Recoating a Condensating Pipeline in Chicago: When Conditions Leave Few Options

 Pipeline rehabilitation projects are rarely simple—but every now and then a job comes along that checks nearly every “difficult application” box imaginable.

Today’s example takes us to Chicago, where a client needed to rehabilitate a 36-inch pipeline that had originally been coated with coal tar epoxy. Over time, the coating had begun to fail, and the operating conditions were creating continuous condensation on the pipe surface.

Recoating a sweating pipeline is already challenging. Add tight working conditions and limited surface preparation, and suddenly the list of viable coating systems becomes very short.

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A Challenging Environment

The pipeline in question included both horizontal and vertical sections, and the working space around the pipe was extremely limited.

Just as importantly, the environment did not allow abrasive blasting, which meant achieving the typical high-level surface preparation required by many coatings simply wasn’t possible.

That left the client with a very demanding checklist for any potential coating system:

• Minimal surface preparation requirements

• Ability to be applied in tight spaces

• High flexibility

• Tolerance for high humidity

• Capability to be applied to a sweating (condensating) pipe

• A system capable of extending asset life by at least 25 years

In other words—no big deal, right?

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When the Checklist Seems Impossible

Many conventional coating systems would immediately struggle with these conditions.

Most coatings require abrasive blasting to achieve proper adhesion. Others simply cannot tolerate moisture during application, let alone a pipe that is actively condensating.

And when a pipe is constantly expanding, contracting, and exposed to humidity, flexibility becomes critical to long-term performance.

Fortunately, there are systems specifically designed for these kinds of environments.

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The Stopaq Solution

For this project, the solution centered around Stopaq Wrappingband WSH from Stopaq (Seal For Life Industries).

One of the key advantages of the WSH system is its ability to displace surface moisture during application. That makes it uniquely suited for situations where condensation is unavoidable.

Instead of requiring abrasive blasting, the pipe surface can be prepared to ST2/ST3, which can typically be achieved using hand tools to remove loose, disbonded coating and rust.

Once the loose material is removed, the process is straightforward:

1. Apply Wrappingband WSH, which conforms to the pipe and displaces moisture.

2. Install a protective outerwrap to provide additional mechanical protection.

3. The pipeline is once again protected from corrosion.

Simple, but extremely effective.

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Checking Every Box

What makes this project particularly interesting is how many difficult requirements had to be satisfied simultaneously.

The coating system needed to:

• Perform with minimal surface preparation

• Be installed in tight working conditions

• Handle high humidity

• Be applied to a condensating pipe

• Deliver long-term asset protection

In this case, the Stopaq system checked every box—allowing the operator to rehabilitate the pipeline and extend its service life without the need for blasting or major operational disruptions.

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The Big Lesson

Pipeline rehabilitation isn’t always about finding the “strongest” coating. Often it’s about finding the coating that can actually be installed under the real-world conditions you’re facing.

In environments where traditional surface prep and dry conditions simply aren’t possible, visco-elastic coating systems like Stopaq can make the difference between a project that stalls—and one that succeeds.

And in Chicago, that made all the difference for this 36-inch line.

When the Bore Fights Back: Evaluating Covalence DIRAX in Rocky Soil

 Directional drilling can be unforgiving on pipeline coatings. When pipe is pulled through tight bores filled with rock, friction and abrasion can quickly expose the weaknesses of materials that weren’t designed for that kind of punishment.

A few years ago, we had the opportunity to witness exactly how different coating systems perform under those conditions during a product evaluation for Texas Gas Transmission.

The objective was straightforward: evaluate three coating systems on a 4.5" OD pipe that would pass through a 160-foot directional bore in extremely rocky soil.

As it turned out, the test became even more interesting than planned.

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The Unexpected Test

Halfway through the installation, the drilling equipment failed.

At that point the pipe had already been pulled 80 feet into the bore, meaning the only option was to pull it 80 feet back out in reverse.

Instead of a single pass through the bore, the coatings experienced a 160-foot round trip—80 feet in and 80 feet out—through a very aggressive environment.

For a coating system, that’s a serious test of abrasion resistance and adhesion.

First up was cold applied tape.

Before going any further, it’s worth adding an important disclaimer:
I’m not aware of any cold applied tape manufacturer that recommends their product for directional drilling applications.

But as anyone in the pipeline industry knows, coatings sometimes get used in ways they were never intended to be used.

In this case, the result was dramatic.

When the pipe came back out of the bore, the tape coating had essentially disappeared. It had been stripped off somewhere along the 160-foot journey and deposited in the ground along the way.

Not exactly the outcome you’re hoping for.

Next up was a standard three-layer heat shrink sleeve system.

Again, another quick disclaimer: this is not a product we would typically recommend for a directional drilling application.

When the pipe came out of the bore, the sleeve was still in place, which was certainly better than the tape. However, the backing had been gouged in two locations by the rocky soil.

That kind of mechanical damage can create long-term risks if the coating barrier is compromised.

The third coating evaluated was Covalence DIRAX HDD Coating System from Seal For Life Industries.

DIRAX is a multi-layer coating system with a fiber-reinforced backing, specifically designed to withstand the mechanical forces associated with horizontal directional drilling (HDD).

And in this test, it showed why purpose-built systems matter.

Even in areas where the underlying FBE coating had been scratched by the rocky environment, the DIRAX remained fully intact and undamaged.

No gouging. No disbondment. No missing material.

Just solid protection.

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The Takeaway

Directional drilling puts extraordinary stress on pipeline coatings. Materials designed for conventional trench installations often struggle—or fail entirely—when exposed to the abrasion and mechanical forces inside a bore.

This evaluation was a good reminder of an important principle:

Use coatings designed for the environment they’re going into.

In this case, the product specifically engineered for HDD applications—DIRAX—was the one that handled the challenge with ease.

Sometimes the right answer really is the purpose-built solution.

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.