ASTM_D_4778_-_15.pdf

Designation:D477815Standard Test Method forDetermination of Corrosion and Fouling Tendency ofCooling Water Under Heat Transfer Conditions1This standard is issued under the fixed designation D4778;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 test method provides directions for fabricating andoperating a test apparatus to simultaneously monitor thecorrosion and fouling tendency of real and pilot cooling watersystems under heat transfer conditions.1.2 Interpretation of the results of this test method must beleft to the investigator.Many variables are involved which maynot be easily controlled or fully understood.Variations indesign and operating conditions may produce results that arenot comparable from unit to unit.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:2D1129 Terminology Relating to WaterD2331 Practices for Preparation and Preliminary Testing ofWater-Formed DepositsD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterG1 Practice for Preparing,Cleaning,and Evaluating Corro-sion Test SpecimensG16 Guide for Applying Statistics to Analysis of CorrosionData3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 corrosion,nthe deterioration of the metal by reac-tion with its environment.3.2.2 fouling,ndeposition of organic matter or inorganicmatter,or both,on heat transfer surfaces that result in the lossof heat transfer efficiency.3.2.3 heat flux,nheat transfer per unit area per unit time.4.Summary of Test Method4.1 Water from the system to be tested flows across a heatedtube of the desired metallurgy at a constant flow rate and heatflux.Corrosion rate is determined by weight loss while foulingtendency is determined by the deposit weight.5.Significance and Use5.1 Deposits on heat transfer surfaces reduce efficiency ofthe heat exchanger affected.A method for easily determiningthe corrosion and fouling tendency of a particular water underheat transfer conditions will allow the evaluation of changes inthe various system variables such as heat flux,flow velocity,metallurgy,cycles-of-concentration,and treatment schemes onheat exchanger performance.6.Apparatus(Fig.1)6.1 Test SpecimenA metal tube of38or12in.(9.5 or 12.5mm)outside diameter with sufficient inside diameter to snug-gly accommodate the cartridge heater.The tube should be cutto a length sufficient to extend12in.(12.5 mm)from each endof the test assembly.If both corrosion and deposition are to bedetermined,metallurgy of the test specimen should match thatof the heat exchanger being modeled.6.2 Cartridge HeaterA14or38in.(6.2 or 9.5 mm)diameter.Heated surface should be 4 to 8 in.(10 to 20 cm)longwith a minimum power rating sufficient to provide 110%ofthe heat load required(see Eq 7,8.2.2).The heater should have1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits,Analysis of Water for Power Generation and Process Use,On-Line Water Analysis,and Surveillance of Water.Current edition approved June 1,2015.Published July 2015.Originally approvedin 1988.Last previous edition approved in 2010 as D4778 10.DOI:10.1520/D4778-15.2For 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 an unheated section of sufficient length to allow the center ofthe heated section to be placed consistently in the center of thetest specimen.6.3 Power ControllerA device to set and control thepower to the heater,such as a variable transformer,is used toadjust the heat flux in order to maintain the surface temperatureof the test specimen consistent with the heat exchanger beingmodeled.The power controller should be rated to maintain atleast 120%,but not more than 400%of the power required.6.4 Flow ControlA flow meter or a flow control devicesuch as an orifice,or both,is recommended to mai