The Development of Fire retardant Cable-from Halogen Flame Retardant to Low-smoke and Halogen-free

Ⅰ. What is the fire retardant cable

Fire retardant cable refers to a cable whose sample is burned under specified test conditions. After the test fire source is removed, the flame spreads only within a limited range, and the residual flame or residual burn can be extinguished by itself within a limited time. The fundamental characteristic of flame retardant cables is that they may be burned out and cannot operate in a fire, but they can prevent the spread of fire. In layman's terms, if a wire catches a fire, it can limit the combustion to a local area without spreading, and protect other equipments and avoid greater losses.

Ⅱ. Fire retardant cable in fire

The combustion of wires and cables is caused by external heating to produce flammable gas. To achieve the purpose of flame retardancy, the three elements that cause combustion must be suppressed, namely: flammable gas, heat and oxygen. Therefore, the method generally used for flame retardant cables is to add halogen-containing halides and metal oxides to the sheath material. This is an excellent method to evaluate from the perspective of flame retardancy. However, because these materials contain halides, It releases a large amount of smoke and hydrogen halide gas during combustion, so the visibility during fire is low, which greatly hinders the safe evacuation of personnel and fire fighting, and people are more suffocated to death by toxic gases. In addition, once the hydrogen halide gas reacts with water in the air, hydrohalide acid is generated, which severely corrodes equipment and buildings and causes secondary disasters.

Ⅲ. The development of fire retardant cable

At present, with the continuous improvement of the level of science and technology, the flame retardant problem has been further developed from the halogen flame retardant in the past to the low halogen, halogen-free flame retardant. The insulating layer, sheath, outer sheath and auxiliary materials (tape and filling) of the low-smoke halogen-free flame-retardant cable are all or partly made of halogen-free cross-linked polyethylene (XLPE) flame-retardant material, which not only has more Good flame retardant properties, and no halogen acid gas is released when the cable is burned, and the amount of smoke generated by the cable is also small. The corrosive gas generated by the cable combustion is also a compromise between flame retardancy and reducing the amount of halogen acid gas. Method developed a low-halogen, low-smoke fire retardant cable. Its halogen content is about 1/3 of that of halogen-containing flame retardant cables. The amount of smoke is also close to the recognized low smoke level.

Therefore, from the perspective of environmental protection and fire rescue safety, the performance of low-smoke, halogen-free and flame retardant cables is better. From halogen flame retardant to low-smoke halogen-free flame retardant, it shows the progress of science and technology, and it is also the inevitable to choose the safe cable.