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Dangers Posed by Corrosion Under Insulation (CUI) in Industrial Systems: Leaks, Fire, Shutdown

By CUI, Industrial Insulation, Insulation Failures, Pipe Insulation

Corrosion Under Insulation (CUI) remains one of the most underestimated risks in industrial environments. It develops out of sight, beneath insulation systems that are intended to protect assets but can, under the wrong conditions, accelerate degradation instead. The result is often discovered only after failure — when a leak occurs, a fire risk emerges, or operations are forced to shut down unexpectedly.

For industries such as refining, mining, chemical processing, and critical infrastructure, CUI is not simply a maintenance concern. It is a serious operational and safety risk with the potential to impact personnel, production, and long-term asset integrity.

At Dragon Jacket Insulation, we set out to design and engineer an industrial insulation system that would eliminate (or at least drastically reduce) the risk of CUI, and the result is an insulation system that resists and repels water and moisture from reaching protected pipes and fittings through decades of use.

What Is Corrosion Under Insulation (CUI)?

CUI refers to the corrosion of metal surfaces — typically piping, tanks, or pressure vessels — that occurs beneath insulation. Because insulation systems conceal the underlying metal fittings, corrosion can progress for extended periods without detection.

This form of corrosion is particularly problematic because it does not present obvious external indicators. Unlike exposed corrosion, which can be identified through visual inspection, CUI often advances until the material has significantly weakened. By the time it is discovered, the system may already be close to failure.

CUI most commonly affects carbon steel and low-alloy steel assets, especially those operating in temperature ranges where moisture can accumulate and persist.

Why CUI Presents a Serious Risk

The primary danger of CUI lies in its hidden nature. When corrosion develops unnoticed, it compromises the structural integrity of critical systems without warning. This can lead to sudden and severe consequences.

Failures caused by CUI are not gradual; they are often abrupt and sometimes catastrophic. A pipe wall weakened by corrosion may rupture under pressure, releasing hazardous or high-temperature materials. In refining environments, this can escalate into fire or explosion risks. In other industrial settings, it can result in equipment damage, environmental release, or injury to personnel.

The operational impact is equally significant. Unplanned shutdowns caused by CUI-related failures disrupt production schedules, strain maintenance resources, and can lead to extended downtime while systems are inspected and repaired.

How CUI Develops

CUI occurs when moisture comes into prolonged contact with metal surfaces beneath insulation. This moisture may originate from external sources such as rain or washdowns, or from internal condensation within the system.

Temperature plays a critical role. Systems operating in moderate or cyclical temperature ranges — where water can repeatedly condense and evaporate — are especially vulnerable. These conditions create an environment where corrosion reactions can accelerate over time.

The design and condition of the insulation system itself also contribute. Traditional insulation materials can absorb and retain water, allowing moisture to remain in contact with a metal surface. Over time, insulation may degrade, creating gaps or pathways that allow additional water ingress.

Installation quality further influences risk. In field-applied insulation systems, inconsistencies such as poor sealing, gaps at joints, or uneven coverage can allow moisture to penetrate and become trapped. Once inside, it is often difficult for the system to dry out, sustaining and preserving the corrosive environment.

Documented Incidents and Real-World Impact

CUI has been identified as a contributing factor in numerous industrial failures, some with significant economic and safety consequences.

One of the most widely referenced cases occurred in Alaska in 2006, when corrosion under insulation led to severe wall thinning in an oil pipeline. The resulting rupture caused a spill of more than 200,000 gallons of crude oil, triggering environmental damage, regulatory action, and costly operational disruption. The incident highlighted how undetected corrosion can escalate into large-scale failure.

In refining and chemical processing facilities, investigations by regulatory bodies such as the U.S. Chemical Safety Board have linked CUI to multiple hydrocarbon release events. In several cases, corroded piping failed unexpectedly, releasing flammable materials that ignited and caused fires. These incidents not only damaged infrastructure but also placed personnel at risk and required emergency shutdowns.

CUI has also been associated with high-pressure steam line failures in power generation and industrial plants. When these systems rupture, they can release energy and materials capable of causing severe injury or damage. Similarly, storage tanks affected by CUI have experienced leaks that required extensive cleanup and remediation efforts.

Economic Consequences of CUI

The financial impact of CUI extends well beyond the immediate cost of repair. When a failure occurs, organizations must address both direct and indirect costs.

Direct costs typically include equipment replacement, emergency repairs, environmental cleanup, and potential regulatory penalties. However, indirect costs often exceed these initial expenses. Lost production during unplanned downtime, increased inspection requirements, and shortened asset lifespans all contribute to the total economic burden. While general liability insurance can cover some of the costs, insurance cannot remedy personal injuries, lost productivity, and reputational harm.

Across industries, preventing corrosion-related damage accounts for a substantial share of maintenance and capital expenditures. Due to its hidden and progressive nature, CUI concerns represent a significant portion of these costs. 

Why Traditional Insulation Systems Fall Short

Many conventional insulation systems were not designed with long-term moisture resistance as a primary consideration; instead, they focus on insulation value. However, over time, these systems are susceptible to water ingress and retention, which not only degrades insulation value, but introduces CUI issues.

Multi-layer systems with numerous seams and penetrations increase the likelihood of water entry. In some cases, external jacketing may trap moisture inside the system, preventing it from drying. Materials that absorb moisture create sustained contact between water and metal surfaces. In large and complex systems, these problems make it difficult to prevent or detect CUI using traditional approaches.

Reducing the Risk of CUI

Addressing CUI requires a shift toward insulation systems and practices that prioritize moisture management, durability, and ease of access. Effective strategies include:

  • Selecting insulation materials that resist water absorption
  • Designing systems with minimal seams and entry points
  • Ensuring consistent, high-quality installation
  • Prioritizing reusability for inspection and maintenance purposes

Prefabricated insulation systems such as those offered by DJI have distinct advantages in this context. DJI provides engineered insulation components with controlled fit and reduced variability. By limiting opportunities for moisture ingress and maintaining consistent performance, DJI’s systems help mitigate one of the primary drivers of CUI.

DJI: Enhancing Inspection and Prevention

Even with improved insulation systems, proactive inspection remains essential. Facilities often implement risk-based inspection programs to identify high-risk areas and prioritize monitoring efforts.

Dragon Jacket’s improved insulation design allows easy inspection that does not destroy either the structural integrity or the R-value of insulation. Each segment of DJI is a rigid, polyurea-coated clamshell that can be removed and replaced without specialized training or tools. Scheduled inspections that allow for early detection of potential issues are easily and swiftly accomplished. This preventative maintenance step, combined with DJI’s improved insulation design, provides a more comprehensive approach to managing CUI risk.

Understanding how CUI develops — and learning from documented failures — underscores the importance of using an insulation system designed to resist moisture, maintain integrity, and support long-term reliability.If you are concerned about CUI risk in your facility, Dragon Jacket Insulation provides a prefabricated insulation solution engineered to reduce moisture intrusion, improve durability, and support safer, more predictable operations. To learn more, obtain a quote, or schedule a demonstration, contact Dragon Jacket Insulation.

May 14, 2026
​Oil & Gas Pipe Insulation: Built for Remote Fields, Coastal Refineries, and Extreme Environments cover

​Oil & Gas Pipe Insulation: Built for Remote Fields, Coastal Refineries, and Extreme Environments

By CUI, Durability, Industrial Insulation, Insulation Failures, Insulation Solutions, Pipe Insulation, Reusability, Sustainability

Oil and gas insulation fails where it matters most: in remote upstream sites, long-exposed midstream runs, and humid, corrosion-prone refineries. Learn why traditional field-assembled systems break down—and how Dragon Jacket’s fully encapsulated design prevents CUI, speeds installs, and stays reliable.

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April 20, 2026
Pipe Fitting Insulation: How Prefabricated Solutions Eliminate Installation Complexity cover

Pipe Fitting Insulation: How Prefabricated Solutions Eliminate Installation Complexity

By CUI, Custom Solutions, Pipe Insulation

Insulation failures usually begin at elbows, tees, valves, and transitions—where field-fabricated materials can’t match complex geometry, creating gaps, seams, and moisture pathways that drive heat loss, CUI, and rework. Prefabricated Dragon Jacket components install fast, fit precisely, and deliver repeatable long-term performance.

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April 10, 2026

Industrial Pipe Insulation for Chemical Plants: Preventing Corrosion Under Insulation

By CUI, Industrial InsulationNo Comments

Modern chemical processing plants operate in some of the most demanding industrial environments. Pipes, valves, reactors, and tanks are exposed to corrosive chemicals, extreme temperatures, weather, washdowns, and continuous production cycles.

In these conditions, insulation serves several critical functions. Beyond thermal efficiency, insulation helps maintain process temperatures, protect equipment from corrosion under insulation (CUI), and ensure safe and reliable plant operations.

In many chemical processes, insulation also plays a key role in maintaining the flow of high-viscosity fluids such as polymers, resins, waxes, syrups, and specialty chemical intermediates. These materials require stable temperatures to remain pumpable. If pipe temperatures drop and viscosity increases, flow rates can decline and pipelines can become restricted or blocked.

For this reason, insulation in chemical plants is essential not only for energy efficiency but also for process stability, corrosion prevention, and long-term asset protection.

Many chemical facilities rely on traditional insulation systems such as fiberglass, mineral wool, elastomeric foam, calcium silicate, cellular glass, or perlite-based insulation. These materials are typically installed in layers and protected with metal or polymer cladding to shield them from environmental exposure. While these systems can provide adequate thermal performance initially, they often struggle in chemical processing environments. Common failure mechanisms include:

  • Moisture intrusion through seams or damaged jacketing
  • Chemical exposure from washdowns or process spills
  • UV degradation of exterior coatings and sealants
  • Mechanical damage during maintenance or inspection

Porous insulation materials can absorb liquids, and brittle materials such as calcium silicate or perlite insulation can crack when exposed to impact or repeated handling. Over time, sealants and tapes degrade, creating pathways for moisture and contaminants.

Once moisture enters the insulation system, corrosion can begin beneath the insulation layer. Because the damage occurs out of sight, corrosion under insulation often progresses undetected until significant pipe damage has already occurred. Insulation failure that leads to CUI results in insulation replacement costs, production downtime, and increased maintenance budgets.

 

Dragon Jacket Insulation (DJI) offers an alternative approach designed for demanding industrial environments.

Dragon Jacket insulation is lightweight, durable, impact-resistant, and engineered to prevent moisture intrusion. Unlike traditional layered insulation systems assembled in the field, Dragon Jacket components are prefabricated, fully encapsulated insulation assemblies designed to protect piping and equipment from environmental exposure.

Because the insulation is fully sealed within a protective outer shell, the system helps prevent moisture infiltration and CUI while maintaining long-term thermal performance.

Dragon Jacket insulation is used across a wide range of applications, from water infrastructure and energy facilities to data centers and chemical processing plants, where durability and corrosion prevention are critical.

 

Why Chemical Plants Are High-Risk for Insulation Failure

Chemical processing facilities present a combination of environmental and operational conditions that can accelerate insulation degradation. Common stress factors include:

  • Frequent washdowns and chemical exposure
  • Condensation on chilled or cryogenic lines
  • High-temperature processes and thermal cycling
  • Outdoor pipe racks exposed to UV radiation, rain, and humidity
  • Mechanical damage from maintenance activity
  • Tight maintenance windows requiring repeated access to equipment

Traditional insulation systems often struggle under these conditions. Porous materials can absorb liquids, cladding can dent or separate at seams, and protective coatings degrade when exposed to chemicals or UV radiation.

When insulation becomes saturated or damaged, heat transfer increases and corrosion risks rise. In addition, insulation degradation can alter pipe temperatures, which may affect fluid viscosity and flow stability in temperature-sensitive chemical processes.

In chemical plants, insulation failure is not just a maintenance issue. It can impact process reliability, equipment lifespan, and plant safety.

 

A Corrosion-Safe Insulation Strategy

Dragon Jacket insulation was engineered to address the root causes of insulation-related corrosion and performance degradation by eliminating the vulnerabilities inherent in traditional insulation methods.

Instead of installing insulation layers and protective cladding separately, Dragon Jacket insulation components are 3D-modeled and prefabricated to match the exact geometry of pipes, fittings, valves, and equipment.

Each component consists of a rigid closed-cell insulation core fully sealed encapsulation within a seamless polyurea shell. This design creates a continuous barrier that prevents liquids, vapors, and contaminants from reaching the pipe surface. By eliminating seams, mastics, and exposed insulation materials, the system reduces pathways for moisture intrusion and corrosion.

As a result, Dragon Jacket insulation provides a solution to problems commonly encountered in chemical processing plants.

 

Moisture and Chemical Resistance

Moisture intrusion is one of the primary causes of insulation failure in chemical facilities.

Dragon Jacket insulation uses a continuous polyurea shell that forms a waterproof barrier around the insulation core. This protective outer layer resists water, oils, and many industrial chemicals while preventing the insulation from absorbing liquids.

Because the system does not rely on tapes, mastics, or field-applied coatings to maintain protection, there are fewer potential failure points where moisture can enter the insulation system.  This design helps maintain insulation performance in environments where traditional materials can degrade due to repeated washdowns, spills, or high humidity.

 

CUI Prevention by Design

Corrosion under insulation occurs when moisture becomes trapped between insulation and the pipe surface. Once moisture penetrates an insulation system, corrosion can develop beneath the insulation layer and progress undetected for long periods of time.

Encapsulated insulation systems help mitigate this risk by preventing moisture from reaching the pipe surface in the first place. When the pipe remains dry, corrosion conditions are significantly reduced.

Dragon Jacket insulation also allows sections to be removed for inspection and reinstalled afterward, enabling maintenance teams to verify pipe condition without destroying the insulation system.

 

Dimensional Stability Under Thermal Stress

Chemical plant operations often involve wide temperature ranges and frequent thermal cycling.

Dragon Jacket insulation uses a closed-cell insulation core designed to maintain stable thermal performance across a wide operating range. The material provides approximately R-6.25 per inch of insulation thickness and supports operating temperatures from −60°F to +350°F.

Maintaining consistent insulation performance helps stabilize pipe temperatures, which supports:

  • Reliable process control
  • Reduced heat loss or heat gain
  • Stable fluid viscosity for temperature-sensitive chemicals

In processes involving high-viscosity fluids, maintaining pipe temperature is particularly important to ensure that materials remain pumpable throughout the piping system.

 

Built for Maintenance-Intensive Facilities

Routine inspection and maintenance are unavoidable in chemical processing facilities. Traditional insulation systems are often damaged during maintenance activities, requiring insulation to be removed and replaced after work is completed.

Dragon Jacket insulation components are designed to be removed and reinstalled repeatedly without damaging the insulation system. When access is required for valves, strainers, pumps, or couplings, maintenance teams can:

  • Remove the securing bands or fasteners
  • Lift off the insulation section
  • Perform the required maintenance
  • Reinstall the same insulation component

This reduces material waste, lowers maintenance costs, and shortens downtime during inspections or repairs.

 

Faster Installation, Fewer Variables

Dragon Jacket insulation systems are manufactured from 3D scans or engineering drawings that match the exact geometry of pipes and equipment. Because the components arrive prefabricated, installation is straightforward:

  • Position the clamshell insulation over the pipe or fitting
  • Secure the section using steel bands or approved fasteners

The system does not require field-applied coatings, cladding fabrication, or specialized insulation tools. Installation can typically be performed by standard maintenance crews using basic equipment.

Prefabricated insulation also reduces installation variability and jobsite waste compared to traditional insulation systems that require cutting and fitting materials on site.

 

DJI: Delivering Long-Term Value in High-Risk Environments

Chemical processing plants require insulation systems that can withstand environmental exposure, mechanical stress, and repeated maintenance activity. Durable insulation systems can deliver long-term operational value through:

  • Extended service life in harsh industrial environments
  • Reduced risk of corrosion under insulation
  • Lower insulation maintenance and replacement costs
  • Stable thermal performance over decades
  • Improved process reliability for temperature-sensitive fluids

Dragon Jacket insulation supports these goals by combining moisture protection, mechanical durability, and consistent thermal performance in a single encapsulated system.

When corrosion, insulation failures, or process temperature instability affect reliability at a chemical processing facility, it may be time to evaluate alternatives to traditional insulation systems. Dragon Jacket insulation provides a corrosion-resistant, moisture-protected solution designed for demanding industrial environments.

Contact Dragon Jacket Insulation today to discuss your application, request engineering specifications, or evaluate insulation solutions designed to support long-term reliability in chemical processing operations.

March 11, 2026