GB/T 38302-2019_English: PDF (GB/T38302-2019)
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Protective clothing -- Thermal protective performance test method
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GB/T 38302-2019
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Standard ID | GB/T 38302-2019 (GB/T38302-2019) | Description (Translated English) | Protective clothing -- Thermal protective performance test method | Sector / Industry | National Standard (Recommended) | Classification of Chinese Standard | C73 | Classification of International Standard | 13.340.10 | Word Count Estimation | 22,293 | Date of Issue | 2019-12-10 | Date of Implementation | 2020-07-01 | Drafting Organization | Institute of Military Engineering and Technology, Institute of Systems Engineering, Academy of Military Sciences, DuPont (China) R&D Management Co., Ltd., Ministry of Public Security Special Police Equipment Quality Supervision and Inspection Center, National Fire Equipment Quality Supervision and Inspection Center, China Academy of Work Safety | Administrative Organization | National Personal Protective Equipment Standardization Technical Committee (SAC/TC 112) | Proposing organization | Ministry of Emergency Management of the People's Republic of China | Issuing agency(ies) | State Administration for Market Regulation, National Standardization Administration | Summary | This standard applies to the thermal protection performance testing of single-layer or multi-layer materials, and applies to the evaluation of thermal protection materials for practitioners exposed to convective and radiant heat hazards. This standard does not apply to the test of non-flame retardant and materials that are easy to melt and drip when exposed to high temperature. |
GB/T 38302-2019
Protective clothing--Thermal protective performance test method
ICS 13.340.10
C73
National Standards of People's Republic of China
Test method for thermal protection performance of protective clothing
2019-12-10 release
2020-07-01 implementation
State Administration of Market Supervision
Published by the National Standardization Administration
Contents
Foreword I
1 range 1
2 Normative references 1
3 Terms and definitions 1
4 Principle 2
5 Health and safety of laboratory personnel 2
6 Equipment and materials 2
7 Sample preparation and conditioning 6
8 Calibration and maintenance 7
9 Test steps 8
10 Results Calculation 9
11 Test report 12
Appendix A (informative) Apparent reaction of the sample under thermal energy exposure 13
Appendix B (informative) Explanation of the difference between thermal protection performance value (TPP) and thermal protection performance evaluation (TPE) 14
Appendix C (Informative) Example of TPE test process 15
Appendix D (informative) Calibration of copper calorimetric sensors 18
References 19
Foreword
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by the Ministry of Emergency Management of the People's Republic of China.
This standard is under the jurisdiction of the National Personal Protective Equipment Standardization Technical Committee (SAC/TC112).
This standard was drafted. Institute of Military Engineering, Academy of Systems Engineering, Academy of Military Sciences, DuPont (China) R & D Management Co., Ltd.
Division, Special Police Equipment Quality Supervision and Inspection Center of the Ministry of Public Security, National Fire Equipment Quality Supervision and Inspection Center, China Safety Science Research Institute
Academy.
The main drafters of this standard. He Qingfang, Zhang Yan, Wu Shuang, Xu Lanyi, Zhang Yong, Zhang Mingming, Zhang Tingting, Wang Xin, Wu Yin, Zhang Jun, Fang Lin,
Zou Liang.
Test method for thermal protection performance of protective clothing
1 Scope
This standard specifies the thermal protection performance value (hereinafter referred to as "TPP") and thermal protection performance evaluation (hereinafter referred to as
"TPE") test method, including principles, health and safety of laboratory personnel, equipment and materials, preparation and conditioning of samples, calibration and
Maintenance, test procedures, calculation of results, etc.
This standard is applicable to the thermal protection performance test of single-layer or multi-layer materials, and is applicable to the practitioners exposed to the convection and radiation heat hazards.
Evaluation of thermal protection materials.
This standard is not applicable to the testing of non-flame retardant materials that are easy to melt and drip at high temperatures.
2 Normative references
The following documents are essential for the application of this document. For dated references, only the dated version applies to this article
Pieces. For undated references, the latest version (including all amendments) applies to this document.
GB/T 6529 Standard atmosphere for humidity control and testing of textiles (ISO 139..2005, MOD)
3 terms and definitions
The following terms and definitions apply to this document.
3.1
Thermal protection performance value
TPP
In the process of testing the thermal protection material, the intersection of the measured heat transfer response curve of the material over the cumulative time and the Stol curve is used to
Determined cumulative energy.
Note. Unit. kilowatt seconds per square meter (calorie per square centimeter) [kW · s/m2 (cal/cm2)].
3.2
Thermal Performance Evaluation
TPE
In the process of testing thermal protection materials, the tangent of the measured heat transfer response curve of the material to the Stol curve over a certain time
(Or approximate tangency) to determine the total accumulated energy.
Note. Unit. kilowatt seconds per square meter (calorie per square centimeter) [kW · s/m2 (cal/cm2)].
3.3
Stolcurve
A standard curve used to predict the time to second-degree burn versus thermal energy.
Note. Energy values falling above the Stol curve are likely to cause second-degree burns, while falling below the Stol curve is not likely to cause second-degree burns.
3.4
Heatflux
The amount of heat transferred in a unit area per unit time.
Note. Unit. kW/m2 [cal/(cm2 · s)] per kilometer per square meter (card per square centimeter second).
3.5
Heat exposure reaction responseoheatexposure
In the thermal protection performance test, the apparent response of the material to heat sources.
Note. Such as cracking, melting, dripping, charring, embrittlement, bulging, shrinking, sticking and burning.
3.6
Breakopen
After the material is heated, the area of not less than 3.2cm2 or any dimension of not less than 2.5cm voids.
Note. A single yarn is allowed in this cavity.
3.7
Embrittlement
Brittle residue formed by high temperature or incomplete combustion.
3.8
Thermal shrinkage
An item or material exhibits a reduction in size in one or more directions at high temperatures.
3.9
Drum
The material appears to form a raised state after being deformed by heat.
4 Principle
The sample was placed horizontally and exposed to a combined heat source of convection radiation, and the total heat flux exposed was (84 ± 2) kW/m2 [(2.00 ± 0.05)
cal/(cm2 · s)]. The copper calorimeter is used to measure and record the temperature change of the sample over time.
The temperature change is converted into the heat energy transmitted through the sample, and the heat transfer response curve of the heat energy with time is obtained. Can take the following two tests
Test method to characterize the thermal protection performance of materials.
a) The first test method. the time corresponding to the intersection between the heat transfer response curve and the Stol curve measured by the copper calorimeter and the material burst
The product of the total heat flux of the dew (that is, the accumulated energy) to obtain the thermal protection performance value (TPP) of the sample;
b) The second test method. the heat transfer response curve and Stol curve recorded by the copper calorimeter after removing the specified convective radiant heat
The product of the exposure time at the tangency (or near tangency) and the total heat flux is the thermal protection performance evaluation (TPE) of the sample.
5 Health and safety of laboratory personnel
The safety and health of laboratory personnel should meet the following conditions.
a) Sample combustion and high temperature testing may produce smoke and toxic gases that affect the health of the operator.
Poison mask. The test instrument can be installed in a fume hood or in a well-ventilated area. Smoke and soot should be discharged after each test.
However, the flame should not be affected by ventilation during the combustion of the sample.
b) Wear high temperature gloves when handling high temperature components (such as specimen holders and sensors under test).
c) During the test, prevent gas leakage to prevent explosion.
d) The operator should wear anti-glare glasses when the radiation lamp is on.
6 Equipment and materials
6.1 General arrangement
The test instrument structure includes a combined convective radiant heat source, a heat shield for controlling exposure time, a sample and sensor support structure,
The sample holder assembly, copper calorimetric sensor assembly, and data acquisition/analysis system are shown in Figure 1.
6.2 Combustion gas source
Uses industrial grade propane (more than 95% purity) or methane (more than 99% purity).
6.3 Gas flow meter
Under standard conditions, a gas flow meter with a range of 0L/min ~ 6L/min and an accuracy of 4%, it is recommended to use a mass flow meter.
6.4 Heat source
6.4.1 Burning lamp
Two combustion lamps for flammable (propane or methane) injection, the diameter of the top nozzle is (38 ± 2) mm, and the diameter of the nozzle is (1.2 ±
0.1) mm. The centerline of the burner lamp is 20 ° to 45 ° obliquely upward from the horizontal direction (20 ° to 30 ° is recommended to achieve a more stable
Test effect). The point of intersection of the outer flame of the fire source sprayed between the two lamps is located at the center point of the sample. The dimensional accuracy is 5%.
6.4.2 Radiant lamps
The radiant lamp consists of nine 500W transparent or translucent quartz infrared lamp tubes arranged side by side. Power can be changed by controller, distance
The front side of the sample is (125 ± 10) mm, and the center distance between the lamps is (13.0 ± 0.5) mm.
6.4.3 Radiation lamp housing
Radiation lamp cover should adopt cooling device to prevent local overheating and operator burns.
6.5 Structure of copper calorimeter
6.5.1 Components of a copper calorimeter
The copper calorimeter consists of the following parts, and its shape is shown in Figure 2.
6.5.2 Surface treatment of copper calorimeter
Use a petroleum solvent such as ethanol or acetone to clean the surface of the copper sheet. The black spray paint on the surface of the single-layer coated copper sheet needs to be resistant to high temperature (300 ℃
Above) Spray paint that is dull and has an absorption rate greater than 0.9. Dry and cure the spray paint in accordance with the process recommended by the supplier to achieve uniform thickness, surface
It is flat and can be cured by heating with an external heat source (such as a radiant lamp).
6.6 Specimen holder
The specimen holder (see Figure 4 with a tolerance range of ± 1mm) requires three complete accessories --- upper plate, lower plate, and distance frame
(It is recommended to use high temperature non-deformation and corrosion resistant materials). A distance box should be used for non-contact testing.
In millimeters
a) upper splint b) lower splint c) spacer frame
Figure 4 Sample holder
6.7 Thermal insulation
Located between the sample holder and the heat source, move back and forth to isolate the heat source. The response time of the heat shield to remove the heat source shall not be greater than 0.5s.
Water cooling is recommended to prevent overheating.
6.8 Data acquisition and analysis system
The data acquisition and analysis system includes the following requirements.
a) can indicate or record the temperature response on the copper heat sensor;
b) calculation of the cumulative heat generated by the temperature response;
c) Determine the end of the test based on the temperature response over time and the intersection with the Stol curve;
d) before the temperature reaches 250 ° C, the minimum frequency of data collection is not less than 10 per second;
e) The minimum resolution of the acquisition is 0.1 ℃, and the accuracy is ± 0.7 ℃;
f) Convert the millivolt signal of J or K thermocouple to temperature, which can be corrected at the cold end.
Note. The software settings need to match different thermocouples.
7 Sample preparation and conditioning
7.1 Sampling
When cutting the sample, the distance from the cloth edge is at least 100mm, and at least three samples are cut from each sample, and the size of each sample is (150 ± 2) mm ×
(150 ± 2) mm, it should be flat without seams. Multi-layer specimens should not contain fusible materials and be tested as a whole. Others such as washing, etc.
The conditions are otherwise stipulated and implemented in accordance with the relevant product standards.
7.2 Standard atmosphere for humidity control and testing
The standard atmosphere for humidity control and testing should meet the requirements of GB/T 6529.
The sample shall be placed in a standard atmosphere at a temperature (20.0 ± 2.0) ℃ and a relative humidity (65.0 ± 4.0)% for 24 hours. After conditioning, the sample should be in
Test completed within 30min. The ambient temperature during the test is not greater than 35 ° C.
7.3 Test conditions
All tests and calibrations need to be performed in a ventilated hood or well-ventilated area to effectively exhaust burned materials, fumes and exhaust gases. Use of copper
The total heat flux measured by the calorimetric sensor is set at (84 ± 2) kW/m2 [(2.00 ± 0.05) cal/(cm2 · s)].
8 Calibration and maintenance
8.1 Calibration
8.1.1 Radiation lamp heat flux calibration and flame adjustment
8.1.1.1 Calibration of radiant lamp heat flux
After the radiation lamp has been preheated for 15 minutes, place the standard radiant calorimeter on the same space position of the copper calorimeter, and adjust the power to achieve the output
The heat flux is (13 ± 4) kW/m2 [(0.3 ± 0.1) cal/(cm2 · s)]. An aging radiant tube needs to increase if adjusting the same heat flux
When the applied voltage is greater than 5V, it should be replaced immediately.
Note. The model of standard radiant heat flow meter is usually Schmidt-Boelter or Gardon.
8.1.1.2 Flame adjustment
Take off the standard radiant heat flow meter and adjust the gas pressure to 40kPa ~ 70kPa. When the radiation lamp is turned on, the {heat flux is (13 ±
4) kW/m2 [(0.3 ± 0.1) cal/(cm2 · s)]}, start the combustion lamp with low air flow, adjust the needle valve and damper of the combustion lamp, make full use of blue
The outer flame burns uniformly and focuses below the center point of the sample. Its shape is shown in Figure 5.
Figure 5 Schematic diagram of the flame state
8.1.2 Calibration of total heat flux
8.1.2.1 Ensure that the sensor surface is clean and level and free of deposits. The connection between the heat insulation plate and the copper sheet is complete without unevenness. Copper sheet surface black
The color coating is smooth, without deposits, blisters, etc. Otherwise, repair the surface of the copper calorimeter according to step 8.2. Sensor temperature stable (within 1 minute
After the temperature change is less than 1 ° C).
8.1.2.2 After the heat source is stabilized, start the data acquisition system and place the sensor (28 ° C ~ 33 ° C) that reaches the initial temperature range in the sample holder
Holder.
8.1.2.3 The duration of exposure of the copper calorimeter to the heat source is 10s, and the timing starts from the moment the heat shield is removed.
8.1.2.4 After the data collection is stopped, remove the sensor, keep it away from the heat source and cool to room temperature.
8.1.2.5 The program uses the calculation method in 10.1 combined with the temperature change data from 0 to 10s recorded by the sensor (the temperature difference is about
144.5 ℃ ~ 151.5 ℃), the average heat flux value obtained is the total heat flux value.
8.1.2.6 If the total heat flux measured in 8.1.2.5 is in the range of (84 ± 2) kW/m2 [(2.00 ± 0.05) cal/(cm2 · s)], this value
It is included in the subsequent sample calculation as the total heat flux calibration value. If the total heat flux value is outside the range, adjust the gas flow meter and repeat the calibration
Process (see 8.1.2.2 ~ 8.1.2.5) until the compliance is completed.
8.2 Maintenance
8.2.1 Sensor surface repair. The sensor surface is stained with deposits, or the black paint coating is uneven, or bare copper appears, and it should be used in a timely manner.
Solvent and black paint repair. Keep solvents away from sources of ignition when using solvents. After recoating, the sensor should be calibrated according to steps 8.1.2.2 ~ 8.1.2.5
Use afterwards.
8.2.2 Maintenance of the sample holder. Keep the sample holder clean, and use an anhydrous solvent to clean tar, soot or other combustion decomposition products.
9 test steps
9.1 Thermal protection performance value test (TPP)
9.1.1 The value of thermal protection performance is the average of the test results of 3 samples.
9.1.2 Calibrate the heat source according to steps 8.1.2.2 ~ 8.1.2.5 so that the total heat flux reaches (84 ± 2) kW/m2 [(2.00 ± 0.05) cal/(cm2 ·
s)], record the total heat flux data. Then remove the sample holder, install the sample and sensor to prepare for testing. It is recommended to complete 3 sets of samples in the test
After re-calibrating the total heat flux of 9 samples, the calibration frequency can be increased.
9.1.3 The front of the sample faces the heat source, and a copper calorimeter is placed on the back. The inner layer of the multilayer specimen faces the sensor. Between sensor and sample
Adding the distance box is non-contact, and the contactless test is not added, which should be indicated in the report. 6.4mm thick spacer frame
Use when trying.
Note. The use of multi-layer sample spacer frames --- Non-contact (plus spacer frame) tests are usually used to simulate the air layer between the inner layer of clothing and the wearer. In this item
In the test method, it is not recommended to use a non-contact (plus spacer) test for multilayer samples with a test time of more than 60s.
9.1.4 Use a heat shield to isolate the heat source before testing. After the heat shield is removed, the specimen is exposed to the center point above the heat source and recording begins
data.
9.1.5 When the cumulative energy measured by the copper calorimeter (see 10.2 for the calculation method) intersects the Stol curve, the test is suspended and the exposure is recorded
At the same time, the sample was removed from the heat source. The calculation formula of Stol curve is shown in 10.1.
9.1.6 The value of thermal protection performance is calculated as the product of the exposure time and the calibrated total heat flux (see 10.3 for the formula).
9.1.7 Record the phenomena observed during testing (see Appendix A).
9.1.8 Cool the sample holder and sensor assembly to 28 ° C ~ 33 ° C (simulating the temperature of the human skin), and then follow steps 9.1.3 ~ 9.1.7
Test the remaining samples. After the three samples are tested, the average value is recorded as the thermal protection performance value of the sample.
9.1.9 Exclude the test results that differ from the average by more than ± 10%, re-cut samples and make up three samples for testing.
9.2 Thermal Protection Performance Evaluation Test (TPE)
9.2.1 For the difference and description of the thermal protection performance value (TPP) and thermal protection performance evaluation (TPE), please refer to Appendix B.
9.2.2 Generally, three groups of samples are required to complete the thermal protection performance evaluation. One group of samples determines the evaluation time, and the latter two groups of samples are used as the evaluation time.
verification.
9.2.3 Calibrate the heat source according to step 9.1.2, and record the total heat flux value.
9.2.4 Test the sample according to the steps 9.1.3 ~ 9.1.5 Thermal protection performance value method to obtain the maximum exposure time (tmax) of the sample.
9.2.5 Divide the maximum exposure time by 2 to obtain the exposure time (ttrail).
9.2.6 Enter the exposure time (ttrail) in the equipment software and prepare the sample for testing.
9.2.7 When the exposure time (ttrail) is reached, the heat shield is reset, the sample leaves the heat source, and the instrument still records data. During this process, the environment
The temperature must not exceed 35 ° C.
Note. If this requirement cannot be met, the sample rack can also be designed as a removable structure as a whole. After the heat shield is reset, the “sample rack /
The “sample/sensor” is removed as a whole away from the heat source, but the data should be continuously recorded.
9.2.8 After the sample is exposed to the heat source, the instrument should continuously collect data for not less than 30s to completely release the accumulated heat on the sample
can. Data collection can be stopped manually when the heat transfer response curve measured on the sensor drops. When the heat transfer response curve does not decrease after 30s, it should be
Extend acquisition time (acquisition time does not exceed 120s).
9.2.9 Determine the thermal protection performance evaluation from the following relationship between the heat transfer response curve measured by the sensor and the Stol curve.
a) If the heat transfer response curve measured by the sensor within 60s (or 120s) exceeds the Stol curve (that is, it exceeds the second degree burn), it is required
Reduce exposure time ttrail. Take the lower exposure time from the previous sequence (the first minimum exposure time is 0s) to the current exposure time ttrail
Median. Set this time and repeat steps 9.2.6 ~ 9.2.8 until the heat transfer response curve of the sample is tangent to the Stol curve, or
The difference between the current exposure time ttrail and the previous exposure time is not greater than 0.5s.The thermal protection performance of this sample group is evaluated as the current
The product of the exposure time ttrail and the calibrated total heat flux value (see Appendix C for examples).
b) If the heat transfer response curve measured by the sensor within 60s (or 120s) is far lower than the Stol curve (that is, the second-degree burn cannot be predicted
Injury), you need to increase the exposure time ttrail, taking the current exposure time and the previous higher exposure time (the first maximum exposure time is 9.2.3
Exposure time tmax), set this time, and repeat steps 9.2.6 ~ 9.2.8. Heat transfer response curve up to the sample
Tangent to the Stol curve, or the difference between the current exposure time ttrail and the previous exposure time is not greater than 0.5s, the thermal protection of this sample group
The protection performance is evaluated as the product of the current exposure time ttrail and the calibrated total heat flux value (see Appendix C for an example).
9.2.10 Record the phenomena observed during the test (see Appendix A).
9.2.11 Repeatedly verify the exposure time ttrail, the thermal protection performance assessment is the product of the verified exposure time ttrail and......
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