Thermal Insulative Coatings Help Pipelines Beat Corrosion and Cut Heat Loss
By NEIL WILDS, Global Product Director-CUI, Sherwin-Williams Protective & Marine; and JIGAR MISTRY, Marketing Director – Functional Coatings, Sherwin-Williams Protective & Marine
(P&GJ) — Energy pipeline infrastructure must contend with some of the harshest operating conditions in industrial environments. Both buried and aboveground pipelines—as well as compressor stations—routinely face wide temperature swings that strain protective systems and accelerate material wear.
For example, heated contents moving through frozen terrain can cause drastic surface temperature shifts when a buried pipe emerges aboveground. Similarly, compressor stations see sharp thermal changes as gases heat up during compression and cool rapidly during decompression.
These temperature dynamics are more than engineering challenges; they’re key contributors to corrosion—one of the most persistent threats to pipeline longevity. Over time, thermal cycling can drive coating failure, trigger moisture accumulation and lead to costly repairs across a range of assets.
When condensation forms due to these fluctuations, it can settle on equipment surfaces and work its way down through protective coatings, eventually reaching the metal substrate and initiating pitting corrosion. Left unchecked, this process can lead to significant material degradation. The problem compounds when moisture drips onto nearby equipment, creating new corrosion sites. Moisture can also become trapped beneath traditional thermal insulation systems, where it quietly contributes to a more insidious form of damage: corrosion under insulation (CUI).
This hidden threat—paired with the added stresses of continual expansion and contraction of materials—can accelerate coating failure and shorten asset life spans.
While some degree of corrosion is inevitable over long service intervals, premature corrosion is preventable. Its occurrence should prompt operators to investigate alternatives that could yield better performance and durability. For buried pipelines, these alternatives might include additional protective layers or selecting coating materials that are better suited to wet or rocky conditions.
For compressor station assets, operators may even consider removing conventional insulation altogether, substituting it with thermal insulative coatings (TICs) that deliver comparable heat retention, reduce condensation risk and eliminate CUI entirely.
By reevaluating and optimizing their protective systems, pipeline operators have an opportunity to significantly extend the service life of their infrastructure. These choices not only mitigate future repair and replacement costs, but they also improve environmental stewardship by reducing material waste and minimizing unplanned disruptions.
Building a better barrier. The need for pipeline repair typically becomes evident through routine line monitoring and various inspection methods, designed to detect early signs of corrosion and degradation. For buried pipelines, technicians often rely on cathodic protection (CP) system readings as a first line of defense. Deviations in CP performance can indicate coating damage or deterioration beneath the surface.
Supplementing these systems, crews use a combination of ultrasonic thickness testing, magnetic particle inspection (MPI) and internal assessments conducted via in-line inspection tools, commonly known as “smart pigs,” to gather data on wall loss and mechanical integrity.
While direct visual inspection of buried pipes is not feasible, exposed, aboveground or non-insulated pipeline sections can be inspected visually for flaking, rust staining, coating delamination or visible wear. These inspections can help confirm suspected problem areas, detected through indirect testing, and they provide an opportunity for field teams to observe whether corrosion has developed (or is likely to), based on operational and environmental factors.
When inspection results reveal existing corrosion or red flags that signal a heightened risk, operators have a valuable chance to improve long-term coating performance. Reviewing the in-service history of the coatings used can serve as a diagnostic baseline. If the performance of the original coating system fails to meet expectations—particularly in light of environmental changes or operational stresses—then operators should strongly consider transitioning to a more robust solution.
One common scenario involves damage to fusion-bonded epoxy (FBE) coatings, which are widely used on pipeline exteriors due to their excellent anti-corrosion properties. However, when FBEs become scratched or gouged during handling, installation or operation, the protective barrier can be breached. The exposed steel substrate is then vulnerable to rapid corrosion, especially in warm or wet environments, where the elevated temperatures accelerate electrochemical activity.
To address this, operators can add additional protective layers, creating a stratified defense that enhances performance from the surface to the steel (FIG. 1). In especially rocky or abrasive soil conditions, where mechanical wear is more likely, the application of a durable abrasion-resistant overcoat (ARO) on top of the FBE layer is highly effective. This dual-layer FBE coating system combines the base FBE for corrosion prevention with a tough ARO to guard against physical damage (FIG. 2). The synergy between these layers helps ensure long-term integrity even under aggressive mechanical stress.
Environmental conditions can also dictate coating strategy. If a pipeline section is buried in soil with an unexpectedly high moisture content, it may experience premature degradation. In such cases, a moisture-resistant overcoat (MRO) can be used in place of a conventional single-layer FBE. These specialized coatings are engineered to significantly reduce moisture ingress, limiting the amount of water that can permeate the film and reach the pipe substrate. This not only improves overall coating adhesion, but it also decreases the risk of coating failure due to cathodic disbondment or loss of film integrity, caused by constant moisture cycling.
In some cases, pipeline operators may require both abrasion and moisture resistance, especially in harsh or unpredictable operating environments. Coating technologies have advanced to offer multifunctional solutions that combine these properties in a single system. One such example is a next-generation coatinga that delivers robust protection against mechanical wear, chemical attack and water ingress. It is rated for service at high operating temperatures, making it an ideal solution for thermally stressed pipelines operating in wet, corrosive or high-impact conditions.
By selecting coatings tailored to the asset’s environmental and mechanical challenges, operators can build a more durable and cost-effective pipeline infrastructure—one that’s better equipped to withstand the rigors of time, temperature and terrain.
Insulative coatings. CUI is particularly common on pipeline infrastructure assets that rely on traditional insulation systems. Such systems are typically composed of thick, mineral-based insulation wrapped around pipes, valves, vessels and fittings, and then they are finished with exterior metal jacketing. They are designed to protect personnel from high temperatures, stabilize internal process conditions and reduce heat loss by minimizing the temperature differential between internal contents and ambient air. In theory, they function well.
However, in practice, they often become a breeding ground for corrosion. Even the most carefully installed cladding systems are vulnerable to breaches through seam gaps, mechanical damage or degradation over time. Once moisture enters the system, it becomes trapped between the insulation and the hot metal surface. With elevated temperatures accelerating chemical activity and electrolytes present, the risk of localized corrosion skyrockets. Worse still, the environment beneath the cladding never truly dries, allowing corrosion to thrive unnoticed for months or even years.
To mitigate this hidden hazard, asset owners can apply specialized CUI-mitigation primersb that deliver proven protection even in high-temperature, moisture-rich environments. These primers form a resilient barrier against both water and heat, safeguarding the metal substrate beneath the insulation. However, applying a primer alone doesn’t address the root cause of CUI: the insulation system itself.
In cases where CUI is active or highly probable, operators may want to reconsider the insulation system entirely and potentially eliminate it. A growing number of pipeline owners are turning to TICs as a more streamlined and effective solution. By applying a high-performance TIC system over a CUI-mitigation primer, operators can achieve thermal retention comparable to that of traditional mineral wool systems, but without the risk of CUI forming underneath. In fact, TICs can often replace bulky physical insulation systems altogether.
These advanced coatings are engineered to act as thermal barriers in their own right. With a few well-applied layers, TICs can deliver impressive insulating properties, while conforming tightly to asset geometries, eliminating the need for cladding and pins. In doing so, they remove the entire corrosion-prone zone between insulation and steel. What remains is a clean, coated surface with no enclosed space where moisture can accumulate, effectively eliminating CUI by default (FIG. 3).
Without traditional insulation in the picture, only atmospheric corrosion remains as a maintenance concern, and it’s one that operators can manage more easily through conventional inspection and recoating intervals. By switching to TICs in areas vulnerable to CUI, operators simplify maintenance routines, reduce failure risks and extend the service life of key infrastructure.
Keeping heat in. The ability to consider replacing conventional insulation systems with TICs hinges on one critical factor: heat retention. A well-formulated TIC must be able to trap process heat within a pipeline or equipment surface with the same effectiveness (or better) than traditional mineral-based insulation. The good news for operators is that this level of performance is not only achievable, but it is also being realized in the field today.
For example, when an advanced energy barrier (AEB)c is applied at a total thickness of just half to three-quarters of an inch, this coating can help assets maintain continuous operating temperatures of up to 350°F (177°C), with short-term excursions reaching as high as 400°F (204°C).
These figures are not hypothetical; they are validated performance metrics. Even at these elevated conditions, the coating retains process heat at levels comparable to traditional cladding-and-mineral-wool insulation systems, while simultaneously avoiding the pitfalls of CUI and reducing material, labor and inspection burdens.
The secret lies in the coating’s high internal insulation particle loading. These particles, evenly dispersed throughout the cured film, trap pockets of air that dramatically slow the transfer of heat through the coating. Air is a poor conductor of heat, so this matrix of air and insulation particles effectively forms a thermal bottleneck. As a result, more energy remains within the process line or vessel, reducing the fuel or electrical input needed to maintain target temperatures. This energy efficiency adds up over time and across a wide array of assets.
In addition to energy savings, TICsc offer long-term consistency in performance. Traditional insulation systems degrade when exposed to moisture, and that degradation can happen quickly. If just 10% water by volume infiltrates the mineral wool insulation, the system’s R-value can drop by up to 85%. Once saturated, mineral insulation loses its effectiveness, and operators may not realize that until energy consumption has already increased. Thermal imaging or temperature differentials at the asset surface may eventually reveal the issue, but by then, energy loss and possible corrosion have already occurred.
TICs avoid this issue entirely. Their dense, closed-cell structure is engineered to minimize moisture ingress. If water is absorbed during exposure, it can typically dissipate within 24 hours through natural heating and evaporation. This moisture-resilient characteristic allows TICs to maintain stable, predictable thermal performance over their full-service life, without the drop-offs associated with compromised traditional systems.
Thanks to this stability, operators can more confidently manage heating loads across their systems, knowing that the insulation value of their TIC-coated assets won’t erode with time or exposure. That predictability translates into greater control over energy budgets and fewer surprises during seasonal shifts or inspection intervals.
The practical implications are far-reaching. Pipeline operators and facility managers may now consider replacing a wide range of traditional insulation systems with TICs during maintenance or upgrade cycles. This can include insulation on compressors, process piping, coolant lines, elbows, flanges and other complex geometries that are often difficult to insulate with physical wraps (FIG. 4). TICs can also be used on segments of aboveground pipelines, particularly in remote, harsh or frozen environments, where burying pipe is impractical. In permafrost zones or desert applications, where exposure is high and maintenance access is limited, TICs offer an elegant, long-term solution with a simplified system design.
Condensation control. TICsc are valuable not just for retaining internal heat, but also for controlling surface temperature to reduce condensation risks. These coatings provide a critical barrier in environments where large temperature differentials between the internal contents of a pipe or vessel and the ambient air can lead to surface condensation. This is especially pronounced in compressor stations, where gases experience dramatic swings in temperature, rapidly heating during compression and cooling just as quickly during decompression.
As warm gases expand and cool while the surrounding ambient air remains significantly colder, the surface of the asset often becomes a point of moisture accumulation. This condensation is more than a nuisance; it’s a corrosion catalyst. Moisture can collect in droplets or thin films on asset surfaces, eventually seeping into joints, seams or coating discontinuities. Over time, this leads to localized corrosion on the asset itself and on adjacent equipment, as well as when moisture is allowed to drip or pool.
In cold climates, the issue becomes even more pronounced. Persistent condensation can freeze, forming thick ice that envelops valves, flanges and controls, sometimes rendering critical equipment inoperable (FIG. 5). These icing events not only compromise reliability and safety, but they also complicate maintenance by requiring deicing before inspection or repairs can proceed.
TICs play a central role in mitigating these outcomes. By insulating the exterior surface of an asset, they narrow the temperature delta between the pipe surface and ambient air, reducing the dew point intersection and significantly minimizing the opportunity for condensation to form. When condensation is minimized, the chances for both corrosion and icing are dramatically reduced. This is particularly advantageous for aboveground pipelines and equipment positioned at soil-to-air interfaces, where buried segments transition to exposed ones. These areas are notorious for condensation in colder months, as the pipe contents remain significantly warmer than the freezing air, creating a perfect storm for moisture accumulation.
In conventional systems, condensation beneath the cladding often soaks into mineral wool insulation. This absorbent medium then holds water against the pipe’s surface. The saturated insulation not only loses its insulating performance, but it also creates ideal conditions for hidden corrosion. By replacing bulky, moisture-trapping materials with an impermeable, closed-cell coating system, TICs remove the possibility of CUI at the source.
This dual function—minimizing condensation while eliminating CUI—makes TICs a powerful tool in managing the long-term durability and operability of pipeline infrastructure. Especially in climates with extreme cold, high humidity or temperature volatility, TICs help make sure that pipelines and equipment remain accessible, efficient and protected.
Reducing costs. Notable cost and environmental savings are possible when replacing traditional insulation systems with TICs. The most immediate benefit comes from eliminating the need for thick mineral-based insulation, plus associated materials like wiring, pins, banding and exterior metal cladding. All of these components add to project costs and contribute to the environmental footprint of insulating hot assets.
By switching to a coating-based solution, operators remove the material, shipping and storage demands tied to conventional systems. They also simplify installation and reduce waste, particularly on large-scale projects where insulation infrastructure can be extensive. Additional savings come from eliminating CUI, which in turn reduces the volume of steel that corrodes and needs to be replaced over time.
Operational savings also add up. TICs remove the need for complex CUI inspection protocols, where technicians must disassemble cladding to assess underlying corrosion. With a coated surface, inspections are simpler and less invasive, allowing for longer intervals between maintenance cycles and freeing up resources for other priorities.
Extending lifespan. Addressing corrosion on pipeline infrastructure assets, as well as considering alternative solutions when coatings underperform, is critical to extending service life and minimizing maintenance costs. Temperature extremes and condensation can accelerate corrosion, but with the right coating system, operators can target these risks.
Advanced TICs offer a compelling option for insulated applications. By retaining process heat, reducing condensation and eliminating conditions for CUI, they enhance protection without the downsides of traditional insulation systems.
Replacing conventional insulation with TICs can lead to meaningful cost savings, sustainability gains and extended asset life, resulting in more resilient, lower-maintenance pipeline operations. As the industry evolves, coatings will play an increasingly strategic role in lifecycle planning. Advanced solutions like TICs address known risks and help redefine what’s possible in pipeline protection.
NOTES
a Pipeclad® HOT 150 Flex MRO Abrasion-Resistant Overcoat
b Heat-Flex® ACE
c Heat-Flex® Advanced Energy Barrier (AEB)
About the Authors
NEIL WILDS is the Global Product Director – CUI for Sherwin-Williams Protective & Marine. With 39 yrs of technical coatings experience, Wilds develops strategies for long-term asset protection and directs the development of specifications and testing programs. He is a member of several coatings associations, including AMPP, NORSOK M501, the International Organization for Standardization (ISO) and others. Contact: Neil.Wilds@sherwin.com
DR. JIGAR MISTRY is the Marketing Director – Functional Coatings Sherwin-Williams Protective & Marine and based in Minneapolis, Minnesota. With approximately 20 yrs of experience in the coatings and chemical industry – both as an educator and a Sherwin-Williams team member – he has specialized in multiple subject matters related to corrosion, coatings performance, asset protection, and coating solutions.