ASTM_E_2021_-_15.pdf

Designation:E202115Standard Test Method forHot-Surface Ignition Temperature of Dust Layers1This standard is issued under the fixed designation E2021;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 a laboratory procedure todetermine the hot-surface ignition temperature of dust layers,that is,measuring the minimum temperature at which a dustlayer will self-heat.The test consists of a dust layer heated ona hot plate.2,31.2 Data obtained from this test method provide a relativemeasure of the hot-surface ignition temperature of a dust layer.1.3 This test method should be used to measure and describethe properties of materials in response to heat and flame undercontrolled laboratory conditions and should not be used todescribe or appraise the fire hazard or fire hazard risk ofmaterials,products,or assemblies under actual fire conditions.However,results of this test method may be used as elementsof a fire risk assessment that takes into account all of the factorsthat are pertinent to an assessment of the fire hazard risk of aparticular end use product.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in Section 8.2.Referenced Documents2.1 ASTM Standards:4E771 Test Method for Spontaneous Heating Tendency ofMaterials(Withdrawn 2001)5E1445 Terminology Relating to Hazard Potential of Chemi-calsE1491 Test Method for Minimum Autoignition Temperatureof Dust Clouds2.2 IEC Standard:6IEC 1241-2-1 Electrical Apparatus for Use in the Presenceof Combustible Dust;Part 2:Test MethodsSection 1:Methods for Determining the Minimum Ignition Tempera-tures of Dusts,Method A3.Terminology3.1 DefinitionsFor definitions of other terms used in thisstandard,see Terminology E1445.3.2 Definitions of Terms Specific to This Standard:3.2.1 hot-surface ignition temperature of a dust layer,nlowest set temperature of the hot plate that causes ignitionof the dust layer.3.2.2 ignition of a dust layer,ninitiation of self-heating orcombustion in a material under test.3.2.3 ignition time,ntime between the start of heating andthe point at which the maximum temperature or flamingcombustion is reached.3.2.4 temperature rise,T,nthe difference between Tmaxand the initial set temperature of the hot plate.3.2.5 Tmax,nmaximum temperature measured during test.4.Summary of Test Method4.1 The test material is placed within a metal ring on top ofa hot plate,that is at a preset constant temperature.4.2 The sample temperature is monitored to determinetemperature rise due to oxidative reactions or decompositionreactions,or both.4.3 Ignition is considered to have taken place when either ofthe following occurs:1This test method is under the jurisdiction of ASTM Committee E27 on HazardPotential of Chemicals and is the direct responsibility of Subcommittee E27.04 onthe Flammability and Ignitability of Chemicals.Current edition approved July 1,2015.Published July 2015.Originally approvedin 1999.Last previous edition approved in 2013 as E2021 09(2013).DOI:10.1520/E2021-15.2This test method is based on recommendations of the National MaterialsAdvisory Board of the National Academy of Sciences(1).33The boldface numbers in parentheses refer to the list of references at the end ofthis standard.4For 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.5The last approved version of this historical standard is referenced onwww.astm.org.6Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.3.1 Temperature in the dust layer at position of thermo-couple rises at least 50C above the hot plate temperature,or4.3.2 Visible evidence of combustion is apparent,such asred glow or flame.4.4 Hot plate surface temperature is varied from test to test,as necessary,until the hot-surface ignition temperature isdetermined.5.Significance and Use5.1 This test method is applicable to dusts and powders,andprovides a procedure for performing laboratory tests to evalu-ate hot-surface ignition temperatures of dust layers.5.2 The test data can be of value in determining safeoperating conditio