ASTM_G_189_-_07_2013.pdf

Designation:G18907(Reapproved 2013)Standard Guide forLaboratory Simulation of Corrosion Under Insulation1This standard is issued under the fixed designation G189;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide covers the simulation of corrosion underinsulation(CUI),including both general and localized attack,on insulated specimens cut from pipe sections exposed to acorrosive environment usually at elevated temperature.Itdescribes a CUI exposure apparatus(hereinafter referred to asa CUI-Cell),preparation of specimens,simulation proceduresfor isothermal or cyclic temperature,or both,and wet/dryconditions,which are parameters that need to be monitoredduring the simulation and the classification of simulation type.1.2 The application of this guide is broad and can incorpo-rate a range of materials,environments and conditions that arebeyond the scope of a single test method.The apparatus andprocedures contained herein are principally directed at estab-lishing acceptable procedures for CUI simulation for thepurposes of evaluating the corrosivity of CUI environments oncarbon and low alloy pipe steels,and may possibly beapplicable to other materials as well.However,the same orsimilar procedures can also be utilized for the evaluation of(1)CUI on other metals or alloys,(2)anti-corrosive treatments onmetal surfaces,and(3)the potential contribution of thermalinsulation and its constituents on CUI.The only requirementsare that they can be machined,formed or incorporated into theCUI-Cell pipe configuration as described herein.1.3 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2A106/A106M Specification for Seamless Carbon Steel Pipefor High-Temperature ServiceC552 Specification for Cellular Glass Thermal InsulationC871 Test Methods for Chemical Analysis of Thermal Insu-lation Materials for Leachable Chloride,Fluoride,Silicate,and Sodium IonsD1193 Specification for Reagent WaterG1 Practice for Preparing,Cleaning,and Evaluating Corro-sion Test SpecimensG3 Practice for Conventions Applicable to ElectrochemicalMeasurements in Corrosion TestingG5 Reference Test Method for Making PotentiodynamicAnodic Polarization MeasurementsG15 Terminology Relating to Corrosion and Corrosion Test-ing(Withdrawn 2010)3G31 Guide for Laboratory Immersion Corrosion Testing ofMetalsG46 Guide for Examination and Evaluation of Pitting Cor-rosionG59 Test Method for Conducting Potentiodynamic Polariza-tion Resistance MeasurementsG102 Practice for Calculation of Corrosion Rates and Re-lated Information from Electrochemical Measurements3.Terminology3.1 The terminology used herein,if not specifically definedotherwise,shall be construed to be in accordance with Termi-nology G15.1This guide is under the jurisdiction of ASTM Committee G01 on Corrosion ofMetals and is the direct responsibility of Subcommittee G01.11 on ElectrochemicalMeasurements in Corrosion Testing.Current edition approved Aug.1,2013.Published August 2013.Originallyapproved in 2007.Last previous edition approved in 2007 as G189 07.DOI:10.1520/G0189-07R13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2 Definitions of Terms Specific to This Standard:3.2.1 corrosion under insulation(CUI)the corrosion ofsteel or other materials under thermal insulation due to thepresence of water,oxygen or other corrodants,or combinationsthereof.3.2.2 control conditionan exposure condition using apre-selected environment without the inclusion of inhibitors,protective treatments,or additives to the thermal insulation orexposure environment.It is selected to provide baseline data towhich data from other exposure conditions can be compared.3.2.3 protection ratioratio of the corrosion rate with thesurface treatment or particular insulative material,or both,withthat obtained for the control condition.4.Summary of Guide4.1 The CUI-Cell consists of three to six ring specimensseparated by non-conductive