GB/T 5454-1997 Textiles combustion performance test oxygen index method

This standard specifies the test method for measuring the minimum oxygen concentration (also known as the limiting oxygen index) required for the sample to just maintain combustion in a mixed flow of oxygen and nitrogen under vertical test conditions. This standard is applicable to the determination of the combustion performance of various types of textiles (including single-component or multi-component), such as woven fabrics, knitted fabrics, non-woven fabrics, coated fabrics, laminated fabrics, composite fabrics, carpets, etc. (including flame retardant treated and untreated). This standard is only used to determine the combustion performance of textiles under laboratory conditions and control product quality, and cannot be used as a basis for assessing the fire hazard under actual use conditions, or can only be used as one of the factors for analyzing a fire in a special purpose material. GB/T 5454-1997 Oxygen Index Method for Combustion Performance Test of Textiles GB/T5454-1997 Standard Download Decompression Password: www.bzxz.net

13. Fireproof materials
This standard is under the jurisdiction of the Seventh Subcommittee of the National Technical Committee for Fire Protection Standardization. This standard was drafted by the Sichuan Fire Science Research Institute of the Ministry of Public Security. This standard was formulated with reference to the American ASTM D1360 "Standard Test Method for Fire Retardant Performance of Coatings (Small Chamber Method)". The main drafters of this standard are Chen Genbao, Shen Shufeng, and Cheng Daobin. 1043
12. "Oxygen Index Method for Textile Combustion Performance Test" GB/T5454-19971 Scope
This standard specifies the test method for measuring the minimum oxygen concentration (also known as the limiting oxygen index) required for the specimen to just maintain combustion under vertical test conditions in a mixed flow of oxygen and nitrogen. This standard is applicable to the determination of the combustion performance of various types of textiles (including single-component or multi-component), such as woven fabrics, knitted fabrics, non-woven fabrics, coated fabrics, laminated fabrics, composite fabrics, carpets, etc. (including flame retardant treatment and untreated). This standard is only used to determine the combustion performance of textiles under laboratory conditions and control product quality, but cannot be used as a basis for evaluating the fire hazard under actual use conditions, or as one of the factors for analyzing a fire in a special material. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest versions of the following standards.
GB6529-86 Standard atmosphere for humidification and testing of textiles 3 Definitions
This standard adopts the following definitions.
3.1 Afterflame time The time for a material to continue to burn with flames after the ignition source is removed (ignited) under specified test conditions. 3.2 Afterglow time
The time for a material to continue to burn without flames after the flaming combustion stops or the ignition source is removed (ignited) under specified test conditions.
3.3 Damaged length
The maximum length of the damaged area of ​​the material in the specified direction under the specified test conditions. 3.4 Limiting oxygen index LO1% limiting oxygen index LO1% The minimum oxygen concentration required for the material to just maintain the combustion state in the oxygen-nitrogen mixture under the specified test conditions. 4 Principle
The sample is clamped on the sample clamp vertically in the combustion tube. In the upward oxygen-nitrogen flow, the upper end of the sample is ignited, its combustion characteristics are observed, and its afterburning time or damaged length is compared with the specified limit value. By testing a series of samples in different oxygen concentrations, the minimum oxygen concentration value expressed as the percentage of oxygen content when maintaining combustion can be measured. Among the tested samples, 40% to 60% must exceed the specified afterburning and smoldering time or damaged length. 1044
Part 1 Test method standards for major building materials 5 Health and safety of test personnel
The smoke and gas produced by the combustion of textile materials are toxic and will affect the health of workers. The test instrument can be installed in a fume hood, and smoke and dust can be removed after each test. However, the ventilation system should be closed during the combustion of the sample to avoid affecting the test results.
6 Equipment and materials
6.1 Oxygen index meter (see Figure 1). Instruments with the same effect can also be used. Exhaust device
Combustion section
Measurement section
Figure 1 Schematic diagram of oxygen index tester installation
1-Combustion tube; 2-Sample; 3-Sample bracket; 4-Metal mesh; 5 Glass beads; 6-Combustion tube bracket; 7-Oxygen flowmeter; 8-Oxygen flow regulator; 9-Oxygen pressure gauge; 10-Oxygen pressure regulator; 11, 16-Purifier; 12-Nitrogen flowmeter; 13-Ammonia flow regulator; 14 Nitrogen pressure 15-nitrogen pressure regulator; 17-mixed gas flowmeter; 18-mixer; 19-mixed gas pressure gauge; 20-mixed gas supplier; 21-oxygen cylinder; 22-nitrogen cylinder; 23, 24-gas pressure reducer; 25-mixed gas thermometer 8
Figure 2 Sample clamp
Unit: mm
6.1.1 Combustion cylinder: It is composed of a heat-resistant glass tube with an inner diameter of at least 75mm and a height of at least 450mm. The bottom of the cylinder is connected to the air inlet pipe and filled with glass beads with a diameter of 3-5mm. The height is 80-100mm. A metal mesh is placed above the glass beads to withstand the possible dripping during combustion and keep the bottom of the cylinder clean. 6.1.2 Sample clamp: The sample clamp is a U-shaped clamp with an inner frame size of 140mm×38mm (see Figure 2).
6.2 Gas source: industrial oxygen and nitrogen.
6.3 Gas pressure reducer: can indicate that the high pressure in the cylinder is not less than 15MPa and the gas supply pressure is 0.1~0.5MPac
6.4 Ignitor: a tube with an inner diameter of (2±1)mm is passed with propane or butane gas, and ignites at the end of the tube. The flame height can be adjusted by the gas valve. It can be extended from the top of the combustion tube to ignite the sample. The flame height is 15~20mm. 6.5 Stopwatch: the accuracy is 0.2.
6.6 Steel ruler: the accuracy is 1mmc
6.7 Sealed container: used to store the samples to be tested. 7 Samples and humidity adjustment
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7.1 The sample should be cut from a position 1.10 width away from the edge of the fabric. The size of each sample is 150mm×58mm. For general fabrics, at least 15 pieces are taken in the warp (longitudinal) and weft (transverse) directions. 7.2 Humidity treatment of the sample: According to the humidity requirements of standard CB6529, the sample is humidified for 8 to 24 hours depending on its thickness. After the moisture absorption balance is reached, it is taken out and placed in a sealed container for testing. It can also be treated according to the atmospheric conditions agreed upon by the parties concerned. 8 Test steps
8.1 Test device inspection: Open the valve of the gas supply part and select the mixed gas concentration at will, with a flow rate of about 10L/min. Close the outlet and inlet valves, and record the pressure and flow rate of oxygen, nitrogen, and mixed gas. Leave it for 30 minutes, then observe the values ​​shown by each pressure gauge and flow meter, and check with the previous recorded values. If there is no change, it means that the device has no leakage. 8.2 Test temperature and humidity The test is carried out in an atmosphere with a temperature of 10 to 30°C and a relative humidity of 30%-80%. 8.3 Preliminary selection of sample oxygen concentration: When the oxygen index value of the sample to be tested is completely unknown, the sample can be ignited in the air. If the sample burns quickly, the oxygen concentration can start from about 18%. If the sample burns gently or unstably, select an initial oxygen concentration of about 21%. If the sample cannot continue to burn in the air, select an initial oxygen concentration of not less than 25%. Based on the estimated oxygen concentration, find the corresponding oxygen flow and nitrogen flow from Appendix B. When changing the oxygen concentration, it should be noted that the total flow of the mixed gas is between 10 and 11.4 L/min. 8.4 Place the sample in the middle of the sample clamp and fix it, then vertically insert the sample clamp together with the sample on the sample support in the combustion glass cylinder, with the upper end of the sample not less than 100 mm from the cylinder mouth, and the lowest end of the exposed part of the sample not less than 100 mm from the top surface of the gas distribution device at the bottom of the cylinder.
8.5 Open the oxygen and nitrogen valves, adjust the corresponding oxygen and nitrogen flow found in Appendix B, and let the adjusted air flow flow to flush the combustion cylinder for at least 30 seconds before the sample is ignited, and keep this flow unchanged during the ignition and combustion process. 8.6 Ignite the igniter: point the igniter tube upwards, adjust the flame height to 15-20mm, and ignite at the upper end of the sample. After the upper end of the sample is completely ignited (the ignition time should be controlled within 1015s), remove the igniter and immediately start measuring the afterburning and smoldering time, and then measure the damaged length. 8.7 Determination of initial oxygen concentration: Take any interval as a variable and use the "up-down method" to conduct the test according to 8.7.1 to 8.7.3. 8.7.1 If the sample extinguishes itself immediately after ignition, the afterburning, smoldering, or afterburning and smoldering time is less than 2min, or the damaged length is less than 40mm, the oxygen concentration is too low and the reaction symbol is recorded as "O", and the oxygen concentration must be increased. 8.7.2 If the afterburning, smoldering, or afterburning and smoldering time exceeds 2min after the sample is ignited, or the damaged length exceeds 40mm, the oxygen concentration is too high and the reaction symbol is recorded as "×", and the oxygen concentration must be reduced. 8.7.3 Repeat steps 8.7.1 to 8.7.2 until the difference between the two oxygen concentrations is ≤1.0, one of which has a reaction symbol of "○" and the other has a reaction symbol of "×". The one with the reaction symbol of ○\ in this pair of oxygen concentrations is the initial oxygen concentration (co). 8.8 Determination of limiting oxygen concentration:
8.8.1 Using the initial oxygen concentration co, while maintaining the oxygen concentration interval of d=0.2%, repeat the operations of 8.7.1 to 8.7.2 to obtain a series of oxygen concentration values ​​and corresponding symbols. The last reaction symbol "\" or "×" is the first data of 8.8.2 in the oxygen index determination NL series (see Appendix D).
8.8.2 Continue to repeat 8.7.1 to 8.7. with an oxygen concentration interval of d=0.2%.2. Measure four more samples, record the oxygen concentration of each time and its corresponding reaction number, and the oxygen concentration of the last sample is expressed in cF (see Appendix D, Part II Examples). 1046
Part I Test Method Standards for Major Building Materials 9 Calculation and Result Expression
9.1 Calculation of Limiting Oxygen Index
Express the limiting oxygen index LOI in volume percentage and calculate according to formula (1): LOI = cF + Kd
Where LOI
Limiting oxygen index (%);
-The last oxygen concentration in 8.8.2, take one decimal place (%); CF
d—--The difference between the two oxygen concentrations in 8.8, take one decimal place (%); K—Coefficient, refer to Table 1.
When reporting LOI, take one decimal place and calculate the standard deviation. When reporting LOI, take one decimal place and calculate the standard deviation. 9.2K Determination of value
9.2.1 If the first reaction symbol of the last five oxygen index values ​​measured by the test in accordance with 8.8.1 is "×", find the corresponding reaction symbol of the last five measurements in the first column of Table 1, and then find the K value corresponding to the number of "○\" in Table 1 (α).
9.2.2 If the first reaction symbol of the last five oxygen index values ​​measured by the test in accordance with 8.8.1 is "O", find the corresponding reaction symbol of the last five measurements in the sixth column of Table 1, and then find the K value coefficient corresponding to the number of "×" in Table 1 (b), but the sign of the K value number is different from that in the table. The signs of positive and negative numbers are opposite. The reaction signs of the last five measurements
|tt||×000x
×00x×
×o×xo
×o×××
×x000
×x00x
×xoxx
××.×00
×××0x
××××o
×××××
××××
××××
Ox××x
O×××Q
O× ×ox
0x ×00
Qxox×
0x0×0
0x × ×
00× ×0
000x x
The last five measurements
reaction symbols
9.3 Oxygen concentration interval verification
The oxygen concentration interval verification is calculated according to formula (2):
Where d is the interval of oxygen concentration used in 8.8.1, %; one standard deviation.
The standard deviation is calculated according to formula (3):
Thirteen, fireproof materials
[(c; -LO)
(n -1)
wherein. ——Standard deviation;
c:——Oxygen concentration of the last 6 samples in -8.8; -Number;
LOI——Oxygen index value calculated according to formula (1). If the standard deviation of the measurement is calculated according to formula (3). If the following formula is met: d
Number is combined, then LOI If the result calculated by formula (1) is valid, the limiting oxygen index or d = 0.2, d>
If α>d or d>
, repeat steps 8.7.1 to 8.7.2 until formula (2) is satisfied. Except for the requirements of relevant materials, the value of d is generally not less than 0.2%. 9.4 Precision
For materials that are easy to ignite and stable to burn, this method has the precision shown in Table 2. Table 2
95% confidence level approximation
Standard deviation
Repeatability
Reproducibility R
Intra-laboratory
Inter-laboratory
Note: The data shown in the table were determined by international inter-laboratory tests conducted by 16 laboratories and 12 samples between 1978 and 1980. 10 Test report
The report shall include the following contents:
a. Explanation that the test is conducted in accordance with this national standard. If there are any changes, the details shall be stated; 6. Description of the sample: including the type, name, and organization specifications of the fabric; c. Conditioning conditions of the sample, and the ambient temperature and humidity during the test; d. Limiting oxygen index values ​​of the sample in the warp (longitudinal) and weft (transverse) directions; e. Combustion characteristics, such as carbonization, melting, shrinkage, curling, etc.; f. Test date and personnel; g. Statement that the test results are only used to evaluate the combustion characteristics of the material under specified conditions and cannot be used to infer the fire hazard of the material under other conditions or in other shapes. Appendix A
(Standard Appendix)
Calculation of oxygen concentration
A1 When it is necessary to calculate the oxygen concentration more accurately, calculate according to formula A1: 100Vo
co=o+ V
Wherein, co is the oxygen concentration expressed as volume percentage (%); Vo is the volume of oxygen in unit volume of mixed gas at 23°C; Vn is the volume of nitrogen in unit volume of mixed gas at 23°C. (A1)
A2 When considering the ratio of oxygen contained in each gas in a mixed gas composed of oxygen and nitrogen, for example, the mixed gas is composed of oxygen containing 98.5% (V/V) oxygen and nitrogen containing 0.5% (V/V) oxygen, the oxygen concentration is calculated according to formula (A2) (assuming that the flow rates of several gases are at 23°C and the same pressure): co=
98.5Vo+0.5Vn
Vo+ V'N
wherein Vo is the volume of oxygen per unit volume of the mixed gas; VN is the volume of nitrogen per unit volume of the mixed gas; Appendix B
(Suggested Appendix)
Relationship between oxygen concentration and oxygen and nitrogen flow rates The relationship between oxygen concentration and oxygen and nitrogen flow rates is shown in Table B1. Oxygen concentration
Oxygen flow
(L/min)
Nitrogen flow
(L/min)
Oxygen concentration
Oxygen flow
(L/min）
Nitrogen flow
(L/min)）
Ammonia concentration
Oxygen flow
(L/min)
Nitrogen flow
(L/min)
Thirteen. Fireproof materials||tt| |Oxygen concentration
Oxygen flow
(L/min）
Nitrogen flow
(L/min)
Oxygen concentration
Part 1 Testing methods for main building materials Standard oxygen flow
(L/min)
Nitrogen flow
(L/min）
Oxygen concentration
Oxygen flow
(L/min）
Nitrogen flow
(L/min）| |tt||Oxygen concentration
Oxygen flow
(L/min)
Nitrogen flow
(L/min)
XIII. Fireproof materials
Oxygen concentration
Fluorine flow
(L/min)
Nitrogen flow
(L/min)
Oxygen concentration
Part I
Testing methods and standards for major building materials
Oxygen flow Quantity
(L/min)
C1 Calibration of gas flow rate control
Ammonia flow
(L/min)
Oxygen concentration
Appendix C
(Suggested Appendix)
Calibration of equipment
Oxygen flow
(L/min）
Nitrogen flow
(L/min）
The gas flow rate flowing through the combustion cylinder can be calibrated using a water-sealed drum rotometer or other equivalent device. Its accuracy is ±2mm/s of the flow rate through the combustion tube, which can also be calculated by formula (C1): F=1.27×106 y
Wherein, F---gas flow rate through the combustion tube (mm/s); Qv---total gas flow through the combustion tube at 23℃±2℃ (L/s); D---inner diameter of the combustion tube (mm).
C2 Calibration of oxygen concentration control
The oxygen concentration in the mixed gas entering the combustion tube should be calibrated to 0.1% (V/V) of the mixed gas. The calibration method can be to take samples from the combustion tube for analysis, or to use a calibrated oxygen analyzer for on-site analysis. At least three different concentrations should be calibrated,Represent the maximum, minimum and middle values ​​of the oxygen concentration range to be used by the equipment. C3 Calibration of the whole instrument
By testing a group of materials with known oxygen index, the results are compared with the expected results. Appendix D
(Suggested Appendix)
Test result examplewww.bzxz.net
Thirteen, flame retardant
Using the oxygen index inferred by GB/T5454 standard, the test results can be recorded in the following form: Flame retardant textiles
Test date: October 16, 94.
Temperature and humidity during the test: temperature 25℃, relative humidity 58%. Oxygen concentration variable (d): 0.2%.
Part I The results of the determination of the initial oxygen concentration are recorded in Table D1. Oxygen concentration (%)
Burn length (mm)
Burn time (s)
Reaction symbol
(\O\ or \×\)
In a pair of \×" and "○" reactions with an oxygen concentration interval of no more than 1%, the oxygen concentration co=30.0 of the O\ reaction symbol is the initial oxygen concentration, which is used as the first measured value of the second part. The second part of the oxygen index determination (according to 8.8.1 and 8.8.2) is recorded in Table D2. Table D2
Oxygen concentration (%)
Burn length (mm)||tt ||Burning time (s)
Reaction symbol
(\O\ or \×\)
According to 9.2.2, the first reaction symbol of the last five measurements is \O”. Look up Table 1 and in the 6th column, we get K=-1.24LOI=cF+Kd=29.8+（-1.24×0.2）=29.5% (one decimal place) or LOI=cz+Kd=29.8+（-1.2×0.2）=29.55% (two decimal places, for calculation and verification d in Part 3)
Verification of oxygen concentration interval d%.
Part 3
Standard deviation formula: =(c;-LO1)2
The calculation process is recorded in Table D3.
Last 6 test results
c -LOI
(c; - LOI)z
Testing methods for main building materials
Last 6 test results
Column c; in the table includes the oxygen concentration n=6 used to determine cE and the first 5 times. (0.115 0)2
Valid for formula
LO1=29.5.
c -LOI
(c; - LOI)2
13. "Determination of Surface Combustion Performance of Textile Fabrics" GB8745--881 Subject content and scope of application
This standard specifies the method for determining the surface combustion performance of textile fabrics. This standard is applicable to the determination of the surface combustion performance of textile fabrics with raised surfaces (i.e., raised, pile, loop, tufted or similar surfaces).
2 Definitions
2.1 Surface burning: The flame spreads on the surface of the material without igniting the basic structure of the material (see 2.2). 2.2 Surface flash: The flame spreads rapidly on the surface of the material without igniting the basic structure of the material. Note: However, if the ignition of the basic structure of the material occurs simultaneously or successively with the surface flash, it cannot be considered as part of the surface flash. 2.3 Surface burning time: When tested using this standard, the time required for plush or raised fabric to burn to a certain distance. The surface burning time is expressed as the minimum time among several measurement data obtained when testing the fabric. 3 Principle
Under specified test conditions, the raised surface of a dry specimen supported on a vertical plate is ignited near the top, and the time for the flame to spread downward on the fabric surface to the marked line is measured.
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