Textile combustion testing is an experimental indicator that many textile enterprises need to test, and currently, multiple combustion testing experiments are also required in many industries.

1、 Indicators for characterizing the combustion characteristics of fabrics:

1. The main evaluation indicators in the combustion testing method are:

Continuation time, smoldering time, and degree of surface damage to the fabric. Under standard test conditions, the shorter the time of flame burning and flameless burning, the lower the degree of damage, indicating better flame retardancy of the fabric.

2. Ultimate Oxygen Index:

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

3. Smoke and toxicity

Based on long-term accumulation of various fire data, analyzing the smoke and toxicity of combustibles, their harmfulness is often more serious than the flames and heat generated during combustion. In the smoke emission test method, the transmittance and time curve of the smoke density test can be used to obtain the optical density, high smoke density, average smoke emission rate, and transmittance, as well as the harmful gas content, in order to comprehensively evaluate the combustion performance of flame-retardant textiles.

4. Heat release rate:

The heat release rate during material combustion, which refers to the amount of heat released by material combustion per unit time, is an important fire parameter that characterizes the combustion hazard of materials in a fire.

2、 Common terms for combustion performance:

1. Combustion: The exothermic oxidation reaction that occurs when combustible substances leave a source of fire, accompanied by the emission of light in the flameless combustion zone.

2. Burning: When flammable substances come into contact with a fire source, the solid state of flameless combustion process is accompanied by the phenomenon of luminescence in the combustion zone.

3. Residual combustion: After leaving the ignition source, the burning substance still continues to burn with flames.

4. Yinhuo: After leaving the source of fire, the burning substance still continues to burn without flame.

5. Flame combustion: a gas-phase combustion phenomenon accompanied by luminescence.

6. Smoke burning: a slow burning phenomenon with no visible light, usually accompanied by smoke.

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

(8) Pyrolysis: The irreversible chemical decomposition of materials at high temperatures without oxidation.

(9) Droplet: Droplets of material melted at high temperatures.

(10) Carbonization: The process by which materials form carbonaceous residues during pyrolysis or non combustion.

(11) Flame retardant: The material has the characteristic of preventing, slowing down, or terminating flame combustion.

(12) Flame Spread: The expansion process of the flame front.

(13) Damage length: The large length in the direction of the material damage area under specified test conditions, also known as charcoal length.

3、 Factors affecting the combustion characteristics of fabrics:

1. Material:

Each fiber material has its own combustion characteristics, for example, polyester combustion exhibits droplet phenomenon. The different moisture regain rates of different raw materials can also affect the heat absorption and release during combustion. There are studies on the heat release sequence and total amount of six materials, namely polyester, acrylic, nylon, cotton, linen, silk, and wool, during combustion. Research has shown that the heat release order of different fabrics in combustion testing is polyester>silk>cotton>linen>silk>acrylic>nylon 6. The total heat release per unit mass of fabric is: cotton>acrylic>nylon 6>polyester>linen>wool>silk. This is because natural fibers have a high moisture regain, and the heat absorbed during this stage is mainly used to evaporate the moisture contained in the fabric itself. After the fabric reaches the ignition point, it begins to release heat. Synthetic fibers have low moisture regain and absorb less heat for evaporating water. This is also related to the degree of sufficient combustion of the fabric.

2. Fabric organization and weight:

When the fabric material is consistent, the shorter the average float length of the fabric structure, the heavier the fabric weight, and the higher the ultimate oxygen index of the fabric.

3. Flame retardant finishing of fabrics:

After flame retardant finishing, the flammability of the fabric decreases.

4. Test conditions:

The volume size of the test box 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 size of the ignition time directly affects the intensity of combustion. Therefore, the testing of fabric combustion performance should be carried out under standard instruments and in accordance with standard regulations to ensure the accuracy of the test results.