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ASTM G189-07(2021)e1
Standard Guide for Laboratory Simulation of Corrosion Under Insulation (Includes all amendments and changes 1/21/2021).
NORMA vydaná dňa 1.1.2021
Informácie o norme:
Označenie normy: ASTM G189-07(2021)e1
Dátum vydania normy: 1.1.2021
Kód tovaru: NS-1016242
Počet strán: 11
Približná hmotnosť: 33 g (0.07 libier)
Krajina: Americká technická norma
Kategória: Technické normy ASTM
Kategórie - podobné normy:
Anotácia textu normy ASTM G189-07(2021)e1 :
Keywords:
corrosion under insulation, CUI, electrochemistry, mass loss, polarization resistance, protection efficiency, thermal insulation,, ICS Number Code 23.040.99 (Other pipeline components)
Doplňujúce informácie
| Significance and Use | ||||||||||||||||||||||||
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5.1?The corrosion observed on steel and other materials under thermal insulation is of great concern for many industries including chemical processing, petroleum refining and electric power generation. In most cases, insulation is utilized on piping and vessels to maintain the temperatures of the operating systems for process stabilization and energy conservation. However, these situations can also provide the prerequisites for the occurrence of general or localized corrosion, or both, and in stainless steels, stress corrosion cracking. For example, combined with elevated temperatures, CUI can sometimes result in aqueous corrosion rates for steel that are greater than those found in conventional immersion tests conducted in either open or closed systems (see Fig. 1).FIG. 1?Comparison of Actual Plant CUI Corrosion Rates Measurements (Open Data Points Shown is for Plant CUI) with Laboratory Corrosion Data Obtained in Open and Closed Systems 5.2?This guide provides a technical basis for laboratory simulation of many of the manifestations of CUI. This is an area where there has been a need for better simulation techniques, but until recently, has eluded many investigators. Much of the available experimental data is based on field and in-plant measurements of remaining wall thickness. Laboratory studies have generally been limited to simple immersion tests for the corrosivity of leachants from thermal insulation on corrosion coupons using techniques similar to those given in Guide G31. The field and inplant tests give an indication of corrosion after the fact and can not be easily utilized for experimental purposes. The use of coupons in laboratory immersion tests can give a general indication of corrosion tendencies. However, in some cases, these procedures are useful in ranking insulative materials in terms of their tendencies to leach corrosive species. However, this immersion technique does not always present an accurate representation of the actual CUI tendencies experienced in the service due to differences in exposure geometry, temperature, cyclic temperatures, or wet/dry conditions in the plant and field environments. 5.3?One of the special aspects of the apparatus and methodologies contained herein are their capabilities to accommodate several aspects critical to successful simulation of the CUI exposure condition. These are: 5.4?With the CUI-Cell, the pipe material, insulation and environment can be selected for the desired simulation needed. Therefore, no single standard exposure condition can be defined. The guide is designed to assist in the laboratory simulation of 1.1?This guide covers the simulation of corrosion under insulation (CUI), including both general and localized attack, on insulated specimens cut from pipe sections exposed to a corrosive environment usually at elevated temperature. It describes a CUI exposure apparatus (hereinafter referred to as a CUI-Cell), preparation of specimens, simulation procedures for isothermal or cyclic temperature, or both, and wet/dry conditions, which are parameters that need to be monitored during the simulation and the classification of simulation type. 1.2?The application of this guide is broad and can incorporate a range of materials, environments and conditions that are beyond the scope of a single test method. The apparatus and procedures contained herein are principally directed at establishing acceptable procedures for CUI simulation for the purposes of evaluating the corrosivity of CUI environments on carbon and low alloy pipe steels, and may possibly be applicable to other materials as well. However, the same or similar procedures can also be utilized for the evaluation of 1.3?The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.4?This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5?This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. |
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| 2. Referenced Documents | ||||||||||||||||||||||||
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