ASTM_D_5391_-_14.pdf

Designation:D539114Standard Test Method forElectrical Conductivity and Resistivity of a Flowing HighPurity Water Sample1This standard is issued under the fixed designation D5391;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 covers the determination of electricalconductivity and resistivity of high purity water samples below10 S/cm(above 0.1 Mohm-cm).It is applicable to bothcontinuous and periodic measurements but in all cases,thewater must be flowing in order to provide representativesampling.Static grab sampling cannot be used for such highpurity water.Continuous measurements are made directly inpure water process lines,or in side stream sample lines toenable measurements on high temperature or high pressuresamples,or both.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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:2D1066 Practice for Sampling SteamD1125 Test Methods for Electrical Conductivity and Resis-tivity of WaterD1129 Terminology Relating to WaterD1192 Guide for Equipment for Sampling Water and Steamin Closed Conduits(Withdrawn 2003)3D1193 Specification for Reagent WaterD2186 Test Methods for Deposit-Forming Impurities inSteamD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3864 Guide for On-Line Monitoring Systems for WaterAnalysisD4519 Test Method for On-Line Determination of Anionsand Carbon Dioxide in High Purity Water by CationExchange and Degassed Cation Conductivity3.Terminology3.1 DefinitionsFor definitions of other terms used in thesetest methods,refer to Terminology D1129.3.1.1 electrical conductivityrefer to Test Methods D1125.3.1.2 electrical resistivityrefer to Test Methods D1125.3.2 Definitions of Terms Specific to This Standard:3.2.1 cell constant,nthe ratio of the length of the path,L(cm),and the cross-sectional area of the solution,A(cm2),between the electrodes of a conductivity/resistivity cell,withunits of cm1.3.2.1.1 DiscussionIn high purity water measurements,thecell constant is normally between 0.001 and 0.1 cm1toprevent electrical interference.This is lower than the 1 cm1ofthe standard centimetre cube and is taken into account by directreading instrument ranges that are matched with specific cellconstants.4.Summary of Test Method4.1 Conductivity or resistivity is measured with a cell andtemperature sensor or compensator in a flowing,closed systemto prevent trace contamination from wetted surfaces and fromthe atmosphere.Specialized temperature compensation cor-rects the measurement to 25C,taking into account thetemperatureeffectsontheionizationofwater,thecontaminants,and interactions between the two.In the absenceof specialized temperature compensation,the sample tempera-ture is controlled to 25 6 0.2C.4.2 To determine the cell constant of a high purity conduc-tivity cell with an instrument capable of accurate measurementover the range of pure water to 150 S/cm with a single cell1This 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 Feb.1,2014.Published February 2014.Originallyapproved in 1993.Last previous edition approved in 2009 as D5391 99(2009).DOI:10.1520/D5391-14.2For 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 constant,Test Methods D1125 are used directly.Manufactur-ers certification of cell constant traceability by this means is anacceptable alternative.4.3 To determine the cell constant of a high purity conduc-tivity cell with an instrument which does not accurately coverthe range from pure water to 150 S/cm with a single cellconstant,a secondary standard cell is used that has an inter-mediate cell constant with precise value determined by TestMethods D1125.That secondary standard cell is then used inlow conductivity water(not a