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Between a Rock and a Rusty Place


By Warren Brand

My eldest daughter, Jessica, 21, excitedly called me a few months ago to tell me about a new hobby she’s taken up: bouldering. If you’re anything like me, you’ve just had the response, “Huh? Is that a thing?”

She explained that you take a mattress—or a bouldering pad, if you’re a more sophisticated “boulderer”; lay it (you guessed it) under a boulder; and then, well, climb around on the boulder.

Crack climbing
Warren Brand

In the sport of bouldering, my daughter has solved how to climb this rock by “crack” climbing it—that is, inserting her fist to secure and climb.

When Jessica came home for winter break, she promptly took me to our health club, which had a climbing wall, and we began to boulder.

There were, in fact, areas on the climbing wall demarked as bouldering routes. 

To my surprise, it was a thing—a big thing. When I searched Google, it came up with more than 5,000,000 million hits—all in under 0.063 seconds, by the way.

It is typically used to increase strength, agility and intellect for climbing. It’s also really cool to watch, and I encourage you to search Google for some videos.

Finding a Solution

Bouldering at first seems really easy. Then, once you understand it and the “problems” associated with bouldering, it quickly becomes impossibly difficult.   

Just this past week I had the opportunity to take my family to Estes Park, CO, the doorstep to Rocky Mountain National Park. One day, we combined a bouldering hike to Dream Lake, 2.2 miles into the Rockies at an elevation of 9,910 feet (but who’s counting).

In the photo below, I am spotting Jess she begins to plot a “solution” for a highly technical bouldering problem, bouldering pads below. In this case, she will be inserting her fists into a crack to begin “crack” climbing, as shown in the photo above.

Spotting a boulderer
Warren Brand

Here, I spot Jess as she begins to plot a “solution” for this climb's problem; in this case, she’s inserting her fists into a crack to begin her climb.

‘There Is Technique to Everything’

By now you may be wondering, “OK, where’s he going with this? How’s he going to bring this around to something rusty?”

Well, as I was watching and spotting Jess, I was re-reminded of a phrase I use often: There is technique to everything. This is true even with something as seemingly simple as climbing a rock.

And then, naturally, as anyone in the pristine Rocky Mountains spotting his bouldering daughter would, I thought of corrosion under insulation (CUI). 

The Origins of CUI

CUI is a relatively new phenomenon borne of the oil crises of the 1970s when the price of oil soared.

Companies were grasping at ways to save money and realized they were wasting billions of dollars a year in wasted heating and cooling costs, primarily on piping—so they started insulating. 

However, the instant owners started insulating their pipes, corrosion rates skyrocketed. 

CUI course photo
Peter Bock

Pipes that otherwise would have exhibited little to no external corrosion for decades were now corroding to perforation in less than a year, primarily due to wet insulation but for other reasons as well. 

CUI Challenges

CUI is perhaps the most complex and confusing corrosion mechanism we, as coating professionals, face.

While it may look simple (like a boulder), once you start to understand the problem (as in bouldering), the solution becomes exponentially complex.

I could, quite literally, write a small book on the topic, but some of the challenges include:

  1. Temperature ranges from subzero to greater than 700 degrees Fahrenheit;
  2. Temperature cycling;
  3. Freeze/thaw conditions;
  4. Damp insulation and cycling insulation;
  5. Inability to visually inspect;
  6. Complexity in coating pipes, flanges, fittings, supports, etc.; and
  7. Perhaps the most challenging: a simple lack of data.

Identifying Variables

Duplicating the environments that lead to CUI in a lab setting, and attempting to gather accelerated testing data, is like trying to grab smoke because of the complexity of the variables involved. 

For example, one insidious variable, which is almost impossible to capture in a lab, is the type of insulation and the environment at a typical petrochemical facility. 

Absorbent insulation (which ideally should not be used) acts exactly like a sponge. And, like a sponge, it will absorb not only rainwater and humidity but also whatever chemicals and contaminants are in the surrounding atmosphere. 

For example, let’s say we have a pipe that cycles between ambient and 250 degrees Fahrenheit. (By the way, if the pipe stayed at 250 degrees Fahrenheit, corrosion would not be an issue because no liquid moisture could stay in contact with the pipe).

CUI course photo
Peter Bock

As the insulation absorbs salts from the air and dries out, the salt concentration on the pipe wall will increase over time, increasing the rate of corrosion on any exposed steel.

Plotting a Solution

Last year I was hired by a large petrochemical company to research a specific type of corrosion protection mechanism for CUI and was stunned at the lack of published and available data. 

There are a variety of organic, inorganic and metallic (in the form of thermal sprayed aluminum and other alloys) coatings that are able to provide barrier protection to the steel, but the insulation, in terms of type and design, is also of great concern.

Then there are other technologies, such as standoff insulation. 

But the work can be not unlike Jess’s approach to climbing a boulder—first, you must plot a “solution” for a highly technical problem in its unique environment.

During my research, however, I was fortunate enough to speak with some of the legends in the fight against CUI, and there is, just now, beginning to be consensus on how to solve this complex problem.

As followers of this blog know, I’m a fanatical devotee of education, which is why I started Engineered Corrosion Solutions, my ongoing technical conference on corrosion (2016 was our third year).

In our continuing fight against corrosion, I will be working with one of these legends, Peter Bock, in a three-day class on CUI sometime this fall.

Peter is a petrochemical coatings consultant and CUI expert with nearly 40 years of experience in our field. He is past president of the NACE New Orleans section, NACE CIP 3 certified and an all-around good egg.   

Our goal is to continue to shed light and clarity on the challenges surrounding all issues pertaining to corrosion.


Warren Brand

Warren Brand’s coatings career has ranged from entry-level field painting to the presidency of two successful companies. Over nearly three decades, he has project-managed thousands of coating installations and developed specs for thousands of paint and coating applications. NACE Level 3 and SSPC PCS certified, Brand, an MBA and martial-arts instructor, now heads Chicago Corrosion Group, a leading coatings consultancy. Contact Warren.



Tagged categories: Coating Materials; Consultants; NACE; Protective Coating Specialist (PCS); Protective coatings; Specification writing; SSPC; Asia Pacific; Corrosion control coatings; Corrosion protection; Corrosion Under Insulation (CUI); EMEA (Europe, Middle East and Africa); Latin America; North America; Quality Control

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