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Understanding Insulation Chemistry Proven to Inhibit CUI

By David Shong | Published: October 2, 2015
Key Takeaways

Johns Manville Industrial expert David Shong addresses the options available for CUI prevention, explains the ASTM test methods used to evaluate an insulation’s CUI performance, and talks about the chemistry behind CUI.

Lou: Welcome again everyone. Good morning, good afternoon or good evening to all of you who have joined us worldwide for, what we believe will be an excellent presentation on the often debated topic of Corrosion Under Insulation. I’m Lou Frank, publisher of the Corrosion Media Network. That includes Corrosionpedia and... web-based platforms designed to help corrosion professionals globally.

Corrosionpedia is honored to host today’s presentation, featuring David Shong, a 22-year veteran in the construction realm with the focus on insulation. He will address various options and some of the latest technologies available for CUI prevention. As we all know, there are many approaches, professionals have taken to preventing corrosion under insulation, usually referred to as CUI. They’ve the gamut from hydrophobic insulations to active-corrosion inhibitors and more.

David is uniquely qualified this week on this topic. He’s been a purchaser of insulation materials while working for a major contractor. He’s been on the distribution side. And today, he’s part of the team of dedicated professionals, dedicated to the unique products manufactured by Johns Manville, specifically for CUI applications.

David, welcome!

David: Thanks, Lou. I’m delighted to be here. I’m really looking forward to delivering some more valuable information to our listeners today.

Lou: Excellent. Looks like we still have few people coming in. So, let me just run through just a quick thing about you, David.

David is the Senior Western Specification representative for Johns Manville Industrial Insulation Group. He has spent his entire career in construction materials, and early on, developed a passion for insulation. David’s role involves providing educational assistance to owners, EPC firms, consulting engineers, facility maintenance personnel and mechanical contractors regarding the benefits and design guidelines in specifying mid to high temperature industrial pipe and vessel insulation. He is primarily responsible for Western United States, Canada and Mexico that helps people all over the world with news related to industrial insulation applications.

David, we’re really excited to have you here today. We’re excited to have such a strong audiences as well. Looking over the list of attendees, we’ve got some amazing professionals onboard with us.

Those of you in the audience, I’m sure some of you have come with questions already in hand. After all, CUI is a fairly debated topic. And if you have questions that may arise during the presentation, at any time, please use that dialogue box on the right side of your screen to post those questions. We encourage them. I promise that we’ll get to them immediately following David’s presentation.

David, you’ve been immersed in the insulation industry for over a couple of decades. During our preparation for today’s webinar, you told me a story about getting a call from an engineer in Canada, who is frantically seeking a solution to insulate several high-temperature vessels. In particular I think his emphasis was on CUI prevention, if I remember. While we’re waiting for the rest of the audience to join in, how about relating that story for us?

David: Sure, Lou. Thanks for the chance. I received a call recently from an engineer in Canada that was working on some insulation specifications for some pretty high-temperature vessel. They’re around 1100 °F. He’s considering another thin blanket insulation that he was looking at. And unfortunately, due to the high temperature, they were looking at about nine layers of material, and was really concerned about the over-all cost of that. He asked me if we had any solutions.

And after our short conversation, I was able to recommend a combination of materials. He was a little perplexed for that. He said that everyone he had spoken to up to this point had come to their one and only product offering as a recommendation for his project. And he asked why I would recommend a hybrid?

Well, we firmly believe that there is no such thing as one material that’s good for every project and application. That’s exactly why Johns Manville manufactures a lot of different types of materials. We have the ability to recommend hybrid solutions a lot of the time because you’ll find that they provide the best performance and also the lowest install cost.

Lou: Hey, that’s a neat story. I appreciate it. Thank you, David.

Well, I think we’ve been around here long enough for any of the late arrivals. I see few people I know on this list and welcome all of you.

Let’s move on, though, with the presentation. We’re here today not so much to talk about you, David, but more about the challenges and available technologies to combat CUI.

One thing before we get started. Today’s presentation is sponsored by Johns Manville. For more than 150 years, Johns Manville has focused on developing materials to make diverse environments stronger, more durable, more energy efficient and comfortable. JM manufactures premium quality building and mechanical insulations, along with other construction materials. And its industrial insulation group is focused on providing many different types of ambient to high temperature pipe and vessel insulations commonly used in oil and gas, power generation and chemical processing facilities to improve both process control and worker safety.

Thanks to Johns Manville for making this presentation possible.

Now, if I may, to the audience, one last reminder about questions. Please post them either now or as they arise during the presentation using that dialogue box in the lower right side of your screen. We welcome those questions. Bring them on.

Alright, David. It’s all yours.

David: Thanks, Lou. I appreciate the opportunity to be here to speak today regarding integral chemistry proven to inhibit corrosion under insulation. Just a quick note, as Lou mentioned, our company has been in business since 1858. And in 2001 was purchased by Berkshire Hathaway.

As you can see, Warren Buffet is our CEO. Er, excuse me, Chairman and CEO of Berkshire Hathaway. And on the picture on the right, you see Mary Rhinehart, who is also our President-CEO and Chairman of Johns Manville. She’s been with the company for 36 years. Started in position in finance as an Auditor and worked her way all the way up to our present CEO. We’re very proud of Mary and her accomplishments in running a very, very large company in really a male-dominated field for most construction products.

Johns Manville Industrial Insulation Group works primarily on the mid-to-high temperature process, ranges. We’ve worked with folks that work in oil refineries, SAGD Extraction like in Canada. We also work with a lot of downstream process or in petrochemical plants and power generation. Anything that utilizes a mid-to-high temperature piping or vessel, we’ll have an opportunity to work with at some point.

Let’s quickly cover the reasons that folks look to insulate their high temperature pipes and processes. The most important thing that most engineers have portrayed to me is the concept of personnel protection. Using insulation to reduce the outside surface temperature, pipes or processes, down to a level wherein if a worker accidentally touches the pipe without a gloved hand, that they won’t sustain any serious contact burn. OSHA and a lot of other organizations have established that temperature at around 140 °F or 60 °C.

Another important reason is for a process control or e-conservation. We really want to make sure that the temperatures do not fluctuate too much as the fluids and material run through different parts of the plant. Also in Canada, and the colder climates, we see freeze protection as something that we are definitely concerned with, along with fire protection.

The main reason that we’re here to talk today is specifically regarding corrosion protection, properly designed as mechanical insulation systems can really improve the CUI potential in order to if we look at it as a system.

In addition to the natural resources, environmental and so forth, that can also be achieved using insulation, one of the most important financial aspects of using insulation is that it really pays for itself. As Lou mentioned, I’ve been focused on insulation my entire career. I really enjoy working with the material because it has the ability to pay itself back. You should really expect that every penny that you invest in insulation should be paid back in a very short amount of time.

In fact, most papers and technical.... realize that a good benchmark for return on investment for mechanical insulation is between 12 and 18 months. So every dollar can be recuperated. And then, as long as that particular system remains its way that you provide additional return on investment throughout the life of a system.

Now, as I mentioned before, Johns Manville manufactures a lot of different types of materials. We firmly believe that there is not one single solution for every application. So while all of our competitors really focus on manufacturing one product, we like to be able to help our customers by offering more than one choice. We manufacture calcium silicate, expanded perlite, mineral wool also known as stone wool. We also produce fiberglass and fire-proofing board along with our newest product which is a hydrophobic thin blanket. This material was designed specifically to meet or exceed all of the single property of silica aerogel, which is another product that we do not manufacture at this time.

We also have adhesives, cements and coatings that go along with different types of insulation in order to provide a more predictable and quick install.

So, let’s dive right into Insulated System Design and really recognize that the key – first line defense to prevent CUI is looking at system as a properly detailed and designed weatherproofed system.

Here, we have a picture of design of a pipe that you can take a look at and we’ll see some animations here. Now, not withstanding all of the work that has been done by coating manufacturers to prevent CUI, since the 1970s where CUI really became... issue. Coating manufacturers have been working very hard to address this issue. Now, we are not experts in the coating industry, although there are many in the industry that are valuable resources. We would just like to quickly point out a piece from NACE SP0198 which is regarding the use of Zinc based coatings. It said ‘Do not use Zinc-based coatings above 140 °F because the Zinc may undergo a galvanic reversal and become cathodic to carbon steel.’

I’ve actually seen this personally in a plant in State of Washington where I live. They used several parts that were actually hot and galvanized on a heat exchanger. And because of that, the Zinc coating were able to cause some pretty serious... corrosion on the heat-exchanger. So, typically, when we’re looking at temperatures above 140 °F, we look at other types of coatings. Immersion grade epoxy coatings or thermal sprayed aluminums are very commonly specified to provide additional layer of corrosion protection.

So, let’s take a look now to see how the pipe is insulated. So typically, it’s coated. And then we will have clamshell preformed insulation that’s installed on to the pipe. Now, this insulation is designed to sit around the sides of the pipes that’s in question along with its thickness that’s required. Generally attached with either fiberglass strapping tape or it can be used to be installed with stainless-steel wires. Those wires are generally 3 or 4 stainless steel wrapped around by the contractor during installation.

After the insulation is on the pipe, a jacketing will be installed. That’s generally either aluminum or stainless steel. We say about 90% of the market being aluminum, and then stainless steel being used when... fire protection condition.

One thing that we want to have folks to understand is that, in order to create a predictable weatherproof barrier that sheds water, it’s important that the joints be sealed. The circumferential joints are also the ones the tubal joints. We highly recommend the use of temperature-appropriate flexible sealant that can be used in-between the joint. As you can see here, this diagram, where we want to show people that having a properly sealed system is really the key to keeping water out. And because we know water is the key indicator for CUI, we want to do everything we can to ensure that water does not infiltrate the system.

However, with the best of intention, with the best specifications, we all know that people make mistakes, that sealants can fail over time – that they can get hard, they can crack. The jacketing can be damaged. There will be at some point in your system a place where water can get into your system. So we really want to take the time to introduce a system that will provide a backup plan – one of a belt-and-suspenders approach, focusing that the jacketing should be primary weather-barrier. But if water gets in, what’s going to happen to the insulation?

This is a cross-section diagram of an insulated pipe showing the pipe with insulation and jacketing. Now, this particular picture I took from Seattle because that’s where I live, it rains all the time.

Let’s look what happens when it rains. When water falls on to the jacketing, it’s supposed to shed. That’s the way it works. It works very, very well. And primarily, we see failures in the jacketing due to either penetrations or failed sealant, or maybe some poor workmanship. Should they be working too quickly? Who knows?

We want to say that it’s not really a question of if the water will get in to your system, but when. Once water gets in to the system, that’s really the key that turns on the engine of what we call XOX. It’s a corrosion inhibiting package that we’ve introduced into two of our insulation materials.

Now, one of things that has been promoted very widely throughout the US and throughout most of the world is the concept of using hydrophobic insulations to address the issue of CUI. A lot of folks have been talking recently about that. And there are, in fact, a number of insulations that are treated with a hydrophobic agent.

The first thing to know in regards to this is that there’s really no such thing as an insulation that’s inherently hydrophobic. Every single insulation will absorb water, and the only reason that finished insulations do not is because of a silicon emulsion that’s added to the insulation product. So for instance, on the top, we’ll see expanded perlite that has the silicon emulsion. We also have our thin blanket material on the top right that also has the same additive. Mineral wool is actually, in fact, treated with the same silicon. And silica aerogel, which we do not manufacture at this time, will shed bulk water.

So, it’s kind of – think of it like your car. When you put wax on your car, that’s when it... So it’s not inherently that the car will shed water but, it works when it’s properly waxed and sealed. It’s the same kind of analogy that we’re looking at here. Unfortunately, because this silicon based emulsions are in fact organic, they will burn off starting at around 450 °F.

Many industrial process temperatures are above that. In fact, all of the insulations shown here are in fact rated to 1200 °F. So, it’s really in the bottom 3rd of their operating range where you can see that they’re hydrophobic. Above that temperature range, there’s really no such thing as a hydrophobic insulation.

In addition, all – nearly all insulations except for one, which is called cellular glass, that has a perfectly zero vapor... rating, where the rest of insulations that are used in hot surface are going to be vapor permeable. Which means, in humid conditions, it is possible for humidity and vapor in the air to pass through the insulation. And depending on operating temperatures and conditions, it will condense in the insulation and cause moisture to be trapped inside of the insulation. So, even hydrophobic insulations will still absorb water in humid conditions.

Now, a lot of folks have asked as well, ‘We know that calcium silicate is not hydrophobic. It does not have a hydrophobic agent. It absorbs water fairly readily.’ The fact is that, we could take that same hydrophobic agent that we used to put on mineral wool (expanded perlite). We could also put it on calcium silicate, and this is what happens. There’s a video that shows an untreated piece of calcium that’s absorbing water, and here’s a piece that’s showing a treated piece. Notice how it sheds the water. So, it’s really not that complex. We can really add hydrophobic treatment to most anything.

The question is would it be worth it? In the case of calcium silicate, it would nearly double the cost. So, we would like to ask the market in general, would that be worth it, and do you think you’d be willing to pay for it? The short answer is that we do not think it’s worth it, and we’ll show you why the corrosion aspect of it can be addressed even without a hydrophobic agent.

Lou: David, wow. Thanks for powering through the first half here. Your presentation is excellent. We already have a few questions post which is kind of fun. That means we’ve got an engaged audience. And we’ll address those questions at the end of the presentation. For all the rest of you, please keep those coming in.

And just as a reminder, today’s presentation is sponsored by Johns Manville, manufacturers of premium quality building and mechanical insulations along with other construction materials, to make diverse environment stronger, more durable, more energy efficient and safer.

David, would you say you’re ready to get into the heart of the presentation?

David: I’m ready, Lou. Let’s do this. Let’s talk about corrosion under insulation.

Lou: You got it.

David: Well, CUI is really the heart of the conversation. We’re going to focus the last portion directly on the conditions that are required for CUI, and how our corrosion inhibiting package works.

So, in order to have the conditions that are necessary to promote corrosion under insulation, these are from documents from NACE and also from API. You’ll see temperatures in the range of between 100-350 °F from mild steel. In stainless steel, it can be as low as 25 °F. We also have to have oxygen, liquid water and corrosive chemical compounds. Those compounds could come from the insulation itself or from the surrounding environment. But fortunately, in industrial plants, we know that there’s no corrosive compounds, right? I’m just joking. That’s a big joke.

We also know that the water that’s in the insulation has to have a pH of less than 7. Meaning, that has to be acidic. So, what can we do about those different conditions? Well, we really can’t do anything about the operating conditions because they’re fundamental to the process, whether be cyclical, be done during shutdowns, or just in the process of normal operation.

There’s always oxygen in the atmosphere, we can’t do anything about that. We can really do our best to keep liquid water out, but we’ve kind of established that it’s going to get in at some point, somehow. What we can do is address the issue of corrosive compounds and we can also address the pH. Let’s talk about how that happens.

So, if you’ll look at all of the different types of insulation that are available on the market, all of them fall into the corrosion bandwidth in terms of temperature ratings. So from that 100-350 °F, which is represented by the two vertical blue lines, you’ll see that every single type of insulation is used within that surface temperature range.

The top 5, as I mentioned before, Johns Manville manufactures; and the bottom ones, we do not currently manufacture. And so, each insulation that will be used has to be used and considered in terms of how it affects corrosion.

In order to prevent corrosion, we really have to understand how it occurs. It’s really quite simple, and I will not get too nerdy about it, although I’d like to and would be happy to do so with any folks afterwards that would like to contact me.

In regards to corrosion, it’s really something that can be analogized to a battery. Without a connection, there’s no cathodic flow. So, on the right side, you’ll see a picture that shows a cathode and anode on a piece of a metal pipe. In order for corrosion to occur, acidic electrolytes, which are contained in the water, must contact the surface of the pipe. What happens is those acidic electrolytes basically create a closed electrical circuit. As the connection is made, what happens is that you’ll lose some electrons, from the iron. You have some protons move up into the water and will bond with – to create hydroxyl ion, which then bond with the positively charged iron. It creates what’s called hydrous iron oxide, also known as rust.

So, remember back to high school when we talked about the law of conservation of mass, we’re not actually losing any material, it’s just changing from one form to another. So, when you see that... that’s the corrosion loss, and then the product or the rust on top is the result of a chemical change that occurs.

So what we want to do is look at some ASTM Corrosion test methods. It’s remarkable to know that in terms of thermal insulations and corrosion, the first corrosion test method was developed in 1971. There was another one that was developed in 1977, and this method, which is ASTM C1617, was not developed all the way until 2005. So even though this is 10 years old, it’s still considered the newest ASTM corroding method. But remarkably, a lot of people that are in the industry still do not know about this system. So what it does is involves lining up insulation and creating extraction solutions, and then pumping them on to coupons that are heated to 100 °C. And what we’re doing is basically testing the chemical formulations on each insulation as compared to some various control solutions.

Now, this test method has been incorporated into several different insulation product standards. For instance, ASTM CU1728 which is the standard specification for silica aerogel blanket. They’re referenced into the test method of C1617. What we have to do is look a little bit deeper and determine what the rate is of the corrosion that’s acceptable in order for it to “pass the test”. So, as we read here specifically, ‘It shall not exceed the rate of a 5-ppm chloride solution’.

So there are three different control solutions in this test method. One of them is the ionized water. The other is 1-ppm chloride solution. And the last one is the 5-ppm chloride solution.

So we see here that the aerogel... mineral wool, and a few others, must pass below the rate of 5-ppm. What’s significant is that if you look at the standard specification for calcium silicate, the passing rate is much more aggressive. In order to pass calcium silicate, the Mass Loss Corrosion Rate must be less than the DI water control solution. Meaning that if you look at 2 data sheets, both of them say passed regarding C1617. They will not perform the same in terms of the bar that’s set in order to pass.

So why is that the case? If certain insulations that are being promoted as hydrophobic, and therefore, by association can create less corrosion, why is it that a hydroscopic insulation that does absorb water can create lower corrosion rates than other types of materials?

So, we would like to share with you, by way of information, a comparative test data. This was procured from a 3rd party laboratory called Tisco. They’re in Grand Junction, Colorado. This was done in 2014. What we did was we paid a lot of money to have this test run on lots and lots of different types of insulation. A lot of them we make, and some of them we got. We wanted to be able to create a comparative data that would show the chemical composition how each insulation will affect the aqueous corrosion of metals.

As you can see, the top line, the top blue vertical line, is the average corrosion rate – or what we call Mass Loss Corrosion Rate – of the 1-ppm chloride control solution. Now to be fair, mineral wool and silica aerogel – again, we saw that they have to pass below the 5-ppm, which would be much, much higher on the chart if it was even showing. So we’re not saying that they don’t pass their own product specific standard. But if you compare them side by side, you will find that the XOX treated insulations, including expanded perlite and Calcium silicate, do provide corrosion rates that are consistently less than the ionized water.

What’s significant to me is, in the middle of this chart, you’ll see Pre-2002 CalSil, versus on the right hand side which is the XOX treated version of CalSil. We fully recognized that prior to 2002, that the calcium silicate cause more corrosion than it does today. This data is very significant. So, if you’ve had previous experience in the past where calcium silicate caused corrosion, since 2002 – so, 13 full years of data now – shows that the XOX treated materials caused less corrosion to deionized water.

So, what are the corrosion inhibitor? It’s really any chemical compound that decreases the rate of corrosion on any surface of metal. One of the most common mechanisms that we use for inhibiting corrosion is this idea of performing a coating or what we call Passivation Layer. This prevents that electrical surface contact that I mentioned before.

So, here’s how XOX works. And again, XOX is kind of a fancy name for our corrosion inhibiting package that is integral to our calcium silicate and our expanded perlite. It works on two levels. First of all, by creating a physical coating on the pipe; and it also works by creating a pH buffering effect.

I’d like to show you a quick illustration of how it actually works in terms of providing protection. So when the water enters the insulation and is absorbed in to the insulation, what will happen is, the water will dissolve various silicate anions that are contained within the insulation itself. Through the process of osmosis, the water dissolves the silicate – and in this case, we’re demonstrating sodium silicate that migrates out of the insulation and settles on the surface of the pipe. With time and with heat, the sodium silicate will bond with any of the free-roaming iron ions, and it will form an iron silicate gel, which is an inorganic coating that’s not affected by heat.

So really, the key to activating the XOX reaction is water. If you get water into the insulation, that’s when it starts working. If the insulation is dry, it’s not required. So, it remains dormant in the dry state. And then if any water were to get in to the insulation temporarily, that’s really what activates the silicate reaction.

Now this effectively blocks any of silica electrolytes from contacting the surface of the pipe. Remember, that was the key to creating corrosion, is that electrolyte contacting the surface. So just like using a CUI coating, this provides a secondary passivation layer that can work as a belt-and-suspenders approach should there be either failure in the coating – whether it be a... or maybe the operating temperature burned it off. So, this is really a back-up plan.

What’s also important is the pH buffering effect of XOX-treated insulations. As I mentioned before, in order to create corrosion, you have to have a pH – that water has to have a pH of less than 7 to be an acidic component. Now, various other silicate cations that are contained and integral to those XOX treated materials really have the ability to buffer the pH and allow it to consistently maintain the pH of any absorbed water at around 10. So it’s more basic solution and it fundamentally prevents silica electrolytes from existing.

Now, just to make a quick analogy of how it works. Just think about baking soda and vinegar. Baking soda is highly basic, and vinegar is somewhat acidic. When you mix the two together, they neutralize each other by stripping off the hydrogen atoms from the acid. So, this is exactly what’s happening when we talk about neutralizing or buffering the pH.

Now, it’s important to know how this works. It’s really fundamental to the insulation. This is not a magic dust that we add to it. It’s in fact 95% of the raw material inputs that we put into calcium silicate and expanded perlite. They contribute to 1 of 5 of the different silicate corrosion-inhibiting ions. And those silicates are aluminum silicate, magnesium silicate, potassium silicate, calcium silicate, and sodium silicate. Each one of those will do something in terms of creating either that protective coating or buffering the pH of any acidic component that get into the water.

Now it’s important to remember that this is not something that will be in the insulation in the beginning. And then if it gets wet, it will dissolve out and then will become ineffectual. Because these materials are integral and compromised such a large percentage of the raw materials, this really is fundamental to the product. It’s not going to dissolve out. It’s going to last much longer than the typical service life of these types of insulations.

These materials have been on the market for over 40 years. We have a lot of solid data that says because they are so highly durable and effective at doing their job in industrial facility, we see a lot of these materials that’s been on pipes and vessels for over 25 years. So we know that it will continue to work throughout and will be on the life of a typical service.

Again, the first line of defense of CUI is a well-maintained weather protection layer that’s properly sealed and maintained. But, if there is some ingress of water, the very mode of failure, which is that water ingress, that’s what triggers the active CUI... So it’s really a great system, in my opinion, because it’s there when you need it, and it’s there when you don’t need it.

I would like to provide one more additional data point regarding the efficacy of the integral inhibitors. As I mentioned before, back in 1970s, there was a test method that was developed called the ASTM C692. This was regarding thermal insulation and stainless steel. So what we’ve done is, to show a little bit more aggression, we want to modify this test method somewhat in terms of a couple of pieces, and here they are.

Instead of using stainless steel coupons, we’re doing mild-steel coupons, which is very, very common in industrial market. We also dripped more corrosive solutions onto the insulation instead of deionized water. I just had never seen any deionized water dripping from the sky at an industrial plant. So we wanted it to be a little bit more real world. We also preheated the insulation samples to burn off that hydrophobic treatment that I talked about. So the traditional test allows the hydrophobe to be intact because it doesn’t have to be preheated. But we know that high temperature industrial processes will burn that off very quickly. We also reduced the time down because it’s a more aggressive condition.

So, if you’ll look closely here at your screen, this is important data. What we’ve done is take a 300-ppm chloride solution. That, by the way, is less than 1% of the salt content in the ocean. And it’s a good representation of about 5-10 really good soaking rainstorms, about a 100 miles from a body of saltwater. So a lot of industrial plants fall within that area. Again, we also preheated these samples to 450 degrees to burn off that hydrophobe. We wanted to show what happens when all... absorbs water.

Here are the actual results that you can see for yourself of the corrosion coupon that were tested with this more aggressive method. As you can see, on the right hand side, 3 of those insulations are treated with a hydrophobe. And on the left, the calcium silicate is not. So, as we can see, the corrosion that occurs is really outside of this idea hydrophobicity.

Now, please don’t think for a second that we’re saying that these insulations caused this corrosion. Clearly, the 300-ppm chloride solution caused the corrosion. But what we are saying is that the XOX-treated calcium silicate outperformed all of the other insulations because, and strictly because, it’s able to neutralize all of the acidic chloride solutions that were dripped into it. So this could be hydrochloric acid. This could be sulfuric acid – any of the acids that you might see in the industrial plant that might drip on to the pipe jacketing and then kind of get dissolved during rainstorms or wash downs. And this really shows the ability for passivation to continue to work well after the insulation has lost its ability to shed bulk water. So I feel this data is highly significant and adds some additional credibility to XOX treated insulations.

Notice on the right hand side that there are other insulations that have some inhibitors. In fact, the silica aerogel has a... regarding their magnesium based inhibitor, and basically states that it’s highly durable. What that means is that it’s actually highly insoluble. So the idea is that if you’re going to use an active inhibitor that’s contained in the insulation, we really want something that has the ability to dissolve out of the insulation and migrate towards the metal. Otherwise, it’s really ineffectual. So we see here that the XOX treated insulations do perform very, very well in terms of preventing corrosion.

In conclusion, we would like to just remind everyone that a well-detailed, sealed and maintained jacketing is the first battle against CUI. We’d like to change the paradigm a little bit in terms of this idea that wetting and non-wetting insulations are really the key difference. We’ve seen a lot of specifications recently where they are not allowing any absorbent insulations and it has to be only hydrophobic. This is really an over simplification of the issue, increases cost and ignores the thermodynamic degradation of hydrophobic treatments that are added to the insulation.

Calcium silicate will absorb water at all temperatures. We are the first to admit that. And in the past, it was just historically associated with corrosion due to its chemical composition. However, in 2002, JM’s scientists and chemical engineers were able to discover and implement a package called XOX into all domestically produced calcium silicate and expanded perlite... Every single piece of insulation that has been produced in United States of those two formulas since 2002, has had this XOX package. It is integral. It is non-optional. And we also show that XOX treated materials exhibit the lowest ASTM tested corrosion rates of all industrial insulations.

In conclusion, here’s my contact information. I would love for you to contact me directly if you have any questions or would like to follow up or discuss any particular projects.

Thank you very much for your time. I appreciate your attentiveness and willingness to learn a little bit about our corrosion inhibiting package.

Lou: David, thank you. Wow, a very informative presentation. Thank you as well to the interested women and men in our audience for joining us today. We do have a few questions that have come in, and if you have other questions, please send them along.

Thank you as well to Johns Manville - manufactures of premium quality building and mechanical insulations to make diverse environments stronger, more durable, and more energy efficient and safer.

David, this... is great. I do see a couple of questions. Let’s take as many as we have time for.

Early on, Suzie asked a question about a hybrid solution. Her question is “Regarding a hybrid solution, are you, David, referring to those solutions as coming from the same manufacturer? And if not, do you think there could be compatibility issue?

David: In this particular case that I mentioned, both of the products that I’ve suggested in the hybrid were manufacture by our company. It was a thin blanket material to reduce the interface temperature, and then an outer-layer of mineral wool. Now, that could very well be because we’re not the only manufacturer of mineral wool, depending on the market and the pricing. Some or another manufacturer may in fact get to provide that material instead of us. There would still be no compatibility issue. We don’t really look at it as “Hey, we’re only going to help you if you can use our products. There’s oftentimes where I suggest other materials that we don’t produce because it’s the best solution. We’re not here to really sell only what we make. We want to provide solutions that are credible, so that maybe at some point, when you do consider other materials that we might be a good option for you.

Lou: Got you. Good answer. Suzie has a couple of follow up questions, but I want to kind of get back to one of the previous slides. It has different bars in it. And... has asked in that slide with comparative products. I think it’s two or three slides back, David. What are those different bars? What do they stand for?

David: Let me just get to that real quick. Here we go. And that’s a good question... I had the same question when I first saw it. Each one of the bar is a representative of a test lot. So each one of those bars will have five corrosion coupons of each one of the control solutions. So you’ll have the insulation on the left hand side where we have the various colored bars of mineral wool and all the insulations. This represents a lot of five coupons, and this is the second lot and this is the 3rd one. So they basically ran the same test on each one of the materials, three separate times to provide a standard deviation, and also just to get more data.

Lou: Good answer. We appreciate that. Tom just chimed in with a question, but let me get to one of Suzie’s follow up questions first. Regarding the operating temperatures on equipment, are you referring to operating temperatures more than 350 F, and are you suggesting that there is no CUI issue if it’s above 350 °F? And if yes – this is the most important part of this – what about an operating condition where the equipment is cyclic or in shutdown mode?

David: Absolutely. The corrosion range kind of has been established for that 100 or 350 °F from mild steel, and that’s really that 350 °F is kind of the upper limit where liquid water can exist before it vaporizes into its gaseous state. We are definitely not saying that only equipment that operates in-between that temperature range is subject to CUI. Every piece of equipment on an industrial facility, in my opinion, is subject to CUI because of the high temperature ranges that often are cyclical that will drop down into the CUI range. Snd then also during maintenance and outages, you will see those equipment brought down out of service, and can see significant amounts of time where they’re in that CUI danger range. So, definitely, we want to help people understand that bandwidth is really – if I don’t have something operating in that operating condition, then, I don’t have to worry. That is absolutely not the case. CUI can occur at any operating temperature range because of those cyclical and outage condition.

Lou: Great. One other question here, and I’ll get over to Tom’s question. Does the XOX corrosion inhibitor have to be maintained at a particular thickness? And how would someone who has specified and put this product in place know when it’s time to add additional product to maintain that optimum thickness to repel water?

David: Okay. So the XOX is effectual at all thicknesses. So the calcium silicate and expanded perlite, the minimum thickness is 1 inch. And then, it’s really just depending on the operating conditions in terms of what type of process efficiency and safe-to-touch temperatures we’re looking for, which can determine the thickness that is required for a given application. And we’re very happy to help you with those thermal calculations and determining the right thicknesses for each project.

Lou: So, can I just say it’s project by project basis?

David: Yeah. The thickness really has nothing to do with XOX’s ability to perform.

Lou: Gotcha. So Tom has asked, “What are the best ways to monitor, and what are . . .” Sorry, I’m trying to interpret this here. What is the best way to monitor after the insulation has been installed? In other words, what’s the best way to monitor whether you’ve got a CUI issue after all these insulation product has been installed?

David: Yes, Tom, that’s a great question, and very salient for the industry as a whole. There are a lot different ways to create an effective CUI management program. There are companies that provide infrared ultrasonic scanning that can rundown an insulated pipe in kind of a non-destructive format, but it’s fairly localized to the areas that it scans. Obviously, there’s a cost involved with that. People can also drill inspection ports on the bottom of elbows or penetrations where you might see water ingress and kind of do CUI inspections there, and then install a properly sealed inspection plug back into the jacketing, the insulation.

For the most effective way, in my opinion, is to just have a systematic CUI inspection program, where in areas where you know that you’re in that danger zone, that you routinely do a risk-based analysis and tear off a certain percentage of the insulation in that section where you think that you might have a problem. Just inspect the base metal. And if needed, remove any corrosions through blasting and recoating, and then just go ahead and re-clad that.

So there’s really a multi-prong approach to managing CUI. I’m just very grateful that the industry is really taking a pro-active approach to this because it is a very, very important safety issue.

Lou: Good answer, David. We have several more that had popped in, and I’m going to ask them, and let’s see if we can help quickly, we can... through this, because we need to respect everyone’s time here.

Mike asks whether it is JM’s, your company’s, opinion that no coatings should be used in conjunction with your product?

David: Great question. We are too conservative to say that outright. But the use of expanded perlite has been for over 40 years, and we’ve seen a lot of great documentation from other authors that say corrosion inhibiting was possible using expanded perlite prior to the advent of insulation coatings.

Lou: Got you.

David: So we’re too conservative to say that...

Lou: Good enough.

David: Omar asks, how could your product help on chiller pipes where moisture condensation due to humidity is causing corrosion?

Lou: Great question. Our particular – we... have expertise is on higher temperature or mid-to-high temperature insulations. So we don’t really work in that temperature range at this point, but I can certainly provide you with contact information from other manufacturers that work in that temperature range.

David: That’s great. And Omar actually – a different Omar – is asking whether the application, he said the application looks great. But what about elbows and valves, and all those other non-straight sections where you’re trying to prevent CUI?

Lou: Great question. That’s really a lot of the places where you see problems with penetration details and sealants really kind of a clear, open highway for water to get in those joints. So there are two kinds of schools of thoughts either hard insulated with calcium silicate or expanded perlite and jacket it like you would the rest, or they use a removable blanket, depending on how often you need to access those valves and Ts. You know you kind of have to based it on that.

So, unfortunately, we see a lot of removable blankets and that really isn’t in the possibility of using these types of... insulation. They have to be flexible. Some types of materials are commonly used for those types of blankets.

Lou: Good stuff, David. Bill asks whether CUI, in your approach and your company’s approach to CUI. Is it similar to MIC, and does XOX address the MIC issue as well?

David: You’ll have to forgive me if I don’t understand that acronym. Are you referring to microbiological induced corrosion?

Lou: And I’m sorry. Bill simply referred to it as MIC in the question box. So, but he quickly answered, ‘Yes, it is microbiology.’

David: Okay, we have not done any testing relative to that. If I had to theorize a guess, I would say that a lot of those bacteria have difficulty living in higher basic environments. I don’t know that for a fact, but it would just be a guess on my part, but we can definitely look into it.

Lou: That sounds really good. Let me see if I’ve got one other here. The questions asked by Fred is, “You said no insulation is inherently hydrophobic. Explain how high service…” – and I know we’re running short on time, David. I hope you do this one quickly. “Explain how high-service temperatures affect the ability for treated insulations to shed bulk water?”

David: As I mentioned, those silicon-based emulsions that are put on the insulations do begin to oxidize at 450 degrees. So, even though the outside temperature of the insulation will never get that hot – if you’re using the correct amount of insulation – where the rubber-meets-the-road, it’s where the insulation contacts the metal. That’s where the CUI occurs. And if you’re working at operating temperatures over 450 degrees, that insulation will absorb water right next to the pipes. So you need to know how that is affecting your overall system. What does the water do to the material? Does it activate a corrosion inhibitor, or does it just kind of create a space... for that water to collect?

Lou: Well, that’s an excellent answer. Well, we promised people that we wouldn’t keep them too long. David, if you would, scroll to the final contact slides because a couple of people have asked how they might reach you. And what you might do is just bark off that information really quickly.

David: You bet. Connect with me on LinkedIn, David Shong, or you can email me at [email protected]. Also, available via mobile and again, primarily covering Western-North America, but very happy to engage with anyone who would like to discuss industrial insulations worldwide.

Lou: That’s excellent. Thank you, David. Thanks to all of you who attended and thank you Johns Manville for sponsoring this highly informative event. Note that each of you who registered will be able to access this recorded webinar through A link will be emailed to you when it’s available. Thanks to all. And from the Corrosion Media Network, we hope you’ll have an excellent day!

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Corrosion Prevention Corrosion Management Chemical Property CUI

Written by David Shong

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David Shong has spent his entire career in the construction materials industry and developed an early passion for insulation. He has worked in the industrial insulation field since 2014.

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