ASTM_D_1169_-_19a.pdf

Designation:D116919aStandard Test Method forSpecific Resistance(Resistivity)of Electrical InsulatingLiquids1This standard is issued under the fixed designation D1169;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the determination of specificresistance(resistivity)applied to new electrical insulatingliquids,as well as to liquids in service,or subsequent toservice,in cables,transformers,circuit breakers,and otherelectrical apparatus.1.2 This test method covers a procedure for making refereetests with dc potential.1.3 When it is desired to make routine determinationsrequiring less accuracy,certain modifications to this testmethod are permitted as described in Sections 19 26.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.See 17.4.3 for a specific warning statement.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D150 Test Methods for AC Loss Characteristics and Permit-tivity(Dielectric Constant)of Solid Electrical InsulationD257 Test Methods for DC Resistance or Conductance ofInsulating MaterialsD923 Practices for Sampling Electrical Insulating LiquidsD924 Test Method for Dissipation Factor(or Power Factor)and Relative Permittivity(Dielectric Constant)of Electri-cal Insulating LiquidsD2864 Terminology Relating to Electrical Insulating Liq-uids and Gases3.Terminology3.1 Definitions Definitions of terms used in this testmethod are given in Terminology D2864.4.Significance and Use4.1 The resistivity of a liquid is a measure of its electricalinsulating properties under conditions comparable to those ofthe test.High resistivity reflects low content of free ions andion-forming particles,and normally indicates a low concentra-tion of conductive contaminants.5.General Considerations5.1 Theory and measuring equipment pertaining to thismethod shall be in accordance with Test Methods D257.5.2 Where both ac loss characteristic(dissipation factor orpower factor)and resistivity measurements are to be madeconsecutively on the same specimen,make the ac measurementbefore applying the dc potential to the specimen,and shortcircuit the cell electrodes for 1 min immediately prior tomaking the resistivity measurements.5.3 Make referee tests for resistivity in an atmosphere ofless than 50%relative humidity.For repeatable results makethese tests under carefully controlled atmospheric conditions.5.4 Aside from the adverse influence of contamination onresults of the resistivity test,there are other factors that cancontribute to variations in the test results as follows:5.4.1 The use of an instrument not having an adequate rangefor accurately measuring the current flowing in the circuit.(SeeSection 6 for two types of recommended instruments.)1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and is the direct responsibility of Subcom-mittee D27.05 on Electrical Test.Current edition approved Oct.1,2019.Published October 2019.Originallyapproved in 1951 as D1169 51 T.Last previous edition approved in 2019 asD1169 19.DOI:10.1520/D1169-19A.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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 5.4.2 When the time of electrification is not exactly thesame for every test.Upon the application of voltage,thecurrent flow through the specimen decreases asymptoticallytoward a limiting value.Variation in the time of electrificationcan result in appreciable variation in th