Guidance on the determination of physico-chemical properties of pesticides—Part 11：Flash point
Some standard content:
ICS65.020
Agricultural Industry Standard of the People's Republic of China
NY/T1860.11—2010
Guidance on the deterimination of physico--chemical properties for pesticidesPart ll: Flash point
2010-05-20 Release
2010-09-01 Implementation
Released by the Ministry of Agriculture of the People's Republic of China
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NY/T1860 "Guidelines for the Determination of Physical and Chemical Properties of Pesticides" is a series of standards, with a total of 22 parts: Part I: pII value:
Part 2: Acidity (base);
Part 3: Appearance;
-Part 4: Technical stability;
-Part 5: UV/visible light absorption:
Part 6: Explosiveness;
Part 7: Photolysis in water;
Part 8: Octanol/water partition coefficient! Part 9: Hydrolysis;
-Part 10: Oxidation-reduction/chemical incompatibility! …-Part 11: Flash point;
Part 12: Fire point;
Part 13: Solubility in non-polar organic solvents;-Part 11: Saturated vapor pressure;
Part 15: Solid flammability:
Part 16: Corrosiveness to packaging materials:
Part 17: Density:
Part 18: Specific rotation;
-Part 19: Boiling point,
Part 20: Melting point,
Part 21: Viscosity;
Part 22: Solubility.
This part is Part 11 of the Guidelines for the Determination of Physical and Chemical Properties of Pesticides. Appendix 8 of this part is an informative appendix. This part was proposed and managed by the Department of Crop Production, Ministry of Agriculture of the People's Republic of China. NY/T 1860. 11-2010
The responsible drafting units of this part are: Pesticide Control Institute, Ministry of Agriculture, Beijing Yingtai Jiahe Technology Co., Ltd., Beijing Ejiahe Analysis Technology Co., Ltd.
The main drafters of this part are: Gong Silian, Yang Jian, Chen Tiechun, Bu Xiangdong, Zhao Yonghui, Li Hongxia, Wen Huazhen, Wu. http
1 Scope
Test Guide for Determination of Physical and Chemical Properties of Pesticides
Part 11: Flash Point
NY/T1860.11—2010
This part specifies the basic requirements for the test method and test report for the flash point determination of liquid pesticide products. This part is also used in the pesticide registration test to determine the flash point of active ingredients, active ingredients and preparations of pesticides. 2 Normative References
The following documents are indispensable for the application of this part. For all referenced documents with dates, the versions with the dates are applicable to this part. For all undated referenced documents, the latest versions (including all amendments) are applicable to this part. GB/T514 Technical conditions for glass thermometers for testing petroleum products GB/T261-2008 Flash point determination method Penski-Martin closed cup method GB/T3536-2008 Flash point and fire point determination method for rock products (Cleveland closed cup method) GB/T21789-2008 Flash point determination of rock products and other liquids Abel closed cup method GB/T21929-2008 Tager closed cup method 3 Terms and definitions
The following terms and definitions apply to this part. Flash point flash point
Flash point, also known as flash point, is the temperature at which the vapor generated by the surface of a flammable liquid or solid flashes for the first time under the action of a test fire in a stable and specific air environment, that is, the temperature at which the flammable liquid or solid can release sufficient vapor and ignite on the surface of the liquid or solid in the container used. The lowest temperature at which a flammable mixture with air is formed. 4 Requirements
The appropriate method should be selected according to the properties of the test object and the flash point range: - If the flash point is lower than 79°C and the viscosity is less than 9.5×10-m/s at 25°C, the Tiger closed cup method should be used for determination; liquids with a flash point greater than 49, liquids with a viscous surface or solid suspensions should be determined using the Pansky Martens closed cup method:
Liquids or mixtures (liquids, viscous substances or solids) with a flash point within the range of -30%-~70% should be determined using the Abel closed ring method;
Flash points between -18°C and 165°C should be determined using the Tiger open cup method; flash points between 79°C and 400°C should be determined using the Clisson open cup method. 5 Test method
5.1 Principle
Place the test object in the test container According to the method, heat the test object and slowly raise the temperature at a specified speed until it approaches the flash point. Try to ignite it with an ignition source at a specified time or temperature interval. The temperature when the flash flame is first detected is the flash point. 5.2 Tiger closed cup method
5.2.1 Reagents and materials
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NY/T1860.11—2010
Low-volatile aromatic solvent (excluding chlorinated solvent) is used to clean a small amount of residual sample on the sample cup. The choice of solvent depends on the viscosity of the residue of the sample tested last time. Mixed solvents such as methyl-1-aminobutyric acid (TAM) are good solvents for cleaning colloidal deposits. 5.2.2 Instrument
5.2.2.1 Tiger closed cup flash point instrument
Use the closed cup flash point instrument in Appendix A of GB3/T21929-2008. 5.2.2 .2 Test cup thermometer
According to the expected flash point of the test object, select an appropriate thermometer according to the requirements of Table 1. Table 1 Selection of thermometers for different test temperature ranges Requirements Test temperature range
Scale of thermometer
Measurement range
Minimum scale
-20℃.-50℃
A'C~-29T
-20~-50℃
-5℃-~110r
℃~110℃
5.2.2.3 Heating tank thermometer
Use any thermometer that can cover the test temperature range, but using the same thermometer as the test cup thermometer can be convenient 5.2.2.4 Timer
Electronic meter attachment, the measurement accuracy reaches 0.75s~-0.80s or 1s. 5.2.2.5 Barometer
A barometer that can read to 1h10.1.kPa. Do not use a barometer calibrated to sea level atmospheric pressure, such as aneroid barometers used at weather stations and airports.
5.2.3 Instrument preparation
The test should be carried out in a darkened room. Place the flash point apparatus on a stable and level table, insert a water bath thermometer, connect the overflow pipe, and add water to the water bath. The water temperature should be 11°C lower than the expected flash point when the test is started. The test should be conducted in a draft-free room or by using wind screens on three sides of the apparatus, each side approximately 460 mm wide and 610 mm high. 5.2.4 Procedure 5.2.4.1 Preparation Place the oil cup in a water bath and measure 50 μL ± 0.5 μL of sample using a graduated cylinder. Carefully pour the sample into the test cup to avoid the cup wall above the condensate level. If necessary, pre-cool the sample and the cylinder to ensure that the sample temperature is 11 °C lower than the expected flash point during the measurement. Air bubbles on the surface of the sample can be removed with a clean dry paper or other suitable tool. Clean the inside of the lid with a clean cloth or absorbent paper, then cover the lid with the thermometer inserted. 5.2.4.2 Pre-test Connect the gas pipeline. If there is no gas, pass a cotton wick through the gas pipe of the lamp, place a little cotton in the oil chamber (gas chamber) and pour in enough signal oil, whale oil, lard or similar flames, cover the oil chamber cover, but do not tighten it, so that when the fuel is gradually consumed, air can enter and replenish the pressure in the oil chamber. Light the test flame and adjust the flame length to make it consistent with the size of the flame ball under the lid. Light the heating lamp (coal lamp or alcohol lamp) and place it in the middle of the water bath container. Adjust the size of the lamp flame so that the temperature rise rate of the sample in the test cup is (1-0.1)/min.
Record the barometer reading. Record the starting temperature of the sample. When the sample overflow is 5% lower than the predetermined flash point, turn the knob on the cup cover to introduce the test flame into the vaporization space in the cup, and immediately screw the cup cover back (do not snap it back). The operation time of the whole process is 1. The time for each introduction and lifting of the flame should be consistent, and there should be no hesitation in the operation. If a flash occurs at the beginning of the operation, terminate the test and discard the result. Cool a new sample again to a temperature 10°C lower than the original sample.
Every 0.6℃, measure once until a flash flame is obtained, and record the temperature at this time as the flash point. Do not confuse the flash of the real flash point with the blue halo or expanding flame that appears occasionally during the test flame. The real flash flame will consume the gas at the top of the test cup and cause a slight explosion.
If the temperature rise rate of the sample is not within the range of (1±0.1)℃/min from the first ignition to the flash flame, the water bath heating flame should be adjusted:
Be careful when operating the test flame. If the fire melts and smoke extinguishes and the sample cannot be ignited, the gas will enter the gasification time and affect the test results. At this time, the test should be terminated and the sample should be re-sampled for testing. Do not extinguish the test flame after completing the pre-test, remove the heating flame, lift the oil cup cover, wipe the thermometer liquid ball, remove the oil cup, pour out the test object and wipe it clean.
5.2.4.3 Flash point determination
Pour cold water into the water bath, and the overflow water should be drained into the sewer or sink until the water temperature is 8℃ lower than the flash point determined in the preliminary test. Place the oil cup in the water bath, measure 50 mL ± 0.5 ml of the sample with a graduated cylinder, and carefully put it into the test cup to avoid wetting the wall of the cup above the liquid. Use a clean, dry paper or other suitable tool to eliminate air bubbles on the surface of the sample, wipe the inside of the cover with a clean cloth or absorbent tissue, and then cover the cover with the thermometer inserted. Move the hot flame back to the water bath and record the sample and water bath temperatures. Repeat the test according to the steps of the preliminary test, but the first ignition temperature should be 5.5℃ lower than the flash point determined in the preliminary test. 5.2.5 Result correction
The test results should be corrected for pressure. When making corrections, according to the barometer reading, find the correction value from Table 2 according to the barometer reading, and add the measured value and the correction value to get the corrected flash point. Table 2 Correction values for different air pressures
Steam pressure gauge reading
intnHg
5.2.6 Result precision
Flash point upper value
Barometric pressure reading
Flash point correction
The temperature difference between the two measurements should not be less than 0.6℃, otherwise the third test should be carried out, and the maximum difference between the three measurement results should not exceed 1.1℃. If the results meet the requirements, calculate the average value. 5.3 Pansky-Martens closed cup method
5.3.1 Reagents and materials
Low volatility aromatic solvent (without rice) is used to clean the sample cup and remove a small amount of residual sample. The choice of solvent depends on the viscosity of the sample residue from the previous test. Mixed solvents such as toluene-acetone-methanol (TAM) are good solvents for cleaning colloidal deposits. 5.3.2 Instrument
5.3.2.1 Pansky-Martens closed cup flash point instrument The Pansky-Martens closed cup flash point instrument in Appendix B of GB/T261-2008 is used. 5. 3.2.2 Thermometer
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NX/T1860.11—-2010
According to the expected flash point of the test object and the requirements of Table 3, select an appropriate thermometer. Table 3 Selection of thermometers under different test temperature ranges Requirements Test temperature range
Measurement model
Crystal meter format
5. 3.2. 3 Timer
Minimum scale
Low: 93℃
-5℃--110℃
93℃~110℃
-5℃-~110℃
Electronic timer, measuring accuracy reaches 0.75$~0.80 or 1s.90℃～370℃
110--870
90℃~-370℃
5.3.2.4 Barometer
Barometer readable to 1Pa (0.1kla). Do not use a barometer calibrated to sea level pressure, such as the dead liquid barometer used in meteorological stations and peach fields.
5.3.3 Instrument preparation
Measurement should be carried out in a dark room. Place the flash point apparatus on a stable and level table. The test should be conducted in a draft-free room or with a wind screen on three sides of the apparatus, approximately 45 mm wide and 600 mm high on each side. 5.3.4 Procedure
5.3.4.1 Sample determination of liquids that do not tend to form films on the surface, liquids without suspended particles, or low-viscosity materials Thoroughly rinse and dry all parts of the test cup and accessories. To avoid the influence of residual solvent on the next measurement, carefully pour the sample into the test cup to the scale line, avoiding wetting the cup wall above the armpit surface. Use a clean, dry paper or other suitable tool to eliminate air bubbles on the surface of the sample. Wipe the inside of the lid with a clean cloth or absorbent tissue, cover the lid, and place the test cup on the heater and fix it correctly with the positioner. Insert the appropriate Overflow thermometer. Light the test flame and adjust the flame diameter to 4mm. Start heating, with the heating rate within the range of 5℃～6℃/min, the stirring speed within the range of 90~120 rpm, and the stirring force direction should be downward. Carry out the first pilot test when the temperature is 17℃ lower than the expected flash point, and then pilot test once every 1.1℃. When the temperature reaches 104℃, pilot test once every 3℃. When piloting, the test temperature should be reduced to a low position within 0.5$, maintained for 1$, and then quickly returned to a high position. Stirring should be stopped during the pilot test. When the flash flame appears, record the reading of the test thermometer, which is the flash point. Do not confuse the flash of the real flash point with the blue halo that sometimes appears around the test flame.
5.3.4.2 Liquids with a tendency to form a film on the surface, liquids with suspended particles, or high viscosity For sample determination of high-temperature materials, adjust the starting temperature of the sample and the instrument to (15-5.5)°C or 11°C lower than the expected flash point (the lower of the two values), and fill the gap between the test cup and the test cavity with water at the same temperature as the sample and the instrument. The stirring speed is within the range of (250-10) rpm, and the stirring force should be in the downward direction. During the entire measurement process, the heating rate is within the range of 1°C/min to 1.5°C/min. Except for the requirement in 1, the measurement is carried out in full accordance with the steps in 5.3.4.1. 5.3.5 Result Correction
Record the barometer reading. Unless there is a dispute, there is no need to perform pressure correction on the measurement result. When there is a dispute, the barometer reading is corrected for every 25mmFg or more below the standard atmospheric pressure (760irmHg, 101.3ka). 3.33kPa, the measured value plus 0.9℃ is the corrected flash point, and the pressure gauge reading is 25mmHg or 3.33kPa higher than the standard atmospheric pressure (750mmHg, 101.3kPa), the measured value plus 0.9℃ is the corrected flash point. 5.3.6 Repeatability of results
The difference in the results of two consecutive tests on the same test material by the same operator and the same instrument under the same operating conditions, under the premise of correct operation according to the standard of the test method, only one out of 20 tests will exceed the requirements of the table: 4
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Samples of different solid suspensions
Table 4 Repeatability of the determination of different test objects
Flash point range ()
40~-250
Table trend! Film-forming paralyzed bodies, concentrated bodies with suspended particles or materials with poor viscosity 5.4 Abel closed cup method
5.4.1 Reagents and materials
5.4.1.1 Low volatility aromatic solvent (excluding benzene) NY/T 1860.11—2010
0.029× flash point determination value
Wash a small amount of residual sample on the sample cup with d-butyl. The choice of solvent depends on the viscosity of the residual sample from the previous test. Mixed solvents such as benzene-acetone-methanol (TAM) are good solvents for cleaning crystalline deposits: 5.4.1.2 Ethylene glycol or glycerine with corrosion inhibitor added 5.4.1.3 Silicone lubricant
5.4.2 Instruments
5.4.2.1 Abel flash point instrument
Use the Abel oil tester in Appendix A of CB/T21789-2008 5.4.2.2 Test cup thermometer
Use a test cup thermometer that meets the specifications given in Appendix B of GB/T21789-2008. The thermometer can be fixed on the small ring in Appendix B.
5.4.2.3 Heating tank thermometer
Use a heating tank thermometer that meets the specifications given in Appendix C of GB/21789-2008. The thermometer can be fixed in the ring shown in Appendix B.
5.4.2.4 Low-temperature thermometer
Use a low-temperature thermometer that meets the specifications given in Appendix C of GB/T21789-2008 or a thermoelectric bias with a similar sensitivity and better accuracy than the thermometer.
5.4.2.5 Timer
Electronic timer with a measurement accuracy of 0.75 s~0.80 s or 1 s: 5.4.2.6 Barometer
A barometer that reads to 1 hPa (0.1 kFa). Do not use a barometer calibrated to sea level, such as a liquid gas gauge used in weather stations and airports.
5.4.2.7 Cooling bath
Liquid, metal block or circulating cooler. 5.4.2.8 Test cup insulation
Use a foam plastic lid or a wool cover. 5.4.3 Instrument preparation
Place the Abel flash point apparatus on a stable table. The test should be carried out in a room without drafts, or use an air cover on three sides of the apparatus, each side of which is about 450mm wide and 600mm high.
5.4.4 Procedure
Perform the determination in accordance with the procedure of Section 10 of GB/T21789-2008. 5.4.5 Result correction
Read the barometer reading when obtaining the flash point, and correct the result in accordance with the procedure of Section 11 of GB/T21789-2008. The report shall issue the corrected result, accurate to 0.5℃.
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5.4.6 Repeatability of results
The difference in the results of two consecutive tests on the same test material by the same operator and the same instrument under the same operating conditions shall not exceed 1.0.
: The repeatability values quoted in this section are applicable to flash point sources from 5℃ to 66.5℃. 5.5 Open cup method
5.5.1 Reagents and materials
5.5.1.1 Low volatility aromatic solvents (without benzene) are used to clean small amounts of residual sample on the sample cup. The choice of solvent depends on the viscosity of the sample residue from the previous test. Mixed solvents such as benzene-methyl alcohol (TAM) are good solvents for cleaning colloidal deposits. 5.5.1.2 Ethylene glycol
5.5.1.3 High boiling point liquid silicone oil
5.5.1.4 Dry ice or other refrigerants
5.5.1.5 Acetone
5.5.2 Instruments
5.5.2.1 Tiger open cup flash point instrument
Use the Tiger open cup flash point instrument in Appendix A. 5.5.2.2 Thermometer
Select a suitable thermometer or temperature measuring element from Table 5 as required. Table 5 Requirements for selection of thermometers under different test temperature ranges Flash point/ignition point
-18℃-13℃
157~-9312
93'℃-~165℃bZxz.net
5.5.2.3 Timer
Temperature tooth measurement range
-38℃-.42℃
5℃--]10%
90~3~170℃
Electronic timer, measuring accuracy reaches 0.75s~-0.80s or 1s5.5.2.4 Barometer
Division value
th 5℃
Readable to 1hPa (0.1kPa), do not use a barometer calibrated to sea level atmospheric pressure, such as aneroid barometers used at weather stations and airports.
5.5.3 Instrument preparation
The measurement should be carried out in a darkened room. Unless the test is carried out in a room without airflow, a wind screen should be used on three sides of the instrument. During the test, the case temperature is preferably controlled within the range of (24 + 3)℃. Place the flash point instrument on a stable and horizontal table, insert the water bath temperature, the thermometer should be vertical, and its position should be the center of the test cup and the center of the cup wall, and the bottom of the thermometer glass ball should be 6.4mn from the bottom of the test mark. Connect the overflow pipe. Add bath liquid to the bath (between -18℃~-93℃, the bath liquid can be a 1:1 oil-water mixture, between 16℃ and 93℃, water can be used as the bath liquid, between 93℃ and 165℃, liquid silicone oil with a high boiling point can be used, and the flash point of silicone oil should be at least 60℃ higher than the test temperature. Other appropriate bath liquids can also be used), and the bath liquid should be 3.2mm lower than the edge of the bath. The bath liquid temperature should ensure that it is 17℃ lower than the expected flash point when the measurement starts. If necessary, the bath liquid can be cooled to 30℃ with a mixture of decaprylate and acetone. Be careful not to let acetone or decaprylate contaminate the water-gas mixture. Adjust the horizontal and vertical positions of the test flame lamp. The arc radius of the test flame when it rotates horizontally should be at least 150mm: and pass above the center of the test cup. The arc should be perpendicular to the temperature and 3.2mm higher than the upper edge of the test cup. 5.5.4 Instrument calibration
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5.5.4.1 Standard materials
NY/T 1860.11--2010
According to the expected flash point temperature range of the test object, select appropriate standard materials from Table 6 to calibrate the instrument. Table 6 Standard materials available for selection under different test temperature ranges Temperature range
Standard materials
Water content
Standard flash point and acceptable range
5.5.4.2 Calibration
18℃--16
n-heptane
(~5 1.5))
16℃~93℃
P-methane
0.863±0, 003(15.5$℃)
93℃165℃
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5.5.5.1 Preliminary test (Note that to obtain good results, attention should be paid to various details of the test flame, including the size of the test flame, the speed of the test flame rising, the speed of the test flame passing over the sample, etc.)
5.5.5.1.1 Flash point and ignition point are within the range of -18℃~16℃5. 5.5.1.1.1 Sample preparation
Cleaning acetone mixture Cool the 1:1 water-ethylene glycol mixture to -30℃. Be particularly careful to avoid acetone or deicing contamination of the mixture. Pour the mixed liquid into the bath until the liquid level is 3.2 mm below the upper edge of the test cup. Cool the sample to 25°C with a mixture of ice and acetone. Be careful to avoid contamination of the sample with acetone or ice. Pour the cooled sample carefully into the test cup until the liquid level is 3.2 mm below the upper edge of the test cup. Use a clean, dry piece of paper or other suitable tool to eliminate air bubbles on the surface of the sample. 5.5.5.1.1.2 Flash Point Prediction Test
Light the test flame and adjust the flame diameter to 4 mm. When the temperature reaches 10°C below the expected flash point, adjust the sample liquid level to 3.2 mm below the upper edge of the test cup. Two preliminary tests may be required to determine the correct adjustment liquid temperature. Do not heat when the temperature starts to rise: allow it to rise naturally: after the temperature rise rate is less than 1°C/min, light the heating lamp (gas lamp or alcohol lamp) and place it in the middle of the bottom of the water bath container. Adjust the flame size so that the temperature rise rate of the sample in the test cup is (1-0.25)℃/min (when the sample is viscous, it may be difficult to control such a temperature rise rate). Start the first test immediately after adjusting the liquid level, and let the test flame sweep over the test cup within 1 hour to determine the pre-flash point. Then test once every 1℃. During the test, the test flame can only move in one direction, sweeping from one end to the other, and passing through the center of the test cup. When the test flame is at both ends of the stroke, it should be set to the "closed" position, and only set to the "open" position during the test. If any test substance climbs up the wall of the test cup, wipe it clean with absorbent paper before testing.
When the test substance is thick or has a film on the surface, insert a stirring hammer vertically to 15tmm below the liquid surface 15s before testing. Stir back and forth for 3-4 seconds along the movement trajectory of the test flame. Then take out the stirring rod and test. If the test substance has boiled before the flash point is measured, stop heating and testing and record "no flash point before boiling point". 5.5.5.1.2 Flash point is within the range of 16℃~93℃ 5.5.5.1.2.1 Sample preparation
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Pour the cold bath liquid (water or water-ethylene glycol mixture) into the bath until the liquid is 3.2mm below the edge of the test cup. It should be at least 17℃ lower than the expected flash point. Pour the sample carefully into the test cup until the liquid level is 3.2mm below the upper edge of the test cup. The sample temperature should be at least 10℃ lower than the expected flash point. When cooling the bath liquid, be careful not to contaminate the sample with the coolant. Clean, dry paper or other suitable tools can be used to eliminate air bubbles on the surface of the sample.
5.5.5.1.2.2 Preliminary test
Light the test flame and adjust the flame diameter to 4mm. Light the heating lamp (gas lamp or alcohol lamp) and place it in the middle of the water bath container. Adjust the flame size so that the temperature rise rate of the sample in the test cup is (1±0.25)/min (when the sample is viscous, it may be difficult to control such a temperature rise rate). When the temperature reaches 10°C below the expected flash point, adjust the sample liquid level. It may take 2 preliminary tests to determine the correct adjustment of the liquid level. Start the first test immediately after adjusting the liquid level, and let the test flame sweep over the test cup within 1s to determine the expected flash point. Test once every 1°C thereafter. During the test, the test flame can only move in one direction, from one end to the other end of the blade. When the test flame is at both ends of the stroke, it should be in the "closed" position, and only in the "open" position when testing. If the test object climbs along the wall of the test cup, wipe it clean with absorbent paper before testing.
When the test object is a viscous liquid or a film on the surface, 15s before testing, the stirring sample should be vertically inserted 15mm below the liquid surface, and stirred back and forth 3-~4 times along the movement trajectory of the test flame, then the stirring rod should be taken out and the test should be carried out. If the test object has boiled before the flash point is measured, stop heating and testing. Record the "light flash point before boiling point". 5. 5.5.1.3 Flash point in the range of 93℃～165℃ 5.5.5.1.3.1 Sample preparation
Pour the high boiling point silicone oil bath liquid into the bath bottle until the liquid level is 3.2mm away from the upper edge of the test cup. Carefully pour the room temperature sample into the test cup until the liquid level is slightly greater than 3.2mm1 from the upper edge of the test cup. Use a clean, dry piece of paper or other suitable tool to eliminate air bubbles between the sample surfaces.
5.5.5.1.3.2 Pre-test
Light the test flame and adjust the flame diameter to 4mm. Light the heating lamp (gas lamp or alcohol lamp). Fine lamp), place it in the middle of the bottom of the water bath container. Heat with maximum fire. When the sample temperature rises to ℃, adjust the size of the lamp flame so that the heating rate of the test cup sample is (1±0.25)℃/min (when the sample is viscous, it may be difficult to control such a heating rate). When the temperature reaches 10℃ below the expected flash point, adjust the sample liquid level. It may be necessary to conduct 2 preliminary tests to determine the correct temperature for adjusting the liquid level. The heating device of some instruments is difficult to control the above heating rate above 120℃. At this time, it can be controlled by adding an auxiliary heating flame. , increase the voltage of the electric heater or wrap the test cup with insulation material, etc. It is very important to ensure that the heating rate is (1.25)℃/min. Start the first test immediately after adjusting the liquid, and let the test flame sweep the test cup within 16 hours to determine the expected flash point. Then test once every 1℃. During the test, the test flame can only move in one direction, sweeping from one end to the other. When the test is at both ends of the stroke, it should be placed in the "closed" position, and only in the "open" position during the test. If the test object climbs along the wall of the test cup, wipe it with absorbent paper before the test.
When the test object is a viscous liquid or a film on the surface, 15 minutes before the test, insert the stirring rod vertically to 15mm below the liquid, and stir it back and forth 3 to 4 times according to the movement trajectory of the test flame. Then take out the stirring rod and test. If the test object boils before the flash point is measured, stop heating and testing, and record "no flash point before boiling point". 5.5.5.2 Flash point determination
Repeat the determination three times according to the following method:
After the accurate pre-flash point is measured, prepare the bath liquid, sample, etc. according to the flash point range according to the steps of 5.5.5.1.1.5.5.5.1.2 and 5.5.5.1.3, and the temperature should be more than 10℃ lower than the expected flash point. Raise the temperature according to the steps of 5.5.5.1.1.5.5.5.1.2 and 5.5.5.1.3, and when the sample temperature just rises to 10℃ lower than the expected flash point, adjust the sample liquid level to 3.211m lower than the upper edge of the test cup. After adjusting the liquid level, start the test immediately, and let the test flame pass through the test cup within 1s. Test once every 3℃ for the first two times, and test once every 1℃ thereafter, until the flash point is measured. During the test, the test flame can move in one direction, sweeping from one end to the other. When the test flame is at both ends of the stroke, it should be placed in the "closed" position, and only in the "open" position when the pilot is tested. If the test object climbs along the wall of the test cup, wipe it clean with absorbent paper before the pilot. When the test object is a viscous liquid or a film on the surface, it should be vertically captured with a stirring rod 15mm below the liquid surface 15s before the pilot: stir back and forth 3 times according to the movement trajectory of the test flame, then take out the stirring bridge and conduct the pilot. When the difference between the maximum and minimum values of the three measurement results is no more than 1℃, the result is valid and can be used to calculate the mean. 5.5.6 Result Correction
Correct the test result to the flash point under standard atmospheric pressure according to the following formula: TT-0.25X(101.3 p)
In the following formula:
TFlash point value after correction to standard atmospheric pressure: T-flash point value obtained by measurement;
PMaximum pressure during measurement
Corrected result is rounded to the nearest multiple of 0.5°C. 5.5.7 Repeatability
The same operator and the same instrument conduct continuous tests on the same test material under the same operating conditions (3 times per group), and the difference between the average results shall not exceed the values given in Table 7. Table 7 Repeatability requirements for determination in different temperature ranges Flash point range Repeatability limit 5.6 Cleveland open cup method 18℃~93r 3℃~163℃ 5.6.1 Reagents and materials Low volatility aromatic solvent (without benzene) is used to clean the sample cup and a small amount of residual sample. The choice of solvent depends on the viscosity of the sample residue from the previous test. Mixed solvents such as benzophenone-methanol (TAM) are good solvents for cleaning colloidal deposits. 5.6.2 Instrument 5.6.2.1 Cleveland open cup instrument Use the Cleveland open cup instrument in Appendix A of B3536-2008. 5.6.2.2 Thermometer Use a thermometer that meets the requirements of GB5 in GB/T514. 5.6.2. 3 Timer
Electronic timer, measuring accuracy of 0.75%~0.80s or 155.6.2.4 Barometer
Barometer with a readable range of 0.1kPa. Do not use a barometer calibrated to sea level atmospheric pressure, such as liquid barometers used in weather stations and airports.
5.6.3 Instrument preparation
Measurements should be carried out in a room with good light. Place the Clifford open pocket instrument on a stable table. Unless the test is carried out in a room without drafts, a windscreen should be used on three sides of the instrument, with a maximum width of 460mm on each side. Height 610mm. Note: If the vapor or pyrolysis products of the sample are harmful, the instrument with a protective screen can be placed in a ventilation door, and the ventilation can be adjusted so that the vapor of the sample can be discharged and there is no air circulation above the test cup. Wash the test cup with solvent to remove all oil marks, traces or residues left by the previous test. If carbon potential exists, it should be removed with steel wool. Rinse the test cup with cold water and dry it up and down over an open flame or a hot plate for several minutes to remove residual traces of solvent and water. The test cup should be cooled to at least 56℃ below the expected flash point before use. htti
NY/T 1860. 11—2010
Place the thermometer in a vertical position with the glass bulb end 6 mm from the bottom of the test cup and located at the midpoint between the center of the test cup and the line swept by the test flame, aligned with the igniter arm. 5.6.4 Instrument calibration
5.6.4.1 Standard substances
According to the expected flash point temperature range of the test object, select appropriate standard substances from Table 8 to calibrate the instrument. Table 8 Standard substances available for different test temperature ranges Standard substances
|n-Tetradecane
n-1-hexadecane
5.6.4.2 Calibration
Purity (mole%)
Flash point (℃)
Acceptable range ()
If the instrument is used all the time, it should be calibrated at least once a week. If the instrument is only used occasionally, it should be calibrated before each use. According to the flash point range to be measured, select appropriate standard substances, measure their flash points according to the corresponding operating steps, and make corrections based on the barometer reading. The results should be within the range shown in the table above. If exceeded, the height of the test flame from the upper edge of the test cup, the position of the thermometer and the heating rate should be adjusted accordingly. Repeat the measurement until the result is within the acceptable range. 5.6.5 Sample preparation
Carry out the calibration according to the steps in Section 9 of G3/T3536-2008, 5.6.6 Determination steps
The determination shall be carried out in accordance with the steps in Section 10 of GB/T3536-2008. The average value of two qualified continuous determination results shall be taken as the determination result. 5.6.7 Result correction
The determination result shall be corrected to the flash point under standard atmospheric pressure according to the following formula: T=T-0.25X(101.3-p).
In other words:
T-flash point value after correction to standard atmospheric pressure: T-flash point value obtained by determination;
-maximum pressure during determination.
5.6.8 Repeatability
The same operator and the same instrument shall conduct two groups of continuous tests (3 times each) on the same test material under the same operating conditions. The difference between the average results shall not exceed 8°C.
6 Report
The flash point shall be reported in degrees Celsius. The flash point test report should generally include the following: (1) the name, specification, dosage form, batch number, producer, source, production date and test date of the test substance. (2) the test conditions and methods, including the temperature change program, the atmospheric pressure during the test, the name of the flash point instrument and its manufacturer and specifications, etc. The standard method used should be indicated, and if there are any differences from the standard method, they should be pointed out. (3) The test results should include the numerical and average values of all test results. (4) Other information related to the interpretation of the results: 10
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