Standard Test Method for Minimum Explosible Concentration of Combustible Dusts

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 the 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.

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09-Jul-2003
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ASTM E1515-03 - Standard Test Method for Minimum Explosible Concentration of Combustible Dusts
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1515 – 03
Standard Test Method for
1
Minimum Explosible Concentration of Combustible Dusts
This standard is issued under the fixed designation E 1515; 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.
INTRODUCTION
This test method describes procedures for measuring the minimum concentration of a combustible
dust (dispersed in air) that is capable of propagating a deflagration. The tests are made in laboratory
chambers that have volumes of 20 L or larger.
1. Scope D 3173 Test Method for Moisture in the Analysis Sample of
2
Coal and Coke
1.1 This test method covers the determination of the mini-
D 3175 Test Method for Volatile Matter in the Analysis
mum concentration of a dust-air mixture that will propagate a
2
Sample of Coal and Coke
deflagration in a near-spherical closed vessel of 20 L or greater
E 681 Test Method for Concentration Limits of Flammabil-
volume.
3
ity of Chemicals
NOTE 1—The minimum explosible concentration (MEC) is also re-
E 1226 Test Method for Pressure and Rate of Pressure Rise
ferred to as the lower explosibility limit (LEL) or lean flammability limit
3
for Combustible Dusts
(LFL).
1.2 Data obtained from this test method provide a relative 3. Terminology
measure of the deflagration characteristics of dust clouds.
3.1 Definitions of Terms Specific to This Standard:
1.3 This test method should be used to measure and describe
3.1.1 dust concentration, n—the mass of dust divided by the
the properties of materials in response to heat and flame under
internal volume of the test chamber.
controlled laboratory conditions and should not be used to
3.1.2 (dP/dt) , n—the maximum rate of pressure rise dur-
ex
describe or appraise the fire hazard or fire risk of materials,
ing the course of a single deflagration test.
products, or assemblies under actual fire conditions. However,
3.1.3 minimum explosible concentration (MEC), n—the
results of this test may be used as elements of a fire risk
minimum concentration of a combustible dust cloud that is
assessment that takes into account all of the factors that are
capable of propagating a deflagration through a well dispersed
pertinent to an assessment of the fire hazard of a particular end
mixture of the dust and air under the specified conditions of
use.
test.
1.4 The values stated in SI units are to be regarded as the
3.1.4 P , n—the absolute pressure at the time of
ignition
standard.
ignition.
1.5 This standard does not purport to address all of the
3.1.5 DP , n—the pressure rise in the chamber due to
ignitor
safety concerns, if any, associated with its use. It is the
the ignitor by itself in air at atmospheric pressure
responsibility of the user of this standard to establish appro-
3.1.6 P , n—the maximum explosion pressure (absolute)
ex,a
priate safety and health practices and determine the applica-
reached during the course of a single deflagration test (see Figs.
bility of regulatory limitations prior to use. Specific precau-
1 and 2).
tionary statements are given in Section 8.
3.1.7 pressure ratio (PR), n—defined as PR =
(P −DP )/P .
ex,a ignitor ignition
2. Referenced Documents
2.1 ASTM Standards:
1
This test method is under the jurisdiction of ASTM Committee E27 on Hazard
Potential of Chemicals and is the direct responsibility of Subcommittee E27.05 on
Exposibility and Ignitability of Dust Clouds.
2
Current edition approved July 10, 2003. Published September 2003. Original- Annual Book of ASTM Standards, Vol 05.05.
3
lyapproved in 1993. Last previous edition approved in 2000 as E 1515 – 00. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E1515–03
FIG. 1 Typical Recorder Tracings for a Weak Dust Deflagration in a 20-L Chamber, using a 2500 J Ignitor
FIG. 2 Typical Recorder Tracings for a Moderate Dust Deflagration in a 20-L Chamber, using a 2500 J Ignitor
4. Summary of Test Method 5.2 The MEC as measured by this test method provides a
relative measure of the concentration of a dust cloud necessary
4.1 A dust cloud is formed in a closed combustion chamber
for an explosion.
by an introduction of the material with air. The test is normally
5.3 Since the MEC as measured by this test method may
made at atmospheric pressure.
vary with the uniformity of the dust dispersion, energy of the
4.2 Ignition of this du
...

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