Subsea pipelines operate in one of the most unforgiving environments imaginable.
Constant exposure to saltwater, pressure, and shifting seabeds can wreak havoc on protective coatings, the first line of defense against corrosion and damage.
Ignoring the warning signs of coating failure can result in costly repairs, downtime, and environmental hazards. Each failure point opens the door to more serious damage, compounding over time.
For subsea pipeline engineers, the difference between catching an issue early and a catastrophic failure is often hidden in the subtle signs of coating degradation.
Here are the five telltale signs that your pipeline coatings may be deteriorating—and why addressing them immediately could save you from facing operational nightmares down the line.
1. Cracking or Blistering
Even the best pipeline coatings can start to show signs of wear over time, and one of the earliest—and most dangerous—signs is cracking or blistering.
At first glance, these small imperfections might seem harmless, but they signal a much larger issue brewing beneath the surface. Cracks expose the underlying pipeline to saltwater and other corrosive elements, allowing moisture to seep in and initiate corrosion.
Blistering, on the other hand, typically results from trapped moisture or gases underneath the coating. These bubbles of trapped pressure slowly degrade the bond between the coating and the pipeline, making the material more prone to peeling and eventually, full detachment. As the blisters grow, they weaken the coating's protective barrier, creating pathways for corrosion to spread across larger areas.
The dangerous part?
Cracking and blistering often start small and go unnoticed during regular maintenance checks, especially in hard-to-reach subsea locations. By the time the damage is visible, the coating’s protective ability has already been compromised. If left untreated, this can lead to accelerated metal loss, structural instability, and ultimately, costly repairs or even catastrophic failure. The sooner the issue is addressed, the better chance you have of preventing further damage to your pipeline.
2. Discoloration or Fading
Pipeline coatings are formulated to withstand harsh environments, but their visual appearance can tell a revealing story about their health. One of the subtler warning signs of coating failure is discoloration or fading.
While it might seem cosmetic at first, changes in color are often the first visual indication that the coating is breaking down. UV rays, chemicals, and constant exposure to seawater slowly degrade the pigments and integrity of the coating, weakening its protective properties.
When coatings begin to fade or lose their color, it signals that the material’s resistance to corrosion and abrasion is diminishing. Discoloration can also indicate chemical reactions occurring between the coating and the environment, reducing the material’s ability to shield the pipeline from the aggressive elements in the subsea world. In extreme cases, discoloration can be the precursor to more severe issues like delamination or corrosion, which are harder and more expensive to fix once they set in.
This subtle change may seem like just a surface issue, but the real danger lies in what's happening beneath. A faded coating is essentially losing its ability to protect, and the pipeline beneath it could be at risk of developing corrosion or other damage that isn't visible until it's too late. If you notice patches of discoloration, especially in areas exposed to high UV or chemical exposure, it’s a sign that the coating may have reached the end of its effective life.
Regular visual inspections are key in catching these early warning signs. Addressing discoloration early by refreshing or reapplying coatings can significantly extend the life of your pipeline, preventing the need for more extensive repairs or replacements down the road.
3. Peeling or Flaking
Few things are more alarming for a subsea pipeline engineer than seeing the coating of a pipeline begin to peel or flake.
This is a clear and unmistakable sign that your pipeline's protective layer has failed. When coatings begin to detach from the pipeline surface, the underlying metal is exposed to seawater, oxygen, and other corrosive elements that can cause rapid degradation. Peeling coatings mean that the adhesive bond between the coating and the pipeline has been compromised, either due to environmental stress, poor application, or simply the natural aging of the material.
Peeling is often triggered by improper surface preparation before the coating was applied, leading to poor adhesion. Over time, as the subsea environment batters the coating with pressure changes, water currents, and temperature shifts, the weak spots begin to give way, and the coating lifts off in layers. Flaking is similarly dangerous, as small fragments of coating fall away, leaving pockets of exposed metal where corrosion can take hold.
These failures aren’t just aesthetic—once the coating begins to peel, it means your pipeline is actively unprotected in those areas. The longer the peeling or flaking is left untreated, the more damage accumulates. The resulting corrosion can weaken the pipeline’s structural integrity, leading to cracks, leaks, or even breaks that could have catastrophic environmental and financial consequences.
When peeling or flaking is observed, immediate action should be taken. This may involve spot repairs, recoating, or in severe cases, replacing entire sections of the pipeline’s coating. It's critical to treat peeling as an urgent problem, not just a surface-level annoyance, because the damage to your pipeline is often far more extensive than what is visible.
4. Visible Rust or Corrosion
Rust on a pipeline is the equivalent of a flashing red light—by the time you see it, significant damage has already occurred.
Visible rust or corrosion is a clear sign that the protective coating has failed completely in that area, allowing moisture, saltwater, and oxygen to penetrate and attack the metal beneath. This isn’t just a surface issue—corrosion works its way through the metal, weakening the structure, and if left unchecked, it can lead to serious failures such as cracks or pipeline leaks.
For subsea pipelines, the stakes are even higher. Corrosion spreads rapidly in marine environments, where saltwater accelerates the oxidation process. Once rust is visible, it’s likely that the underlying pipeline has already suffered a significant loss of metal thickness, reducing its ability to withstand pressure and carry loads safely. Even minor spots of rust can be the starting point for major corrosion pits that weaken the entire system.
Rust doesn’t happen overnight. It's the result of prolonged exposure to water and air, meaning the protective coating was compromised long before the rust became visible. When you detect rust, it’s a late-stage warning that immediate action is required. The affected areas should be cleaned, evaluated, and either patched with new coating or, in more severe cases, sections of the pipeline may need to be replaced.
Ignoring visible rust or treating it as a cosmetic issue can have disastrous consequences, especially in high-pressure subsea environments where pipeline failure could lead to environmental spills or even human safety risks. Preventative maintenance and regular inspections are key to spotting rust early before it spreads and causes more severe damage.
5. Increased Maintenance and Inspection Failures
A rising frequency of maintenance issues or failed inspections is one of the more subtle, yet critical, signs that your pipeline coatings are deteriorating.
For subsea pipeline engineers, staying ahead of coating failure means paying attention to these trends. While the coating might not show obvious external signs of wear, ongoing failures during inspections are often the first clue that something is wrong beneath the surface.
As coatings age and wear, they lose their ability to protect against corrosion, abrasions, and chemical damage. This degradation can manifest in a variety of ways, from minor leaks to more frequent pipeline integrity concerns.
If your pipeline begins to require more patch-ups, repairs, or recoating than in the past, this uptick in maintenance activity is likely due to coating breakdown. It's often a slow process, creeping up as coatings thin out, lose adhesion, or develop micro-cracks that can’t be seen with the naked eye.
Inspection failures are particularly telling.
Modern non-destructive testing methods, such as ultrasonic or radiographic inspections, can detect early signs of coating wear and under-film corrosion that are invisible during visual inspections. These warning signals, when ignored, lead to more extensive damage over time, requiring costly overhauls and risking unplanned downtime. Consistently failing these inspections is a sure sign that your pipeline’s coatings are no longer doing their job effectively.
Taking a proactive approach when maintenance and inspection reports flag repeated issues is crucial. This is the time to consider not just repairing the affected sections, but reevaluating the entire pipeline’s coating system. Waiting too long can result in system-wide failures that are far more expensive—and hazardous—to fix.
When it comes to subsea pipelines, coating failure isn’t just a minor inconvenience—it’s a potential disaster waiting to happen. The warning signs, from cracking and discoloration to peeling and rust, are all signals that your pipeline’s protective shield is breaking down. Ignoring these signs can lead to costly repairs, environmental hazards, and even pipeline failure.
But you don’t have to wait for these problems to escalate.
Mark Tool’s SplashTRON® and ThermoTRON® coatings are engineered to provide unparalleled protection in the harshest subsea environments. Designed to withstand the constant assault of saltwater, pressure, and shifting seabeds, these coatings ensure that your pipelines remain protected, minimizing the risk of corrosion and extending the life of your infrastructure.
By investing in high-performance coatings like SplashTRON® and ThermoTRON®, you’re protecting your operations, your budget, and the environment from the disastrous effects of coating failure. Don’t let minor issues become major crises. Contact Mark Tool to request a quote today.