Low Smoke Halogen-free Cable

The conductor materials of wires are generally copper and aluminum, and other materials are mainly insulating materials. The original insulation material of wires and cables is mainly PVC, but PVC contains halogen. In case of accident combustion of wires and cables, it will release toxic smoke, seriously pollute the environment, and hinder the fire fighting and evacuation of firefighters. Environmentally friendly wires and cables refer to wires and cables with "green" insulating materials. These "green" insulating materials do not produce harmful substances when burning, flame retardants do not contain halogen, and do not emit toxic gases during daily operation. In addition, no additives containing harmful heavy metals and no plasticizers required for ordinary PVC are used, many of which are carcinogenic and teratogenic. Therefore, environmentally friendly wires shall be "green" wires that do not contain substances harmful to the environment.

Heavy smoke and a large amount of toxic gas will be produced after the ignition of wires and cables. In previous fires, the diffuse smoke made the people who escaped confused and panicked, and prolonged their stay in the fire scene. In addition, most of the unfortunate victims died of suffocation due to inhalation of toxic gas. It can be said that toxic gas is the number one killer in the fire. Developed countries have developed halogen-free low smoke cables in the 1980s, and strongly recommend the use of such harmless wires and cables to replace and gradually abandon the use of toxic PV C wires and cables. That is to say, the toxicity released by halogen-containing cables in the fire is very terrible. If the toxicity index of the gas concentration that can cause death in 30 minutes is determined as 1, the toxicity index of PVC is 15.01 and the toxicity index of halogen-free polyolefin is 0.7 9. People can only survive in the smoke of PVC for 2 minutes, but if halogen-free materials are replaced, people's survival in the smoke can be extended to 40 minutes, which greatly increases the escape time in case of fire. In addition, according to relevant materials, the light transmittance of smoke emitted by flame-retardant PVC cable during combustion is less than 15%, that is, in this concentration of smoke, the naked eye sight distance is about 2m. Therefore, in the fire, the strong smoke makes the victims dizzy and unable to distinguish the direction, prolonging the stay time in the fire, resulting in further inhalation of smoke and toxic gas and suffocation.

In a large number of tests, it is found that the smoke density and volatile amount of halogen acid gas released during combustion of materials with polyolefin as base material and hydrated metal compound Al (OH) 3 or Mg (OH) 3 as flame retardant can meet the requirements of IEC standard. Al (OH) 3 or Mg (OH) 2 is an inorganic hydroxide, which has excellent flame retardancy, low toxicity, smoke suppression and low corrosion. It has good smoke suppression, because smoke suppression and flame retardancy are equally important.

From Karamay theater in Xinjiang to a video hall in Jiaozuo, Henan, 370 people were burned to death. The harmful factors of Z in these fires are toxic gas and smoke, and halogen-free low smoke flame retardant environment-friendly wires and cables solve the above problems. Halogen free, low smoke, flame retardant and environment-friendly wires and cables have been used in closed places and medium and high-rise buildings where many people gather. The South cable wires produced by Guangdong South cable have been successfully applied to places requiring high safety in all walks of life, such as Guangzhou Metro, Guangzhou tower, Jieyang Chaoshan airport, Guangzhou Shangri La Hotel, Shenzhen Metro and so on.

Low smoke halogen-free flame retardant polyolefin is flame retardant by endothermic and metal oxide oxygen isolation methods. Its flame retardant mechanism is as follows: first, when wires and cables are burned, the surface hydroxide decomposes. This reaction is an endothermic reaction, which absorbs a large amount of heat in the surrounding air and reduces the surface temperature of wires and cables; Second, the generated water molecules also absorb a lot of heat on the surface of wires and cables, and the water vapor also isolates oxygen; Third, the metal oxide crusts produced prevent oxygen from contacting with organic matter again.