Materials corrosion under insulation cui thermal spray. For this corrosion to occur, water must collect in the insulation and oxygen must be present. Another zone next to the dry out has pores of insulation, but they are filled with saturated salt solution. Corrosion under insulation is difficult to find because of the insulation cover that masks the corrosion problem until it is too late. To ensure controllable processes with little energy loss, columns, equipment, and pipes in refineries are insulated. The 7 inspection methods you must know about published on april 14, 2016 april 14, 2016 745 likes 74 comments. Cui is a common problem shared by the refining, petrochemical, power, industrial, onshore and offshore industries. Protection of corrosion under insulation using vapor phase. Corrosion under insulation cui is a severe form of localized external corrosion which occurs in carbon and low alloy steel pipe that has been insulated.
The integrity of pipelines and process equipment carrying hydrocarbons under pressure is essential and a potential leak or breakage can have catastrophic results. Corrosion under insulation cui occurs when watermoisture is trapped under insulationfireproofing. Concern about corrosion under insulation is shown by major oil companies who operate above the arctic circle. According to one specifier from a major oil company, cui problems account for more unexpected downtime than all other possible causes combined.
Corrosion under insulation is caused by the ingress of water into the insulation, which traps the water like a sponge in contact with the metal surface. Corrosion under insulation cui refers to the external corrosion of piping and vessels that occurs underneath externally cladjacketed insulation as a result of the penetration of water. Jun 18, 20 components resulting from water trapped under insulation in conjunction with other variables that accelerate and drive the corrosion external chloride stress corrosion cracking of austenitic and duplex stainless steel under insulation, again with other variables present that accelerate the corrosion cui is a phenomenon that has plagued the oil. Corrosion under insulation cui and how to prevent it. The type and rate of corrosion under insulation will vary. Corrosion under insulation cui is a problem in the industrial sector, including refining, petrochemical, power, industrial, onshore and offshore industries and it is a real threat to the on stream reliability of many of todays plants.
According to many corrosion engineers, problems such as major equipment stoppages unexpected maintenance costs stemming from cui result in. Corrosion under insulation cui is defined as a severe localized form of corrosion due to entrapped water under the insulation layer of piping and vessels. Vice president mechanical products division polyguard products, inc. Apr 05, 2018 the international standard organization iso has, under tc67, formed a working group wg11, which is going to develop isonp 19277 methods for control of corrosion under thermal insulation and fireproofing materials. These coatings are often used in process facilities such. I want to do research on the topic of corrosion under insulation for my msc in. This can be a particularly severe form of corrosion because of the difficulty in detection due to the corrosion occurring beneath insulation. Save energy control process temperatures protect workers from high temperatures nace standard rp0198981 is a good source of information, but electrolytes will eventually find their way.
Learned from corrosion under insulation overton, t, more lessons re. A holistic approach to insulation system design to reduce risk of cui on industrial piping. Because the corrosion is hidden under the insulation, cui tends to. Api rp 583 corrosion under insulation and fireproofing. Corrosionunderinsulation cui refers to the external corrosion of piping and vessels that occurs underneath externally cladjacketed insulation as a result of the penetration of water. Cui is common in refineries and process plants that typically operate equipment at elevated temperatures and can quickly lead to structural failure which can have catastrophic consequences. Because this corrosion problem has many facets and impacts several technologies, a systems approach has been adopted.
Pdf analysis of a corrosion under insulation failure in. Corrosion under insulation cui is a serious concern both. These cover deep pitting, as well as general corrosion, that have occurred on galvanized steel. Api rp 583 corrosion under insulation and fireproofing, first edition. Reducing the amount of energy used from fossil fuels is the most important factor in. Stp880 corrosion of metals under thermal insulation. Jun 12, 2017 for the love of physics walter lewin may 16, 2011 duration. The water can come from rain water, leakage, deluge system water, wash water, or sweating from temperature cycling or low temperature operation such as refrigeration units. Standard practice control of corrosion under thermal. Cui is a subject that is wellresearched and understood.
This standard is intended for use by corrosioncontrol personnel and others concerned with corrosion under insulation andor fireproofing of. This article was originally published in the january 1988 national board bulletin. A refinerys steel piping, storage tanks, container vessels and other process equipment are subject to temperature fluctuations. A novel electrochemical method for monitoring corrosion under insulation article pdf available in anticorrosion methods and materials 533. Patiphon suksawat slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. In this investigation, four api 5l x65 steel pipes were insulated to determine the effectiveness of a commercially available vapor phase corrosion inhibitor. For the love of physics walter lewin may 16, 2011 duration.
Corrosion rates of carbon steel can be significant if operating at high temperatures and subject to temperature cycling, particularly when thermally insulated approximately 35% of incidences of corrosion failures, or near failures were caused as a result of corrosion under insulation this statement follows a 2 year survey of. Inspections for corrosion under insulation are generally not completed regularly enough to. Although the extent and resultant cost of corrosion under insulation cui are not known exactly, j. It can happen when a corrosive fluid, including process fluids which have leaked, is. Corrosion under insulation loop steam drum present by. Corrosion under insulation cui corrosion under insulation is one of the costliest problems attacking industry today. Corrosion under insulation cui is a localized corrosion occurring at the interface of a metal surface and the insulation on that surface. Protective coatings under insulation are effectively used to prevent the contact between the water that has infiltrated through the insulation system and the steel and hence, mitigating corrosion. Api rp 583 corrosion under insulation and fireproofing, first edition api on. Corrosion under insulation cui is one of the most wellknown phenomena in the process industries, and yet it still makes up an inordinately large percentage of global maintenance expenditures. Warm temperatures, normally between 30200c 32390f along with the ingress of any form of moisture and oxygen, create an environment that may accelerate corrosion. Pdf a novel electrochemical method for monitoring corrosion.
Corrosion under insulation cui cui is a particularly severe form of localized corrosion that has been plaguing chemical process industries since the energy crisis of the 1970s forced plant designers to include much more insulation in their designs intruding water is the key problem in cui. The water entering into the insulation reaches a point of dry out at the equipment wall or the hot pipe. What is latest research in corrosion under insulation. Identify those areas andor processes on the site that have insulated pipe and equipment. Api rp 583, corrosion under insulation and fireproofing, covers the design, maintenance, inspection and mitigation practices for pressure equipment, piping, and storage tanks due to external corrosion under insulation cui and corrosion under fireproofing cuf. However, all types of coatings will not have an indefinite lifetime, and there are several limitations to the conditions under which they should be used.
Corrosion under insulation cui is the corrosion of piping and vessels that occurs beneath insulation as a result of water penetration. Corrosion under insulation inspection and prevention. Ability to measure the steel thickness through the coating with thickness up to 250mm ability to inspect through non conducting and non magnetic materials such as insulating materials like aluminum and. Corrosion under insulation cui is a very important issue in industry and its importance is being more and more acknowledged. Ability to measure the steel thickness through the coating with thickness up to 250mm ability to inspect through nonconducting and nonmagnetic materials such as insulating materials like aluminum and. By its very nature cui tends to remain undetected until the insulation and claddingjacketing is removed to allow inspection or when leaks occur.
Corrosion under insulation cui is external corrosion of pipes and vessels. A guide to galvanized steel free pdf downloads provided by. Corrosion under insulation cui refers to the external corrosion of piping and vessels fabricated from carbon manganese, low alloy and austenitic stainless steel that occurs underneath externally cladjacketed insulation due to the penetration of water. Corrosion under insulation cui occurs when watermoisture is trapped under insulation fireproofing. Corrosionpedia what is corrosion under insulation cui. The document discusses the external corrosion of carbon and low alloy steels under insulation and fireproofing and the external chloride stress corrosion cracking ecscc of austenitic and duplex stainless steels under insulation.
Even the best surface coating system can be compromised due to mechanical damages of the surface coating and when the defect is hidden under the. Cosasco corrosion under insulation cui corrosion sensors. Corrosion under insulation cui guidelines 1st edition. And other crevice corrosion using surface conversion technology patrick j, dunn sr. Corrosion under insulation cui cui is a particularly severe form of localized corrosion that has been plaguing chemical process industries since the energy crisis of the 1970s forced plant designers to include much more insulation in their designs. Pect is capable of detecting corrosion hidden under insulation and offers the following advantages. The cui cell consisted of six carbon steel ring specimens separated by insulation spacers and. Corrosion under insulation cui is one of the costliest problems facing the petrochemical industry today. The following article is a part of the national board technical series. Apr 14, 2011 corrosion under insulation cui is the corrosion of piping and vessels that occurs beneath insulation as a result of water penetration. The problem of corrosion under insulation us coatings. Corrosion under insulation and fireproofing 1 scope this recommended practice rp covers the design, maintenance, inspection, and mitigation practices to address external corrosion under insulation cui and corrosion under fireproofing cuf. This is a localized external corrosion occurring in equipment made of insulated carbon and lowcarbon steels.
When an ammonia refrigeration system in their plant. Analysis of a corrosion under insulation failure in a carbon steel refinery hydrocarbon line article pdf available in case studies in engineering failure analysis 14. These coatings are often used in process facilities such as refineries, oil and gas, and petrochemical plants. There is no doubt that industry has taken the issue of corrosion under insulation cui seriously over the last 40 years. Part of this is to develop a standard that can be used to test and evaluate insulation systems and the effect of cui.
Theres only one way to determine that corrosion under insulation is under control. Corrosion under insulation cui is one of the costliest problems facing the oil and gas industry today. Often ingress of water can happen when there is damaged insulation, break in vapour barrier, break in mastic sealing or areas of entrapment, such as the end of flanges or equipment with insulation support rings can serve as areas for water entrapment. Until the late 1970s, petrochemical equipment designers and maintenance managers worked under the incorrect. Corrosion under insulation cui cui has been recognized as a problem in many industries insulation is a necessary component of the system and is designed to. If you continue browsing the site, you agree to the use of cookies on this website. The european federation of corrosion efc working parties wp and wp15 have worked to provide guidelines on managing cui together with a number of major european refining, petrochemical and offshore companies including bp, chevrontexaco, conocophillips, eni, exxonmobil, ifp, mol, scanraff, statoil, shell, total and borealis. This standard is intended for use by corrosion control personnel and others concerned with corrosion under insulation andor fireproofing of equipment. Jul 07, 2010 corrosion under insulation loop steam drum present by.
The piping system was insulated with calcium silicate insulation and operated at temperatures 50 100. Abstract contents there is no doubt that industry has taken the issue of corrosion under insulation cui seriously over the last 40 years. Delahunt in corrosion control under thermal insulation and fireproofing 1 shows the seriousness of the problem by presenting case histories. The recommended practices in this standard are intended to provide the user with information that will improve plant reliability by. Recently we discussed the basics of high temp coatings. Corrosion under insulation cui guidelines 2nd edition. Here a leak can cause safety and environmental concerns, and international headlines as well. The volume of data on the history, causes and challenges associated with cui is expansive. Pdf analysis of a corrosion under insulation failure in a. Corrosion under insulation cui is a major safety threat to chemical processes with pipes and pressure vessels for moving and storing fluids where anions and cations are transported via water to pipe surfaces to corrode away pipe surfaces. The document discusses the external corrosion of carbon and low alloy steels under insulation and fireproofing and the external chloride stress corrosion cracking ecscc of austenitic and. Aug 31, 2017 definition what does corrosion under insulation cui mean.
825 848 337 1313 1130 324 1478 1345 1074 568 470 237 1575 289 1435 500 820 56 1508 1532 737 1135 1560 1255 719 1363 354 791 219 647 1343 598 1426 228 1399 755