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ASTM E2019-99

(Test Method)

Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air

Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air

SCOPE
1.1 This test method determines the minimum ignition energy of a dust cloud in air by a high voltage spark. This test method is intended to develop data to be used in deciding whether or not combustible dust-air mixtures are considered to be ignitable with respect to electrical discharge. Ignition energies determined by this method would be compared with ignition energies of other dusts to assess the relative hazard with regard to ignition by a pointed source, for example, electrostatic discharges, sparks from electrical equipment, friction sparks. Data obtained from this test method provide a relative data of ignition sensitivity of a dust cloud. Appendix X2 of this test method includes guidance on the significance of minimum ignition energy with respect to electrostatic discharges.

General Information

Status
Historical
Publication Date
09-Jun-1999
ICS
13.230 - Explosion protection
Technical Committee
E27 - Hazard Potential of Chemicals
Drafting Committee
E27.05 - Explosibility and Ignitability of Dust Clouds
Current Stage
Ref Project

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ASTM E2019-99 - Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air
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Standards Content (Sample)

Designation: E 2019 – 99
Standard Test Method for
1
Minimum Ignition Energy of a Dust Cloud in Air
This standard is issued under the fixed designation E 2019; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Method for Determining Minimum Ignition Energy of
Dust-Air Mixtures
1.1 This test method determines the minimum ignition
energy of a dust cloud in air by a high voltage spark. This test
3. Terminology
method is intended to develop data to be used in deciding
3.1 Definitions of Terms Specific to This Standard:
whether or not combustible dust-air mixtures are considered to
3.1.1 spark discharge, n—transient discrete electric dis-
be ignitable with respect to electrical discharge. Ignition
charge, which takes place between two conductors, which are
energies determined by this this method would be compared
at different potentials. The discharge bridges the gap between
with ignition energies of other dusts to assess the relative
the conductors in the form of a single ionization channel.
hazard with regard to ignition by a pointed source, for example,
3.1.2 minimum ignition energy, n—electrical energy dis-
electrostatic discharges, sparks from electrical equipment,
charged from a capacitor, which is just sufficient to effect
friction sparks. Data obtained from this test method provide a
ignition of the most ignitable mixture of a given fuel-mixture
relative data of ignition sensitivity of a dust cloud. Appendix
under specific test conditions.
X2 of this test method includes guidance on the significance of
3.1.3 ignition delay time, n—the time between the onset of
minimum ignition energy with respect to electrostatic dis-
dispersion of the dust sample into a cloud and the activation of
charges.
the ignition source.
2. Referenced Documents
4. Summary of Test Method
2.1 ASTM Standards:
4.1 A dust cloud is formed in a laboratory chamber by an
D 3173 Test Method for Moisture in the Analysis Sample of
2 introduction of the material with air.
Coal and Coke
4.2 Ignition trials of this dust-air mixture are then at-
D 3175 Test Method for Volatile Matter in the Analysis
2 tempted, after a specific ignition delay time, by a spark
Sample of Coal and Coke
discharge from a charged capacitor.
E 789 Test Method for Dust Explosions in a 1.2 Liter
3 4.3 The stored energy discharged into the spark and the
Closed Cylindrical Vessel
occurrence or nonoccurrence of flame are recorded.
E 1226 Test Method for Pressure and Rate of Pressure Rise
3 4.4 The minimum ignition energy is sought by varying the
for Combustible Dusts
4
dust concentration, the spark discharge energy and optionally
2.2 NFPA Publications:
the ignition delay time.
NFPA 69 Standard on Explosion Prevention System
4.5 Ignition is determined by visual observation of a flame
NFPA 77 Recommended Practice on Static Electricity
propagation away from the spark gap.
NFPA 654 Standard for the Prevention of Fire and Dust
Explosions from the Manufacturing, Processing, and Han-
5. Significance and Use
dling of Combustible Particulate Solids
5 5.1 This test method provides a procedure for performing
2.3 IEC Standards:
laboratory tests to determine the minimum ignition energy of a
1241-2-3, 1994 Electrical Apparatus for Use in the Presence
dust cloud.
of Combustible Dusts, Part 2: Test Method, Section 3:
5.2 The data developed by this test method may be used to
assess the spark ignitibility of a dust cloud.
5.3 The values obtained are specific to the sample tested, the
1
This test method is under the jurisdiction of ASTM Committee E-27 on Hazard method used and the test equipment used. The values are not to
Potential of Chemicalsand is the direct responsibility of Subcommittee E27.05on
be considered intrinsic material constants.
Exposibility and Ignitability of Dust Clouds.
5.4 The MIE of a dust as determined using this procedure
Current edition approved June 10, 1999. Published November 1999.
2
can be compared with the MIE’s of reference dusts (using the
Annual Book of ASTM Standards, Vol 05.05.
3
Annual Book of ASTM Standards, Vol 14.02.
same procedure) to obtain the relative sensitivity of the dust to
4
Available from National Fire Protection Association, Batterymarch Park,
spark ignition. An understanding of the relative sensitivity to
Quincy, MA 02269–9101.
5 spark ignition can be used to minimize the probability of
Available from IEC Case Postale 56, CH-1211 Geneva, 20, Switzerland.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
E 2019
contamination of the surface with carbon and other materials. The
explosions due to spark ignition.
resistance may be directly measured using an electrometer, such as in Fig.
1 circuit, a decr
...

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5.1 This test method is applicable to dusts and powders, and provides a procedure for performing laboratory tests to evaluate hot-surface ignition temperatures of dust layers.  
5.2 The test data can be of value in determining safe operating conditions in industrial plants, mines, manufacturing processes, and locations of material usage and storage.  
5.3 Due to variation of ignition temperature with layer thickness, the test data at one thickness may not be applicable to all industrial situations (see Appendix X1). Tests at various layer thicknesses may provide a means for extrapolation to thicker layers, as listed in the following for pulverized Pittsburgh bituminous coal dust (2). Mathematical modeling of layer ignition at various layer thicknesses is described in Ref. (3).
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5.4 This hot plate test method allows for loss of heat from the top surface of the dust layer, and therefore generally gives a higher ignition temperature for a material than Test Method E771, which is a more adiabatic system.  
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Note 1: Much of the literature data for layer ignition is actually from a basket in a heated furnace (4), known as the modified Godbert-Greenwald furnace test. Other data are from nonstandardized hot plates (5-9).  
5.6 Additional information on the significance and use of this test method may be found in Ref. (10).
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1.2 Data obtained from this test method provide a relative measure of the hot-surface ignition temperature of a dust layer.  
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1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.2 The MEC as measured by this test method provides a relative measure of the concentration of a dust cloud necessary for an explosion.  
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5.4 If too weak an ignition source is used, the measured MEC would be higher than the “true” value. This is an ignitability limit rather than a flammability limit, and the test could be described as “underdriven.” Ideally, the ignition energy is increased until the measured MEC is independent of ignition energy. However, at some point the ignition energy may become too strong for the size of the test chamber, and the system becomes “overdriven.” When the ignitor flame becomes too large relative to the chamber volume, a test could appear to result in an explosion, while it is actually just dust burning in the ignitor flame with no real propagation beyond the ignitor.  
5.5 The recommended ignition source for measuring the MEC of dusts in 20-L chambers is a 2500 or 5000 J pyrotechnic ignitor.4 Measuring the MEC at both ignition energies will provide information on the possible overdriving of the system.5 To evaluate the effect of possible overdriving in a 20-L chamber, comparison tests may also be made in a larger chamber, such as a 1 m3-chamber.  
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5.1 This test method provides a procedure for performing laboratory tests to evaluate deflagration parameters of dusts.  
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1.1 Purpose. The purpose of this test method is to provide standard test methods for characterizing the “explosibility” of dust clouds in two ways, first by determining if a dust is “explosible,” meaning a cloud of dust dispersed in air is capable of propagating a deflagration, which could cause a flash fire or explosion; or, if explosible, determining the degree of “explosibility,” meaning the potential explosion hazard of a dust cloud as characterized by the dust explosibility parameters, maximum explosion pressure, Pmax; maximum rate of pressure rise, (dP/dt)max; and explosibility index, KSt.  
1.2 Limitations. Results obtained by the application of the methods of this standard pertain only to certain combustion characteristics of dispersed dust clouds. No inference should be drawn from such results relating to the combustion characteristics of dusts in other forms or conditions (for example, ignition temperature or spark ignition energy of dust clouds, ignition properties of dust layers on hot surfaces, ignition of bulk dust in heated environments, etc.)  
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1.1 This test method is designed to determine the limiting oxygen concentration of a combustible dust dispersed in a mixture of air with an inert/nonflammable gas in a near-spherical closed vessel of 20 L or greater volume.  
1.2 Data obtained from this method provide a relative measure of the deflagration characteristics of dust clouds.  
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SIGNIFICANCE AND USE
5.1 This test method provides a procedure for performing laboratory tests to determine the minimum autoignition temperature (MAIT) of a dust cloud.  
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5.3 The MAIT data can also be used in conjunction with minimum spark ignition data to evaluate the hazards of grinding and impact sparks in the presence of dust clouds (1 and 2).3  
5.4 The test values obtained are specific to the sample tested, the method used, and the test equipment utilized. The test values are not to be considered intrinsic material constants, but may be used as a relative measure of the temperature at which a dust cloud self ignites.  
5.5 The test data are for cloud ignition. Dust in the form of a layer may ignite at significantly lower temperatures than the same dust in the form of a cloud (3). For liquid chemicals, see Test Method E659.
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1.1 This test method covers the minimum temperature at which a given dust cloud will autoignite when exposed to air heated in a furnace at local atmospheric pressure.  
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1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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SIGNIFICANCE AND USE
5.1 This test method provides a procedure for performing laboratory tests to determine the minimum ignition energy of a dust cloud.
Note 1: For gases and vapors, see Test Method E582.  
5.2 The data developed by this test method may be used to assess the spark ignitibility of a dust cloud. Additional guidance on the significance of minimum ignition energy is in X1.1.  
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1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.  
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Standard Terminology Relating to the Compatibility and Sensitivity of Materials in Oxygen Enriched Atmospheres

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1.1 This terminology defines terms related to the compatibility and sensitivity of materials in oxygen enriched atmospheres. It includes those standards under the jurisdiction of ASTM Committee G04.  
1.2 The terminology concentrates on terms commonly encountered in and specific to practices and methods used to evaluate the compatibility and sensitivity of materials in oxygen. This evaluation is usually performed in a laboratory environment, and this terminology does not attempt to include laboratory terms.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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SIGNIFICANCE AND USE
5.1 This test method is applicable to dusts and powders, and provides a procedure for performing laboratory tests to evaluate hot-surface ignition temperatures of dust layers.  
5.2 The test data can be of value in determining safe operating conditions in industrial plants, mines, manufacturing processes, and locations of material usage and storage.  
5.3 Due to variation of ignition temperature with layer thickness, the test data at one thickness may not be applicable to all industrial situations (see Appendix X1). Tests at various layer thicknesses may provide a means for extrapolation to thicker layers, as listed in the following for pulverized Pittsburgh bituminous coal dust (2). Mathematical modeling of layer ignition at various layer thicknesses is described in Ref. (3).
Layer Thickness, mm  
Hot-Surface Ignition Temperature, °C  
6.4  
300  
9.4  
260  
12.7  
240  
25.4  
210  
5.4 This hot plate test method allows for loss of heat from the top surface of the dust layer, and therefore generally gives a higher ignition temperature for a material than Test Method E771, which is a more adiabatic system.  
5.5 This test method for dust layers generally will give a lower ignition temperature than Test Method E1491, which is for dust clouds. The layer ignition temperature is determined while monitoring for periods of minutes to hours, while the dust cloud is only exposed to the furnace for a period of seconds.
Note 1: Much of the literature data for layer ignition is actually from a basket in a heated furnace (4), known as the modified Godbert-Greenwald furnace test. Other data are from nonstandardized hot plates (5-9).  
5.6 Additional information on the significance and use of this test method may be found in Ref. (10).
SCOPE
1.1 This test method covers a laboratory procedure to determine the hot-surface ignition temperature of dust layers, that is, measuring the minimum temperature at which a dust layer will self-heat. The test consists of a dust layer heated on a hot plate.2,3  
1.2 Data obtained from this test method provide a relative measure of the hot-surface ignition temperature of a dust layer.  
1.3 This test method should be used to measure and describe the properties of materials in response to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire hazard risk of materials, products, or assemblies under actual fire conditions. However, results of this test method may be used as elements of a fire risk assessment that takes into account all of the factors that are pertinent to an assessment of the fire hazard risk of a particular end use product.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM
ASTM E1515-14(2022)(Test Method)
Standard Test Method for Minimum Explosible Concentration of Combustible Dusts

SIGNIFICANCE AND USE
5.1 This test method provides a procedure for performing laboratory tests to evaluate relative deflagration parameters of dusts.  
5.2 The MEC as measured by this test method provides a relative measure of the concentration of a dust cloud necessary for an explosion.  
5.3 Since the MEC as measured by this test method may vary with the uniformity of the dust dispersion, energy of the ignitor, and propagation criteria, the MEC should be considered a relative rather than absolute measurement.  
5.4 If too weak an ignition source is used, the measured MEC would be higher than the “true” value. This is an ignitability limit rather than a flammability limit, and the test could be described as “underdriven.” Ideally, the ignition energy is increased until the measured MEC is independent of ignition energy. However, at some point the ignition energy may become too strong for the size of the test chamber, and the system becomes “overdriven.” When the ignitor flame becomes too large relative to the chamber volume, a test could appear to result in an explosion, while it is actually just dust burning in the ignitor flame with no real propagation beyond the ignitor.  
5.5 The recommended ignition source for measuring the MEC of dusts in 20-L chambers is a 2500 or 5000 J pyrotechnic ignitor.4 Measuring the MEC at both ignition energies will provide information on the possible overdriving of the system.5 To evaluate the effect of possible overdriving in a 20-L chamber, comparison tests may also be made in a larger chamber, such as a 1 m3-chamber.  
5.6 If a dust ignites with a 5000 J ignitor but not with a 2500 J ignitor in a 20-L chamber, this may be an overdriven system.5 In this case, it is recommended that the dust be tested with a 10 000 J ignitor in a larger chamber, such as a 1 m3-chamber, to determine if it is actually explosible.  
5.7 The values obtained by this test method are specific to the sample tested (particularly the particle size distribution) and the met...
SCOPE
1.1 This test method covers the determination of the minimum concentration of a dust-air mixture that will propagate a deflagration in a near-spherical closed vessel of 20 L or greater volume.
Note 1: The minimum explosible concentration (MEC) is also referred to as the lower explosibility limit (LEL) or lean flammability limit (LFL).  
1.2 Data obtained from this test method provide a relative measure of the deflagration characteristics of dust clouds.  
1.3 This test method should be used to measure and describe the properties of materials in response to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire risk assessment that takes into account all of the factors that are pertinent to an assessment of the fire hazard of a particular end use.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  Specific precautionary statements are given in Section 8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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