Textile combustion test is an experimental index that many textile enterprises need to test. At present, multi-combustion test is required in many industries.

I. Index of fabric combustion characteristics:

1. The main evaluation indexes of the combustion test method are as follows:

After burning time, smouldering time, degree of fabric surface damage.Under standard test conditions, the shorter the time of flame burning and non-flame burning, the lower the degree of damage, the better the flame retardant property of the fabric.

2. Oxygen limit index:

The minimum concentration of oxygen in a mixture of nitrogen and oxygen required to maintain the combustion state of the material under specified test conditions.

3. Smoke and toxicity

According to the long-term accumulation of all kinds of fire data, analyzing the smoke and toxicity of the combustion material, its harmfulness is often more serious than the flame and heat generated during combustion.In the smoke property test method, the light density, maximum smoke density, average smoke emission rate, light transmittance and harmful gas content can be obtained by means of smoke density test transmittance and time curve, so as to comprehensively evaluate the combustion performance of flame retardant textiles.

4. Heat release rate:

The heat release rate of the material during combustion, namely the heat released by the material in unit time, is the most important fire parameter to characterize the combustion risk of the material in the fire.

Ii. Common terms of combustion performance:

1. Combustion: The oxidative exothermic reaction produced when combustible materials leave the fire source, accompanied by the phenomenon of luminescence in the non-flame combustion zone with flame.

2. Burning: the flameless burning process in the solid state when combustible materials contact with the ignition source, accompanied by the luminescence phenomenon in the burning area.

3. Residual combustion: after the burning material leaves the fire source, there is still continuous flame combustion.

4, smouldering: after the burning material leaves the fire source, there is still a continuous non-flame combustion.

5. Flame combustion: gas phase combustion accompanied by luminescence.

6. Smoke combustion: A slow burning with no visible light, usually accompanied by smoke.

7. Ignition temperature: The minimum temperature at which a material begins to burn continuously under specified test conditions, commonly referred to as the ignition point.

8. Pyrolysis: irreversible chemical decomposition of materials at high temperature without oxidation.

9. Droplet: molten material drops at high temperature.

10. Carbonization: The formation of carbonaceous residues during the pyrolysis or incomplete combustion of materials.

11. Flame retardant: The material has the property of preventing, slowing down or stopping flame combustion.

12. Flame spread: the expansion process of flame front.

13. Length of damage: Under specified test conditions, the maximum length of material damage area in the specified direction, also known as carbon length.

IIi. Factors influencing fabric combustion characteristics:

1. Materials:

Each fiber material has its own combustion characteristics, such as the droplet phenomenon in polyester combustion.Different moisture regain of different raw materials will also affect the heat absorption and release during combustion.The heat release sequence and total amount of polyester, acrylic, polyamide, cotton, hemp, silk and wool during combustion were studied.The results showed that the heat release sequence of different fabrics in the combustion test was polyester > silk > cotton > hemp > silk > acrylic > polyamide 6.The total amount of heat release per unit mass of the fabric was: cotton > acrylic > polyamide 6 > polyester > hemp > wool > silk.This is due to the high moisture regain rate of natural fibers. The heat absorbed at this stage is mainly used to evaporate the moisture contained in the fabric. The fabric begins to heat out after the temperature reaches the ignition point.Synthetic fibers have low moisture regain and are used to evaporate water and absorb less heat.It also depends on how well the fabric burns.

2. Fabric texture and weight:

In the case of uniform fabric material, the shorter the average float length of fabric, the heavier the fabric weight and the higher the ultimate oxygen index of fabric.

3. Flame retardant finish for fabric:

The flammability of fabric is reduced after finishing.

4. Test Conditions:

The size of the test chamber affects the oxygen content in the combustion environment.The distance between the test flame and the sample, the length of the flame affects the way the fabric is ignited, and the burning time directly affects the burning intensity.Therefore, the test of fabric combustion performance should be carried out in accordance with standard instruments to ensure the accuracy of test results.

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