ASTM_G_87_-_02_2013.pdf

Designation:G8702(Reapproved 2013)Standard Practice forConducting Moist SO2Tests1This standard is issued under the fixed designation G87;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers the apparatus and procedure to beused in conducting qualitative assessment tests in accordancewith the requirements of material or product specifications bymeans of specimen exposure to condensed moisture containingsulfur dioxide.1.2 The exposure conditions may be varied to suit particularrequirements and this practice includes provisions for use ofdifferent concentrations of sulfur dioxide and for tests eitherrunning continuously or in cycles of alternate exposure to thesulfur dioxide containing atmosphere and to the ambientatmosphere.1.3 The variant of the test to be used,the exposure periodrequired,the type of test specimen,and the criteria of failureare not prescribed by this practice.Such details are provided inappropriate material and product purchase specifications.1.4 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.1.5 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.For a specificwarning statement,see 4.3.2.Referenced Documents2.1 ASTM Standards:2D714 Test Method for Evaluating Degree of Blistering ofPaintsD1193 Specification for Reagent WaterD1654 Test Method for Evaluation of Painted or CoatedSpecimens Subjected to Corrosive EnvironmentsG1 Practice for Preparing,Cleaning,and Evaluating Corro-sion Test SpecimensG46 Guide for Examination and Evaluation of Pitting Cor-rosion3.Significance and Use3.1 Moist air containing sulfur dioxide quickly produceseasily visible corrosion on many metals in a form resemblingthat occurring in industrial environments.It is therefore a testmedium well suited to detect pores or other sources ofweakness in protective coatings and deficiencies in corrosionresistance associated with unsuitable alloy composition ortreatments.3.2 The results obtained in the test should not be regarded asa general guide to the corrosion resistance of the testedmaterials in all environments where these materials may beused.Performance of different materials in the test should onlybe taken as a general guide to the relative corrosion resistanceof these materials in moist SO2service.4.Apparatus4.1 The apparatus required for moist SO2testing consists ofa test chamber having an internal capacity of 300 L(10.6 ft3),a supply of sulfur dioxide with metering device,specimensupports,provisions for heating the chamber,and necessarymeans of control.The size and detailed construction of theapparatus are optional,provided the conditions obtained meetthe requirements of this practice.Suitable apparatus which maybe used to obtain these conditions is described in Appendix X1.4.2 Drops of condensing moisture which accumulate on theceiling of the chamber shall not be permitted to fall on thespecimens being tested.4.3(WarningSuck-back into cylinder may cause explo-sion.Always use a check valve,vacuum break,or otherprotective apparatus in any line or piping from cylinder to testchamber to prevent suck-back.Installation of the chamberunder a fume hood is recommended.)5.Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,1This practice is under the jurisdiction of ASTM Committee G01 on Corrosionof Metals and is the direct responsibility of Subcommittee G01.05 on LaboratoryCorrosion Tests.Current edition approved May 1,2013.Published July 2013.Originally approvedin 1997.Last previous edition approved in 2007 as G87-02(2007).DOI:10.1520/G0087-02R13.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 where such specifications are available.3Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water as definedby Type IV of Specification D1193.5.3 A commercially available source