GB/T 16428-2026 Determination for the minimum ignition energy of dust cloud English, Anglais, Englisch, Inglés, えいご
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ICS 13.220.10
CCS H 57
National Standard of the People's Republic of China
GB/T 16428-2026
Replaces GB/T 164281996
Determination for the minimum ignition energy of dust cloud
粉尘云最小着火能量测定方法
Issue date: 2026-01-28 Implementation date: 2027-02-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Sample selection and preparation
4.1 Sample selection
4.2 Sample preparation
5 Test apparatus
5.1 General requirements
5.2 Electric spark generation system
6 Test procedure
6.1 Theoretical calculation of spark energy
6.2 Measurement procedure
6.3 Determination of minimum ignition energy
6.4 Calibration of test apparatus
7 Safety precautions8 Test report
Annex A (Normative) 1.2 L Hartmann tube
Annex B (Normative) 20 L spherical explosion test vessel
Annex C (Informative) Electric spark generation system
C.1 General
C.2 Three-electrode auxiliary spark trigger system
C.3 Electrode movement trigger system
C.4 Voltage ramp (trickle charge circuit) trigger system
C.5 Two-electrode system with auxiliary spark trigger
C.6 Square-wave spark generation system
Determination of minimum ignition energy of dust clouds
1 Scope
This document specifies requirements for sample selection and preparation, test apparatus, test procedure, safety precautions and test report for the determination of minimum ignition energy of dust clouds.
This document applies to the determination of minimum ignition energy of dust clouds that rely on oxygen in air to sustain oxidation reactions.
This document does not apply to explosives or other dusts that can burn or explode without relying on oxidizing gases.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application.For dated references, only the edition cited applies.For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 150 (All parts) Pressure vesselsGB/T 15604 Terminology for dust explosion prevention and protection
3 Terms and definitions
The terms and definitions defined in GB/T 15604 and the following apply to this document.
3.1
dust cloudA mixture of combustible dust at a certain concentration suspended in a gaseous oxidant under atmospheric conditions.[Source: GB/T 15604 2024, 3.3]
3.2
minimum ignition energyEminThe minimum spark energy capable of igniting a dust cloud and sustaining combustion.[Source: GB/T 15604 2024, 4.11, modified]
3.3
spark dischargeAn instantaneous discharge between two conductors at different potentials.
3.4
ignition of a dust cloudThe initial phenomenon of explosion of a dust cloud (3.1) in air due to energy transfer.[Source: GB/T 15604 2024, 3.11]
3.5
ignition delay timeThe time interval between the start of dust injection and the occurrence of spark discharge.
4 Sample selection and preparation
4.1 Sample selection
4.1.1 The test sample shall be representative of the dust condition in the actual process.The moisture content and particle size distribution of the actual test sample shall be measured and recorded.
4.1.2 If the sample cannot represent the actual process or the dust condition is uncertain,a sample with particle size less than 75 μm and moisture content not exceeding 5% shall be used for testing.
4.2 Sample preparation
4.2.1 For samples with large particle size, sieving may be performed using a large aperture sieve (e.g. 500 μm),and the undersize shall be taken for testing. The sieve aperture used shall be indicated in the report.
4.2.2 Grinding, sieving or drying may be performed on the samplewithout changing or affecting its composition and chemical characteristics.
4.2.3 For comparative tests, samples shall be prepared using the same methodto ensure consistent particle size distribution and moisture content.
5 Test apparatus
5.1 General requirements
The determination of minimum ignition energy of dust clouds shall be carried outusing a 1.2 L Hartmann tube specified in Annex Aor a 20 L spherical explosion test vessel specified in Annex B.
Other apparatus may also be used if they meet the calibration requirements of Clause 6.4.
5.2 Electric spark generation system
The electric spark generation system shall have the following characteristics:
a) Inductance of discharge circuit: 1 mH to 2 mH.When this value is used to evaluate electrostatic hazards,the inductance of the discharge circuit shall not exceed 25 μH.
b) Resistance of discharge circuit: not more than 5 Ω.
c) Electrode material: stainless steel, brass, red copper or tungsten.
d) Electrode diameter and shape: (2.0 ± 0.5) mm, with hemispherical tips.
e) Electrode gap: normally 6 mm.For low ignition energy tests of certain materials,the gap may be reduced to initiate ignition.In such cases, the largest possible gap shall be used,and the gap shall not be less than 2 mm.
f) Energy storage capacitor: low inductance type,capable of withstanding repeated pulse currents.
g) Capacitance formed by electrode arrangement: as small as possible.
h) Insulation resistance between electrodes: sufficiently high to prevent leakage.
The electric spark generation system should adopt one of the five types listed in Annex C.
6 Test procedure
6.1 Theoretical calculation of electric spark energy
The test dust shall be uniformly sprayed into the test apparatusat ambient temperature and pressure to maintain a suspended state,and ignited by capacitive electric spark.
The energy of the capacitive spark shall be calculated according to Formula (1).When the spark energy exceeds 100 mJ, it shall be calculated according to Formula (2).
6.2 Measurement procedure
6.2.1 Inspect the test apparatus to ensure it is clean and operates normally.
6.2.2 Ensure the oxygen concentration of the dust injecting air is (20.9 ± 0.5) %.Oxygen content that is too high or too low will affect the minimum ignition energy result.
6.2.3 Use compressed air to disperse the dust sample into the ignition vessel through a diffuser,while the charged capacitor discharges a spark.
6.2.4 When testing with a 1.2 L Hartmann tube,video recording shall be used to record the ignition process,and ignition shall be judged from images.When testing with a 20 L spherical explosion vessel,a pressure sensor shall be used to record pressure changes,and ignition shall be judged by explosion overpressure.
6.2.5 At a given dust concentration,start with a spark energy that reliably ignites the dust cloud.Reduce the spark energy step by step by halfby adjusting the capacitance and/or charging voltage,until the minimum energy for 10 consecutive ignitionsand the maximum energy for 10 consecutive non ignitions are found.
6.2.6 At different dust concentrations,determine the appropriate dust injection pressureand repeat 6.2.5 until the corresponding ignition energy is found.
6.2.7 Under the combination of dust concentration and ignition energy determined above,adjust the ignition delay time step by step.If ignition occurs in any test,repeat 6.2.5 at that ignition delay timeuntil the minimum ignition energy is found.
6.2.8 When using a 20 L spherical explosion test vessel,the test method and procedure shall refer to GB/T 16426,and the ignition delay time shall be 120 ms.
6.2.9 The minimum ignition energy Emin of the dust cloudlies between E1 (maximum energy for 10 consecutive non ignitions)and E2 (minimum energy for 10 consecutive ignitions).
6.3 Judgment of minimum ignition energy
During measurement, ignition of the dust cloud shall be deemed to have occurredif any of the following phenomena appears:
