The document discusses corrosion under insulation (CUI) and provides information on why it occurs, how to detect it, and how to prevent it. CUI is corrosion that occurs underneath insulation on pipes and equipment and can lead to leaks and safety incidents if undetected. It occurs when water or moisture penetrates the insulation system, often through breaks in protective coverings. Various techniques are used to detect CUI, including visual inspection after removing some or all of the insulation, as well as nondestructive methods like moisture meters and infrared thermography. Targeted inspection of areas susceptible to water penetration and insulation damage is recommended.
1957FullText150Corrosion Under Insulation - Facts and Prevents ( corcon 2016...Kumar Kolur Vadivelu
Paper is a thin material produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets. It is a versatile material with many uses including for writing, packaging, cleaning, and more. Sheets of paper can be cut and folded into shapes and forms, with common paper sizes including letter and A4.
This document discusses corrosion under insulation (CUI), which occurs in the space between insulating material and metal surfaces in various industries like oil & gas, chemicals, and food processing. CUI is caused by water collecting in this space from sources like rain, leaks, or condensation. It can lead to localized corrosion and wall loss. The document examines major factors that influence CUI like temperature, insulation design, and environmental conditions. It also identifies specific units and areas that are susceptible to CUI, such as pipes near cooling towers or steam vents. The appearance of CUI and methods to prevent it through coatings and insulation practices are described. Inspection and monitoring techniques for CUI are also discussed, including a probe array sensor
This document discusses corrosion under insulation (CUI). It occurs when moisture accumulates between insulation and equipment, trapping corrosive components. Factors like moisture, corrosive fluids, and elevated temperatures from insulation can cause corrosion rates of around 4 mm per year in carbon steel. Visual inspection is commonly used to detect CUI but has limitations. Preventing CUI involves stopping water penetration into insulation and using protective barriers to isolate the metal surface from corrosives. Improving insulation system designs and maintaining seals are recommended prevention methods.
This document provides a review of corrosion under insulation (CUI), discussing key factors and mechanisms. It summarizes that CUI occurs via a three step process: 1) water ingress, 2) water accumulation under insulation, and 3) dissolution of corrosive species. Five important factors for CUI are discussed: insulation material, coating material, substrate material, atmosphere, and design. Carbon steel is susceptible to general and localized corrosion from CUI, while stainless steel risks pitting and stress corrosion cracking. Proper coating and design can prevent the water accumulation and corrosion processes that cause CUI.
Program for Prevention of CUI at a RefinerySharon Hart
The document outlines a program to minimize occurrences and severity of corrosion under insulation (CUI) at an oil refinery. It identifies 12 common problems that can lead to CUI and recommends solutions. General recommendations include using calcium silicate insulation for temperatures over 350°F, cellular glass below 350°F, and continuing use of aluminum jacketing with a moisture barrier and removable/reusable blankets where needed. Implementing the solutions and recommendations would enhance safety by reducing CUI and extending the life of insulated pipes and equipment at the refinery.
Corrosion is the deterioration of materials through chemical reactions with the environment. It can cause reduced strength, equipment downtime, leaks, loss of surface properties, and reduced value. The consequences of corrosion are more serious than just metal loss, and can lead to failures and need for expensive replacements.
The document summarizes an investigation into structural failures at indoor swimming pools caused by stress corrosion cracking of stainless steel components. The investigation found that standard stainless steel grades 304 and 316 are susceptible to stress corrosion cracking in the chlorinated atmosphere above swimming pool ceilings, posing a safety risk. At least 14 pools in the Netherlands were found to have stainless steel support bars at risk of immediate failure. Only the highly corrosion resistant 6% molybdenum stainless steel grade is suitable for critical load-bearing applications in swimming pool structures.
This document is a health and safety assessment report for the Noble Fire plant prepared by Julian Kalac, P.Eng. It identifies several serious unaddressed health and safety issues at the plant including open MOL orders, lack of machine guarding for welders and plasma cutters, lack of ventilation for toxic fumes, and lack of required safety training for workers. Kalac conducted a review of the issues and applicable safety standards, and provides recommendations to address the issues including redesigning a storage rack, implementing proper guarding, identifying hazardous substances, and providing safety training to workers.
1957FullText150Corrosion Under Insulation - Facts and Prevents ( corcon 2016...Kumar Kolur Vadivelu
Paper is a thin material produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets. It is a versatile material with many uses including for writing, packaging, cleaning, and more. Sheets of paper can be cut and folded into shapes and forms, with common paper sizes including letter and A4.
This document discusses corrosion under insulation (CUI), which occurs in the space between insulating material and metal surfaces in various industries like oil & gas, chemicals, and food processing. CUI is caused by water collecting in this space from sources like rain, leaks, or condensation. It can lead to localized corrosion and wall loss. The document examines major factors that influence CUI like temperature, insulation design, and environmental conditions. It also identifies specific units and areas that are susceptible to CUI, such as pipes near cooling towers or steam vents. The appearance of CUI and methods to prevent it through coatings and insulation practices are described. Inspection and monitoring techniques for CUI are also discussed, including a probe array sensor
This document discusses corrosion under insulation (CUI). It occurs when moisture accumulates between insulation and equipment, trapping corrosive components. Factors like moisture, corrosive fluids, and elevated temperatures from insulation can cause corrosion rates of around 4 mm per year in carbon steel. Visual inspection is commonly used to detect CUI but has limitations. Preventing CUI involves stopping water penetration into insulation and using protective barriers to isolate the metal surface from corrosives. Improving insulation system designs and maintaining seals are recommended prevention methods.
This document provides a review of corrosion under insulation (CUI), discussing key factors and mechanisms. It summarizes that CUI occurs via a three step process: 1) water ingress, 2) water accumulation under insulation, and 3) dissolution of corrosive species. Five important factors for CUI are discussed: insulation material, coating material, substrate material, atmosphere, and design. Carbon steel is susceptible to general and localized corrosion from CUI, while stainless steel risks pitting and stress corrosion cracking. Proper coating and design can prevent the water accumulation and corrosion processes that cause CUI.
Program for Prevention of CUI at a RefinerySharon Hart
The document outlines a program to minimize occurrences and severity of corrosion under insulation (CUI) at an oil refinery. It identifies 12 common problems that can lead to CUI and recommends solutions. General recommendations include using calcium silicate insulation for temperatures over 350°F, cellular glass below 350°F, and continuing use of aluminum jacketing with a moisture barrier and removable/reusable blankets where needed. Implementing the solutions and recommendations would enhance safety by reducing CUI and extending the life of insulated pipes and equipment at the refinery.
Corrosion is the deterioration of materials through chemical reactions with the environment. It can cause reduced strength, equipment downtime, leaks, loss of surface properties, and reduced value. The consequences of corrosion are more serious than just metal loss, and can lead to failures and need for expensive replacements.
The document summarizes an investigation into structural failures at indoor swimming pools caused by stress corrosion cracking of stainless steel components. The investigation found that standard stainless steel grades 304 and 316 are susceptible to stress corrosion cracking in the chlorinated atmosphere above swimming pool ceilings, posing a safety risk. At least 14 pools in the Netherlands were found to have stainless steel support bars at risk of immediate failure. Only the highly corrosion resistant 6% molybdenum stainless steel grade is suitable for critical load-bearing applications in swimming pool structures.
This document is a health and safety assessment report for the Noble Fire plant prepared by Julian Kalac, P.Eng. It identifies several serious unaddressed health and safety issues at the plant including open MOL orders, lack of machine guarding for welders and plasma cutters, lack of ventilation for toxic fumes, and lack of required safety training for workers. Kalac conducted a review of the issues and applicable safety standards, and provides recommendations to address the issues including redesigning a storage rack, implementing proper guarding, identifying hazardous substances, and providing safety training to workers.
The document describes the Goodall BR8 Inferno Steamhose. It addresses 8 common problems with steam hoses: 1) inner layer popcorning, 2) outer layer blowing, 3) metal braid rusting, 4) unclear hose markings, 5) premature aging, 6) hose kinking, 7) static charge build up, and 8) fitting leaks. For each problem, it provides the solution the BR8 Inferno addresses through features like an extruded butyl rubber inner layer, pin-pricked outer layer, brass-coated double braided steel, clear spiral markings, weather-resistant cover, and EN14423 leak-proof couplings.
The document summarizes the services provided by Chicago Corrosion Group, LLC. The company offers corrosion prevention and coating consulting services to help clients identify optimal and cost-effective corrosion prevention solutions. Services include condition surveys, root cause analysis, solution identification, specifications development, project management, quality control, and general contracting. The company aims to act solely in the clients' best interests and help them reduce costs with solutions that have low maintenance, high durability, and good performance.
Rust forms in mission-critical facilities when iron combines with oxygen and water in the presence of an electrolyte like moisture. High humidity above 50% RH causes corrosion to grow exponentially by providing the electrolyte. Maintaining humidity between 45-55% RH prevents rust and dendrites by eliminating electrolytes while avoiding static electricity. Properly sealing facilities with vapor barriers controls humidity and prevents infiltration that can cause equipment failures.
Tempered glass is easy to self explosion. “self-explosion” is the unavoidable problem of tempered glass,In
fact, tempered glass is not horrible, and the potential self-explosion of tempered glass has always been the
focus of attention.
The document discusses common condensation problems that occur in metal buildings due to humidity, and provides tips to address this issue, including using proper insulation to regulate temperature; ensuring a strong, waterproof foundation; installing a vapor barrier between floors; using good sealants on joints and seams; including vents for air circulation; and using a dehumidifier as a last resort solution. The main causes of condensation are humidity building up inside due to improper construction or heating systems, and it commonly appears as visible condensation on surfaces or concealed condensation in wall and roof cavities.
What are the possible exposure sources?
Crystalline silica can be found in certain types of natural materials, such as:
• Sand
• Soil and rock
• Gravel
• Sandstone
• Slate
• Granite
• Clay
107 yun-yu wang - 7538029 - method of room temperature growth of si ox on s...Mello_Patent_Registry
Yun-Yu Wang, Christian Lavoie, Kevin E. Mello, Conal E. Murray, Matthew W. Oonk - Method of Room Temperature Growth of SIOx on Silicide as an Etch Stop Layer for Metal Contact Open of Semiconductor Devices
Water Interactive Wet Welding Consulting - Len Andersen 914-536-7101 knows underwater welding and is known in the industry! The product for the Hurricane damaged platforms and pipelines. These wet welding stick and flux Core can be four time more productive than the old 3.2 mm slow wet weld. You can put in the weldment with 6.5 mm 450 mm electrodes and get production. There is 8018-C3 like stick to let your do higher strength steels! It is a patented proven wet welding process developed by Wet Welding to improve the profitability and potential of wet welding through a dry gelling agent and weld enhancers coating on ARC welding consumables which wets and activates near the ARC forming a gelatinous shielding envelope. The Resulting wet welding being done with as greater or greater ease (operability) than surface welding and a lessening of the cooling rate of the weldment such that 2T bends are obtainable.
Water Interactive Wet Welding Uses
• Pipelines • Sheet Steel Piling
• Offshore Platforms • Docks
• Ships and Barges • Dams and Canals
• US Navy Warships • Marine Salvage
Underwater welding is a specialized welding process that involves welding at depths below the surface of water. It can be classified as wet welding, where welding is done directly in water, or dry welding, where a dry chamber is created to perform the welding. Wet welding uses manual metal arc welding with direct current power and special electrodes. It allows for work in difficult to reach areas but results in lower quality welds due to quenching from the water. Dry welding produces higher quality welds by working in a pressurized chamber, but requires more complex and expensive equipment. Underwater welding is used for offshore construction, ship repair, and pipeline maintenance.
Chemical eye trauma can occur from exposure to strong acids or alkalis and represents 11.5-22% of ocular injuries. Acids like sulfuric acid and hydrochloric acid, as well as alkalis like potassium hydroxide and sodium hydroxide, can cause chemical burns to the eye depending on the concentration, duration of exposure, and type of chemical. Clinical signs include lid edema, corneal scarring, uveitis, and glaucoma. Treatment involves immediate irrigation of the eye, antibiotic eye drops, atropine, steroid drops to reduce inflammation, and surgery for complications like symblepharon or glaucoma. Proper first aid through irrigation can help minimize tissue damage from chemical burns.
This document discusses various methods of underwater welding. It begins by classifying underwater welding into dry welding and wet welding. Dry welding involves welding inside a chamber that is sealed around the structure, while wet welding is performed directly under water. The document then describes the processes and equipment used for dry welding methods like hyperbaric and cavity welding. It also covers the principles, advantages, and disadvantages of wet welding. The document concludes by discussing applications of underwater welding, the effects of the wet environment on welds, and providing a graph showing the relationship between porosity and water pressure during welding.
Underwater welding includes a lot of different processes that join metals on offshore oil platforms, pipelines & ships .It is the process of welding under water using various techniques under various conditions.....etc.!!!
This document describes experiments conducted to develop an improved technique for removing glob top encapsulant from integrated circuit packages during failure analysis. The current method using fuming nitric acid is unable to remove glob top without damaging the package. Experiments using concentrated sulfuric acid at high temperatures were performed on dummy samples. Key findings include: 1) Boiling concentrated sulfuric acid was able to successfully remove glob top and expose the silicon die and bond wires without inducing damage to the package. 2) Fuming nitric acid can over-etch the substrate and cause issues like misplaced die before fully removing the glob top. 3) Proper safety precautions must be followed when using concentrated sulfuric acid due to its corrosive and oxidizing properties.
A welder specializes in fusing materials like metals or plastics together using welding equipment. Welders must have dexterity, technical knowledge of materials, and awareness of safety practices, as welding can be dangerous if not done properly. Personal protective equipment like gloves, jackets and helmets are worn to prevent burns from heat and ultraviolet light exposure. Welding curtains also shield bystanders from ultraviolet light.
underwater welding is the process of welding at elevated pressures, normally underwater. Hyperbaric welding can either take place wet in the water itself or dry inside a specially constructed positive pressure enclosure and hence a dry environment. It is predominantly referred to as "hyperbaric welding" when used in a dry environment, and "underwater welding" when in a wet environment. The applications of hyperbaric welding are diverse—it is often used to repair ships, offshore oil platforms, and pipelines. Steel is the most common material welded.
Welding processes have become increasingly important in almost all manufacturing industries and for structural application.[5] Although a large number of techniques are available for welding in atmosphere, many of these techniques cannot be applied in offshore and marine application where presence of water is of major concern
Tips and Method for Maintenance Metal Roofing | Alpha RainAlpha Rain
Metal roofing contractors norther VA highly recommend that you keep an eye on the shingles. Follow this methods for maintenance of metal roofing. To know more about metal roofing maintenance view our infographic.
Underwater welding is an important technique used for underwater fabrication. There are two main types: wet welding, where welding is performed directly under water using a special electrode, and dry welding, where an enclosed chamber is used to displace water and allow welding in a dry environment filled with gas. Wet welding is more common due to greater freedom of movement but has higher risks, while dry welding has higher costs but lower risks. Underwater welding requires higher currents than air welding due to water cooling the weld. It is used in offshore construction, ship repair, and salvage operations. Underwater welders require commercial diving certification and welding qualifications.
The document provides practical solutions for combating corrosion at home, including removing corrosion mechanically or with chemical products like rust removers. It recommends applying an anticorrosive primer and paint to protect metal surfaces. For tools and equipment, it suggests using desiccant bags to absorb moisture that causes corrosion during storage. The document also discusses how corrosion has some benefits and is a natural phenomenon, rather than something pernicious.
Customer Bulletin 0611 Insulant Impact on Corrosion in Steel Piping Applicati...Dyplast Products
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.
Corrosion Under Insulation Inspection In Ammonia Urea PlantAsirul Hoq
This document discusses corrosion under insulation (CUI) inspection planning for an ammonia and urea plant. It defines CUI and outlines the susceptible materials, temperature ranges, mechanisms, and locations. It provides details on organizing the inspection work, developing a schedule, selecting inspection types, and identifying at-risk equipment. Pipeline CUI is also addressed, highlighting common locations and examples found. The conclusion emphasizes the challenges of CUI detection and recommends design improvements and coatings to reduce corrosion risks over the long-term.
The document discusses corrosion under insulation (CUI) and corrosion under fireproofing materials. It notes that CUI is a widespread issue caused by water and oxygen entering insulated systems. Factors that can contribute to CUI include moisture ingress through insulation or fireproofing cladding, punctures or slipped cladding, and the presence of chlorides or other salts. Advanced non-destructive testing methods like thermography, profile radiography, and pulsed eddy current are useful for inspecting for CUI without removing insulation. Case studies demonstrate examples of CUI due to issues like lack of drain holes in insulated support rings.
This document discusses corrosion protection coatings and systems. It provides information on coating selection processes, construction phases, issues that can cause corrosion, and how to overcome those issues through coatings, sealing, and encapsulating. It also discusses specific coating products, applications, testing, and certifications.
The document describes the Goodall BR8 Inferno Steamhose. It addresses 8 common problems with steam hoses: 1) inner layer popcorning, 2) outer layer blowing, 3) metal braid rusting, 4) unclear hose markings, 5) premature aging, 6) hose kinking, 7) static charge build up, and 8) fitting leaks. For each problem, it provides the solution the BR8 Inferno addresses through features like an extruded butyl rubber inner layer, pin-pricked outer layer, brass-coated double braided steel, clear spiral markings, weather-resistant cover, and EN14423 leak-proof couplings.
The document summarizes the services provided by Chicago Corrosion Group, LLC. The company offers corrosion prevention and coating consulting services to help clients identify optimal and cost-effective corrosion prevention solutions. Services include condition surveys, root cause analysis, solution identification, specifications development, project management, quality control, and general contracting. The company aims to act solely in the clients' best interests and help them reduce costs with solutions that have low maintenance, high durability, and good performance.
Rust forms in mission-critical facilities when iron combines with oxygen and water in the presence of an electrolyte like moisture. High humidity above 50% RH causes corrosion to grow exponentially by providing the electrolyte. Maintaining humidity between 45-55% RH prevents rust and dendrites by eliminating electrolytes while avoiding static electricity. Properly sealing facilities with vapor barriers controls humidity and prevents infiltration that can cause equipment failures.
Tempered glass is easy to self explosion. “self-explosion” is the unavoidable problem of tempered glass,In
fact, tempered glass is not horrible, and the potential self-explosion of tempered glass has always been the
focus of attention.
The document discusses common condensation problems that occur in metal buildings due to humidity, and provides tips to address this issue, including using proper insulation to regulate temperature; ensuring a strong, waterproof foundation; installing a vapor barrier between floors; using good sealants on joints and seams; including vents for air circulation; and using a dehumidifier as a last resort solution. The main causes of condensation are humidity building up inside due to improper construction or heating systems, and it commonly appears as visible condensation on surfaces or concealed condensation in wall and roof cavities.
What are the possible exposure sources?
Crystalline silica can be found in certain types of natural materials, such as:
• Sand
• Soil and rock
• Gravel
• Sandstone
• Slate
• Granite
• Clay
107 yun-yu wang - 7538029 - method of room temperature growth of si ox on s...Mello_Patent_Registry
Yun-Yu Wang, Christian Lavoie, Kevin E. Mello, Conal E. Murray, Matthew W. Oonk - Method of Room Temperature Growth of SIOx on Silicide as an Etch Stop Layer for Metal Contact Open of Semiconductor Devices
Water Interactive Wet Welding Consulting - Len Andersen 914-536-7101 knows underwater welding and is known in the industry! The product for the Hurricane damaged platforms and pipelines. These wet welding stick and flux Core can be four time more productive than the old 3.2 mm slow wet weld. You can put in the weldment with 6.5 mm 450 mm electrodes and get production. There is 8018-C3 like stick to let your do higher strength steels! It is a patented proven wet welding process developed by Wet Welding to improve the profitability and potential of wet welding through a dry gelling agent and weld enhancers coating on ARC welding consumables which wets and activates near the ARC forming a gelatinous shielding envelope. The Resulting wet welding being done with as greater or greater ease (operability) than surface welding and a lessening of the cooling rate of the weldment such that 2T bends are obtainable.
Water Interactive Wet Welding Uses
• Pipelines • Sheet Steel Piling
• Offshore Platforms • Docks
• Ships and Barges • Dams and Canals
• US Navy Warships • Marine Salvage
Underwater welding is a specialized welding process that involves welding at depths below the surface of water. It can be classified as wet welding, where welding is done directly in water, or dry welding, where a dry chamber is created to perform the welding. Wet welding uses manual metal arc welding with direct current power and special electrodes. It allows for work in difficult to reach areas but results in lower quality welds due to quenching from the water. Dry welding produces higher quality welds by working in a pressurized chamber, but requires more complex and expensive equipment. Underwater welding is used for offshore construction, ship repair, and pipeline maintenance.
Chemical eye trauma can occur from exposure to strong acids or alkalis and represents 11.5-22% of ocular injuries. Acids like sulfuric acid and hydrochloric acid, as well as alkalis like potassium hydroxide and sodium hydroxide, can cause chemical burns to the eye depending on the concentration, duration of exposure, and type of chemical. Clinical signs include lid edema, corneal scarring, uveitis, and glaucoma. Treatment involves immediate irrigation of the eye, antibiotic eye drops, atropine, steroid drops to reduce inflammation, and surgery for complications like symblepharon or glaucoma. Proper first aid through irrigation can help minimize tissue damage from chemical burns.
This document discusses various methods of underwater welding. It begins by classifying underwater welding into dry welding and wet welding. Dry welding involves welding inside a chamber that is sealed around the structure, while wet welding is performed directly under water. The document then describes the processes and equipment used for dry welding methods like hyperbaric and cavity welding. It also covers the principles, advantages, and disadvantages of wet welding. The document concludes by discussing applications of underwater welding, the effects of the wet environment on welds, and providing a graph showing the relationship between porosity and water pressure during welding.
Underwater welding includes a lot of different processes that join metals on offshore oil platforms, pipelines & ships .It is the process of welding under water using various techniques under various conditions.....etc.!!!
This document describes experiments conducted to develop an improved technique for removing glob top encapsulant from integrated circuit packages during failure analysis. The current method using fuming nitric acid is unable to remove glob top without damaging the package. Experiments using concentrated sulfuric acid at high temperatures were performed on dummy samples. Key findings include: 1) Boiling concentrated sulfuric acid was able to successfully remove glob top and expose the silicon die and bond wires without inducing damage to the package. 2) Fuming nitric acid can over-etch the substrate and cause issues like misplaced die before fully removing the glob top. 3) Proper safety precautions must be followed when using concentrated sulfuric acid due to its corrosive and oxidizing properties.
A welder specializes in fusing materials like metals or plastics together using welding equipment. Welders must have dexterity, technical knowledge of materials, and awareness of safety practices, as welding can be dangerous if not done properly. Personal protective equipment like gloves, jackets and helmets are worn to prevent burns from heat and ultraviolet light exposure. Welding curtains also shield bystanders from ultraviolet light.
underwater welding is the process of welding at elevated pressures, normally underwater. Hyperbaric welding can either take place wet in the water itself or dry inside a specially constructed positive pressure enclosure and hence a dry environment. It is predominantly referred to as "hyperbaric welding" when used in a dry environment, and "underwater welding" when in a wet environment. The applications of hyperbaric welding are diverse—it is often used to repair ships, offshore oil platforms, and pipelines. Steel is the most common material welded.
Welding processes have become increasingly important in almost all manufacturing industries and for structural application.[5] Although a large number of techniques are available for welding in atmosphere, many of these techniques cannot be applied in offshore and marine application where presence of water is of major concern
Tips and Method for Maintenance Metal Roofing | Alpha RainAlpha Rain
Metal roofing contractors norther VA highly recommend that you keep an eye on the shingles. Follow this methods for maintenance of metal roofing. To know more about metal roofing maintenance view our infographic.
Underwater welding is an important technique used for underwater fabrication. There are two main types: wet welding, where welding is performed directly under water using a special electrode, and dry welding, where an enclosed chamber is used to displace water and allow welding in a dry environment filled with gas. Wet welding is more common due to greater freedom of movement but has higher risks, while dry welding has higher costs but lower risks. Underwater welding requires higher currents than air welding due to water cooling the weld. It is used in offshore construction, ship repair, and salvage operations. Underwater welders require commercial diving certification and welding qualifications.
The document provides practical solutions for combating corrosion at home, including removing corrosion mechanically or with chemical products like rust removers. It recommends applying an anticorrosive primer and paint to protect metal surfaces. For tools and equipment, it suggests using desiccant bags to absorb moisture that causes corrosion during storage. The document also discusses how corrosion has some benefits and is a natural phenomenon, rather than something pernicious.
Customer Bulletin 0611 Insulant Impact on Corrosion in Steel Piping Applicati...Dyplast Products
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.
Corrosion Under Insulation Inspection In Ammonia Urea PlantAsirul Hoq
This document discusses corrosion under insulation (CUI) inspection planning for an ammonia and urea plant. It defines CUI and outlines the susceptible materials, temperature ranges, mechanisms, and locations. It provides details on organizing the inspection work, developing a schedule, selecting inspection types, and identifying at-risk equipment. Pipeline CUI is also addressed, highlighting common locations and examples found. The conclusion emphasizes the challenges of CUI detection and recommends design improvements and coatings to reduce corrosion risks over the long-term.
The document discusses corrosion under insulation (CUI) and corrosion under fireproofing materials. It notes that CUI is a widespread issue caused by water and oxygen entering insulated systems. Factors that can contribute to CUI include moisture ingress through insulation or fireproofing cladding, punctures or slipped cladding, and the presence of chlorides or other salts. Advanced non-destructive testing methods like thermography, profile radiography, and pulsed eddy current are useful for inspecting for CUI without removing insulation. Case studies demonstrate examples of CUI due to issues like lack of drain holes in insulated support rings.
This document discusses corrosion protection coatings and systems. It provides information on coating selection processes, construction phases, issues that can cause corrosion, and how to overcome those issues through coatings, sealing, and encapsulating. It also discusses specific coating products, applications, testing, and certifications.
8. Complex_Structures_Technical Seminar for Cathodic Protection to GOGC Desig...SergeRINAUDO1
Cathodic protection of complex structures refers to protecting structures that cannot be electrically isolated from other metallic structures due to technical or safety reasons. EN 14505 provides guidelines for protecting such complex structures. There are two main approaches - isolated systems where every pipe/structure is isolated, and non-isolated or total systems where all metallic parts are electrically continuous. For complex structures, criteria include demonstrating that protection current can enter the structure and that temporary disconnection of probes/coupons shows the structure is polarized. The presentation covered cathodic protection design challenges and considerations for complex plant facilities with interconnected buried pipes and tanks.
Basic Mechanisms of Corrosion and Corrosion Control for Water and Wastewater ...GustavoGonzlezServa
This document discusses corrosion mechanisms and corrosion control for water and wastewater systems. It begins by defining corrosion and describing the 4 components of an electrochemical corrosion cell: the anode, cathode, electrolyte, and metallic path. It then discusses various corrosion mechanisms for water pipes, including internal corrosion in wastewater systems driven by sulfuric acid formation. The document outlines the 4 main methods for corrosion control: material selection, inhibitors, coatings, and cathodic protection. It emphasizes that corrosion control is a long-term process rather than a single project. Condition assessment techniques for various pipe materials are also summarized.
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 document summarizes a presentation on corrosion under insulation (CUI) and coatings for mitigating CUI. It discusses how CUI occurs due to moisture ingress under insulation and temperature cycling. Several coating types are described that can provide barrier protection for steel under insulation, including epoxy phenolic, silicone acrylic, thermal spray aluminum, titanium modified inorganic copolymers, and inert multipolymeric matrix paints. Test methods for evaluating CUI coatings like cyclic pipe tests and CUI chambers are also summarized. Real-world case studies show how some coatings have performed well under long-term cyclic service conditions.
Crevice corrosion is a localized form of corrosion that occurs in confined, shielded areas where solutions can stagnate, such as under gaskets, fasteners, or deposits. It results from differences in concentration of oxygen and chlorides between the crevice (anode) and outside of it (cathode), which sets up an electrochemical cell. Factors like crevice geometry and chemistry, material composition, and environmental conditions affect its occurrence. It is a significant issue for corrosion-resistant alloys in systems with pure water chemistry and can cause component failure while appearing as minimal overall material loss, making it difficult to detect. Methods to prevent it include eliminating crevices, using solid gaskets, employing higher-alloy materials,
Elysator Professional Summary VDI 2035, Part 2Roger Conarroe
This document summarizes guidelines from VDI 2035 Part 2 on preventing corrosion in hydronic heating systems. Key factors that influence corrosion are dissolved oxygen content, electrical conductivity, and pH of the water. To minimize corrosion, oxygen content should be less than 0.1 mg/L for low-salinity systems and less than 0.02 mg/L for saline systems, while maintaining pH between 8.2-10. Proper sealing and limiting oxygen entry into the system through components like expansion vessels and tubing is important to control these factors and prevent corrosion damage to system materials like steel, copper, aluminum, and others.
This document discusses cathodic protection as a technique to prevent corrosion of reinforced concrete structures. It involves introducing a more negatively charged anode material into the concrete to divert electrons away from the reinforcing steel and prevent corrosion. This provides permanent protection for the 100+ year design life of structures. Case studies show it has been successfully applied to new cooling water structures in the Middle East using Elgard mixed metal oxide ribbon anodes secured to the reinforcement before pouring concrete.
The document discusses preservation and prevention of corrosion. It provides information on different types of corrosion including uniform corrosion, pitting corrosion, crevice corrosion, and intergranular corrosion. It also discusses factors that affect the deterioration of pipe coatings during long-term storage and measures that can be taken to mitigate coating damage and end disbondment. These include selecting coatings that absorb less moisture and are more resistant to UV/heat, improving coating application processes, and developing effective temporary preservation methods for coated pipes in storage.
STAUFF ACT clamps are an innovatively designed solution for installing instrumentation pipework in offshore oil and gas environments where corrosion resistance is critical. The clamps address the issues of crevice and pitting corrosion that often occur under traditional plastic pipe clamps. STAUFF ACT clamps underwent stringent internal testing and independent third party testing, including salt spray tests and field tests on an offshore rig, to validate their ability to prevent crevice corrosion and extend maintenance intervals compared to other solutions. The clamps are constructed of materials compliant with relevant industry standards for offshore use.
- Partial discharge monitoring allows detection of localized dielectric breakdown within electrical insulation systems under high voltage stress, helping locate issues before catastrophic failure.
- At Arrium, failures were costing millions on average and causing production losses, with risk of injury.
- Using an UltraTEV Plus instrument, partial discharge can be safely detected through emitted transient earth voltages and ultrasound, without de-energizing equipment.
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3. CUI Introduction Why CUI Occurs
How to Detect CUI How to Prevent CUI
CORROSION
UNDER
INSULATION
Safety Consequences Due to CUI
Chapters
Awareness
4. CUI Introduction How CUI Occurs
How to Detect CUI How to Prevent CUI
CORROSION
UNDER
INSULATION
Safety Consequence Due to CUI
Chapters
5. CUI Introduction
CUI is known as the hidden enemy, defined as
the external corrosion of piping and
equipment’s fabricated from carbon-
manganese, low alloy and austenitic stainless
steels that occurs underneath externally
jacketed insulation owing to the penetration of
water.
CUI has been occurring for as long as hot or
cold piping and equipment's have been
insulated for:
o Thermal protection
o Energy conservation
o Process stabilization
6. Leaks Due to CUI
CUI Introduction
It is not a new problem, but can be a serious
problem.
CUI is a major common problem on a
worldwide basis that is shared by all the
refining, petrochemical, power, industrial,
onshore and offshore industries.
CUI has been responsible for many major
leaks that lead to health & safety incidents,
result in lost production and are responsible
for the large maintenance budgets which are
required to mitigate the problem.
7. Leaks Due to CUI
CUI Introduction
At one chemical process plant alone, the CUI
cost was reported to be in the million of
dollars.
A common but incorrect assumption is that
insulation also protects against corrosion.
CUI rate depends on temperature and
internal or external containment sources.
o The insulation usually hides the corroding
metal and the problem can go undetected for
years until metal failure occurs.
o CUI problems are commonly found to be
significant after about 5 years.
8. Leaks Due to CUI
CUI Introduction
CUI cannot be visually detected during normal
service without removal of the insulation.
o The corroded surface is mostly hidden by the
insulation system and will not be identified until
the insulation is removed for inspection or in the
event of metal failure leading to health and safety
incidents.
The necessity of protection against CUI must
be determined for each individual plant that
helps preventing un-necessary maintenance,
un-expected shutdowns, and catastrophic
failures that lead to health & safety incidents.
9. Corroded Pipe
o Corrosion or sometimes called rust comes from
“corrous” which means eating away.
o Corrosion can be defined as the destructive
attack of a metal by chemical or electrochemical
reaction with its environment.
Deterioration by physical causes is not called
corrosion, but is described as erosion, galling, or
wear.
o Anode, cathode, metallic pathway, and
electrolyte are known as the corrosion cell.
CUI Introduction
What corrosion is?
10. Corrosion
o On carbon steels, the corrosion under insulation
is usually of a general or pitting type.
CUI Introduction
What corrosion is?
It has been recognized within industry that carbon
steel operating with a skin temperature in the
temperature range of -4°C to 175°C has the
greatest likelihood of CUI.
Insulated surfaces for carbon steel operating
continuously above 175°C or below -4°C do not
present major CUI problems.
However, steadily or cyclically between these
temperature may suffer significant corrosion
problems.
11. Corrosion
CUI Introduction
What corrosion is?
Insulated surfaces for stainless steel operating
continuously above 175°C or below 50°C do not
present major Cl-ESCC problems.
However, steadily or cyclically between these
temperature may suffer significant Cl-ESCC
problems.
o On austenitic or duplex stainless steels, the
corrosion is almost always chloride stress
corrosion cracking (Cl-ESCC).
The temperature range of 50°C to 175°C has the
greatest likelihood of Cl-ESCC.
12. Water
Insulation
Protective
Covering
Pipe/Substrate
Why Does CUI Occur
CUI of carbon-manganese steels and low-
alloy steels usually occurs when steel is
contacted by aerated water.
A source of water, chlorides, and net tensile
stress causes Cl-ESCC of austenitic stainless
steel.
CUI has been reported under all type of
insulation material.
The insulation type may only be a
contributing factor.
13. Water
Insulation
Protective
Covering
Pipe/Substrate
Why Does CUI Occur
Water or moisture (electrolyte) must be
present on the insulated substrate in order to
allow CUI to take place.
There are many sources of water that can
enter into the installed insulation system.
The principle source of water are:
1. Infiltration from external sources
2. Condensation
14. Water
Insulation
Protective
Covering
Pipe/Substrate
Water infiltrates/ingress into the insulation from
the following external sources:
o Rainfall
o Drift from cooling towers
o Condensate falling from cold service
equipment’s
o Steam discharge
o Process liquid spillage
o Spray from fire sprinklers, deluge systems, and
washdowns
o Groundwater
o Condensation on cold surfaces after vapor
barrier damage
Why Does CUI Occur
15. Damaged
Protective Covering
How does water enter in the insulation?
o External water enters an insulated system
primarily through breaks in the protective
covering or weatherproofing.
The protective covering breaks may be the
result of the following:
o Inadequate design
o Improper insulation installation
o Mechanical abuse
o Poor maintenance practice
Why Does CUI Occur
16. Wet Insulation
CUI
Damaged
Protective Covering
Pipe
Water Over Protective Covering
How does condensation occur?
o Condensation results when the temperature of
the metal surface is lower than atmospheric
dew point.
Why Does CUI Occur
17. Moist Insulation
CUI
Damaged
Protective Covering
Pipe
Water Over Protective Covering
Role of the water soluble contaminants
o Contaminants increase the conductivity
and/or corrosiveness of the water
environment under insulation.
o Chlorides and sulfates are the principle
contaminants found under insulation.
o There are two primary sources of
contaminants in water under insulation:
1. Contaminants external to the insulation
materials.
2. Contaminants leached from the insulation
materials and its accessories.
Why Does CUI Occur
18. Moist Insulation
CUI
Damaged
Protective Covering
Pipe
Water Over Protective Covering
Role of the water soluble contaminants
o Whether the sources of contaminants are
external or internal, they are particularly
detrimental and accelerate the rate of corrosion
under insulation.
o External contaminants are generally salts that
come from sources such as:
1. Cooling tower drift
2. Acid rain
3. Firewater deluge
4. Atmospheric emissions etc.
Why Does CUI Occur
19. Moist Insulation
CUI
Damaged
Protective Covering
Pipe
Water Over Protective Covering
Role of the water soluble contaminants
o Sources of Chlorides
o Unless the insulation materials and its
accessories are declared “chloride free”
chlorides can be present in almost all
components of the insulation system such as:
1. Insulation materials
2. Mastic or sealants
3. Vapor barriers
4. Jointing compounds and adhesives
5. Anti abrasive coatings
o Contaminants may also be present over the protective
coating applied on the steel surface to be insulated.
Why Does CUI Occur
20. Moist/Wet Insulation
CUI
Damaged
Protective Covering
Pipe
Water Over Protective Covering
Role of temperature
o Service temperature is an important factor
affecting the rate of CUI of carbon steel because
two opposing factors are involved:
Higher temperatures reduce the time water is in
contact with the carbon steel; however, Reduces
the service life of protective coatings, mastics,
sealants and make the water more corrosive.
Why Does CUI Occur
CUI is a strong possibility If:
o Steel work is not protected with a suitable coating
and the insulation is not installed in a dry state
under dry conditions and protected by adequate
weather-resistant cladding/protective covering.
21. Detecting CUI is a multi-disciplinary work.
How to Detect CUI
Good communication and understanding is
required between the group members.
Best time to execute inspection to detect CUI is
during plant shutdown period and dry season.
Insulation is a hazardous material so proper
safety supervision is also important while
detecting CUI.
22. It’s a difficult task to detect and measure the
effects of CUI as thermal insulation creates a
formidable barrier to easy inspection for
corrosion damage.
How to Detect CUI
Removing all the insulation would be the ideal
method for locating and evaluating CUI, but this
is time-consuming and expensive.
Inside (indoors) areas are less at risk for CUI,
provided that they are not near hose-down,
safety shower, or fire protection deluge systems.
23. There are several ways of detecting CUI on
piping systems.
Detecting CUI on vessels is generally more
difficult, but it is possible using some
techniques.
How to Detect CUI
Before selecting a CUI detection technique or
methods consideration should be given to the
following:
o Utilized metallurgy (CS, SS etc.).
o Operating conditions.
o Insulation and protective covering type and their
thickness.
24. Following techniques are used to detect CUI:
o Visual inspection
How to Detect CUI
100% insulation removal
o Nondestructive moisture and corrosion
detection technique’s
Moisture meter
Partial insulation removal
Infrared thermography
Profile, flash radiography
Pulsed eddy current
Ultrasonic testing
o Options are not limited to the
techniques given here, and other
techniques may also be appropriate.
25. Complete (100%) insulation removal
The most reliable technique to detect CUI is to
physically remove the insulation and visually
inspect the surface damage due to CUI.
How to Detect CUI
This approach is costly and time consuming since
insulation on equipment or piping etc. must be
stripped and reinstalled.
Scaffolding costs to access insulated areas for
insulation removal, inspection and re-insulation can
be significant especially for large vessels or piping
systems on columns or towers.
o The only method that can detect 100% CUI
damage.
26. This Method Involves
Insulation Removal
Check the Surface
Condition
Metal Thickness
Measurement
Rectification of the
Problem Areas
Reinsulate the Surface
Complete (100%) insulation removal
How to Detect CUI
o Process-related problems may also occur if the
insulation is removed while the
piping/equipment is in service.
o This is a qualitative method to detect CUI that
cannot directly measure the loss of metal
thickness, and requires other NDT techniques
such as pit gauge, ultrasonic testing or
radiography to quantify metal loss.
Insulation removal and Inspection personnel may
be exposed to hot surfaces and need to be careful
to avoid contact with surfaces at or above 60°C.
27. Partial Insulation
Removal
Partial insulation removal
How to Detect CUI
o Risk evaluation team of a plant decides if the
removal of insulation is required to be partial
or 100%.
If the evaluated risk level is at high extreme
then 100% insulation removal is necessary.
If the evaluated risk level is medium-high then
greater than 40% of insulation removal is
necessary including all critical points and
damaged area’s.
If the evaluated risk level is medium then 20% of
insulation removal is necessary including all
critical points and damaged area’s.
28. Partial Insulation
Removal
Partial insulation removal
How to Detect CUI
o Risk evaluation team of a plant decides if the
removal of insulation is required to be partial
or 100%.
If the evaluated risk level is low then removal of
insulation at all critical points with evidence of
damage is necessary.
No inspection is required if the evaluated risk
level is negligible.
Risk evaluation team also locates and marks all
critical areas of a piping or equipment to cut
inspection openings for metal thickness
measurement and visual inspection.
29. Inspection Window
Inspection openings
How to Detect CUI
o CUI may be detected through inspection
openings/windows.
o The technique requires a little cost to evaluate
CUI initially.
o Generally carried out as a first pass and is
usually limited by access.
o Only covers small area’s that provide a guide
to potential problem area’s.
o The windows can be a source of water or
moisture ingress.
30. Inspection Window
Inspection Windows
Inspection openings
How to Detect CUI
o Inspection windows are installed on critical
locations where there is a possibility of CUI.
o The openings are removed to access the
condition of the surface under the window.
If there is indication of coating damage or starting of
general corrosion under inspection window some
insulation can be removed and extent of damage is
determined to repair.
o Special consideration is given on the condition
of the coating under insulation.
If the coating under the inspection window is good
then it is an indication of less CUI in the system.
31. Ultrasonic Thickness
Measurement (UT)
Uniform Oxidation
& Thinning
Pit Depth
Measurement
Carbon Steel
Localized Metal
Loss
Stainless Steel
Cl-Stress Corrosion
Cracking
Liquid Penetrant Testing (PT)
Eddy Current Testing (ECT)
Metal Thickness
Measurement
Insulation Removal if
CUI is Detected
This Method Involves
NDT Examination
Rectification of the
Problem Areas
Reinsulate the Surface
Nondestructive (NDT) moisture and corrosion
detection technique’s
How to Detect CUI
o Selecting an NDT technique for detecting CUI
requires detailed knowledge of the piping
system or equipment layout as well as
advantages and disadvantages with a cost to
benefit ratio.
o When insulation removal is not practical, suitable
NDT methods are used for detecting CUI.
o It is also recommended to hire a trained and
certified NDT technician(s) to detect CUI of a
piping or equipment.
33. Regardless the method(s) used to detect CUI, it
is also necessary to consider highly susceptible
CUI area’s of a piping or equipment's, such area’s
can be:
How to Detect CUI
o Water penetration area’s
o Damaged insulation area’s
Experience has shown that the rate of CUI on
these susceptible area’s of a piping or
equipment’s are greater than the other area’s.
Periodic inspection (Visual and/or NDT) is
recommended on these area’s.
= Susceptible Area’s
34. Water penetration area’s
How to Detect CUI
o All penetrations or breaches in the insulation
jacketing systems such as:
Dead legs
Hangers and other supports
Valves and fittings
Bolted-on pipe shoes
Ladders and platforms
Vessel name plates attached by welding
Steam tracer tubing penetrations
Termination of insulation at flanges etc.
35. Damaged Insulation Area
Missing Jacketing
Rust Staining on
Jacketing
Damaged insulation areas are:
How to Detect CUI
o Damaged or missing insulation jacketing.
o Termination of insulation in a vertical pipe or
piece of equipment.
o Caulking that has hardened or separated or
missing.
o Bulges, staining of the jacketing system.
36. Fire Water Line
Above the
Insulated Piping
Other area’s susceptible to CUI
How to Detect CUI
o Area’s exposed to source of water such as:
Mist overspray from cooling towers
To steam vents
To deluge systems
To process spills etc.
CUI
o Systems that normally operates between -5°C
to 175°C (for CS) and 50°C to 175°C (for SS).
Services that are outside of the above range, but
are in intermittent service or are subjected to
frequent outages are also included in the
susceptible to CUI.
37. Damaged Jacketing
Damaged
Caulking or Mastic/Jacketing
How to Detect CUI
o Systems in which vibration has a tendency to
inflict damage on insulation jacketing or
caulking, providing paths for water ingress.
o Systems with deteriorated coating and/or
wrapping.
o Cold service equipment consistently operating
below the atmospheric dew point.
o Steam-traced systems experiencing tracing
leaks, especially at tubing fittings beneath the
insulation.
Other area’s susceptible to CUI
38. No Sealant
How to Detect CUI
o Systems in which vibration has a tendency to
inflict damage on insulation jacketing or
caulking, providing paths for water ingress.
o Systems with deteriorated coating and/or
wrapping.
o Cold service equipment consistently operating
below the atmospheric dew point.
o Steam-traced systems experiencing tracing
leaks, especially at tubing fittings beneath the
insulation.
Other area’s susceptible to CUI
Improper Installation
39. How to Detect CUI
Example of Piping Areas of Concern
40. How to Detect CUI
Example of Vessel Areas of Concern
42. To prevent CUI, a lot of prevention strategies
are required to be taken from the design stage
through construction, plant operation, to
shutdown a plant.
CUI prevention strategies provide long term
and reliable prevention of CUI that move
towards free from “un-necessary shutdowns”,
“un-expected maintenance”, “catastrophic
failure” of the systems and significant
maintenance cost reductions.
How to Prevent CUI
43. How to Prevent CUI
CUI prevention strategies include following
elements:
1. Design – piping, equipment, and tank.
2. Protective coating selection.
3. Insulation installation procedure or specification.
4. Insulation installation by a skilled
craftmanship/contractor.
5. Ongoing inspection (visual and/or NDT) and
maintenance practices during plant operation.
6. Periodic strip, abrasive blast, re-paint and re-
insulate the system during plant operation and/or
shutdown.
44. How to Prevent CUI
Design – piping, equipment, and tank
o Equipment and piping design has an
important influence on CUI.
o If proper consideration is given to CUI at the
design stage it may be possible to eliminate
corrosion altogether, or at least to limit the
potential for CUI and Cl-ESCC.
45. PP Insulation
(Mesh)
How to Prevent CUI
Design – piping, equipment, and tank
o The best way of avoiding CUI is not to insulate
a piping or equipment at all.
o The above statement is not always practical
saying not to insulate a surface when a surface
must be insulated for: heat conservation,
process stabilization, preventing freezing,
reduce noise pollution, and personal protection
etc.
o But, where insulation is required only for
personal protection (PP) it is recommended to
fit metal guards/mesh rather than insulation.
46. Insulated Pipes Placed
too Close
Pipe is Too Close with an
Insulated Equipment
How to Prevent CUI
Design – piping, equipment, and tank
o When designing where to situate equipment
and piping, consideration should be given to
allow effective space for insulation installation,
inspection and maintenance.
Above design problems may allow no sufficient gap/space to insulate a surface, leave chances
of water or moisture intrusion, and are practically impossible to inspect the entire insulated
surface and maintain effectively during construction, operation and maintenance stages.
For example, a designer should not design to
install/situate pipes:
Too closed together
Too closed together with steel structure,
gratings, cable trays etc.
Too closed together with an equipment
47. Water Entry Points
Through Protrusions
How to Prevent CUI
Design – piping, equipment, and tank
o Other undesirable design features of an
equipment or tank that can influence the rate of
CUI are:
Using shapes that funnel water into the insulation,
such as angle-iron brackets.
Items that cause interruption in the
weatherproofing, such as lifting lugs, ladder
brackets, nozzle extensions, decking and platform
supports, nameplates etc.
Using shapes that are likely to retain water, such as
flat horizontal surfaces, vacuum rings and
insulation support rings etc.
48. Breaks in
Weatherproofing
Design – piping, equipment, and tank
How to Prevent CUI
o The more breaks that there in the
weatherproofing, the more likely it will be that
water will enter the insulation and potentially
cause CUI.
o It is therefore essential to minimize the number
of nozzles, supports, vents, drains, and fixings
that will protrude through the weatherproofing.
The good practice is to cut off all unnecessary
protrusion such as lifting lugs once the equipment
has been lifted and securely fixed in position.
49. Load Bearing Support
Design – piping, equipment, and tank
How to Prevent CUI
o It is considered good practice to use high-
density insulation at support locations and to fit
load-bearing supports that will contact the
weather proofing only, thus resulting in a
continuous weatherproofing.
o Locating valves and flanges in the horizontal
part of piping runs rather than the vertical to
limit water retention is also a good practice.
50. Duplex Stainless Steel
The Best Choice for Corrosive
Environment
Design – piping, equipment, and tank
How to Prevent CUI
o If the risk of CUI is considered very high, for, say,
carbon steel, the designer may select another
material of construction that will not suffer from
CUI.
Small diameter piping (3 NPS or less) appears to
be prone to CUI leaks because of its low wall
thickness, increased number of field welds, coating
inefficiency and the tendency to pay less attention
during handling, maintenance and inspection.
Austenitic or duplex stainless steels, may be
selected, accepting that there may still be a risk of
Cl-ESCC.
51. Open Cell Insulation
Closed Cell Insulation
Design – insulation system
How to Prevent CUI
o The next step in the design is proper insulation
selection.
o Generally industrial insulation fall into two
categories:
Low temperature (below ambient)
High temperature (above ambient)
o Low temperature insulation typically includes
PUF, PIR, flexible elastomeric foam, cellular glass
and phenolics etc.
o High temperature insulation typically includes
mineral wool, calcium silicate, perlite, cellular
glass and fiberglass etc.
52. Open Cell Insulation
Closed Cell Insulation
Design – insulation system
How to Prevent CUI
o Each and every insulation material listed in the
previous slide has limitation, advantages and
disadvantages.
o Consideration should be given by the designer
to select an insulation material that minimizes
water ingress and does not retain water.
o Closed cell insulation materials (flexible
elastomeric foam or cellular glass) can provide a
more effective barrier to water ingress than open
cell insulation materials (mineral wool or calcium
silicate).
53. Design – insulation system
How to Prevent CUI
o In addition to water absorbency, another factor
to consider is the chemical content of the
insulation.
Insulation materials and its accessories must be
free from chloride, salts or other contaminants that
can accelerate the rate of corrosion under
insulation.
o High density insulation material is
recommended at area’s of high foot traffic so
that, if the weatherproofing is walked on, it is
not easily damage.
54. Design – insulation system
How to Prevent CUI
o System movement must be allowed for in
insulation system design.
Rigid and semi rigid insulation may require
expansion joints.
Failure to install these joints can result in
uncontrolled movement of the insulation in relation
to the equipment or piping.
This may result in vapor barrier or weatherproofing
breakdown and condensation or ingress of water
into the insulation.
o The linear coefficient of thermal expansion or contraction
of both piping and insulation must also be considered.
55. Design – insulation system
How to Prevent CUI
o Weatherproofing provides mechanical and
weather protection for insulation systems.
o Although weatherproofing acts as a primary
barrier to CUI, it susceptible to weather, chemical
attack and foot traffic damage once it is installed;
therefore consideration should be given to select
an appropriate weatherproofing material that can
resist the above problems.
o Insulation weatherproofing materials are basically
metallic and non-metallic.
The use of UV-cured GRP weatherproofing provides a more robust
barrier that can support foot traffic without becoming damaged.
56. Protective coating selection
How to Prevent CUI
o Protective coatings applied to the external
surface of equipment, tanks, and piping are the
last line of defense in preventing CUI.
o Following coatings and wrapping are most
commonly used to reduce the potential for CUI:
Organic coatings
Thermally sprayed aluminum coatings (TSA)
Aluminum wrapping
o A careful consideration should be given by the
designer to select an appropriate coating or
wrapping to protect the steel from CUI.
57. Protective coating selection
How to Prevent CUI
o Organic coatings
Organic coatings need to be of high-quality
immersion grade to provide a barrier to CUI.
Organic coatings provides good protection
against corrosion, but water ingress into the
insulation causes premature coating
breakdown and significant CUI.
A “brittle” nature of the thin film organic
coatings lead to “nicks and scratches” during
pipe handling and installation.
Permeable nature of the organic coatings
continues to be the weak points in CUI.
58. Protective coating selection
How to Prevent CUI
o Organic coatings
Coatings applied on a prepared steel surface with
good quality control procedures are normally
considered to have a lifetime of 9 – 13 years
before routine inspection and maintenance is
required.
Continued development and evaluation of
organic coatings remains an important
contribution to CUI prevention technology.
59. Protective coating selection
How to Prevent CUI
o Thermally sprayed aluminum coatings
TSA coatings have been applied to carbon steel
piping or equipment to provide an effective barrier to
CUI.
Historically, TSA coatings have been less commonly
applied than organic coatings, one of the reason
could be its initial cost.
Experience has shown that TSA coatings perform
remarkably well preventing CUI with lifetime of 20 –
30 years before first inspection and maintenance are
required.
Therefore, it is important to consider life cycle
costing at the design stage when considering TSA
coatings instead of organic coatings.
60. Protective coating selection
How to Prevent CUI
o Aluminum foil wrapping
Aluminum foil wrapping has most often been
applied to insulated austenitic stainless steel piping
and equipment to limit the potential for Cl-ESCC.
There is good experience within industry that
aluminum foil wrapping has provided a more
effective solution than using organic coating.
Foil can act as both physical barrier and galvanic
barrier to prevent Cl-ESCC.
Care must be taken to ensure that the external
insulation weatherproofing is correctly applied
under the control appropriate quality assurance
level.
61. Insulation Specification
How to Prevent CUI
o Insulation specifications are critical requirements
for insulation system design and insulation work.
o Specification controls material and installation
requirements.
o Loosely written specifications with insufficient
material descriptions and installation
requirements may result in costly repairs during
construction or after the plant is operational.
o A specification needs to be complete and
detailed, it must clearly describe materials,
application, and finishing requirements.
62. Insulation Specification
How to Prevent CUI
o Common specification flaws to be avoided are:
Incorrect application materials
Open cell or wicking type insulation materials, such
as calcium silicate and fibrous products, specified for
below-ambient temperature applications.
Product specification by using a generic name
without stating the properties required for the
intended service.
Improper and unclear application methods
Incorrect multi-layer schedules, lack of expansion
joints, missing vapor barriers, and incorrect
insulation system securement methods etc.
63. Craftmanship – Insulation installation/Maint.
o Another critical factor that is frequently
overlooked is to review in detail with the
supervision responsible for insulation installation
during plant construction stage, maintenance
stage and so forth.
o An skilled and trained workmanship is necessary
to install and maintain an insulation system.
IOGS certified insulation applicators (CIA) are
recommended for installation and maintenance.
o Inspection following installation must be made
frequently on a routine basis by a qualified person.
IOGS certified insulation inspectors (CII) are
recommended to perform insulation inspection.
How to Prevent CUI
64. Ongoing inspection
How to Prevent CUI
o It is considered to be an important duty of a
facility owner to assign a dedicated insulation
team to inspect and maintain an insulation system
during the plant operation and maintenance stage.
o The ongoing inspection should include visual as
well as NDT.
o A plan should be developed to inspect and record
warning signs of CUI.
It is helpful to begin with a plant or area map
indicating location of equipment.
The map should be used as a point of departure to
prioritized, inspect, and record suspect insulation.
65. CUI Warning Signs No Mastic/Caulking
Ongoing inspection
How to Prevent CUI
o Following are the CUI warning signs that the
insulation inspection personnel should look for in
a CUI suspected area of a piping or equipment:
Weathered, damaged, inelastic, or missing
caulking/sealant.
Weathered, split, or missing mastic moisture
barriers.
Punctured, torn, loose, dislodged, slipped, missing
or corroded metal jacketing.
Unsealed piping terminations.
Gaps in jackets around piping hangers, at the tip of
vertical piping runs, and at other protrusions such
as structural stainless steel supports.
66. Staining
Open Joint in Jacket
Weatherproofing joints at 12 O’clock position
Ongoing inspection
How to Prevent CUI
o Following are the CUI warning signs that the
insulation inspection personnel should look for in
a CUI suspected area of a piping or equipment:
Swollen or blistered insulation.
Improper installation interfering with water run-off.
Mildew or moisture at insulation support rings or
vacuum rings.
Unprotected insulation where parts have been
removed.
Unsealed metal wall thickness test points.
Flashing that does not shed water.
Open joints in jackets from physical damage.
67. Patch Removal
CUI
Ongoing inspection
How to Prevent CUI
o Assessment of damage is performed if
investigations or observations indicate wet
insulation/CUI warning(s) listed in previous slide:
The extent of corrosion or structural damage to
the piping or equipment must be assessed.
Insulation removal should be carried out or the
corrosion should be evaluated by a suitable
NDT technique.
Remove a patch insulation, 18 – 24 in2 in area,
from vessel or piping >24in in diameter, or a
section approximately 3ft long from piping
<24in in diameter where there is probable
corrosion damage.
68. Patch Removal
CUI
Ongoing inspection
How to Prevent CUI
o Assessment of damage is performed if
investigations or observations indicate wet
insulation or CUI warnings listed in previous slide:
The extent of corrosion or structural damage to
the piping or equipment must be assessed.
Insulation removal should be carried out or the
corrosion should be evaluated by a suitable
NDT technique.
If CUI has occurred, remove all the insulation
from the damaged areas.
Inspect the total surface area, measure metal
thickness by a suitable NDT technique.
69. Patch Removal
CUI
Ongoing inspection
How to Prevent CUI
o Assessment of damage is performed if
investigations or observations indicate wet
insulation or CUI warnings listed in previous slide:
The extent of corrosion or structural damage to
the piping or equipment must be assessed.
Insulation removal should be carried out or the
corrosion should be evaluated by a suitable
NDT technique.
The damaged parts of the piping/equipment
must be repaired as necessary or replaced.
Surface preparation of the metal must be
carried out before application of the protective
coating, and finally the surface is reinsulated.
70. Patch Removal
CUI
Ongoing inspection
How to Prevent CUI
o Assessment of damage is performed if
investigations or observations indicate wet
insulation or CUI warnings listed in previous slide:
The extent of corrosion or structural damage to
the piping or equipment must be assessed.
Insulation removal should be carried out or the
corrosion should be evaluated by a suitable
NDT technique.
If there is no CUI and the insulation is dry,
replace the removed insulation and seal
thoroughly to avoid water or moisture ingress
using proper insulation installation technique.
71. Patch Removal
CUI
Ongoing inspection
How to Prevent CUI
o Assessment of damage is performed if
investigations or observations indicate wet
insulation or CUI warnings listed in previous slide:
The extent of corrosion or structural damage to
the piping or equipment must be assessed.
Insulation removal should be carried out or the
corrosion should be evaluated by a suitable
NDT technique.
If no CUI is detected upon insulation removal but
the insulation is found wet, remove the insulation
to the point where it is completely dry.
Eliminate the source of water intrusion, replace
the insulation and reinsulate the surface properly.
72. Periodic insulation stripping
o This is mostly seen when a plant is shutdown.
o Insulation removal or stripping may be carried out
based on Risk Based Inspection plan (RBI).
o The insulation stripping may be performed by a
facility owner every 5 years, in which a plant is
shutdown, insulation is removed, surface condition
of the piping or equipment is assessed (visual and
NDT), and method of repair is determined.
Replacement of a pipe/equipment may be necessary
if its integrity is affected by severe CUI of carbon steel
or by Cl-ESCC of austenitic or duplex stainless steel.
o Finally blast cleaning, re-coating, and re-insulation
of the piping or equipment is carried out.
How to Prevent CUI
76. CUI on Valves &
Flanges
CUI on Straight Pipe
How to Prevent CUI
77. CUI on Pipe Support of
an Electrical Traced Line
How to Prevent CUI
78. It is said that the “prevention is better than
cure” thus preventing CUI should be everyone
responsibility.
o It is strongly recommended that everyone who is
working in a plant is responsible for ensuring that
insulated systems are correctly installed, are
inspected and are properly maintained.
o All personnel that are working in the plant are
responsible for reporting damage to insulation
systems when observed.
o The higher management must also ensure that there
is a culture within the organization that reinforces the
need to treat insulated systems in a way that avoids
un-necessary damage that would promote CUI.
How to Prevent CUI
79. How to Prevent CUI
It is said that the “prevention is better than cure”
thus preventing CUI should be every one
responsibility.
o Maintenance department responsibility to ensure that
insulated systems (coating & insulation) are correctly
installed and maintained using approved standards and
that adequate quality checks are carried out.
o Operation department should ensure that damage to
insulation or steam tracing leaks under insulation are
reported immediately to the maintenance department for
repair.
o Inspection department should carry out inspection work
to locate CUI on insulated systems, assess the degree of
corrosion damage, and ensures that appropriate corrective
and preventive measures are taken.
80.
81. Man in the Picture : Southbore
This man order from me to do his
slide. After i done doing his slide, he
refuse to pay me and banned me
instead.
Shame on you...