 Covalence Shrink Sleeves (formerly Raychem)

Seal For Life’s Covalence brand offers a comprehensive range of heat shrinkable products designed for corrosion prevention, mechanical protection, and sealing of pipelines, including field joints and pre-insulated pipe systems. Below is an overview of their main product offerings and applications:

• Covalence provides both 2-layer and 3-layer heat-shrinkable sleeves.

• These sleeves feature irradiation cross-linked polyethylene or polypropylene backings, combined with adhesive layers (either visco-elastic mastic or co-polymer hot melt) tailored for different pipeline operating temperatures and environments.

• The 3-layer systems often include an epoxy primer for enhanced adhesion and are compatible with modern multi-layer mainline coatings, creating a monolithic protection system.

• : A two-layer field-joint coating system designed for corrosion protection of pipelines operating at ambient temperatures. It is among the most widely used solutions for girth weld protection.

• : High-performance, three-layer sleeves with epoxy primer, designed for pipelines with higher operating temperatures and demanding environments. These sleeves offer excellent resistance to cathodic disbondment, hot water immersion, and soil/thermal movement stresses - HTLP60 & HTLP80

• : Specifically engineered for directional drilling and applications requiring extra mechanical strength - DIRAX & CCS Material used to make Caseals and Flangeseals.

• : Designed to provide durable sealing solutions for pre-insulated pipe joints, protecting against moisture ingress and maintaining thermal integrity.

• : Includes joint casings, foaming hole closures, primary joint foam seals, end caps, and sealants to support a wide range of pipeline configurations and field conditions.

• High electrical resistance and low permeability for optimal corrosion prevention.

• Designed for easy installation with minimal tools and surface preparation.

• Approved by major testing agencies worldwide, ensuring suitability for diverse field conditions and compliance with global standards such as ISO, EN, AWWA, NACE, and GOST.

• Proven performance record in major pipeline projects globally, including oil, gas, and water transmission lines.

Product Type	Layers	Key Application	Notable Features
WPCT	2	Field joint corrosion protection	Ambient temperature pipelines
HTLP Series	3	High-temp, high-stress environments	Epoxy primer, soil/thermal resistance
Fiberglass-Reinforced Sleeves	2–3	Directional drilling, mechanical stress	Extra strength, abrasion resistance
Pre-Insulated Pipe Sleeves	2–3	Pre-insulated pipe joints	Moisture and thermal protection

Covalence’s heat shrinkable products are trusted globally for their reliability, versatility, and ease of installation, making them a leading choice for pipeline protection and sealing needs.

Temperature Ratings for Covalence/Raychem Heat Shrink Sleeves

 Temp Ratings for Covalence / Raychem Heat Shrink Sleeves for Corrosion Prevention

     I've found that often conversations about the product are more valuable than simply looking at a website.  I'd love to chat with you about this:  Steve 936/321-3333

    But now, looking at the various maximum temperature ratings for various Covalence / Raychem shrink sleeves:  we are basing these on maximum operating temperature of the pipeline.  In many cases, a pipeline project may list something like "maximum design temperature" and "expected operating temperature".  Very often, coatings are selected that will be able to meet the "maximum design temperature."  Occasionally, a client of ours will direct us to ignore 'max design' and instead quote based on "expected."  That is their choice of course.  

     So from here, I'm looking specifically at the flip side:  what is the maximum operating temperature of a pipeline with specific regard to our coatings (which is actually based almost wholly on the ratings of the adhesive used on that coating. 

WPCT - 140F

WPC65M - 150F

WPC100M - 176F (212F offshore or under insulation)

WPC120 - 251F

HTLP60 - 140F

HTLP80 - 176F

TPS - 140F

    To reiterate:  conversations about your project are MUCH BETTER than simply plugging in something you've read; so please call me to discuss!!

DIRAX Application Instructions

 DIRAX Installation Guideline

    DIRAX is a relatively simple installation.  It does not require any significant skill.  A few of the common tips that we say over and over and over at training sessions are:  1)  You want a broad bushy yellow flame to shrink the sleeve (this requires that you have a regulator of some kind) and 2) Your torch needs to ALWAYS be moving - you can't stay in one spot for too long and you want to make sure it is the yellow flame in contact with the sleeve; not the blue flame and not the 'clear' flame right where it comes out of the torch.  

Clean exposed steel and adjacent pipe coating to be covered by DIRAX sleeve. Remove all contaminants such as oil. Use a solvent that contains no grease or oil type materials.

If not factory beveled, chamfer the adjacent pipe coating to an angle of preferably 15°, maximum 30°. Inspect the edge of the existing pipe coating. Disbonded sections have to be trimmed of and the coating edge has to be beveled again. To avoid possible contamination, it is recommended to use a scrape

Grid blast or sand blast the steel surface to remove loose and foreign materials. The surface should be cleaned to SIS 055900 - SA 21/2

Grid or sand blast the adjacent pipe coating over a distance of at least 200 mm (8"). The total width should be approximately 50 mm larger than the width of the Raychem supplied DIRAX sleeve. Note: prior to blasting, it is recommended to preheat the exposed steel to 40 - 50° C to avoid flash rust formation

Wipe the surface to remove dust and remaining blasting material. Use a clean dry cloth or air blow

Dose the two component Raychem epoxy. Use pre-dosed Raychem epoxy kits or use Raychem calibrated epoxy pumps. For pre-dosed Raychem epoxy kits, pour content of can B into can A and mix for approximately 1 minute. For easy disposal, it is recommended to pour this mixture back into can B and mix for another 30 seconds. As such, the remaining epoxy in both cans will cure and can be easily disposed off. Follow local regulations for safe disposal. 40°C 20°C 2 min Mixed epoxy primer has a pot life of approximately 30 minutes at ambient temperature. As long as the epoxy primer is still liquid, it may be used. For easy mixing and dispensing, the epoxy primer should be used at a temperature of min. 18° C. When necessary, keep the epoxy primer at a heated place or use a Raychem epoxy heater.

Preheat the bare steel surface and adjacent coating to minimum 70°C (160°F), using propane torches. Adjust flame length to approximately 20" (500 mm). In cold conditions extra heavy preheat torches can be used. Check preheat temperature with a contact pyrometer

Using the supplied applicator pad, apply the mixed epoxy primer over the entire surface to be covered. (When PE line coating is used, no primer should be applied over the polyethylene line coating.)

Immediately after application of the epoxy primer, and while the epoxy primer is still wet, loosely wrap the DIRAX sleeve centrally around the welded joint. If present, remove the protective release plastic from the adhesive side of the DIRAX sleeve.  Wrap the sleeve (adhesive side down) around the area to be coated. Make sure the sleeve overlaps the end of the inner layer by at least 50 mm (2”).

Preheat the inside adhesive layer just next to the closure for a few seconds, and press down on the sleeve end to make it stick to the other end.

Using a Raychem propane torch with a flame length of approximately 500 mm (20”), start heating one end of the closure area.

Immediately pat it down firmly with a gloved hand. Continue heating and patting every 10 cm (4”) until the whole patch area is finished.

Start heating the sleeve at the side of the leading edge, the side that first comes in contact with the ground forces. Move the torch continuously in a paint brush motion all the way around the sleeve

After you have finished heating the side at the leading edge, recover the remainder of the sleeve by heating toward the other end of the sleeve

During shrink down, check adhesive flow with finger occasionally. Wrinkles should disappear automatically

After the DIRAX sleeve has shrunk into the joint area and while it is still hot and soft, run a small hand roller over it to push out any trapped air. Pay particular attention to the weld and cutback area. Reheat areas if necessary.

The sleeve is fully recovered when all of the following have occurred: - The sleeve has fully conformed to the pipe and adjacent coating. - There are no cold spots or dimples on the sleeve surface. - Weld bead profile and other step downs can be seen through the sleeve. - Adhesive flow is evident on both edges, after sleeve is cool.

An 80 mm (3.2”) wide sacrificial sleeve is installed on the leading edge to function as a wear cone during pull thru of the pipe. Start by heating the leading edge area to 70°C (160°F).

Wrap the leading edge sleeve over the transition DIRAX - mill coating. Make sure that the closure is placed away from the main sleeve closure. Preheat the inside adhesive layer just next to the closure for a few seconds. Press down to make it stick to the other sheet end

Heat the closure area and immediately pat it down with a gloved hand.

Shrink the leading edge sleeve down by moving the torch all the way around the pipe in a paintbrush motion. Make sure the sleeve has fully shrunk and adhesive flow is evident on both edges.

Smooth down the edges of the sleeve with the Raychem silicone hand roller. Sleeve is fully recovered when all the following have occurred: - The sleeve has fully conformed to the pipe and adjacent coating. - There are no cold spots or dimples on the sleeve surface. - Weld bead profile and other step downs can be seen through the sleeve. - Adhesive flow is evident on both edges after sleeve is cool. Before the DIRAX can be exposed to the soil forces the joint should be cooled down to ambient temperature