GB/T 16429-2026 Determination of the minimum ignition temperature 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 16429-2026
Replaces GB/T 16429-1996
Determination of the minimum ignition temperature of dust cloud
粉尘云最低着火温度测定方法
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 Heating Furnace
5.3 Compressed Air Dust Dispersal System
5.4 Test Temperature Control and Recording System
6 Determination of Ignition
7 Test Procedure
7.1 Test Parameters
7.2 Installation of the Heating Furnace
7.3 Calibration of the Heating Furnace
7.4 Measurement Steps
8 Determination of the Minimum Ignition Temperature
9 Safety Measures
10 Test Report
Annex A (Normative) Godbert-Greenwald Furnace
Determination of the Minimum Ignition Temperature of Dust Clouds
1 Scope
This document specifies the sample selection and preparation, test apparatus, determination of ignition, test procedure, and determination of the minimum ignition temperature for dust clouds.
This document applies to the determination of the minimum ignition temperature of dust clouds that rely on oxygen in the air to sustain their oxidation reaction.
This document does not apply to explosives or other dusts that can burn and explode without relying on a combustion-supporting gas.
2 Normative References
The following documents contain provisions which, through normative reference in this text, constitute essential provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 15604-2024 Terminology for Dust Explosion Prevention
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 15604-2024 and the following apply.
3.1
dust cloud
A mixture of combustible dust, at a certain concentration, suspended in a gaseous oxidant (air) under atmospheric conditions.
[SOURCE: GB/T 15604-2024, 3.3]
3.2
ignition of dust cloud
The initial phenomenon of explosion of a dust cloud (3.1) in air, caused by the transfer of energy.
[SOURCE: GB/T 15604-2024, 3.11]
3.3
minimum ignition temperature of dust cloud
The lowest heating temperature at which a dust cloud, when heated, causes a sudden change (ignition) in its temperature.
[SOURCE: GB/T 15604-2024, 4.15, modified]
4 Sample Selection and Preparation
4.1 Sample Selection
4.1.1 The sample used for testing shall be representative of the dust state in the actual process. The moisture content and particle size distribution of the actual test sample shall be measured and recorded.
4.1.2 For cases where the sample cannot represent the actual process or the actual process dust state is uncertain, it is recommended to use a sample with a particle size less than 75 μm and a moisture content not exceeding 5% for testing.
4.2 Sample Preparation
4.2.1 For samples with larger particle sizes, they can be treated by sieving through a large-aperture screen (e.g., 500 μm). The undersize material shall be used for testing, and the screen aperture used shall be noted in the report.
4.2.2 The sample may be subjected to grinding, sieving, or drying treatment, provided that the composition and chemical properties of the dust are not altered or affected.
4.2.3 For comparative tests, samples shall be prepared using the same method, and the particle size and moisture content of the samples shall be consistent.
5 Test Apparatus
5.1 General Requirements
The determination of the minimum ignition temperature of dust clouds shall use the Godbert-Greenwald (G-G) furnace apparatus specified in Annex A. Other apparatus meeting the calibration requirements of 7.3.2 may also be used.
5.2 Heating Furnace
The heating furnace consists of a vertically mounted heating quartz tube. The outer wall is wound with an electrical resistance alloy wire (total resistance 13 Ω) for heating. Its lower end is open to the atmosphere. The upper end is connected to a dust reservoir via a glass adapter. Thermocouples are installed in the middle and lower-middle part of the tube to control and record the test temperature. The heating furnace is mounted on a support base to allow observation of dust ignition from the bottom of the furnace.
A mirror shall be placed below the lower end of the heating quartz tube to allow observation of the interior of the tube.
5.3 Compressed Air Dust Dispersal System
The compressed air dust dispersal system consists of a small air compressor (or a compressed dry air storage tank), an air reservoir (volume 500 mL), a pressure gauge (or pressure sensor), a solenoid valve, and a dust reservoir. When the solenoid valve opens, compressed air from the air reservoir disperses the dust from the dust reservoir into the heating furnace, forming a dust cloud. The distance from the solenoid valve outlet to the dust reservoir shall not exceed 500 mm.
5.4 Test Temperature Control and Recording System
The thermocouple installed in the lower-middle part of the heating furnace is connected to a temperature controller for regulating the test temperature. The thermocouple installed in the middle part of the heating furnace is connected to a temperature recorder for recording the test temperature.
6 Determination of Ignition
During the test, if a flame is observed ejecting from the lower end of the furnace tube, or a flame is observed ejecting with a delay, it is judged as ignition. If only sparks are observed, or sparks without flame, it is judged as non-ignition.
The dust cloud dispersion and ignition process may be recorded using video during the test. Ignition is judged based on the image frames (image resolution ≥ 1280 × 720).
7 Test Procedure
7.1 Test Parameters
7.1.1 Dust Mass
During the test, the mass of dust (in g) shall be selected from the following values, with a permissible deviation of ±5%:
0.01, 0.02, 0.03, 0.05, 0.10, 0.20, 0.30, 0.50, 1.00, 1.50, ...
7.1.2 Dispersion Pressure
During the test, the dispersion pressure (in kPa) shall be selected from the following values, with a permissible deviation of ±5%:
2.0, 3.0, 5.0, 10, 20, 30, 50.
7.2 Installation of the Heating Furnace
The heating furnace shall be installed under a hood capable of extracting dust and toxic gases, and protected from air drafts.
7.3 Calibration of the Heating Furnace
7.3.1 The thermocouples used with the heating furnace shall be calibrated periodically (every 6 to 12 months).
7.3.2 After installation, the heating furnace shall be calibrated using lycopodium powder. The measured minimum ignition temperature shall be: (450 ± 50)°C. The lycopodium powder used for calibration shall be dried at 50°C under atmospheric pressure for 24 h (moisture content < 5%). The median particle size (d50) of the lycopodium powder shall be (30 ± 5) μm.
7.4 Measurement Steps
7.4.1 Weigh 0.1 g of dust and place it into the dust reservoir. Adjust the furnace temperature to 500°C and set the air reservoir pressure to 10 kPa. Open the solenoid valve to disperse the dust into the furnace. If ignition does not occur, increase the furnace temperature in steps of 50°C, reload the same mass of dust, and repeat the test until ignition occurs, or until the furnace temperature reaches 1000°C.
7.4.2 If ignition occurs, vary the dust mass and dispersion pressure until vigorous ignition is observed. Then, keeping this dust mass and dispersion pressure constant, lower the furnace temperature in intervals of 20°C and repeat the test until no ignition occurs in ten consecutive tests.
7.4.3 If ignition still occurs at 300°C, lower the furnace temperature in steps of 10°C.
7.4.4 When a temperature is reached where no ignition occurs, retest at this temperature using both lower and higher dust mass and dispersion pressure values. If necessary, further reduce the furnace temperature until no ignition occurs in ten consecutive tests.
8 Determination of the Minimum Ignition Temperature
The minimum furnace temperature at which ignition of the dust was observed according to the above method. If this temperature is above 300°C, subtract 20°C. If it is equal to or below 300°C, subtract 10°C. The result is the minimum ignition temperature of the dust cloud.
If ignition of the dust is not observed when the furnace temperature reaches 1000°C, this shall be stated in the test report.
