Aerogel Academy

As facilities engineers and operators know, a Corrosion Under Insulation (CUI) mitigation plan is critical to combating the problems that arise from wet insulation and CUI, such as process instability, reduced outputs, loss of containment, and personnel safety incidents. 

But, it's the designer of industrial insulation systems that creates a system that stands the test of time in CUI defense. That being said, the designer has three main weapons in the fight against CUI. The first and primary defense against CUI is a high quality, immersion-grade coating. The second is a properly designed and installed weather barrier jacketing and, if operating below the atmospheric dew point, vapor barrier. The third and, arguably, least understood element is the choice of insulation material. Historically, hot insulation products have been divided into categories of wetting and non-wetting, or “hydrophobic” materials. The distinction is important because, as pointed out in NACE Standard RP0198-98:

“Because CUI is a product of wet metal exposure duration, the insulation system that holds the least amount of water and dries most quickly should result in the least amount of corrosion damage to equipment.”

A more recent European monograph states flatly:

“Insulation that minimizes water ingress and does not retain water can effectively act as a barrier to CUI.”

The weight of insulation is becoming increasingly critical for today's congested industrial sites. For some sites, turnaround and maintenance schedules can be negatively impacted by space and weight limitations—just think about the use of cranes where space is restricted as an example. In this post, we focus on the weight of thermal insulation, including when it becomes an important consideration for refinery and chemical processing engineers.

Experts agree that when pipe jacketing becomes damaged, the entire CUI defense mechanism rests on properly specified insulation and well-applied coating. In this situation, you must rely on water-repellent insulation--such as Pyrogel--to keep pipes and assets drier for longer. However, if you've selected an insulation that absorbs water, there are damaging and costly short-term effects of wet insulation to look out for:

• Heat loss that leads to increased energy consumption and process instability. 
  Wet insulation has a parasitic, heat and energy sucking effect on pipes and assets. So, when insulation is wet, it impacts your process stability and the energy required to run your processes optimally—costing you time and money. Since the thermal conductivity of liquid water is approximately 20 times that of most industrial insulation materials, choosing an insulation that can absorb water just doesn't make sense. The Facilities Management Team at Duke University came to this conclusion. In our article, the Duke team was faced with the option of resolving their wet insulation problem or adding additional steam capacity to compensate for the network losses. Wisely, they chose to address to parasitic losses in their steam network by replacing water-absorbing insulation with Pyrogel.
  
  
• Personnel safety hazards. 
  Hot or extremely cold piping and equipment presents a safety hazard to your personnel.  ASTM C1055 (Standard Guide for Heated System Surface Conditions that Produce Contact Burn Injuries) recommends that pipe surface temperatures remain at or below 140°F. The reason for this is that the average person can touch a 140°F surface for up to five seconds without sustaining irreversible burn damage. 
  
  Thermal insulation is one of the most effective means of protecting workers from burns resulting from contact, but wetness greatly reduces the effectiveness of your insulation system. Think of an oven mitt. If it is water-logged, its heat protection properties sharply decline—and if you touch a hot oven rack with that wet mitt, you WILL get burned (don’t try this at home, please). When insulation is wet, jacketing surfaces can become extremely hot—increasing the risk of safety incidents or injury to your personnel. So, it is critical that your thermal insulation stay dry to protect your personnel. 
  
  If you've chosen not to insulate because of CUI concerns, perhaps it's time you try Pyrogel. It's unique properties ensure that your pipes remain drier for longer, minimizing risk to your personnel and assets.

• Unplanned shutdown for repair and replacement of piping and equipment. 
  When insulation becomes wet, it loses its ability to conserve energy, protect workers, and maintain system performance. Thermal resistance is decimated, and the increased risk of corrosion may endanger infrastructure. Also in our Duke University case study, we shared the story of a colleague who experienced the consequences of wet insulation in an industrial steam network he had worked on in Europe. It required him to work around periodic reduced capacity and increased condensate production; overloaded steam traps; and increased consumption of fuel, water, and treatment chemicals during winter months. A near disastrous corrosion event on a heavy fuel oil tank roof and wall caused major disruption and expensive repairs. The root cause of the tank performance was CUI—the tank had failed as the result of wet insulation.
  
  Choose hydrophobic, breathable Pyrogel as your insulation to minimize your assets' time in contact with water. Pyrogel helps extend the life of your assets while keeping processes on track, saving you the cost of an unplanned shutdown. 

• Environmental hazards. 
  Thermal insulation plays a significant role in protecting the environment. It reduces energy consumption, which means that less fossil fuel is burned to produce that energy. This, in turn, decreases the amount of polluting gases—such as carbon dioxide and sulfur dioxide—emitted into the atmosphere. When insulation is wet, the energy required to operate your process increases dramatically, along with the pollutants you’re contributing to the environment.

Whether you're motivated by reducing operating and maintenance expense or minimizing emissions, Pyrogel represents the best practice approach to an effective CUI defense strategy. 

Our team of technical experts can help you solve your wet insulation challenges. Visit our CUI Defense Zone or contact us today.

CUI can be difficult to locate, but we know that in order for CUI to be present, there must be the presence of water in a system. Many times you don’t know that CUI is an issue until something goes wrong—such as loss of containment, processes becoming unstable, or your personnel getting injured. After years of aiding customers in defending against CUI with Pyrogel, we offer the following tips for places to check for CUI in your facility.

1. Piping near or above open bodies of water, such as jetty lines.
2. Areas exposed to mist over-spray from cooling water towers, steam vents, and deluge systems.
3. Steam-traced systems, especially those insulated with water-absorbent, and/or rigid insulation materials.
4. Equipment in cyclic (i.e., operating both above and below the atmospheric dewpoint) or intermittent service.
5. Areas where proper application of surface coating is either not feasible, not guaranteed, or where coatings have degraded.
6. Areas subject to heavy foot traffic.
7. Tank roofs, especially those with sub-girt systems and fibrous insulation.
8. Pipe running through sub-surface road crossings.
9. Areas where moisture can pond, such as vertical pipe supports, valve bonnets, and insulation- and/or vacuum support rings.
10. Piping expansion loops, where the elbow jacketing tends to open up and fish-mouth.
11. At the bottom elbow of any vertical pipe run.
12. On horizontal equipment, the areas directly beneath any top-side penetration (nozzles, ladder clips, davits, etc.).
13. Sub-surface vaults where buried pipe systems are joined and valved.
14. Any pipe running within a trench or impoundment area.
15. Low points where the horizontal pipe is insulated with ill-fitting, rigid insulation.
16. Piping systems that have a tendency to move or vibrate, causing damage to insulation jacketing.
17. Top heads of insulated tanks.

How about you? Have you noticed an area more prone to CUI that others? Tell us about in the comments section below.

Need help preventing wet insulation, CUI, and process instability? Visit our CUI Defense Zone.

In this edition of the Aspen Academy Blog we are going to focus on snakes. Yes, great big, venomous, dangerous snakes—the kind that can ruin your day.  You’re probably asking yourself, “What could snakes have to do with thermal insulation?”

Quite a lot, it seems. At the 2009 AIChE Spring Meeting and Global Congress on Process Safety, J.B. Prows delivered a paper¹ that addressed the jet fire event at the Huntsman Petrochemical plant in Port Arthur, Texas. Corrosion under insulation (CUI) due to persistently wet insulation was identified at the primary cause of a catastrophic fire in the Light Olefins Unit. The cost of reconstruction exceeded $300m and took 14 months to complete.  The author likened the potential defects caused by CUI to rattlesnakes, which prompted the title Killing Rattlesnakes Before They Bite You.

The metaphor is not lost on the team at Aspen Aerogels. Our Pyrogel high temperature insulation is engineered to provide superior CUI defense, and is required to meet or exceed a host of test standards. So it was with a sense of great satisfaction that we added a new criteria to our qualification—Pyrogel is snake-safe.

Engineers, by nature, are proactive in their quest to improve the processes, systems, and designs that they work on daily. But, looming deadlines and budget constraints often mean that you make insulation choices without added consideration. Are you choosing insulation because it’s what was already in place and that’s good enough for now?  We’re not knocking that approach; we get it. However, if you’re looking for long term solutions for problems that plague your insulation systems­­—including CUI— we think it’s time to ratchet up your proactive ways and make a different choice. So, let’s talk about that.

Corrosion under insulation can only occur in a wet environment. The implication of wetness on insulation selection is well summarized in section 2.1.2.1 of NACE Standard SP0198 Control of Corrosion Under Thermal Insulation and Fireproofing Materials:

“Because CUI is a product of wet metal exposure duration, the insulation system that holds the least amount of water and dries most quickly should result in the least amount of corrosion damage to equipment.”

In both hot and cold service, non-wicking, non-absorbent insulation is often the preferred material choice. No one wants their insulation to get wet—wet insulation is truly one of industry's contradictions. Yet, today, many facilities continue to use outdated, water-absorbing insulation, putting their processes and profitability at risk, and their assets and risk for CUI. 

It’s a conundrum, for sure. But Pyrogel offers something that proactive engineers are relying on more and more.

Many of you know that Aspen is based outside of Boston and, of course, it is a time for celebration as our beloved Boston Red Sox won the World Series just two nights ago. While we’re enjoying this championship and the fanfare that comes with it, what’s truly inspiring to us is how the team’s preparation and planning led to the ultimate win. The Red Sox won because of their game plan. They were prepared to face the toughest of teams, situations, and challenges. That’s what we do every day at Aspen—we help industrial organizations plan and prepare to keep their assets performing optimally with world-class insulation that prevents Corrosion Under Insulation (CUI).  

The weight of insulation is becoming increasingly critical for today's congested industrial sites. For some sites, turnaround and maintenance schedules can be negatively impacted by space and weight limitations—just think about the use of cranes where space is restricted as an example. In this post, we focus on the weight of thermal insulation, including when it becomes an important consideration for refinery and chemical processing engineers.