ASTM_D_4496_-_13.pdf

Designation:D449613Standard Test Method forD-C Resistance or Conductance of Moderately ConductiveMaterials1This standard is issued under the fixed designation D4496;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 electricalresistance and electrical resistivity of materials that are gener-ally categorized as moderately conductive and are neither goodelectrical insulators nor good conductors.1.2 This test method applies to the materials that exhibitvolume resistivity in the range of 100to 107-cm or surfaceresistivity in the range of 103to 107(per square).1.3 This test method is designed for measurements atstandard conditions of 23C and 50%relative humidity,but itsprinciples of operation can be applied to specimens measuredat lower or higher temperatures and relative humidities.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.Specific precau-tionary statements are given in 8.3.2.Referenced Documents2.1 ASTM Standards:2D257 Test Methods for DC Resistance or Conductance ofInsulating MaterialsD374 Test Methods for Thickness of Solid Electrical Insu-lation(Withdrawn 2013)3D991 Test Method for Rubber PropertyVolume Resistiv-ity Of Electrically Conductive and Antistatic ProductsD1711 Terminology Relating to Electrical InsulationD6054 Practice for Conditioning Electrical Insulating Mate-rials for Testing(Withdrawn 2012)32.2 ASTM Adjuncts:Carbon black test cell(two drawings)43.Terminology3.1 Definitions:3.1.1 moderately conductivea solid material having vol-ume resistivity between 100and 107cm.3.1.2 For definitions of the terms used,but not defined inthis standard,refer to Terminology D1711.3.2 Definitions of Terms Specific to This Standard:3.2.1 steady statefor the purpose of this test method,steady-state is attained if any rate of change in the observedresistance(or conductance)averages less than 0.25%s.4.Summary of Test Method4.1 Specimens of the test material are conditioned at pre-scribed conditions and subjected to direct-voltage stress.Re-sistance or conductance is measured and used with the dimen-sional aspects of the specimen to compute the resistivity of thematerial.The apparatus and techniques used in this test methodare selected in accordance with the general principles set forthin Test Methods D257.5.Significance and Use5.1 This test method is useful for the comparison ofmaterials,as a quality control test,and for specificationpurposes.5.2 This test method is useful in the selection and use ofmaterials in wires,cables,bushings,high-voltage rotatingmachinery,and other electrical apparatus in which shielding orthe distribution of voltage stress is of value.5.3 Commercially available“moderately conductive”mate-rials frequently are comprised of both conductive and resistivecomponents(that is,cellulose fibers with colloidal carbonblack particles attached to portions of the surfaces of thosefibers,or discrete conductive particles adhered to the surfacesof electrical insulating polymers).Such commercially availablematerials are often manufactured in a manner that results in1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.12 on Electrical Tests.Current edition approved May 1,2013.Published July 2013.Originally approvedin 1985.Last previous edition approved in 2004 as D4496 041,which waswithdrawn in January 2013 and reinstated in May 2013.DOI:10.1520/D4496-13.2For 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.4Available from ASTM International Headquarters.Order Adjunct No.ADJD4496.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 anisotropy of electrical conduction.Hence,the significance oftests using this test method depends upon the orientation of thespecimen tested to the direction of the electric field and therelationship between this orientation and the orientation of thematerial in the electrical apparatus,which uses these materials.6.Apparatus6.1 Use apparatus conforming to the general requirementsset forth in Test Methods D257.6.2 Power SourceCapable of limiting the magnitude ofthe direct voltage applied to the specimen.(See Appendix X1for discu