GB/T 5207-1985 Rapid balance method for determining the hazard level of coatings by flash fire test

This standard is applicable to determine whether flammable and combustible liquids such as paints, varnishes, solvents, petroleum and related products flash at the lowest permissible temperature of the corresponding hazard level. It is not applicable to determine the flash point of the product. GB/T 5207-1985 Flash fire test for coatings - Rapid balance method for determining hazard level GB/T5207-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of the danger classification by flash testing (rapid equilibrium method)UDC 667.612/.613
GB 5207—85
This standard is applicable to determining whether flammable and combustible liquids such as paints, varnishes, solvents, petroleum and related products flash at the lowest permissible temperature of the corresponding hazard level. It is not applicable to determining the flash point of products. Note: The hazard level of products for different uses shall be formulated in accordance with relevant national or international regulations. This standard refers to and adopts the international standards ISO1516-1981 "Paints, varnishes, petroleum and related products - Flash fire-no flash fire test - Rapid equilibrium method", closed cup method, ISO3679-1983 "Paints, varnishes, petroleum and related products - Determination of flash point - ISO3680--1983 "Paints, varnishes, petroleum and related products - Flash fire-no flash fire test - Rapid equilibrium method". 1 Principle
Under the conditions specified in this standard, heat the sample in the closed cup. When the sample is kept at the minimum allowable flash fire temperature of the corresponding hazard level for 60 seconds, the escaping vapor has reached the saturated concentration of flammable vapor. The test determines its hazard level by whether the sample flashes when it is exposed to an external flame at the equilibrium temperature. 2 Instruments
2.1 Flash point tester
2.1.1 Test cup
The test cup is made of brass or other suitable corrosion-resistant metal blocks with good thermal conductivity. There is a test groove with a cover of about 50mm in diameter and about 10mm in depth on the upper part of the metal block. The thermometer is inserted into the thermometer hole of the metal block. Figure 1 is its plan view. The main dimensions are shown in Figures 2 to 5.
National Bureau of Standards Issued on July 16, 1985
Implementation on March 1, 1986
GB5207-85
Flash point tester plan view
1—Test cup cover, 2 slide plate; .3—Ignition nozzle, 4—Feeding hole 18.
Figure 2 Sectional view of the tester cut through the nozzle
1—Ignition nozzle, 2—O-type sealing ring (see Note 1), 3—Module, 4—Thermometer (see Note 2) Note, ①O-type sealing ring plays a sealing role when the cover is covered, and is made of a material that can withstand 150℃. ② The thermometer is first coated with a layer of thermoplastic material with good thermal conductivity, and then inserted into the thermometer hole. 251
GB5207-85
Figure 3 Test cup cover
Note: The test cup cover is made of brass or other suitable metal with a thickness of about 2 mm. 12.8*0.85
Figure 4 Slide plate
Note: The slide plate is made of stainless steel or other suitable metal with a thickness of about 1.2 mm. 252bzxZ.net
2.1.2 Test cup cover
GB 520785
Figure 5 Sectional view of the measuring device cut through the feeding hole S10
The test cup cover is equipped with a slide plate that can be switched on and off, and an ignition device that can extend the test flame (diameter of 3.5±0.5mm) into the groove of the sample when the slide plate is opened. When the flame is extended, the nozzle of the test flame should be ±0.1mm away from the bottom of the test cup cover. There is also a small hole on the cover that extends into the sample groove to facilitate the insertion of the sample. In order to ensure the tight combination of the cover and the test cup, an appropriate fixture can be used to make the center line of the three holes on the cover coincide with the diameter of the test groove. When the slide on the cover is in the open position, the two holes on the slide must completely coincide with the corresponding two holes on the cover.
2.1.3 Heating device
The heating device adopts electric heating and is equipped with a temperature controller so that the temperature of the metal block can be controlled within the range of ±0.2℃ of the required temperature.
2.1.4 Cooling device
Cooling is performed by semiconductor cooling elements.
2.1.5 Timing device
Timekeeping is performed by a digital tube.
2.2 Thermometer
A horizontally placed nitrogen-filled mercury glass thermometer with an appropriate range and a minimum graduation of 0.5℃ is suitable for being installed in the thermometer hole on the metal block. The maximum error of measuring the temperature of the test cup should not exceed 0.5℃. The thermometer should be calibrated regularly by the metrology department. 2.3 The syringe
has a capacity of 2ml and an accuracy of ±0.1ml. A spoon can be used for high-viscosity products. 2.4 The fuel of the ignition device
is usually butane, but coal gas or natural gas can also be used. 3 Sampling and sample processing
3.1 According to the provisions of GB3186--82 "Sampling of Coating Products", take a representative sample from the product to be tested. Before the test, the sample should be placed in a closed container, and the free volume in the container should not exceed 10% of the total container capacity. The sample should not be stored in a plastic bottle (such as polyethylene, polypropylene, etc.). 253
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3.2 As volatile components are easy to lose, the sample should be cooled to at least 10℃ lower than the expected flash fire temperature of the dangerous level before opening the sample container to take out the sample; when using method 2 (see 5.2.1), the sample only needs to be cooled to at least 3-5℃ lower than the expected flash fire temperature of the dangerous level. During the test, the sample should be mixed evenly. After taking out the sample, the sample container should be covered immediately to ensure that the loss of volatile combustible components in the container is minimized. Otherwise, the sample cannot be used for testing. 4 Preparation of the instrument
4.1 The instrument should be placed in a place away from wind and soft light, and check whether the slide switch is flexible. Select the temperature according to the expected flash fire temperature of the dangerous level of the sample to be tested.
4.2 When testing with method 2, cooling water should be passed first. 5 Test Procedure
5.1 Method 1: Applicable to liquids with expected flash fire temperatures of room temperature to 110°C (if the flash fire temperature of the hazard level is close to room temperature, Method 2 is recommended).
Note: In case of dispute, the test should be conducted at 25±1°C and relative humidity of 60-70%. 5.1.1 Cool the sample and sample container to 10°C below the expected flash fire temperature of the hazard level. 5.1.2 Ensure that the sample groove, cover and slide plate are dry and clean, cover the cover and close the slide plate. 5.1.3 The test temperature should be calibrated according to the change of standard atmospheric pressure 101.3kPa (1013mbar or 760mmHg), and change 1°C for every 4kPa (40mbar or 30mmHg). Add the correction value if the air pressure is high, and subtract the correction value if the air pressure is low. 5.1.4 Turn on the heating device. When the temperature reaches 3°C lower than the expected flash temperature of the sample to be tested, slowly adjust the controller of the heating device until the sample groove reaches the expected flash temperature of the dangerous level and remains stable. 5.1.5 Use a dry and clean syringe to absorb 2ml of the cooled sample (see 5.1.1) and quickly inject the sample into the sample groove through the feeding hole. Be careful not to cause any loss of the sample. Pull out the syringe and start the timer immediately. Note: If the viscosity of the sample to be tested is high and it is difficult to inject through the feeding hole, you can open the lid and use a spoon to add 2-3ml of the sample into the sample groove. After taking out the sample, the sample container should be covered tightly and returned to a place 10°C lower than the expected flash temperature of the dangerous level. 5.1.6 Open the gas control valve, ignite the test flame, and adjust the flame into a spherical shape with a diameter of 3.5±0.5mm. 5.1. After 760s, it is considered that the test temperature has been reached. Open the slide, extend and remove the flame nozzle, close the slide, and complete the ignition test. The time is 2.5±0.5s. At the same time, observe the flash fire from the opening to the closing of the slide. Note: ① When the temperature of the mixed flammable (or combustible) gas formed by the sample vapor and air reaches the dangerous level flash fire temperature, the ignition will produce a flash fire. If there is any doubt, the test can be repeated with a new sample. When the two observation results are consistent, it can be considered that the sample has flashed. ② When the temperature of the mixed flammable (or combustible) gas formed by the sample vapor and air is lower than the dangerous level flash fire overflow, the ignition will not produce a flash fire. The new sample should be retested at the lowest flash fire temperature of the next dangerous level with a lower flash fire temperature. 5.1.8 Close the gas control valve, clean the sample groove, take the sample again and repeat the test. If flash fire occurs in each test, it can be considered that the sample flashes at the test temperature. 5.2 Method 2: Applicable to liquids with a dangerous level flash fire temperature lower than room temperature. 5.2.1 Cool the sample and sample container to 3-5℃ lower than the expected dangerous flash fire temperature. 5.2.2 Cool the sample groove and slowly adjust it to the expected dangerous flash fire temperature and keep it stable. The sample groove should be kept dry and the slide should be closed.
5.2.3 Use a dry and clean syringe to draw 2ml of sample (see 5.2.1) Quickly inject the sample into the sample groove through the feeding hole, and be careful not to cause any loss of the sample. Pull out the syringe and start the timer immediately. Note: Same as Note 5.1.5.
5.2.4 Open the gas control valve, ignite the test flame, and adjust the flame into a spherical shape with a diameter of 3.5±0.5mm. 5.2.5 After 60s, it can be considered that the sample has reached the corrected expected dangerous level flash temperature (see 5.1.3). Open the slide to extend and remove the flame nozzle, and close the slide to complete the ignition test: the time is 2.5±0.5s, and observe the flash situation from the opening to the closing of the slide.
Note: Same as Note 5.1.7.
GB 5207-85
5.2.6 Close the gas control valve, clean the sample groove and cover. Take the sample again and repeat the test. If flash occurs in each test, the sample is considered to flash at the test temperature. 6 Precision
The result of this standard is flash or no flash, and there is no need to quote the exact value. If it is necessary to express the repeatability and reproducibility of the test result value, it can be measured according to GB5208-85 "Rapid Balance Method for Determination of Flash Point of Coatings". Additional Notes:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China and is under the jurisdiction of the National Technical Committee for Standardization of Coatings and Pigments. This standard was drafted by Working Group 4 (SC1/WG4) of the Technical Committee on Basic Standards of Coatings and Pigments. The main drafter of this standard is Liu Shimin.
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