Corrosion is defined by the National Association of Corrosion Engineers as “the deterioration of a material, usually a metal, by reaction with its environment.” Corrosion under insulation (CUI) is not a distinct form of corrosion; rather it refers to the location where pipe wall material deterioration is occurring—underneath the insulation material and on the external surfaces of piping. CUI (and the corrosion of metal jackets and banding which is not addressed herein) is a recognized problem that must be addressed by designers, specifiers, and end-users. CUI can occur under any type of thermal insulation. The type of corrosion will depend on the metallurgy of the pipe as well as the mix of corrosive elements - - understanding that corrosive elements can be introduced during pipe production, pipe shipping/storage, installation, insulation contact, process liquid contact, weather, or other environmental influences.
As the oil and gas market moves towards new corrosion-resistant materials and alloys, specifying products has become increasingly complex.
When no single material performs well in every application, how can specifiers determine the best fit for a project? And what can be done to predict the expected service life of a component?
This technical seminar, run by Parker on its stand at the major oil and gas event Offshore Europe 2017, looks at:
• Common types of corrosion and their triggers
• Key factors to consider when selecting materials for a project
• Different manufacturer perspectives and the science behind their arguments
• Risks associated with mixing dissimilar materials.
About Clara Moyanno: As an innovation engineer and expert metallurgist working across the globe, Ms. Moyanno, innovation engineer with Parker Hannifin, deals with all sorts of challenges. She is often involved in discussions on materials selection, including advice to oil and gas producers working on new platforms around the world.
Clara specializes in areas such as tackling corrosion, and materials selection for design specifications. She also advises on quality certifications and regulations around the manufacturing of metals.
Learn more http://parker.com/ipd
As the oil and gas market moves towards new corrosion-resistant materials and alloys, specifying products has become increasingly complex.
When no single material performs well in every application, how can specifiers determine the best fit for a project? And what can be done to predict the expected service life of a component?
This technical seminar, run by Parker on its stand at the major oil and gas event Offshore Europe 2017, looks at:
• Common types of corrosion and their triggers
• Key factors to consider when selecting materials for a project
• Different manufacturer perspectives and the science behind their arguments
• Risks associated with mixing dissimilar materials.
About Clara Moyanno: As an innovation engineer and expert metallurgist working across the globe, Ms. Moyanno, innovation engineer with Parker Hannifin, deals with all sorts of challenges. She is often involved in discussions on materials selection, including advice to oil and gas producers working on new platforms around the world.
Clara specializes in areas such as tackling corrosion, and materials selection for design specifications. She also advises on quality certifications and regulations around the manufacturing of metals.
Learn more http://parker.com/ipd
INHIBITION OF CO2 CORROSION BY FORMATE FLUIDS IN HIGH TEMPERATURE ENVIRONMENTS John Downs
Presentation to the Royal Society of Chemistry's "Chemicals in the Oilfield" conference, November 2005
The paper describes how formate brines protect steels against CO2 corrosion. It also shows the results of stress corrosion cracking tests on CRA steel samples exposed to high-density completion brines containing oxygen at 160 deg C. The 13Cr, 22Cr and 25Cr steels all cracked in the presence of calcium bromide brine containing oxygen.
This is a ppt. on protection from corrosion of steel reinforcement in concrete structures. I had prepared this as a part of my class seminar. I made this by referring to the books on Concrete Technology by M.S.Shetty and M.L.Gambhir
Weld Purging ~ Corrosion Problems in Stainless Steel by WeldingRon Sewell
Abstract
Corrosion is not uncommon in stainless steels, despite their name. Salt water environments in particular can give rise to corrosion and this is even noticeable at domestic level where cutlery discolours in mild salt solutions during dishwashing cycles. Loss of corrosion resistance during welding takes place when oxygen levels in shield and purge gases are high enough to deplete the chromium content.
This is a presentation on hydrogen induced cracking ,sulfide stress cracking and test procedure for HIC resistant steel
DENZIL D’SOUZA
denzil22@gmail.com
Parte 2_Corrosão em concreto armado: técnicas de avaliação, monitoramento, prevenção e reabilitação. Adriana Araújo, Instituto de Pesquisas Tecnológicas do Estado de São Paulo (Instituto de Pesquisas Tecnológicas do Estado de São Paulo).
INHIBITION OF CO2 CORROSION BY FORMATE FLUIDS IN HIGH TEMPERATURE ENVIRONMENTS John Downs
Presentation to the Royal Society of Chemistry's "Chemicals in the Oilfield" conference, November 2005
The paper describes how formate brines protect steels against CO2 corrosion. It also shows the results of stress corrosion cracking tests on CRA steel samples exposed to high-density completion brines containing oxygen at 160 deg C. The 13Cr, 22Cr and 25Cr steels all cracked in the presence of calcium bromide brine containing oxygen.
This is a ppt. on protection from corrosion of steel reinforcement in concrete structures. I had prepared this as a part of my class seminar. I made this by referring to the books on Concrete Technology by M.S.Shetty and M.L.Gambhir
Weld Purging ~ Corrosion Problems in Stainless Steel by WeldingRon Sewell
Abstract
Corrosion is not uncommon in stainless steels, despite their name. Salt water environments in particular can give rise to corrosion and this is even noticeable at domestic level where cutlery discolours in mild salt solutions during dishwashing cycles. Loss of corrosion resistance during welding takes place when oxygen levels in shield and purge gases are high enough to deplete the chromium content.
This is a presentation on hydrogen induced cracking ,sulfide stress cracking and test procedure for HIC resistant steel
DENZIL D’SOUZA
denzil22@gmail.com
Parte 2_Corrosão em concreto armado: técnicas de avaliação, monitoramento, prevenção e reabilitação. Adriana Araújo, Instituto de Pesquisas Tecnológicas do Estado de São Paulo (Instituto de Pesquisas Tecnológicas do Estado de São Paulo).
Corrosion represents one of the most serious noticed in the industrial world especially in petrochemical, petroleum, power plants, etc.
Billions of Dollars are lost yearly due to the affect of corrosion in the world.
General Corrosion
Galvanic Corrosion
Concentration-Cell Corrosion
Intergranular Corrosion
Stress Corrosion Cracking
Pitting
This part deals with introduction to corrosion and corrosion failures.
It is very costly phenomenon and should be fought leadi8ng to corrosion prevention and neutralization of corrosion. The US is loosing Billions of Dollars due to corrosion either due to deterioration and imobilization of structures or due to corrosion means of protection as well as the remedial costs of the effected components.
Dyplast’s 0214 Technical Bulletin was focused primarily on examining the cost of insulation systems versus energy savings and long-term performance of polyisocyanurate (polyiso or PIR) and extruded polystyrene (XPS) insulants in lowtemperature applications such as refrigeration and chilled water applications. It’s no surprise that polyisocyanurate was the handsdown selection based purely on physical properties, cost, and demonstrated thermal efficiencies in practice.
Technical Bulletin 0418 Polyiso vs. XPS Pipe Insulation SystemsDyplast Products
Dyplast’s 0214 Technical Bulletin was focused primarily on examining the cost of insulation systems versus energy savings and long-term performance of polyisocyanurate (polyiso or PIR) and extruded polystyrene (XPS) insulants in low-temperature applications such as refrigeration and chilled water applications. It’s no surprise that polyisocyanurate was the hands-down selection based purely on physical properties, cost, and demonstrated thermal efficiencies in practice.
Dyplast has over fifty years of development and manufacturing experience with EPS (expanded polystyrene) rigid foam insulation, enabling unmatched quality, customization, and application resiliency. Product physical properties are independently verified, and our quality processes audited. Our high production capacities, on-hand inventories, and just-in-time deliveries generate advantages for end-users while lowering per-unit costs. While most EPS manufacturers can compete only locally, Dyplast’s transportation networks enable exceptional offerings that can be highly competitive in Florida and the Southeast.
Dyplast has over fifty years of development and manufacturing experience with its GeoFoam product line and applications. Dyplast GeoFoam is produced as a large expanded polystyrene (EPS) rigid foam block, typically used as a light-weight/high-strength structural replacement for soil in geo-technical projects or as structural alternatives in applications such as stadium seating and swimming pool foundations in hi-rise hotels.
Customer bulletin 0717 ISO C1® Polyisocyanurate Insulation Flame Spread and S...Dyplast Products
This Customer Bulletin is another in a series of white papers aimed at providing our clients, engineers, contractors, fabricators, and friends with objective information on competitive products and on items that affect our industry. Marketing literature for insulation products on the internet and in printed media often address the flame spread index (FSI) and smoke developed index (SDI) as measured in accordance with
ASTM E84 or comparable standards. This Customer Bulletin provides factual, clarifying information concerning ISO-C1’s FSI and SDI as well as other important points relating to the combustion properties of polyisocyanurate foam.
LNG Industry Magazine (Commercial Quality Control The Missing Link)Dyplast Products
Dyplast Products has published its latest article in LNG Magazine titled “Commercial Quality Control: The Missing Link”. In an era with disparate pricing, a multiplicity of owners/stakeholders, long-term price volatility, multiple concurrent plant constructions, a shortage of skilled personnel, and increasingly complex technologies, owners/stakeholders in LNG projects increasingly face new risks.
This article introduces commercial quality control as an approach to move more impact factors to the controllable side of the ledger, and also as a way of better identifying and mitigating risks across the project lifecycle – beginning at project inception, but encompassing development, financing, construction and operations.
LNG Industry Magazine (Risk Mitigation Standards) July 2016Dyplast Products
Experience has demonstrated that insulation systems within LNG facilities are often ‘under-designed’ when compared to other mechanical systems. Decades of lessons learned from
under-designing other mechanical systems, such as piping materials, welding, compressors, relief valves, etc., have led to a keen awareness among LNG engineers regarding impacts on safety, plant reliability, process efficiency, energy loss, and
environmental compliance.
The purpose of this article is to offer a macro-level discussion
of the following:The role of standards in mitigating insulation risks. Which standards are becoming dominant for LNG insulation. Where standards must be supplemented with broader risk mitigation.
LNG Industry Magazine (Logical Thinking) Feb 2016Dyplast Products
Dyplast Products’ new article in LNG Industry Magazine titled "Logical Thinking" is an examination of the complexities surrounding insulant performance at cryogenic temperatures.
Physical properties of a particular insulant are often measured only at ambient temperatures. This article aims to use logical thinking to examine the performance of insulants at LNG (cryogenic) temperatures.
Fortunately, standards such as ASTM and CINI increasingly require physical properties to be measured at cryogenic temperatures, so that in the future such logical extrapolations may be less necessary.
Dyplast Products is proud to announce we will be attending the 2015 Polyurethanes Technical Conference October 5-7, 2015 at the Gaylord Palms Resort and Convention Center in Kissimmee, Florida.
Dyplast will be attending the Eastern States Insulation Contractors Association Conference at the Four Seasons Hotel in Baltimore Harbor, Maryland.
ESICA represents both small and large mechanical, commercial, industrial and asbestos abatement contractors as well as various suppliers and distributors of products and services to the industry.
Dyplast has been supporting ESICA over many years, and is eager to again be part of this valuable Conference.
SWICAs EXPO 2015 has expanded and Dyplast will be exhibiting as one of 55 other companies with a table top display featuring Dyplast’s ISO-C1® family of products in the exhibit hall. SWICA Ninth Industrial Insulation Craft Competition will also be held at the EXPO and will have two insulators per model and have refined the removable blanket competition with single or dual optional competitors and added a commercial competition. This is an expensive and timely event that the Craft Education Committee has spent endless hours preparing exams, building models and setting standards long before the actual execution of such an event. The Expo and competition turns out virtually everyone in the industrial insulation industry. This is an opportunity to show support and help the Education Committee set new education and safety standards for our industry. We look forward to seeing you in this one-day educational and information packed exposition, white papers and craft competitions.
Technical Bulletin 0714 Elastomeric insulation versus polyisocyanurate in low...Dyplast Products
PURPOSE
Several of Dyplast’s prior Technical Bulletins have provided in-depth comparisons of various insulants, including polyisocyanurate (polyiso or PIR), polyurethane (PUR), phenolic, polystyrene (expanded EPS and extruded XPS), cellular glass, and fiberglass - - as well as less-than-comprehensive comparisons with elastomeric and aerogel. Now with somewhat more information becoming available from elastomeric manufacturers and the aggressive marketing from elastomeric suppliers for colder applications it is appropriate to dedicate a Technical Bulletin to elastomeric insulants as compared to polyisocyanurate - - and to a much lesser extent phenolic, and cellular glass.
Customer Bulletin 0515 A Comparison of ISO ISO-C1 and HT-300Dyplast Products
PURPOSE
This Customer Bulletin is part of a series of white papers aimed at providing our clients, engineers, contractors, fabricators, and friends with objective information on competitive products. Marketing literature on the internet and in printed media address the physical and performance characteristics of competing polyisocyanurate rigid foam insulations fabricated from bunstock. As is often the case, some literature can be misleading and/or in some cases there may not be sufficient information to credibly compare products. This Customer Bulletin provides factual, clarifying information which should allow for an objective comparison of Dyplast’s ISO-C1® with HiTherm’s HT-300 (each 2 lb/ft3 density).
Technical Bulletin 0213 Polyisocyanurate vs. Cellular Glass InsulationDyplast Products
This Technical Bulletin is another in our series of white papers aimed at providing our clients, engineers, specifiers, contractors, fabricators, and friends with objective information on our products and those of our competitors. This Bulletin focuses on a comparison of the physical properties of closed cell2 polyisocyanurate3 (polyiso or PIR) rigid foam insulation products with those of cellular glass insulation products for demanding below-ambient applications such as cryogenic, refrigerant, and chilled water where energy efficiency, moisture intrusion, and condensation are issues.
Customer Bulletin 0511 Questions You Should Ask When Selecting Mechanical Ins...Dyplast Products
Too often the specifying and selection processes relating to mechanical insulation are jeopardized either due to confusing information or the absence of important information. “What‟s not being said” is sometimes more important than “what‟s being said”! The objective of this document is to itemize key questions that should be asked during discussions with insulant suppliers. Failure to receive a credible response on any question may be an indication that full disclosure is being withheld.
Customer Bulletin 0510 Polyisocyanurate vs Polyurethane InsulationDyplast Products
This Customer Bulletin is one in a series of white papers aimed at providing our clients, engineers, contractors, fabricators, and friends with objective information on our products and those of our competitors. A surprisingly large number of potential buyers of polyurethane (PUR) insulation are unaware of the advantages or even the existence of polyisocyanurate (PIR). Some may even think they're the same thing. The fact is that the differences are considerable.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
Customer Bulletin 0611 Insulant Impact on Corrosion in Steel Piping Applications Below 32F
1. Page 1 of 7
CB 0611 June 2011
CUSTOMER BULLETIN 0611
Insulant Impact on Corrosion in
Steel Piping Applications Below 32°F
BACKGROUND
Corrosion is defined by the National Association of Corrosion Engineers as “the deterioration of
a material, usually a metal, by reaction with its environment.” Corrosion under insulation (CUI) is
not a distinct form of corrosion; rather it refers to the location where pipe wall material
deterioration is occurring—underneath the insulation material and on the external surfaces of
piping. CUI (and the corrosion of metal jackets and banding which is not addressed herein) is a
recognized problem that must be addressed by designers, specifiers, and end-users. CUI can
occur under any type of thermal insulation. The type of corrosion will depend on the metallurgy
of the pipe as well as the mix of corrosive elements - - understanding that corrosive elements
can be introduced during pipe production, pipe shipping/storage, installation, insulation contact,
process liquid contact, weather, or other environmental influences.
Focusing on CUI, the three most common types of CUI include oxidation (rusting), stress
corrosion cracking (SCC), and pitting. Yet there are also several specialized types of CUI such
as formicary corrosion1
of copper which in general are not associated with insulated refrigerant
systems and therefore not addressed herein. Metals vary considerably in their susceptibility to
various types of corrosion.
PURPOSE
The purpose of this Customer Bulletin is to provide general information on the causes of CUI in
steel pipe, which insulants in general terms may be best for low temperature applications, and
how to avoid of CUI in steel piping systems operating at service temperatures below 32°F.
We also discuss how corrosion differs between the two common types of steel2
used in such
piping systems. To keep it simple, we define carbon steel as steel with less than 10.5%
chromium, and stainless steel3
as a steel with a minimum of 10.5% chromium content by weight.
1
Formicary (“ants-nest) corrosion may best be described as micro-pitting most common in refrigeration grade copper tubing in
HVAC systems although other forms of attack, similar in appearance, have been observed in other alloys. Although poorly
understood, attack has been attributed to the growing use of synthetic lubricating oils that were introduced as refrigerant fluids
changed, or to vaporous species derived from the immediate surroundings, including volatiles from process fluids.
2
We define “Steel” as an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight.
3
Refer to http://www.corrosionist.com/Stainless_Steel_grades.htm.
2. Page 2 of 7
CB 0611 June 2011
There are of course many types and grades of both carbon and stainless steels, with varying
degrees of susceptibility to various corrosion processes.
SUMMARY
Too often, discussions of CUI focus only on the insulation, rather than on the broader spectrum
of factors that will more likely be the cause of any CUI. At temperatures below 32F, the
likelihood of any form of CUI is remote. Yet the majority of mechanical systems spend some
time above 32F, such as during outages, so the extent to which an insulant may contribute to
CUI must be considered. There are several premises to keep in mind:
1. CUI can in fact occur under any insulant - - some more likely than others
a. Insulants with higher Water Absorption and Water Vapor Transmission
exacerbate CUI
b. Insulants with higher leachable chlorides (or fluorides) can exacerbate CUI (yet
such ions must be leachable at the actual temperature presents, and the
temperature must be above 32F!)
c. CUI is time and temperature dependent
2. CUI can be prevented from occurring by following basic guidelines:
- Pre-design identification of environmental factors that could exacerbate CUI, such as
rain, acid rain, humidity, “salt air”, wash-down water/chemicals, sprinkler systems,
fire control systems, etc.);
- Pipe/component design using appropriate metallurgy for the conditions, and control
of metallurgy during construction (e.g. welding; pickling/heat treating; avoidance of
dissimilar metals in contact; etc.);
- Proper specification and application of any pipe coatings;
- Proper selection and installation of insulation system materials (insulant, vapor
barriers, jackets, mastics, etc.);
o This includes compliance with the guidelines of the manufacturers of the various
insulation system components as well as the procedures established by a qualified
insulation engineer, including for example, keeping the insulation and pipe surfaces
dry during the installation process.
o Zero-perm vapor barriers can eliminate moisture penetration from the environment.
- Operational diligence, including such action as avoidance of excessive impingement
of water on pipe during wash-downs, periodic inspection for corrosion, and proper
3. Page 3 of 7
CB 0611 June 2011
replacement of the insulation and insulation components after mechanical repairs or
inspection.
Dyplast is not a piping system designer, so cannot provide credible advice on the overall design
of a piping system. We thus focus on insulant selection in the next subsection, and on some
general information on corrosion in the remainder of the document - - so the involved parties
may better understand the issues and thus better able to communicate with system designers,
engineers, and contractors.
Insulant Selection
Selection of the optimal insulant material is first driven by the long term thermal
performance of the insulant, just as the first priority of the piping is to ensure mechanical
integrity of the process. Corrosion mitigation must inevitably be a secondary concern,
unless the pipe system is likely to be exposed to a chemically intense environment, such
as an acid regeneration plant in a steel mill with frequent leaks. In such an environment,
cellular glass may be the only insulant that could withstand the chemical onslaught,
assuming the chemicals do not include hydrogen fluoride, hydrofluoric acid, or related
compounds.
As explained in Customer Bulletin 0411, polyisocyanurate (particularly Dyplast’s ISO-C1)
is inevitably the optimal selection in the vast majority of piping applications with
operating temperatures below 32°F. Polyiso’s thermal conductivity combined with its
moisture resistance characteristics result in energy savings and process control
advantages that far outweigh any concern over corrosion.
The additional good news is that ISO-C1 polyiso is low in leachable chloride. At the low
temperatures typical of a polyiso installation, CUI is highly unlikely. In systems where
there is frequent cycling above 32F, pipe coatings4
can further mitigate any risk of CUI.
CORROSION OF STEEL: GENERAL
While dramatically different in nature, the corrosion through oxidation, SCC, and pitting each
share one common requirement - - moisture. The corrosion of metals is an electrochemical
process. That is, there is an electrical circuit where the exchange of electrons (electricity) is
4
Typical industry practice is to apply an epoxy primer in the following circumstances: 1) for 300 series stainless steel systems
operating in a temperature range between 140°F and 300°F or if in a cycling temperature service where the service temperature is
between 140° and 300°F for more than 20% of the time; and 2) for carbon steel piping operating at a service temperature between
32°F and 300°F or in cycling temperature service where the service temperature is between 32°F and 300°F for more than 20%
of the time shall be at a minimum primer coated with an epoxy coating. Coating manufacturers should be consulted for
appropriate coating materials and application methods for the operating temperature range of the equipment.
4. Page 4 of 7
CB 0611 June 2011
conducted by chemical reactions in part of the circuit. These chemical reactions occur at the
surface of the metal exposed to the electrolyte.
Water in the form of liquid or vapor must be present at the surface of the metal for corrosion to
occur. Therefore, anything that can be done to prevent moisture (rain, wash-down water,
sprinkler systems, condensation, etc.) from reaching the metal surface will help prevent
corrosion from occurring. Selecting an insulant with both low water absorption and water vapor
transmission, and properly installing a zero-perm vapor barrier with a protective jacket is an
appropriate approach in addition to minimizing the external presence of water.
The presence of leachable chloride or certain other elements has been found to exacerbate
corrosion. Too often the search for the source of such ions has been centered incorrectly on the
insulation system components, rather than an external environmental factor which is more often
the cause.
Chemical exposure is the final major environmental element affecting CUI. Acids and acid
gases, hydrochloric acid, sulfuric acid, strong bases (caustics), and salts are aggressive
corrosive agents and will both cause and accelerate CUI. The complexity of addressing the
reaction of various metals to corrosion by chemicals is beyond the scope of this Customer
Bulletin.
OXIDATION
Oxidation (or simply rusting) is sometimes referred to as uniform corrosion, and is one of the
most common mechanisms for corrosion of carbon steel pipe; oxidation does not occur on
stainless steel. Oxidation of carbon steel involves four requisites:
1. High temperature
2. Moisture
3. Oxygen
4. Concentration of corrosive ions
It is an inescapable fact that iron in the presence of oxygen and water is thermodynamically
unstable with respect to its oxides. Because oxidation corrosion is an electrolytic process, the
presence of an electrolyte is required. This should not be taken to mean that the steel surface
must be awash in water; a very thin adsorbed film of water is all that is required.
Oxidation on carbon steel pipe can occur between 32°F and 300°F; the “optimum” temperature
range for aggressive corrosion seems to be between 200°F and 240°F5
. In this range, there is
5
“Is There a Cure for Corrosion Under Insulation?” Michael Lettich, National Insulation Association,
http://www.insulation.org/articles/article.cfm?id=IO051101
5. Page 5 of 7
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plenty of heat energy but not enough heat to efficiently evaporate moisture before it contacts the
equipment surface. Corrosion rates can double for every 18°F rise in temperature6
.
At the service temperatures considered in this paper (below freezing point of water), the
temperature should be insufficient to precipitate corrosion even if water, oxygen, and chloride
ions are present. Yet, virtually all piping systems spend some time at ambient temperatures,
such as during shutdowns for maintenance. Thus there must still be an exerted effort to
minimize moisture and the presence of chloride or other environmental contributors or catalysts
An insulation engineer should be consulted when a carbon steel mechanical system cycles into
service temperatures between 32°F and 300°F for more than 20% of the time. Typical practice
in such circumstance is to apply an epoxy coating, or equivalent.
PITTING (OR CREVICE) CORROSION
Pitting corrosion is a broad term for corrosion that either begins within pits (non-uniformities) in
the pipe surface, or causes pits. Pipe failure can occur if a pit fully penetrates the pipe wall.
Pitting can occur in both carbon steel and stainless steel pipes, although it is more commonly
associated with stainless steels. Pitting is often considered to be more dangerous than uniform
corrosion damage because it is more difficult to detect, predict and design against.
Generally, pitting on pipe exteriors can be associated with:
- Localized chemical or mechanical damage to the protective oxide films in carbon steel;
o chemistry factors such as acidic rain or high concentrations of chloride (as in salt
air that has penetrated the insulation system, or indeed from a poorly selected
insulant itself in certain circumstances) can cause breakdown of a passive film;
and/or
- The presence of non-uniformities in the metal structure of the component (e.g.
nonmetallic inclusions); and/or
- Localized damage to the protective chromium oxide layer on stainless steel (such as at
manganese sulfide inclusions on the steel surface) caused by:
o chloride or chlorine-containing ions
o bromides (fluorides and iodides are not aggressive)
o cupric, ferric and mercuric ions (such ions may act in concert with chloride to
promote pitting without dissolved O2) [or may indeed prevent pitting in a
phosphoric acid environment (e.g. it’s complicated)];
6
Mechanical Integrity and Carbon Steel Refrigerant Piping, Daniel J. Dettmers and Douglas T. Reindl, ASHRAE Journal,
October 2007
6. Page 6 of 7
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o thiosulphate ions (S2O3) may also promote pitting.
Metals that are susceptible to uniform corrosion (e.g. carbon steel) do not tend to suffer from
pitting. Thus, carbon steel will corrode uniformly in sea water, while stainless steel will pit. An
addition of about 2% of molybdenum increases pitting resistance of stainless steels.
Note that crevice corrosion takes place where physical crevices are present, such as at the joint
between two overlapping sheets of stainless steel, in the crevice between a stainless steel
flange and a non-metallic gasket or under surface deposits.
STRESS CORROSION CRACKING
SCC is the initiation and propagation of micro-cracks caused by the combined effects of tensile
stress coupled with direct surface contact with an enabling chemical7
. The stress can be
externally applied, thermal, or residual from the manufacturing process. This stress, coupled
with a susceptible material and environment, causes small cracks inherent or formed in the
material to propagate - - thereby relieving the material’s stress. If the stress level is low, the
cracks will self-limit (stop propagating) prior to fully penetrating the pipe wall. If the stress level is
high, the cracks have the potential to propagate completely through the entire wall thickness,
resulting in a leak.
Contrary to conventional wisdom, Stress Corrosion Cracking (SCC) can occur in carbon steels
as well as stainless steels. Yet SCC in carbon steel pipes is unusual on the exterior of the pipe
since it requires exposure to either hydroxides, nitrates, carbonate, bicarbonates, liquid
ammonia, or CO/CO2/H2O at very low temperatures. SCC in carbon steel is more of a concern
on the inside the pipe in certain ammonia refrigerant applications/conditions where oxygen may
be present.
The most common form of SCC in mechanical systems within the temperature ranges
addressed in this document is Chloride Stress Corrosion of stainless steel pipe, which involves
four requisites:
1. High temperature
2. Chloride (or fluoride or similar) ions
3. Moisture (dissolved oxygen)
4. Metal is under tensile stress
Chloride SCC can occur between 140°F and 300°F for 300 series stainless steel. The
"optimum" temperature range for aggressive corrosion on 300 series stainless steel seems to
7
American Society of Materials International. 2003. ASMI Handbook Volume 13a, Corrosion: Fundamentals, Testing, and
Protection, “Selecting Materials to Prevent or Control Corrosion.”
7. Page 7 of 7
CB 0611 June 2011
be between 200°F and 240°F. Chloride SCC is most commonly overcome by using a duplex
stainless steel, such as 2205, or a grade with a higher nickel content, such as a 6% Mo material
or high-nickel alloys like Alloy 825 (N08825). Ferritic stainless steels are very resistant to SCC
but grades with equivalent pitting resistance to the austenitic grades have other major
drawbacks.