Sunday, June 29, 2014

Tools To Prevent CUI: Insulation materials

Many different types of insulation materials are used on above-ambient pipes and equipment in industrial facilities. It is important to understand that if the facility owner keeps water from intruding into the insulation system in the first place, the facility is not likely to suffer from CUI. 

If water does occasionally intrude, coatings on the carbon steel pipes and equipment are a backup defense in the CUI prevention battle, as they protect the pipe itself. If this has been done, then any type of thermal insulation, well maintained and operating within its normal temperature limits, can be used without CUI occurring. Nevertheless, under certain circumstances, water, with dissolved corrosive chemicals, sometimes does intrude. It sits on an uncoated carbon steel pipe for extended periods of time. In those cases, certain types of insulation have features that make them tools in the CUI prevention toolbox.

The first of these is hydrophobic (or waterproof) insulation. Several types of commercially available insulation materials have a chemical hydrophobe added in sufficient quantity to make them truly water repellent. These include perlite block and pipe, aerogel blankets, and certain designated hydrophobic microporous insulations (those specifically coated with a hydrophobe). Mineral fiber insulation materials use the same type of hydrophobe, but in lesser percentages than the other materials, and they can still absorb water. Hence, while mineral fiber insulation is somewhat water repellent, it is a wicking material and cannot really be considered water repellent in the way that the other three materials can.

The hydrophobe typically used for some of these hydrophobic insulations is an organic silicone emulsion. It can be added during material manufacturing process. In the case of aerogel insulation, the material is made hydrophobic by virtue of the manufacturing process, by which organic methyl groups are added to the inorganic silica aerogel material. In all cases, this hydrophobic treatment will remain functional apparently up to a temperature range of 400° to 600°F. In that temperature range, the organics, that make the insulation hydrophobic, start to decompose and the insulation becomes less hydrophobic. Therefore, service temperature is the major limitation of the hydrophobe within hydrophobic insulation, regardless of insulation type.

There is an ASTM test for insulation hydrophobicity after heat aging. ASTM C610, the standard for expanded perlite block and pipe material, includes a water-absorption test for material first heat aged in a 600°F oven. The maximum allowable water absorption, after subsequent immersion in water for 48 hours, is 50 percent by weight. Nevertheless, when this material does absorb water and remains wet for a prolonged period of time, the chemical bonding agent is susceptible to failure, possibly leading to physical degradation of the material. However, a major benefit of this behavior is that the bonding agent is an excellent chemical inhibitor against CUI. Expanded perlite has this advantage and hence can be considered a tool in the CUI prevention toolbox for two reasons: One is its hydrophobicity and the other is that it contains a chemical inhibitor against corrosion.

As discussed above, aerogel blanket insulation and hydrophobic microporous insulations are hydrophobic in the service temperature range where the organic material, that make the insulation hydro-phobic, does not thermally decompose. Once the organics decompose, if these insulations are later exposed to water, they will then absorb the water. Later, if dried out, thermal conductivity will have permanently increased due to damage to the tiny pores that make these types of insulation so thermally effective when new. At that point, the insulation will no longer be as effective a thermal insulation as when new. Nevertheless, these two types of insulation can be valuable tools in the CUI prevention toolbox for service temperatures from ambient to the range of 400° to 600°F. For use above that temperature range where CUI prevention is a goal, the insulation manufacturers of these materials should be consulted to ensure that conditions are avoided where excessive loss of hydrophobic treatment and subsequent absorption of water might occur.

How about the effectiveness of closed cell inorganic insulation? There is only one: cellular glass insulation. Indeed, it holds very little water due to its closed cell structure and the fact that water does not pass between the cell walls. While not exactly hydrophobic, it will not absorb water. This behavior can be an important potential contributor to preventing CUI. In “Corrosion Under Insulation: Prevention Measures” (Insulation Outlook, October 2007), Dr. Hira S. Ahluwalia recommends the use of cellular glass. However, since cellular glass is fragile, it is susceptible to vibration-induced damage and can suffer from boiling water trapped between the pipe and the insulation. Therefore, its effectiveness can be limited. Further, as with many types of insulation, the boiling of water is damaging to the cellular glass structure. One point worth noting, since stress relief cracking of cellular glass typically begins to occur at service temperatures above 450° to 500°F, the manufacturer should be consulted for the best method for insulating these systems. While cellular glass insulation has some limitations in above-ambient applications, it can be considered an effective tool against CUI for applications up to 450° to 500°F.

What about corrosion inhibitors? It was already mentioned that expanded perlite contains an excellent corrosion inhibitor. Some types of calcium silicate also contains a considerable quantity of chemical inhibitor—not as a bonding agent but as an additive specifically intended to be a chemical inhibitor and thereby to prevent CUI. If calcium silicate insulation with a chemical inhibitor absorbs water, the chemical inhibitor dissolves and inhibits against corrosion.

In general, high-compressive-strength insulation provides better resistance to external loads than low-compressive-strength insulation does. These materials provide better support for the metal jacketing, limiting its compression, denting, and opening of gaps.

Expanded perlite and calcium silicate insulations both have high compressive strengths. The compressive strength for expanded perlite, per ASTM C610, is a minimum of 60 pounds per square inch (psi). For calcium silicate, the compressive strength is a minimum of 100 psi, per ASTM C533. That is the highest value of any commercially available block and pipe insulation.

On an insulated pipe or surface that is subjected to external loads, such as foot traffic, the high compressive strengths of perlite and calcium silicate will provide extra support to the metal jacketing system, helping prevent the jacketing from “fish-mouthing” at the overlaps. Fish-mouthing of the metal jacketing will allow for rainwater intrusion. By virtue of providing better support of the metal jacketing, calcium silicate and perlite insulations are considered valuable tools for CUI prevention, with calcium silicate being the strongest material available. As mentioned above, both of these materials contain a corrosion chemical inhibitor. Furthermore, expanded perlite has been included above due to its hydrophobicity.

Summary

There really is no single “silver bullet” that will prevent CUI in all circumstances and all applications. However, there are a number of different tools that can be used, each of which brings numerous features and benefits. By combining several of these tools, the facility owner can reduce the instances of CUI to the point of prevention. This may require spending more money up front on the new facility, specifying and selecting the protective jacketing system and insulation materials more carefully and thoroughly, and spending time and money maintaining the insulation system. If it is done, however, it will reduce the overall operating cost for the facility. As always, “an ounce of prevention is worth a pound of cure.”

Saturday, June 21, 2014

Available Tools To Prevent CUI: Protective coatings

These coatings can protect carbon steel pipe from water, air, and corrosive chemicals. With those three elements, as well as time and a certain temperature range, corrosion will occur. The first line of defense is the protective jacketing. The second line of defense is insulation system maintenance. Protective coatings on the pipe provide a third line of defense in the prevention of CUI.

Immersion-grade coatings, which are organic, are becoming widely used to coat and protect pipes that operate at or below 300°F. The reason for this temperature limitation is that above that temperature, most organic coatings thermally decompose. Therefore, immersion-grade coatings are an effective tool up to a 300°F operating temperature. They can be considered a valuable tool on carbon steel pipes. The drawback to facility owners, of course, is that they are a financial investment—one that not every facility has been willing to make when operating on inadequate budgets.

In the article, “Corrosion Under Insulation: Prevention Measures” (Insulation Outlook, October 2007), Dr. Hira S. Ahluwalia describes thermal spray aluminum (TSA) coating in great detail. He points out that TSA coating is effective up to a maximum temperature of 1,000°F, much greater than the 300°F limitation of organic, immersion-grade coatings. This type of coating is reportedly more expensive than the immersion-grade coatings, and some facility owners may not think that CUI prevention is worth the investment. 

However, the expense needs to be evaluated financially through a life-cycle cost analysis, considering not just the initial cost of the TSA coating, but also the value of the pipe, its life expectancy, and the financial risks associated with repairing corroded pipes, fittings, and other components. If the facility is to be brought out of service for any extended period of time, offering an opportunity for water to intrude and CUI to occur, then TSA coatings should be considered. Therefore, TSA coatings are a valuable tool to prevent CUI for piping systems that operate at temperatures between 300°F and 1,000°F.

Thursday, June 19, 2014

5 signs You're going to make it Big One Day

We’ve all got dreams of making it ‘big’ one day, but how many of us actually follow through with those dreams? We make excuses for our lack of success, saying things like, “Life got in the way,” or “I can’t handle anymore rejection.”
But not you! You’re on the fast-track to fame and success. Or are you?
Think you’ve got what it takes to make it big? Here are some signs you’re right:
1. You’ve Got A Dream (A Big One!)
What’s your vision? What do you want to accomplish? What are your hopes and dreams? Having a dream – even if it’s a little vague – is crucial for success. Before you can start your journey, you need to have a goal in mind!
In the words of Walt Disney, "If you can dream it, you can do it." (And before you can do it, you've got to dream it!)

2. You’ve Got A Road Map, But You're Prepared To Take Detours
They say success is where preparation and opportunity meet. So, when opportunity comes ‘a knockin,’ you’re going to want to have your plan already in place. Think of it as your road map to making it big!
What steps do you need to take to get where you want to be? Who do you need to know? What skills do you need to have?
But, let's be real here, nothing EVER goes exactly according to plan. You need to be able to adapt to whatever life throws at you. Think of those things as detours. They're not a huge deal as long as you figure out how to get back on the main road!
3. You’re Extremely Curious
You need to have an innate fascination with whatever it is you’re working toward. You've got to learn as much as you can about the industry, the people, the culture, and so on. You need towant to be consumed by it. You've got to understand the problems and be excited about finding solutions. You’ve got to be passionate, excited, and curious about all areas of the biz.
When Larry King made his debut in radio, he made a point to become consumed in the biz. In addition to doing his own show, he did the weather reports, the sports updates, and the news broadcasts. He even volunteered to fill in in for people who were out sick, and took on double shifts.
Why? He wanted to learn all there was to know about the biz. He wanted to practice. He wanted to be good at what he did. The only way to do that was to explore and go above and beyond what was asked of him. He called it "taking extra batting practice."
4. You’re A Little Cocky (Just A Little)
If you really want to make it, you’ve got to have confidence in yourself and your abilities. Without confidence, you can so easily get crushed by negativity and criticism – things you will have to deal with once you hit the spotlight.
You have to be confident. You have to trust yourself. And you have to have a deep understanding that you’re going to make it. For actress Jennifer Lawrence, that understanding came at a young age.
“I always knew that I was going to be famous,” she told Vogue magazine. “I honest to God don't know how else to describe it. I used to lie in bed and wonder: ‘Am I going to be a local TV person? Am I going to be a motivational speaker?’ It wasn't a vision. But as it's kind of happening, you have this buried understanding: Of course.”
5. You Realize Failure Is A Minor Setback, Not A Game Changer
If you’re even thinking about making it big one day, the word “quit” can’t be in your vocabulary. In the end, you don’t succeed because you don’t fail; you succeed because you don’t give up. The second you quit, you’ve lost.
Take Michael Jordan, for example. He has a famous quote, "I've failed over and over again in my life, and that is why I succeed." The only reason he succeeded was because he didn't let those failures discourage him to the point of quitting. Why? Because he realized his failures were only minor setbacks - not game changers.
I guarantee you that everyone you look up to has failed at one point or another, but did that stop them from picking themselves back up and moving forward? 
If you’ve got all of these qualities – congratulations. I’m sure we’ll be hearing your name sometime soon!


Friday, June 6, 2014

Tools To Prevent CUI: Insulation system maintenance

If the pipe insulation is covered with well-designed, well-installed, and well-sealed jacketing, as discussed in the above section, then it is well protected against CUI. However, once this has been accomplished, the system must be maintained. Therefore, the next tool in the CUI prevention toolbox is insulation system maintenance.

For example, consider an insulated pipe that:
  • is several decades old
  • has an original insulation system of the same age;
  • is located in a relatively rainy climate (something other than the U.S. desert southwest and, at the extreme, along the coast of the Gulf of Mexico);
  • has been shut down for an extended period of time during the system’s life;
  • is uncoated; and
  • has been poorly maintained.
In this case, it is highly likely that the pipe has suffered from CUI. It would be completely unrealistic for the owner or anyone else to expect to not find CUI. In such a case, the CUI is not necessarily the fault of the insulation system design. It further is probably not the fault of the protective jacketing or the insulation material(s). The problem is that when a system has not been well maintained, water—perhaps with dissolved salts from the Gulf of Mexico spray—eventually will get beneath the jacketing between the pipe and the insulation materials, and it will lead to corrosion of the pipe.

In his article, “Is There a Cure for Corrosion Under Insulation?” (Insulation Outlook, November 2005), Mike Lettich emphasizes the necessity for effective maintenance in the battle to prevent CUI. For example, if the insulated pipes have been walked on, resulting in denting of the metal jacketing, there will be water intrusion. If the caulk along the overlapped butt joints has not been periodically replaced, it will become brittle and lose its sealing capability, and rainwater eventually will leak into the system. If caulk around the penetrations—particularly along the top sides of the pipes—has not been examined and replaced as necessary, water will intrude.

For better or worse, the world experienced a prolonged period of very low energy prices from about 1985 to about 2002, with a few, occasional short-term spikes in natural gas prices. With low energy prices, many process pipelines simply were not well maintained due to inadequate maintenance budgets. (This was not the case with all facilities, but it occurred all too often.) With a poorly installed jacketing system—and one inadequately maintained—the insulation system will simply leak rainwater, and CUI will eventually occur. All types of insulation material can be used effectively, up to their design temperatures, if water is kept out of the system. If water gets into the insulation and CUI results, to then simply put all the blame on the materials that make up the insulation system is to put the blame where it should not be placed.

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