Jiangsu Textile Research Institute Inc.

There are usually three methods for testing the performance of flame-retardant fabrics.

1. Combustion test method: According to the relative position of the sample and the flame, it can be divided into vertical method, 45 degree method and horizontal method.

Vertical flame testing is one of the most common flame retardant performance testing methods. During the test, hang the fabric sample vertically on the stand, ignite the bottom of the sample, observe the flame spread, and record the flame spread speed and burned length. This testing method can effectively simulate the flame contact conditions that flame-retardant fabrics may encounter in actual use.

Horizontal flame testing is another commonly used testing method. During the test, place the flame-retardant fabric sample horizontally on the stand, ignite one end of the sample, observe the flame spread, and record the time and distance of the flame spread.

2. Extreme oxygen index method: Place the clamped sample vertically into a transparent combustion tube. There is an upward moving oxygen and nitrogen gas flow in the tube. Ignite the sample end, then observe the combustion phenomenon, and compare its continuous combustion with the specified limit value. Time or damage length, through experiments on a series of samples in different oxygen concentrations, the lower oxygen concentration value required for combustion can be maintained.

The judgment is made by measuring the extreme oxygen index (LOI) of the sample: the oxygen index refers to the amount of oxygen required for the fabric to burn. The higher the oxygen index, the higher the oxygen concentration required to maintain combustion, which means the harder it is to burn. The volume concentration of oxygen in the air is approximately 21%. If the oxygen index is less than 20%, it is a flammable fiber; if the oxygen index is between 20% and 26%, it is a flammable fiber; if the oxygen index is between 26% and 34%, it is a flame-retardant fiber; if the oxygen index is above 35%, it is a non-flammable fiber.

3. Carbonization length test: The carbonization length test measures the length of the remaining carbonized part after burning the fabric sample to evaluate its flame retardant performance. During the test, the fabric sample is placed in a flame and burned for a certain period of time, and then the length of the charred part is measured.

The char length test is mainly used to evaluate the fire resistance and charring characteristics of fabrics, especially whether the fabric will continue to burn or extinguish after the flame leaves.