A Look Back at Innovation (and Cigarettes) on the Pipeline Right-of-Way

 

Let’s start with the real question—because you know it crossed your mind too: back in the 1970s, how many packs of cigarettes did a pipeline crew go through in a single day? A carton? More? Honestly… I’d believe it.

Different time, different jobsite culture. And while a lot has changed since then, one thing hasn’t: the constant push to solve problems in the field.

We’re still in Bakersfield, California, in the early days of wrap-around shrink sleeve technology. At this point, the industry was transitioning from tubular sleeves—an important innovation, but one that came with limitations.

This particular project introduces a new challenge: an insulated pipeline.

The original tubular sleeves developed by Raychem were designed to slide over the pipe before welding. That works well—until insulation enters the picture.

With an insulated line, a tubular sleeve would have needed to:

• Be large enough to fit over the insulation during installation
• Still be capable of shrinking tightly down onto the steel pipe

That’s a big ask.

This is where the wrap-around shrink sleeve starts to shine.

Instead of sliding over the pipe, it wraps around the joint after welding—making it far more adaptable, especially in cases like insulated lines or field repairs.

It’s another example of Raychem doing what they did best:

• Thinking ahead
• Solving problems before they became widespread
• Constantly innovating for new applications 

It’s a mindset you still see today from companies like Henkel—always working multiple angles and anticipating what the market will need next.

Now, if you take a closer look at this particular installation… it’s not winning any awards.

There are visible wrinkles in the closure strip—something that would raise eyebrows today. But context matters:

• The technology was brand new
• Installers were still learning the process
• Best practices were being developed in real time

So if you happen to be the installer from 1976 reading this—no disrespect. You were laying the groundwork the rest of the industry would build on.

Understanding Covalence’s WPCT Thermal Indicator: A Built-In Inspection Tool

For those who may not be familiar, WPCT from Covalence is a wrap-around heat-shrinkable sleeve designed for pipeline corrosion protection. One of the most interesting features of this product is its built-in thermal indicator, which essentially acts as a built-in inspection tool for installers and inspectors in the field.

When the sleeve is first supplied, the backing material displays a distinct cross-hatch pattern. This pattern is intentional and serves a very practical purpose.

During installation:

• Before heating: The sleeve shows the cross-hatch pattern across the backing.

• During proper heating: As the installer applies heat, the backing begins to shrink.

• After reaching the correct temperature: The cross-hatch pattern disappears and becomes smooth.

That smooth appearance indicates two important things have happened:

1. The sleeve has shrunk as much as the pipe substrate allows.

2. The mastic sealant has reached the correct temperature to properly flow and fill, ensuring a complete seal around the pipe.

In other words, the visual change from cross-hatched to smooth confirms that the sleeve has reached the proper installation temperature.

For pipeline inspectors and coating crews, this built-in indicator provides a simple but powerful benefit: instant visual confirmation of proper installation.
This type of backing technology isn’t limited to WPCT alone. Variations of the same thermal indicator backing are used across several products in the Covalence lineup, including:
Despite many innovations in pipeline coating systems over the years, Covalence heat shrink sleeves remain widely used both in the United States and around the world. Their durability, ease of inspection, and reliable sealing performance continue to make them a trusted choice for field joint coatings.

Rather than relying solely on temperature guesses or installer experience, the sleeve itself provides feedback. If the cross-hatch pattern remains visible, more heat is required. When the backing becomes smooth, the sleeve has reached the correct thermal state.

This feature helps improve:

• Installation consistency

• Inspection confidence

• Long-term coating performance

This same backing is used with the following products (and some that I haven't listed)

• WPCT

• WPC65M

• WPC100M

• HTLP60

• HTLP80

• WPC120

• TPS

Each of these products utilizes similar heat-shrink technology designed to provide reliable sealing and corrosion protection for pipeline field joints.

Today, Covalence operates as part of Seal For Life / Henkel, and the technology traces its origins back to the pioneering pipeline innovations of Raychem Corporation.

Even decades after their introduction, these heat-shrink systems continue to prove that simple visual engineering can make a big difference in the field.

 

 A Trip Down Memory Lane: Raychem’s Relentless Pursuit of “Better Than Good Enough”

For this week’s trip down memory lane, we’re heading back to Des Moines, Iowa — September 1974.

Last week, I shared the results of a Raychem product evaluation involving a shrink sleeve applied to corrugated pipe. The verdict? It didn’t go particularly well.

But if there’s one thing Raychem was known for, it was thoroughness. When a company invests a significant portion of its revenue into research and development, it doesn’t walk away from a challenging application after a single setback. Quite the opposite.

So the story continues.

This time, Raychem evaluated whether a heat-shrink sleeve could successfully seal a simple corrugated pipe connection. By most accounts, the results were… okay.

And that was the problem.

“Okay” was never the goal. In fact, good enough was never good enough in Raychem’s world. If a product didn’t meet the high standards Raychem was known for in the marketplace, it simply wasn’t acceptable—regardless of whether it technically worked.

That relentless mindset—pushing past acceptable and striving for truly dependable solutions—is a big reason Raychem became the industry leader it was. And thankfully, that same philosophy still lives on today within the Henkel family of companies.

Because real innovation isn’t about settling. It’s about learning, improving, and refusing to compromise—especially in demanding, real-world applications.

Up next week: heat-shrinkable sleeves used to repair leaking gas lines. You won’t want to miss it.

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.

WPCT Frequently Asked Questions

 Covalence WPCT: Product Overview and Frequently Asked Questions

    Covalence (formerly Raychem) WPCT is a widely recognized solution for field-joint corrosion protection in pipelines. Originally developed by Raychem, a pioneer in heat-shrinkable technology, Covalence WPCT continues to set industry standards for reliability and ease of use in pipeline protection applications.

---

Product Overview

What is Covalence WPCT?
Covalence WPCT is a two-layer, wraparound, heat-shrinkable sleeve system designed for corrosion protection of field girth weld joints in distribution and transmission pipelines. It is suitable for pipelines operating at ambient and moderately elevated temperatures, up to 140°F (60°C).

Key Features:

• Two-Layer Construction:

  • First Layer: Visco-elastic butyl-based low preheat adhesive.

  • Second Layer: Radiation cross-linked, high-density polyethylene with a Permanent Change Indicator (PCI) for correct installation verification.

• No primer required; the sleeve is wrapped around the cleaned and preheated pipe surface and then shrunk using a heat source, forming a tight, protective fit.

• Compatibility: Works with all standard pipe coatings and can be used on bare replacement sections or large-radius bends.

• Application: Designed for ease of installation with minimal preheating, making it ideal for large diameter water pipes and standard buried applications (not recommended for road bores or directional drilling).

• Corrosion Protection: The adhesive flows during installation to bond with the pipe, while the outer layer provides a durable barrier against mechanical damage and moisture ingress.

---

Frequently Asked Questions (FAQ)

1. What does WPCT stand for?
WPCT stands for "Wraparound Pipe Coating with Thermal indicator," referencing its wraparound, heat-shrinkable design for pipe joint protection.

2. What temperatures can WPCT withstand?
WPCT is rated for pipelines operating at temperatures up to 140°F (60°C).

3. Is a primer required for installation?
No primer is needed. The system is designed for direct application to cleaned and preheated pipe surfaces, simplifying installation and reducing labor time.

4. How do I know if WPCT has been installed correctly?
The sleeve features a dimpled backing that smooths out when heated, serving as a Permanent Change Indicator (PCI) to visually confirm proper installation.

5. What pipeline coatings is WPCT compatible with?
WPCT is compatible with all standard pipeline coatings, including those commonly used for distribution and transmission systems.

6. Can WPCT be used for directional drilling or road bores?
WPCT is not recommended for high-shear or high-stress environments such as road bores or directional drilling. For such applications, higher-performance sleeves like DIRAX are required.

7. What pipe sizes are supported?
WPCT is available in standard widths (11", 17", 24", 34") and can be custom-sized to fit any pipe diameters.

8. What are the main benefits of using WPCT?

• Fast, primerless installation

• Reliable corrosion protection

• Visual installation indicator (PCI)

• Compatibility with standard coatings

• Durable, mechanical and moisture barrier

9. Who manufactures Covalence WPCT?
Covalence is a brand under Seal For Life Industries, carrying forward the legacy of Raychem’s heat-shrinkable technology.

10. What is the history of Covalence and Raychem?
Raychem, founded in 1957, pioneered heat-shrinkable tubing and related technologies. The Covalence brand continues this legacy, offering advanced pipeline protection products worldwide.

---

Summary Table: Covalence WPCT Key Facts

Feature	Description
Product Type	Two-layer, heat-shrinkable wraparound sleeve
Application	Field girth weld joints, replacement sections, bends
Temperature Range	Up to 140°F (60°C)
Installation	No primer, minimal preheat, PCI visual indicator
Compatibility	Most standard pipe coatings
Recommended Use	Standard buried pipelines, not for HDD/road bores
Sizes	11", 17", 24", 34" widths; custom sizes available

---

Covalence WPCT remains a trusted, efficient solution for pipeline corrosion protection, combining ease of installation with proven field performance.