Mitigating Corrosion under Insulation (CUI) while Reducing Carbon Emissions—A Winning Combination
By Ronald (Ron) L. King
Achieving decarbonization goals is complex and requires addressing multiple aspects of decarbonization. The National Insulation Association (NIA) commissioned a study to examine the impact mechanical insulation systems can have on reducing energy demand, reducing greenhouse gas emissions, and increasing energy efficiency.
The study points out the obvious savings but, most importantly, highlights what could be saved if mechanical insulation was viewed as a proven decarbonization technology that is immediately available.
The study conservatively examined the emissions savings and losses for one year, 5 years, and cumulatively over an 11-year period. Over 7.5 million metric tons were saved, but over 751 million metric tons of carbon reduction opportunity was lost due to under-insulated areas.
Figure 1: Summary Results of Savings from Mechanical Insulation
Defining Mechanical Insulation:
All insulation systems deliver energy savings and emission reductions, so why should mechanical insulation be looked at differently? The answer is related to temperature differential and heat loss/gain.
Mechanical insulation encompasses all thermal, acoustical, and personnel safety requirements for mechanical piping and equipment, heating and ventilation, and air conditioning (HVAC) applications. The operating or service temperatures for those applications can range from cryogenic levels (for example, -300°F [-184°C]) to over 1,000°F (538°C).
Other insulation industry segments typically focus on building envelope applications and heating-cooling requirements for residential and commercial buildings. Piping and equipment requiring insulation in these applications usually range from 40°F (4°C) to 250°F (-121°C). The greater temperature differentials in mechanical insulation applications yield much more significant energy and emission savings, and accordingly, they are utilized heavily in markets that experience corrosion under insulation (CUI).
Decarbonization:
Decarbonization has two fundamental aspects. The first entails reducing the greenhouse gas emissions produced by the combustion of fossil fuels. The second is energy efficiency, which reduces the demand for energy.
As decarbonization efforts continue to be developed and implemented, energy efficiency becomes more critical than ever. The impact insulation industry segments can contribute to that effort should not be overlooked or underappreciated.
Impact of Under-Insulated Areas
Mechanical insulation is highly subject to damage from various sources, from outdoor weather events to indoor personnel and mechanical abuse. Potential damage also occurs due to improper installation, lack of repair, or removal of part of the insulation in a system without replacement.
For purposes of the study, “under-insulated mechanical insulation systems” was defined to include the following:
- Items left uninsulated that could have been insulated (e.g., unions, flanges, valves);
- Items that are not updated to be code compliant with the most current model energy or building codes;
- Items that are not specification compliant;
- Items with poor installation quality;
- Insulation removed for maintenance or other purposes without replacement, thus exposing the remaining insulation system to potential damage;
- Parts with improper or untimely maintenance;
- Damaged insulation as a result of:
- Other trades and facility or maintenance personnel;
- Weather-related events (e.g., wind, hail, flooding);
- Moisture or other contaminants intrusion (e.g., product, oil, grease);
- Mechanical equipment (e.g., forklifts, scaffolding, ladders);
- Poor installation quality;
- Removal for maintenance without replacement, thus exposing the remaining insulation system;
- Environmental elements (corrosive or contaminant environment);
- Improper or untimely maintenance;
- System penetration (destructive testing) for inspection purposes without proper, timely repairs; and
- Wash down or similar occurrences.
The question is how much is under-insulated, and over time, does the problem manifest itself to a much bigger number?
Most facilities will acknowledge the problem, but they generally do not have a formal estimate of the magnitude, only a general estimate, which can vary greatly depending on who you ask. Each facility or project would need to determine its estimated percentage of under-insulated areas.
As with all facility systems, mechanical insulation systems should have regular inspection and timely, proper maintenance or the problem will become worse. What today may be a simple repair could be a major problem tomorrow. Additionally, other potential consequences, such as personnel and process safety concerns, process control, and corrosion under insulation (CUI), need to be considered.
Figure 2: Images of Damaged Insulation
Industrial vs Commercial Market Segment:
The industrial segment represents a larger percentage of under-insulated areas than the commercial segment. Many of the insulated piping systems in the commercial segment are located in wall cavities or above ceilings and, accordingly, are not exposed to weather elements or potential mechanical or personnel abuse on a regular basis.
Because the breakdown between market segments is unknown and unknowable through a series of estimates, assumptions, and extrapolations, the total savings was allotted between the two market segments: on average, based on the variable percentages of under-insulated areas, the potential loss equates to 10%. For the Commercial Market, 1.7% was allocated, and for the Industrial Market segment, it was 8.3%, or an approximate ratio of 1 to 5. Over 751 million metric tons of carbon reduction opportunity was lost due to under-insulated areas.
Recognizing that mechanical insulation is highly subject to damage from various sources provides the bridge to the discussion of mitigating CUI.
Figure 3: Cumulative Savings vs. Potential Loss from Under-Insulated
Areas in the Industrial Market Segment
Corrosion Under Insulation:
One of the most common concerns about mechanical insulation systems is the risk of CUI. The 2013 NACE Impact Study estimated the cost of CUI in the U.S. industrial market segment alone at over $300 billion. On a global scale, across all economic sectors, the cost of CUI was estimated at over $2.5 trillion in 2013.
It is important to understand that insulation does not cause corrosion. CUI is an electrochemical process. For CUI to start and continue, a combination of the following conditions must be present:
- Oxygen
- Corrosive chemicals or compounds – pH < 7
- A temperature at the metal surface between 50°F and 350°F (or a cyclic system that passes through this range on some regular frequency)
- An electrolyte (liquid water) to “close” the anode/cathode pathway
Most industry experts agree that the primary cause of corrosion under insulation is moisture/water ingress into the insulation system that migrates to the exposed metal surface beneath. Those same experts also believe that moisture/water will eventually get into the metal/insulation interface.
How does water get into a mechanical insulation system? Look back at the list of “under-insulated” areas and consider the following occurrences:
- Mother nature—rainwater including flooding conditions
- Surrounding environment—cooling towers as an example
- Condensation development—on or in the insulation system
- Sprinkler and/or fire control efforts
- Wash water and/or deluge system water
- Pipe or equipment leakage
To mitigate CUI, you have to keep the moisture out or get it out. You also have to think about mechanical insulation as a system, starting with a coating of the substrate and the design and selection of all materials within the “insulation system,” ensuring the initial installation is correct and followed by timely and proper maintenance.
We look back at the degree of potential conflicting specifications, lack of accepted application standards, improper installations, and the amount of under-insulated areas, and we ask why or how this happened. That answer comes to a few basic topics for most applications.
- Understanding and appreciating that mechanical insulation systems require continual inspection and maintenance.
- Capital cost is the primary focus of new construction, often at the expense of future operational and maintenance cost considerations.
- The consequences of improper installation and maintenance is only fully appreciated once problems occur.
- The investment aspect (financial and emission return on investment components) of maintaining an insulation system is not being considered, thus potentially creating barriers to change.
- Hurdles are being continuously created by conflicting business and decarbonization/sustainability objectives.
- Lack of knowledge and education about all aspects of mechanical insulation systems.
The solutions are complex; there are many opinions as to the best paths to follow, and effective change will take time. But, the one change that can happen immediately is to view mechanical insulation as a proven technology that will help achieve a company’s and our country’s decarbonization and sustainability objectives while taking a big step in mitigating CUI.
The challenge for the business, finance, and policymakers is identifying how best to use the time and resources, and especially solutions that are available now, to advance the changes needed.
Next Steps
While each business or company may have unique circumstances, structures, and procedures to consider, a few common “next steps” should be considered in determining how and to what level mechanical insulation can help achieve the respective decarbonization goals while helping mitigate CUI.
- Commit to investigating and developing a better understanding of the benefits of mechanical insulation and the consequences of not having up-to-date specifications, improper installation, or insufficient or improper maintenance.
- Complete a thorough and objective review of current project or company specifications or standards and develop recommended changes, if any.
- Develop and implement specific mechanical insulation energy efficiency and emission reduction appraisals/audits and assessments of existing mechanical insulation with inspectors and appraisers certified in those fields.
- Determine the internal and external hurdles or barriers to implementing mechanical insulation energy and carbon reduction initiatives.
- “Inspect what you expect” not only in monitoring and recording progress of specific plans, but during the initial installation and maintenance processes.
- Develop an annual inspection and maintenance program for existing facilities. This will benefit short- and long-term operational and capital budget planning, and the information could be used in internal and external climate change/sustainability programs, and to mitigate CUI.
- Ensure you have transition plans to transfer the mechanical insulation expertise and technology to your personnel. So often, knowledge is lost by right-sizing, downsizing, attrition, changes in responsibility, change of ownership, or mergers.
The technology known as Mechanical Insulation is available now, and it impacts every state, county (providence) city, labor group, all direct or indirect related businesses, and this and future generations.
That is potentially the industry’s greatest challenge – hopefully, articles like this can be the nucleus of impacting change.
Aiming to establish a unified mechanical insulation standards program, the NIA and the AMPP recently formalized a partnership by signing a Joint Standards Development Agreement. This collaboration is a step forward in their mutual commitment to sustainability, decarbonization, safety, and enhancing the value insulation brings to the global market. NIA is an authority in the mechanical insulation sector, and AMPP aims to foster a unified approach to industry standards and elevate corrosion control standards.
Together, they are setting a new benchmark for quality and performance, ensuring that our industries not only meet but exceed the expectations of today and the demands of tomorrow.
Ronald L. King Biography
Ron King was a Past President and Honorary Member of the National Insulation Association (NIA) and the Southwest Insulation Contractors Association (SWICA). He was awarded NIA’s President’s Award in 1986 and again in 2001, and in 2024, the award was named after him. He was a 50-year veteran of the commercial and industrial insulation industry, holding management positions at a large national insulation distributor/fabricator, an accessory manufacturer, and a specialty insulation contractor. Ron served as a full-time consultant to the NIA on a variety of educational, outreach and governmental initiatives, including coordinating many allied association alliance-partnership activities and as the head instructor for NIA’s Thermal Insulation Inspector Certification Program™. On behalf of NIA he served as Chair of AMPP’s Standard Committee on Mechanical Insulation (SC-27), Chair of the Consultative Council, the National Institute of Building Sciences’ National Mechanical Insulation Committee, and the World Insulation and Acoustic Organization, and liaison to the Federation European Insulation Societies (FESI), which represents the European mechanical insulation market. For questions on mechanical insulation, email niainfo@insulation.org.