The flame retardant properties of flame retardant fabrics are generally judged by two criteria:
One is to judge by measuring the oxygen index (also called the limiting oxygen index) of the flame retardant fabric sample. Oxygen is required for the combustion of the fabric. The oxygen index LOI is the expression of the amount of oxygen required for the combustion of the sample. Therefore, the flame retardancy of the fabric can be determined by measuring the oxygen index. The higher the oxygen index, the higher the oxygen concentration required to maintain combustion, which means that the more difficult it is to burn. The index can be expressed as the minimum volume percent of oxygen required to maintain a candle-like combustion in a nitrogen and oxygen mixture. Theoretically, as long as the oxygen index of the textile material is greater than 21% (the volume concentration of oxygen in the natural air), it has self-extinguishing properties in the air. According to the size of the oxygen index, textiles are generally classified into flammable (LOI < 20%), flammable (LOI = 20% ~ 26%), flame retardant (LOI = 26% ~ 34%) and non-combustible (LOI > 35%) Four levels. In fact, almost all conventional textile materials (fibers) are in a flammable or combustible range, and the flame retardant fabrics produced by Yulong Textile generally have an oxygen index of 28% to 32%.
The second is to judge from the burning rate of the flame retardant fabric. The flame retardant fabric is contacted with the flame for a certain period of time according to the prescribed method, and then the flame is removed, and the flame-retardant time of the flame retardant fabric and the time of the flameless burning, and the degree of damage of the flame retardant fabric are determined. The shorter the time of flame burning and the time of flameless burning, the lower the degree of damage, the better the flame retardant performance of the flame retardant fabric; on the contrary, the flame retardant performance of the flame retardant fabric is not good.