ASTM_E_2019_-_03_2013.pdf

Designation:E201903(Reapproved 2013)Standard Test Method forMinimum Ignition Energy of a Dust Cloud in Air1This standard is issued under the fixed designation E2019;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 determines the minimum ignitionenergy of a dust cloud in air by a high voltage spark.1.2 The Minimum Ignition Energy(MIE)of a dust-cloud isprimarily used to assess the likelihood of ignition duringprocessing and handling.The likelihood of ignition is used toevaluate the need for precautions such as explosion preventionsystems.The MIE is determined as the electrical energy storedin a capacitor which,when released as a high voltage spark,isjust sufficient to ignite the dust cloud at its most easily ignitableconcentration in air.The laboratory test method described inthis standard does not optimize all test variables that affectMIE.Smaller MIE values might be determined by increasingthe number of repetitions or optimizing the spark dischargecircuit for each dust tested.1.3 In this test method,the test equipment is calibrated usinga series of reference dusts whose MIE values lie withinestablished limits.Once the test equipment is calibrated,therelative ignition sensitivity of other dusts can be found bycomparing their MIE values with those of the reference dustsor with dusts whose ignition sensitivities are known fromexperience.X1.1 of this test method includes guidance on thesignificance of minimum ignition energy with respect toelectrostatic discharges.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 and health practices and determine the applica-bility of regulatory limitations prior to use.Specific precau-tionary statements are given in Section 8.2.Referenced Documents2.1 ASTM Standards:2D3173 Test Method for Moisture in the Analysis Sample ofCoal and CokeD3175 Test Method for Volatile Matter in the AnalysisSample of Coal and CokeE582 Test Method for Minimum Ignition Energy andQuenching Distance in Gaseous MixturesE789 Test Method for Dust Explosions in a 1.2-Litre ClosedCylindrical Vessel(Withdrawn 2007)3E1226 Test Method for Explosibility of Dust CloudsE1445 Terminology Relating to Hazard Potential of Chemi-cals2.2 IEC Standards:41241-2-3,1994 Electrical Apparatus for Use in the Presenceof Combustible Dusts,Part 2:Test Method,Section 3:Method for Determining Minimum Ignition Energy ofDust-Air Mixtures3.Terminology3.1 DefinitionsFor additional definitions,see Terminol-ogy E1445.3.2 Definitions of Terms Specific to This Standard:3.2.1 spark discharge,ntransient discrete electricdischarge,which takes place between two conductors,whichare at different potentials.The discharge bridges the gapbetween the conductors in the form of a single ionizationchannel.3.2.2 minimum ignition energy(MIE),nelectrical energydischarged from a capacitor,which is just sufficient to effectignition of the most easily ignitable concentration of fuel in airunder the specific test conditions.3.2.3 ignition delay time,nthe time between the onset ofdispersion of the dust sample into a cloud and the activation ofthe ignition source.1This test method is under the jurisdiction of ASTM Committee E27 on HazardPotential of Chemicalsand is the direct responsibility of Subcommittee E27.05 onExplosibility and Ignitability of Dust Clouds.Current edition approved Oct.1,2013.Published November 2013.Originallyapproved in 1999.Last previous edition approved in 2007 as E2019 03(2007).DOI:10.1520/E2019-03R13.2For 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 International Electrotechnical Commission(IEC),3 rue deVaremb,Case postale 131,CH-1211,Geneva 20,Switzerland,http:/www.iec.ch.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Summary of Test Method4.1 A dust cloud is formed in a laboratory chamber by anintroduction of the material with air.4.2 Ignition trials of this dust-air mixture are thenattempted,after a specific ignition delay time,by a sparkdischarge from a charged capacitor.4.3 The stored energy discharged into the spark and theoccurrence or nonoccurrence of flame are recorded.4.4 The minimum ignition energy is sought by varying thedust concentration,the spark discha