ASTM_D_4470_-_97_2010.pdf

Designation:D447097(Reapproved 2010)Standard Test Method forStatic Electrification1This standard is issued under the fixed designation D4470;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 generation of electrostaticcharge,the measurement of this charge and its associatedelectric field,and the test conditions which must be controlledin order to obtain reproducible results.This test method isapplicable to both solids and liquids.This test method is notapplicable to gases,since a transfer of a gas with no solidimpurities in it does not generate an electrostatic charge.Thistest method also does not cover the beneficial uses of staticelectrification,its associated problems or hazards,or theelimination or reduction of unwanted electrostatic charge.21.2 The values stated in SI units are to be regarded as thestandard.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:3D618 Practice for Conditioning Plastics for TestingD5032 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Glycerin SolutionsE104 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Solutions3.Terminology3.1 Definitions:3.1.1 conducting material(conductor),na material withinwhich an electric current is produced by application of avoltage between points on or within the material.3.1.1.1 DiscussionThe term“conducting material”is usu-ally applied only to those materials in which a relatively smallpotential difference results in a relatively large current since allmaterials appear to permit some conduction current.Metalsand strong electrolytes are examples of conducting materials.3.1.2 electric field strength,nthe magnitude of the vectorforce on a point charge of unit value and positive polarity.3.1.3 excess electrostatic charge,nthe algebraic sum ofall positive and negative electric charges on the surface of,orin,a specific volume.3.1.4 insulating material(insulator),na material in whicha voltage applied between two points on or within the materialproduces a small and sometimes negligible current.3.1.5 resistivity,surfacethe surface resistance multipliedby that ratio of specimen surface dimensions(width of elec-trodes defining the current path divided by the distancebetween electrodes)which transforms the measured resistanceto that obtained if the electrodes formed the opposite sides ofa square.3.1.5.1 DiscussionSurface resistivity is expressed inohms.It is popularly expressed also as ohms/square(the size ofthe square is immaterial).Surface resistivity is the reciprocal ofsurface conductivity.3.2 Definitions of Terms Specific to This Standard:3.2.1 apparent contact area,nthe area of contact betweentwo flat bodies.3.2.1.1 DiscussionIt is the area one would calculate bymeasuring the length and width of the rectangular macroscopiccontact region.3.2.2 dissipative material,na material with a volumeresistivity greater than 104ohm-cm and less than 1012ohm-cm,a resistivity range between conductive and insulating materialas defined in this test method.3.2.3 real contact area,nthe regions of contact betweentwo bodies through which mechanical actions or reactions aretransferred.3.2.3.1 DiscussionSince real bodies are never perfectly1This 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 Oct.1,2010.Published October 2010.Originallyapproved in 1985.Last previous edition approved in 2004 as D4470 97(2004).DOI:10.1520/D4470-97R10.2Vosteen,R.E.,and Bartnikas,R.,Chapter 5,“Electrostatic ChargeMeasurements,”Engineering Dielectrics,Vol.IIB,Electrical Properties of SolidInsulating Materials,Measurement Techniques,R.Bartnikas,Editor,ASTM STP926,ASTM,Philadelphia,1987.3For 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.4Annual Book of ASTM Standards,Vol 11.03.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 smooth,at least on a microscopic scale,the real contact area ofapparently flat materials is always less than the apparentcontact area.3.2.4triboelectric charge generationthe formation,withor without rubbing,of electrostatic charges by separation ofcontacting materials.54.Significance and Use4.