This test method is used to determine the ignition temperature (auto-ignition temperature) of chemically pure flammable liquids and gases in air at atmospheric pressure. GB/T 5332-1985 Test method for ignition temperature of flammable liquids and gases GB/T5332-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Method of test for ignition temperatureof flammable iquids and gasesUDC 662. 681. 69
: 662.612.5
GB 5382-85
This standard is equivalent to IEC79-41975 edition "Electrical Equipment in Explosive Gas Atmospheres-Part 4-Ignition Temperature Test Method".
1 Scope
This test method is used to determine the ignition temperature (auto-ignition temperature) of chemically pure flammable liquids and gases in air at atmospheric pressure. 2 Definitions
The following definitions are used for the relevant terms used in this standard: 2.1 Ignition
The chemical reaction of a flammable liquid or gas in a heated test flask with a clearly visible flame and (or) explosion, and the delay time of this reaction does not exceed 5 minutes.
2.2 Ignition temperature The lowest temperature at which ignition occurs when tested according to the method specified in this standard. 2.3 Ignition lag The time required from the moment the sample is completely injected into the flask to the occurrence of ignition. 3 Overview of test method
Pour a certain amount of flammable liquid or gas sample into a heated, open, 200ml conical flask, and observe in a dark room whether ignition occurs in the flask. By repeating the test at different temperatures and different sample amounts, the lowest temperature of the flask when ignition occurs is taken as the ignition temperature of the sample under atmospheric pressure in air. 4 Test apparatus
The test apparatus is described in the following clauses:
4.1 Test flask
A conical flask made of borosilicate glass with a volume of 200mL should be used. Clean flasks cleaned by chemical methods should be used for the test of each sample and the last group of tests.
When the ignition temperature of the sample exceeds the softening point of the borosilicate glass flask or the sample is chemically corrosive to the flask, a quartz flask or a metal flask may be used, but this should be noted in the test report. 4.2 Heating furnace
A heating furnace is used to heat the test flask uniformly. An example of a heating furnace suitable for this purpose is described in Appendix A (Supplement).
When the test is carried out according to the test procedure of this standard, if the ignition temperature of the substance in the following table is within the error range given in Chapter 7, it can be considered that the test flask is heated uniformly and the selected temperature measurement position is appropriate. The purity of the test sample used should not be less than 99.9%.
Promulgated by the National Bureau of Standards on August 31, 1985
Implemented on May 1, 1986
N-heptane
GB 5332 85
Degrees, ℃
4.3 Thermocouple
Use a calibrated thermocouple with a diameter not greater than 0.8 mm to measure the temperature of the flask. The thermocouple should be installed at the selected position on the outer wall of the flask (see 4.2) and should be in close contact with the outer surface of the flask. 4.4 Sample injector
4.4.1 A 0.25 or 1 mL syringe with a graduation value not greater than 0.01 mL and a stainless steel needle with an inner diameter not greater than 0.15 mm should be used to inject liquid samples. If a calibrated 1 mL pipette is used to inject liquid samples, 1 mL of distilled water should be discharged in 35 to 40 drops at room temperature.
4.4.2 The gas sample is injected using a 200mL syringe equipped with a glass three-way stopcock, a flame arrester and a right-angle glass catheter. The method used is shown in Schematic A4 in Appendix A (Supplement).
4.5 Timer
Use a timer with a graduation value not greater than 1 s to measure the ignition delay time. 4.6 Reflector
In order to conveniently observe the ignition of the sample inside the flask, install a reflector about 250mm above the flask. 5 Test steps
5.1 Preparation before the test
Check whether the circuit and injection system are intact. Prepare the sample. The liquid sample should be placed in a closed container. When the boiling point of the sample is close to room temperature, ensure that the state of the sample before being injected into the flask remains unchanged. When determining the ignition temperature of the toxic sample, the test should be carried out in a fume hood. 5.2 Adjust the temperature
Adjust the temperature of the heating furnace to make the flask reach the required temperature and ensure that its temperature is uniform. 5.3 Injection of Samples
5.3.1 Liquid Samples
After repeatedly washing the clean syringe or pipette with the sample, draw in the required amount of sample and vertically inject the sample in the form of small drops into the bottom center of the conical test flask at a uniform speed as quickly as possible, then immediately withdraw the syringe or pipette. The entire operation should be completed within 2 seconds. Avoid wetting the flask wall when injecting.
5.3.2 Gas Samples
First fill the syringe and its connection system with the gas sample, repeatedly flush the injection system with the test gas, and then draw in the required amount of gas sample. Insert the right-angle glass tube vertically into the center of the flask, inject the gas sample at a speed of about 25mL/s, keep the speed as stable as possible during injection, and then withdraw the right-angle glass tube from the flask as quickly as possible. 5.3.3 Initial Sample Volume
In the initial test, the liquid sample volume is 0.07mL and the gas sample volume is 20mL. 5.4 Observation and timing
Start the timer immediately after the sample is completely injected into the flask. When flame and (or) explosion appear, stop the timer immediately and record the corresponding temperature and ignition delay time. If the above phenomenon does not occur, stop the timer and terminate the test after 5 minutes. 5.5 Cleaning the flask
At the end of each test, blow out the residual gas in the flask thoroughly with clean and dry air. If adsorbed matter is found in the flask, replace the clean flask in 26
.
5.6 Continuity test
GB 5332-85
Repeat the operations of 5.2 to 5.5 at different temperatures and with different sample amounts. The test close to the ignition temperature should be carried out with a temperature difference of 2 ℃ until the lowest temperature at which ignition occurs is obtained. 5.7 Confirmation test
The last group of tests should be repeated 5 times. If none of them ignites, the test is terminated. 6 Determination of ignition temperature
If the test results meet the requirements of Chapter 7, the lowest temperature at which ignition occurs in the test described in Chapter 5 shall be recorded as the ignition temperature, and the corresponding ignition delay time and atmospheric pressure shall be recorded at the same time. Validity of test results
7.1 Repeatability
The error of repeated test results measured by the same tester shall not exceed 2%. 7.2 Reproducibility
The average error of repeated test results measured by different laboratories shall not exceed 5%. 8 Contents of the report
The name, source, physical properties, test number, test date, ambient temperature, humidity, atmospheric pressure, sample size, ignition temperature and ignition delay time of the combustible material shall be stated in the report. 27
GB 8382 —85
Appendix A
Heating furnace
(Supplement)
The heating furnace manufactured according to the following conditions is suitable for the tests described in this standard. The heating furnace (see schematic diagram A1) is a cylinder made of refractory material, with an inner diameter of 127mm and a height of 127mm. A nickel-chromium resistance wire with a power of 1200W is spirally, spaced and evenly wound in the outer circle of the cylinder along the vertical direction of the axis. The upper part of the heating furnace is equipped with a neck heater with a power of 300W (see schematic diagram A2) and an asbestos cement plate annular cover, which is matched with the outer plate of the asbestos cement plate fixed above the furnace body through a boss. The lower part of the heating furnace is equipped with a bottom heater with a power of 300W (see schematic diagram A3). Three thermocouples are used, two of which are installed 25mm and 50mm below the neck heater, and the other is placed at the center of the bottom of the flask.
The three heaters should be independently controlled so that the temperature measured by each thermocouple is within ±1°C of the required test temperature. 28
GB 5832 --- 85
The dotted line indicates the winding method
Technical requirements
The notch on the inner and outer diameters of the field is 1.5 mm wide
deep 1.5 mm. The length of the nickel-chromium wire is about 4500 mm
and the diameter is 0.4 mm.
Technical requirements
The groove cut on the outer diameter of the disk is about 1.5 mm wide and 1.5 mm deep. The length of the chrome-lined wire is about
2500 mm and the diameter is 0.4mm. wwW.bzxz.Net
The dotted line indicates the winding method
GB 5882—85
Neck heater
Bottom heater
GB 5882 85
Additional instructions:
GB 5382 — 85
This standard is proposed by the Ministry of Public Security of the People’s Republic of China. This standard was drafted by the Tianjin Fire Research Institute of the Ministry of Public Security and the Sichuan Fire Research Institute of the Ministry of Public Security. The main drafters of this standard are Du Manxiang, Fu Xuecheng and Yi Guoming. 32
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